Glands of the body list. Comprehensive Guide to Body Glands: Functions, Disorders, and Treatments

03.06.197927.11.2021 by alexxlab

What are the main glands in the human body. How do sweat glands function. What are parathyroid glands and their role in calcium regulation. What are common parathyroid disorders and their symptoms. How are parathyroid disorders diagnosed and treated.

Содержание

The Intricate Network of Human Body Glands

The human body is a complex system of organs and tissues working in harmony to maintain homeostasis. Among these, glands play a crucial role in regulating various bodily functions through hormone secretion. Let’s delve into the fascinating world of body glands and their importance in our overall health.

Understanding Sweat Glands: Types and Functions

Sweat glands are essential components of our skin that help regulate body temperature and eliminate toxins. There are two main types of sweat glands:

Eccrine glands
Apocrine glands

Eccrine Glands: The Body’s Cooling System

Eccrine glands are found over most of the body and open directly onto the skin’s surface. These glands are responsible for producing the majority of our sweat, which is primarily composed of water and salt. When our body temperature rises, eccrine glands secrete sweat, which evaporates from the skin surface, cooling us down.

Apocrine Glands: More Than Just Sweat

Apocrine glands are located in areas with abundant hair follicles, such as the scalp, armpits, and groin. Unlike eccrine glands, apocrine glands open into hair follicles before reaching the skin surface. The secretions from apocrine glands are thicker and contain proteins and lipids. When these secretions interact with bacteria on the skin, they can produce body odor.

How do sweat glands contribute to our overall health? Sweat glands play a vital role in:

Thermoregulation
Electrolyte balance
Skin hydration
Elimination of toxins

The Parathyroid Glands: Tiny But Mighty

While the thyroid gland often gets more attention, the parathyroid glands are equally important for maintaining our body’s calcium balance. These small endocrine glands, typically four in number, are located near the thyroid gland in the neck.

Anatomy and Function of Parathyroid Glands

Each parathyroid gland is approximately the size of a grain of rice, measuring about 3-5 millimeters in diameter and weighing between 30-60 milligrams. Despite their small size, these glands have a significant impact on our body’s calcium homeostasis.

What is the primary function of parathyroid glands? The main role of parathyroid glands is to produce and secrete parathyroid hormone (PTH), which regulates calcium levels in the bloodstream. PTH works by:

Increasing calcium release from bones
Enhancing calcium reabsorption in the kidneys
Promoting vitamin D production, which aids in calcium absorption from the intestines

Parathyroid Disorders: When Calcium Balance Goes Awry

Disorders of the parathyroid glands can lead to imbalances in calcium levels, which can have wide-ranging effects on the body. The most common parathyroid disorder is hyperparathyroidism, characterized by excessive production of PTH.

Hyperparathyroidism: Causes and Types

Hyperparathyroidism can be classified into three main types:

Primary hyperparathyroidism: Caused by a problem within the parathyroid glands themselves, often due to a benign tumor or gland enlargement
Secondary hyperparathyroidism: Occurs as a response to low calcium levels caused by other conditions, such as kidney disease or vitamin D deficiency
Tertiary hyperparathyroidism: Develops in patients with long-standing secondary hyperparathyroidism, where the glands become autonomously overactive

Symptoms and Complications of Hyperparathyroidism

What are the common symptoms of hyperparathyroidism? Patients with hyperparathyroidism may experience:

Fatigue and weakness
Bone pain and increased risk of fractures
Kidney stones
Abdominal pain
Depression and cognitive issues
Increased thirst and frequent urination

If left untreated, hyperparathyroidism can lead to serious complications, including:

Osteoporosis
Cardiovascular disease
Kidney damage
Pancreatitis

Diagnosis and Treatment of Parathyroid Disorders

Accurate diagnosis of parathyroid disorders is crucial for appropriate management. Healthcare providers use a combination of blood tests, imaging studies, and sometimes biopsies to diagnose these conditions.

Diagnostic Approaches for Parathyroid Disorders

How are parathyroid disorders diagnosed? The diagnostic process typically involves:

Blood tests to measure calcium, PTH, and vitamin D levels
Urine tests to assess calcium excretion
Imaging studies such as ultrasound, CT scan, or sestamibi scan to locate abnormal parathyroid glands
Bone density scans to evaluate the impact on bone health

Treatment Options for Hyperparathyroidism

The treatment approach for hyperparathyroidism depends on the underlying cause and severity of the condition. Options may include:

Watchful waiting: For mild cases without significant symptoms or complications
Medication: Calcimimetics or bisphosphonates may be prescribed to manage calcium levels and protect bone health
Surgery: Parathyroidectomy (removal of one or more parathyroid glands) is often the definitive treatment for primary hyperparathyroidism
Vitamin D supplementation: In cases of secondary hyperparathyroidism due to vitamin D deficiency
Treatment of underlying conditions: For secondary hyperparathyroidism caused by kidney disease or other medical issues

The Importance of Endocrine Health: Beyond Parathyroid Glands

While we’ve focused on sweat glands and parathyroid glands, it’s essential to recognize that these are just two components of the broader endocrine system. The endocrine system consists of various glands that produce hormones regulating numerous bodily functions.

Major Endocrine Glands and Their Functions

What are the main endocrine glands in the human body? The major endocrine glands include:

Pituitary gland: Often called the “master gland,” it controls many other endocrine glands
Thyroid gland: Regulates metabolism and energy production
Adrenal glands: Produce stress hormones and regulate blood pressure
Pancreas: Controls blood sugar levels through insulin and glucagon production
Ovaries (in females) and testes (in males): Produce sex hormones
Pineal gland: Regulates sleep-wake cycles

Each of these glands plays a crucial role in maintaining overall health and well-being. Disorders affecting any of these glands can have far-reaching consequences on various bodily functions.

Maintaining Glandular Health: Prevention and Lifestyle Factors

While some glandular disorders are due to genetic factors or unavoidable circumstances, there are steps we can take to promote overall endocrine health and potentially prevent certain disorders.

Lifestyle Choices for Optimal Glandular Function

How can we support the health of our endocrine system? Consider incorporating these practices:

Balanced diet rich in essential nutrients, including vitamin D and calcium
Regular exercise to support bone health and overall endocrine function
Stress management techniques, such as meditation or yoga
Adequate sleep to support hormonal balance
Limiting exposure to endocrine-disrupting chemicals in food and personal care products
Regular health check-ups and screenings to detect potential issues early

By understanding the intricate workings of our body’s glands and taking proactive steps to maintain their health, we can contribute to our overall well-being and potentially prevent or manage various endocrine disorders.

Emerging Research and Future Directions in Glandular Health

The field of endocrinology is continuously evolving, with new research shedding light on the complex interactions between various glands and their impact on overall health. Recent advancements are opening up exciting possibilities for improved diagnosis, treatment, and prevention of glandular disorders.

Cutting-Edge Diagnostic Tools

What are some innovative approaches to diagnosing glandular disorders? Emerging diagnostic techniques include:

Advanced imaging technologies, such as 4D CT scans for parathyroid localization
Genetic testing to identify hereditary endocrine disorders
Biomarker discovery for early detection of glandular dysfunction
Artificial intelligence-assisted analysis of hormonal patterns

Novel Treatment Strategies

Researchers are exploring new treatment modalities for various glandular disorders, including:

Targeted drug therapies with fewer side effects
Gene therapy for inherited endocrine conditions
Stem cell treatments to regenerate damaged glandular tissue
Personalized medicine approaches based on individual genetic and hormonal profiles

These advancements hold promise for more effective and tailored treatments for patients with glandular disorders, potentially improving outcomes and quality of life.

As our understanding of the intricate relationships between various glands and their impact on overall health continues to grow, we can expect to see further innovations in the field of endocrinology. This ongoing research not only enhances our ability to diagnose and treat glandular disorders but also underscores the importance of maintaining optimal glandular health as part of our overall well-being.

Sweat glands – Mayo Clinic

Your skin has two types of sweat glands: eccrine and apocrine. Eccrine glands occur over most of your body and open directly onto the surface of your skin. Apocrine glands open into the hair follicle, leading to the surface of the skin. Apocrine glands develop in areas abundant in hair follicles, such as on your scalp, armpits and groin.

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Parathyroid Disorders | Michigan Medicine

Parathyroid disorders lead to abnormal levels of calcium in the blood that can cause brittle bones, kidney stones, fatigue, weakness, and other problems.

At the University of Michigan, our experts are focused on making an accurate diagnosis through comprehensive testing and providing the best therapy options for each patient.

What are the Parathyroid Glands?

There are typically four parathyroid glands located near the thyroid gland. Each parathyroid gland is normally about the size of a grain of rice (about 3-5 millimeters in diameter and 30 – 60 milligrams in weight). Although the thyroid and parathyroid glands are physically near each other and are both part of your body’s endocrine system, their functions are unrelated. Parathyroid glands release parathyroid hormone (PTH) which controls the calcium levels in the blood stream. Other areas of the body, especially the bones, kidneys and small intestine, respond to PTH by increasing calcium levels in the blood. Calcium is very important for our bodies, especially for muscle and nerve function.

About Parathyroid Disorders

As a rule, if the calcium level in the blood is low, the parathyroid glands sense this and release PTH. PTH then causes release of calcium from the bones into the bloodstream, increases vitamin D production from the kidney which ultimately increases absorption of calcium from the intestines. If the calcium level is too high, then PTH secretion should decrease to a very low level.

Hyperparathyroidism exists when the parathyroid glands produce too much parathyroid hormone (PTH). This may be due to multiple reasons, and the reason helps determine the appropriate type of treatment. Sometimes treatment is as simple as replacing vitamin D when the parathyroid gland is responding appropriately to a problem elsewhere in the body. In other cases, there is an issue with the gland itself and surgery is required. Excess parathyroid hormone can lead to negative effects on the body such as osteoporosis which can lead to fractures, kidney stones, decreased kidney function, heart disease, pancreatitis, increased acid secretion in the stomach and ulcers. Many patients experience symptoms of fatigue, depression, anxiety, difficulty concentrating, difficulty with their memory, insomnia, generalized muscle aches and pains, frequent urination (especially at night), and constipation. Because these symptoms may be related to many other disorders, it is never known until after treatment whether or not these will improve.

The opposite problem, hypoparathyroidism, occurs when the parathyroid glands do not produce enough PTH. This leads to a low blood calcium level and can adversely affect muscle, nerve and other functions.

Diagnosis of Parathyroid Disorders

We diagnose parathyroid disorders through comprehensive testing that starts with a complete history and physical exam. Diagnosis of the type of hyperparathyroidism is based on blood work and other types of laboratory testing. Imaging tests are not used to diagnose parathyroid disorders, but may be ordered once the presence of a parathyroid disorder has been confirmed by lab tests.

Disorders of the Hypothalamus and Pituitary Gland

Of the endocrine glands, the hypothalamus and pituitary glands are of major importance since they act as the coordinating centers of the endocrine system.

The hypothalamus is responsible for maintaining the body’s internal balance (homeostasis) by stimulating or inhibiting major bodily functions such as the heart rate and blood pressure, body temperature, fluid and electrolyte balance, appetite and body weight, sleep cycle and function of the gastrointestinal track. The hypothalamus is also considered the master regulator of the endocrine system; Regulatory hormones secreted by the hypothalamus are transported by the hypophyseal-portal system to the anterior and posterior pituitary (Figure 2), prompting the release of secondary hormones that can affect various organ functions.

Figure 2. The hypophyseal-portal system

Hormones typically bind to membrane or nuclear receptors of specific target glands/organs, which in turn release hormones that exert negative feedback control on the releasing sites. (Figure 3).

Figure 3. Example of negative (in red) feedback inhibition:

The hypothalamus secretes releasing factors that act on the pituitary gland to stimulate the release of trophic hormones.

Trophic hormones act then on target organs (e.g., adrenal, thyroid or gonads), which in response produce other

hormones/signals, shutting down the production of releasing or/and trophic hormones.

The hypothalamus secretes various hormones that are then transported to the anterior pituitary (Figure 4):

Corticotropin releasing hormone (CRH)

Growth hormone releasing hormone (GHRH)

Thyrotropin releasing hormone (TRH)

Gonadotropin releasing hormone (GnRH)

Somatostatin (inhibits growth hormone secretion)

Prolactin releasing and prolactin inhibitor hormones

Figure 4. Overview of hypothalamic and pituitary hormones and their actions

The pituitary gland also secretes hormones in response to hypothalamic release hormones:

Thyroid stimulating hormone (TSH)

Adrenocortical stimulating hormone (ACTH)

Follicle stimulating hormone (FSH)

Luteinizing hormone (LH)

Prolactin

Melanocyte-stimulating hormone

Endorphins

Supraoptic and paraventricular nuclei of the hypothalamus also secrete hormones that are transported to the posterior pituitary to be released into the circulation. These are:

Anti-diuretic hormone (ADH): regulates plasma osmolality

Oxytocin: regulates ejection of milk and uterine contractions.

Disorders of the hypothalamus can result in appetite, temperature and sleep disorders. As an example, hypothalamic obesity occasionally develops in response to major hypothalamic injury/damage affecting the centers of appetite regulation and energy balance. Hypothalamic obesity is characterized by an uninhibited eating disorder that often results in morbid obesity and can be associated with other obesity complications like diabetes, dyslipidemia, obstructive sleep apnea, mood disorder etc.

Disorders of the hypothalamus and/or anterior pituitary can also result in hypopituitarism, including adrenal insufficiency (see adrenal disorders section), hypothyroidism (see thyroid disorders section), hypogonadism (see puberty and its disorders section), growth hormone deficiency (see growth disorders section) and prolactin deficiency (inability to lactate).

Disorders of the posterior pituitary can result in diabetes insipidus and disorders pertaining to oxytocin deficiency (like inability to lactate, vaginal dryness, decreased libido etc.).

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List of Three’s

List of Three’s in Anatomy

The structure of the human body is organized into groups of three with remarkable frequency. I have listed several examples of this tendency by region. This list does not include structures contributing to form the many “triangles” in the body. If you know of any more, please let me know John A. McNulty, Ph.D.


General


	3 body planes - frontal
			  sagittal
			  transverse
			  
	3 layers of skin- epidermis
			  dermis
			  hypodermis

	3 general venous circulations- systemic
			  pulmonary
			  portal		  

Embryology

	3 germ layers-	endoderm
			mesoderm
			ectoderm

	3 divisions of somites-	sclerotome
				dermatome
				myotome

	3 definitive kidneys-	pronephros
				mesonephros
				metanephros
				
	3 derivatives of skull-	desmo/dermatocranium
				splanchno/viscerocranium
				chondrocranium
				
	3 initial embryonic divisions of the brain-	prosencephalon
							mesencephalon
							rhombencephalon

Back

	3 parts of the erector spinae m. -	iliocostalis
						longissimus
						spinalis
			each are divided again into 3 parts

	3 parts of the transversospinalis m. -	semispinalis m.
						multifidus m.
						rotator m.

	3 coverings of the spinal cord-	dura mater
				        arachnoid
					pia
					
	3 spaces surrounding spinal cord-	epidural
				        	subdural
						subarachnoid

	3 borders of the scapula-	medial (vertebral)
					lateral
					superior

	3 angles of the scapula


Neck

	3 parts of the axillary artery
		3rd part has 3 branches-	subscapular
						anterior humeral circumflex
						posterior humeral circumflex
					
	Brachial plexus
		3 trunks-	upper
				middle
				lower
		3 posterior divisions
		3 anterior divisions
		3 cords-	lateral
				medial
					3 branches off medial cord-	medial brachial
									medial antebrachial
									medial pectoral
				posterior
					3 branches off posterior cord- upper subscapular
									lower subscapular
									thoracodorsal

	3 branches off the thyrocervical trunk-	transverse cervical
						suprascapular
						inferior thyroid
						
	3 veins drain the thyroid gland -	superior (into internal jugular)
						middle (into internal jugular)
						inferior (into left brachiocephalic)
						
	3 scalene muscles-		anterior
					middle
					posterior

	3 muscles attach to spine of C2-	semispinalis cervicis
						obliquus capitis inferior
						rectus capitis posterior major
					
	3 constrictor muscles-	superior
				middle
				inferior
					
	3 parts of the pharynx-	nasopharynx
				oropharynx
				laryngeopharynx
					
	3 parts to the hyoid bone-	body
					greater horn
					lesser horn
					
	3 structures inside carotid sheath-	common carotid artery
						internal jugular vein
						vagus nerve
						
	3 ganglia in sympathetic cervical chain-	superior (magnum)
							middle
							inferior (stellate)


Head

	3 parts of the maxillary artery-	mandibular
						pterygoid
						pterygopalatine
						
	3 divisions of the trigeminal n. -	V1 - ophthalmic - has 3 branches
							frontal
							nasociliary
							lacrimal
						V2 - maxillary
						V3 - mandibular- has 3 parts
							undivided trunk
							anterior division
							posterior division-  has 3 branches
								auriculotemporal
								lingual
								inferior alveolar
								
	3 cranial fossae-	anterior
				middle
				posterior
					
	3 nuchal lines-	inferior
			superior
			highest

	3 layers to calvarium-		outer table
					diploe
					inner table
	
	3 clinoid processes of the sphenoid bone- anterior
			  middle
			  posterior

	3 cranial nerves pass through jugular foramen-	C.N. IX
							C.N. X
							C.N. XI
													
	3 cranial nerves travel in the wall of the cavernous sinus-	C.N. III
									C.N. IV
									C.N. V
									
	3 cranial nerves carry parasympathetics to the head-	C. N. III
								C.N. VII
								C.N. IX
								
	3 nasal conchae-	superior
				middle
				inferior

	3 principal components of the temporal bone-	squama
							petro/mastoid
							tympanic ring

	3 bones of the upper jaw/palate-	premaxilla
						maxilla
						palatine
				
	3 salivary glands-	parotid
				submaxillary
				sublingual
				
	3 muscles innervated by 3 cranial nerves attach to the styloid process-			
                stylohyoid - C.N. VII
		stylopharyngeus - C.N. IX
		styloglossus - C.N. XII
		
	3 layers in tympanic membrane (derived from 3 germ layers)
									
	3 cranial nerves innervate the external tympanum-	C.N. V
								C.N. VII
								C.N. X

	3 middle ear bones-	incus
				malleus
				stapes
				
	3 parts of the ear-	outer
				middle
				inner
				
	3 semicircular canals
	
	3 membranes of the cochlea-	Reissner
				Tectorial
				Basilar
				
	3 intrinsic muscles of the tongue-	longitudinal
						vertical
						transverse
																			
	3 muscles elevate the mandible-	masseter m. 
							temporalis m.
							medial pterygoid m.
						
	3 branches of the posterior auricular artery-	stylomastoid branch
						auricular branch
						occipital branch
						
	3 branches of the ophthalmic nerve (VI)-	nasociliary n.
						frontal n.
						lacrimal n.
																			
	3 superior alveolar nerves-	anterior superior alveolar n.
							middle superior alveolar n.
							posterior superior alveolar n.
						
	3 types of deciduous teeth-	incisors
					canine
					molars

	3 layers of dentition-	enamal
				dentin
				pulp
					
	3 general layers of the eye - 	retinal
					choroidal/ciliary body
					scleral/corneal
					
	3 color receptors in cone cells - 	red
						blue
						yellow
						
	3 nerves to the larynx -  external laryngeal n.
						internal laryngeal n.
						recurrent laryngeal n.
										
	3 cerebral arteries - 		anterior
					middle
					posterior

	3 arteries supply the cerebellum - 	superior cerebellar
						anterior inferior cerebellar
						posterior inferior cerebellar


Shoulder

	3 muscles attach to coracoid process -	coracobrachialis
						pectoralis minor
						short head of biceps
						
	3 parts of the axillary a. ; 3rd part has 3 branches-	subscapular a.
								anterior circumflex humeral a.
								posterior circumflex humeral a
								
	3 muscles of the rotator cuff are rotators
	
	3 glenohumeral ligaments - superior
						middle
						inferior

Arm

	3 muscles in anterior comparment-	biceps brachii
						coracobrachialis
						brachialis
							
	3 heads of triceps brachii m.-	long
					lateral
					medial
							
	3 muscles attach to greater tubercle of the humerus- 	supraspinatus
								infraspinatus
								teres minor

	3 parts of the ulnar collateral ligament of the elbow - anterior
							posterior
							oblique



Forearm

	3 muscles in deep anterior compartment -	flexor digitorum profundus
							flexor pollicis longs
							pronator quadratus


Hand

	3 muscles in thenar eminence- 	opponens pollicis
					flexor pollicis brevis
					abductor pollicis brevis
					
	3 muscles in hypothenar compartment-	flexor digiti minimi
						abductor digiti minimi
						opponens digiti minimi
							
	3 phalanges in fingers-	proximal
				middle
				distal
					
	3 palmer interossei


Thorax

	3 compartments-	mediastinum
			left pleural cavity
			right pleural cavity
			
	3 branches off the aortic arch-	brachiocephalic a. 
					left common carotid a.
					left subclavian a.
					
	3 parts of the aorta-	ascending
				arch
				descending
				
	3 principal surfaces of the pleura-	costal
						diaphragmatic
						mediastinal
							*the cupola is the superior extension
							
	3 lobes of the right lung-	superior
					middle
					inferior
					
	3 bronchopulmonary segments of the upper right lobe-	apical									
								posterior
								anterior

	3 muscles of interthoracic wall-	external intercostal									
						internal intercostal
						intercostalis intimus
								
	3 false ribs on each side
	
	3 cusps of the semilunar aortic and pulmonary valves of the heart
	
	3 cusps of the tricuspid valve
	
	3 main arteries of the heart-	circumflex
					anterior interventricular
					right coronary
					
	3 splanchnic nerves-	greater
				lesser
				least



Abdomen

	3 folds in anterior abdominal wall-	median (obliterated urachus)
						medial (obliterated umbilical a. )
						lateral (inferior epigastric a.)

	3 muscles contribute to linea semilunaris/rectus abdominus aponeurosis -
				internal oblique
				external oblique
				transversus abdominus
						
	3 openings in diaphragm-	aortic
					esophageal
					inferior vena cava
					
	3 arcuate ligaments of diaphragm-	median over aorta
						medial over psoas major m.
						lateral over quadratus lumborum m.
						
	3 parts of the stomach-	fundus
				body
				pylorus
				
	3 smooth muscle layers of the stomach-	oblique
						longitudinal
						circular

	3 unpaired branches of the abdominal aorta-	celiac a.
							superior mesenteric a.
							inferior mesenteric a.
							
	3 branches of celiac a.-		left gastric a.
					splenic a.
					common hepatic a.
					
	3 branches of common hepatic a.-	right gastric a.
						proper hepatic a.
						gastroduodenal a. 

	3 arterial branches supply adrenal glands-	inferior phrenic
							aorta
							renal
							
	3 structures lie within porta hepatis-		proper hepatic a.
							portal vein
							common bile duct
							
	3 principal veins contribute to the portal vein-	splenic v.
								superior mesenteric v.
								inferior mesenteric v.
								
	3 parts of the small intestine-	duodenum
					jejunum
					ileum
					
	3 parts of large intestine-	ascending
					transverse
					descending
					
	3 tenia of large intestine
	
	3 coverings of the spermatic cord-	external spermatic fascia
						cremasteric fascia
						internal spermatic fascia
	
	3 vessels in the umbilical cord
						umbilical vein
						2 umbilical arteries
	



Pelvis and Perineum

	3 bones in os coxae-	pubis
				ilium
				ischium
				
	3 parts of the pubis-	body
				superior ramus
				inferior ramus
				
	3 foramina in the pelvis-	obturator foramen
					greater ischiadic foramen
					lesser ischiadic foramen
					
	3 gluteus muscles-	gluteus maximus
				gluteus medius
				gluteus minimus
				
	3 rectal arteries-	superior rectal from inferior mesenteric a. 
				middle rectal from internal iliac a.
				inferior rectal from internal pudendal a.
				
	3 branches of the posterior division of internal iliac a.-	iliolumbar
									lateral sacral
									superior gluteal
									
	3 openings in the urinary bladder- 	left ureter
						right ureter
						urethra
				
	3 parts of the urethra-	prostatic
				membranous
				spongy
				
	3 parts of the uterus-	fundus
				body
				cervix
				
	3 erectile compartments of the penis-	corpus spongiosum
						left corpus cavernosum
						right corpus cavernosum
						
	3 muscles in superficial perineal pouch-	bulbospongiosus
							ischiocavernosus
							superficial transverse perineus
							
	3 arteries supply the rectum-	superior rectal (from inferior mesenteric)
					middle rectal (from internal iliac)
					inferior rectal (from internal pudendal)
					
	3 valves in the rectum-	superior
				middle
				inferior


Gluteus

	3 gluteal muscles-	gluteus maximus
				gluteus medius
				gluteus minimus
				
	3 muscles innervated by superior gluteal n. -	gluteus medius
							gluteus minimus
							tensor fascia lata



Thigh

	3 hamstring muscles-	biceps femoris
				semitendinosus
				semimembranosus
				
	3 compartments in the femoral sheath
	
	3 muscular compartments of the thigh-	anterior
						medial
						posterior
						
	3 branches of the lateral femoral circumflex a.-	descending branch
								transverse branch
								ascending branch
								
	3 muscles contribute to the pes anserinus-	sartorius
							semitendinosus
							gracilis


Leg

        3 compartments in the leg
        
        3 muscles in anterior compartment -	tibialis anterior
						extensor digitorum
						extensor hallucis
						
        3 branches of the peroneal artery in the leg -	anterior tibial a.
							posterior tibial a.
							peroneal a. 
	
        3 peroneal muscles in the leg -	peroneus longus m.
							peroneus brevis m.
							peroneus tertius m.
							
        3 muscles that comprise the triceps surae -	grastrocnemius m.
							soleus m.
							plantaris m.
							
        3 muscles in the deep posterior compartment -	tibialis posterioris m.
							flexor hallucis longus m.
							flexor digitorum longus m.

Foot

	3 cuneiform bones-	medial
				intermediate
				lateral
				
	3 phalanges in toes-	proximal
				middle
				distal
				
	3 plantar interossei

				
	3 described arches -	medial
				lateral
				transverse

Miscellaneous

	3 exams in the course

If you like this kind of stuff, you may want to visit Michael Eck’s Book of Threes

Other contributors include:

Diego Villa Restrepo
Cindy Kuiper
Erika Goodwin
Rob Grieve

Brain anatomy, Anatomy of the human brain

Overview

The brain is an amazing three-pound organ that controls all functions of the body, interprets information from the outside world, and embodies the essence of the mind and soul. Intelligence, creativity, emotion, and memory are a few of the many things governed by the brain. Protected within the skull, the brain is composed of the cerebrum, cerebellum, and brainstem.

The brain receives information through our five senses: sight, smell, touch, taste, and hearing – often many at one time. It assembles the messages in a way that has meaning for us, and can store that information in our memory. The brain controls our thoughts, memory and speech, movement of the arms and legs, and the function of many organs within our body.

The central nervous system (CNS) is composed of the brain and spinal cord. The peripheral nervous system (PNS) is composed of spinal nerves that branch from the spinal cord and cranial nerves that branch from the brain.

Brain

The brain is composed of the cerebrum, cerebellum, and brainstem (Fig. 1).

Figure 1. The brain has three main parts: the cerebrum, cerebellum and brainstem.

Cerebrum: is the largest part of the brain and is composed of right and left hemispheres. It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement.
Cerebellum: is located under the cerebrum. Its function is to coordinate muscle movements, maintain posture, and balance.
Brainstem: acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. It performs many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing.

Right brain – left brain

The cerebrum is divided into two halves: the right and left hemispheres (Fig. 2) They are joined by a bundle of fibers called the corpus callosum that transmits messages from one side to the other. Each hemisphere controls the opposite side of the body. If a stroke occurs on the right side of the brain, your left arm or leg may be weak or paralyzed.

Not all functions of the hemispheres are shared. In general, the left hemisphere controls speech, comprehension, arithmetic, and writing. The right hemisphere controls creativity, spatial ability, artistic, and musical skills. The left hemisphere is dominant in hand use and language in about 92% of people.

Figure 2. The cerebrum is divided into left and right hemispheres. The two sides are connected by the nerve fibers corpus callosum.

Lobes of the brain

The cerebral hemispheres have distinct fissures, which divide the brain into lobes. Each hemisphere has 4 lobes: frontal, temporal, parietal, and occipital (Fig. 3). Each lobe may be divided, once again, into areas that serve very specific functions. It’s important to understand that each lobe of the brain does not function alone. There are very complex relationships between the lobes of the brain and between the right and left hemispheres.

Figure 3. The cerebrum is divided into four lobes: frontal, parietal, occipital and temporal.

Frontal lobe

Personality, behavior, emotions
Judgment, planning, problem solving
Speech: speaking and writing (Broca’s area)
Body movement (motor strip)
Intelligence, concentration, self awareness

Parietal lobe

Interprets language, words
Sense of touch, pain, temperature (sensory strip)
Interprets signals from vision, hearing, motor, sensory and memory
Spatial and visual perception

Occipital lobe

Interprets vision (color, light, movement)

Temporal lobe

Understanding language (Wernicke’s area)
Memory
Hearing
Sequencing and organization

Language

In general, the left hemisphere of the brain is responsible for language and speech and is called the “dominant” hemisphere. The right hemisphere plays a large part in interpreting visual information and spatial processing. In about one third of people who are left-handed, speech function may be located on the right side of the brain. Left-handed people may need special testing to determine if their speech center is on the left or right side prior to any surgery in that area.

Aphasia is a disturbance of language affecting speech production, comprehension, reading or writing, due to brain injury – most commonly from stroke or trauma. The type of aphasia depends on the brain area damaged.

Broca’s area: lies in the left frontal lobe (Fig 3). If this area is damaged, one may have difficulty moving the tongue or facial muscles to produce the sounds of speech. The person can still read and understand spoken language but has difficulty in speaking and writing (i.e. forming letters and words, doesn’t write within lines) – called Broca’s aphasia.
Wernicke’s area: lies in the left temporal lobe (Fig 3). Damage to this area causes Wernicke’s aphasia. The individual may speak in long sentences that have no meaning, add unnecessary words, and even create new words. They can make speech sounds, however they have difficulty understanding speech and are therefore unaware of their mistakes.

Cortex

The surface of the cerebrum is called the cortex. It has a folded appearance with hills and valleys. The cortex contains 16 billion neurons (the cerebellum has 70 billion = 86 billion total) that are arranged in specific layers. The nerve cell bodies color the cortex grey-brown giving it its name – gray matter (Fig. 4). Beneath the cortex are long nerve fibers (axons) that connect brain areas to each other — called white matter.

Figure 4. The cortex contains neurons (grey matter), which are interconnected to other brain areas by axons (white matter). The cortex has a folded appearance. A fold is called a gyrus and the valley between is a sulcus.

The folding of the cortex increases the brain’s surface area allowing more neurons to fit inside the skull and enabling higher functions. Each fold is called a gyrus, and each groove between folds is called a sulcus. There are names for the folds and grooves that help define specific brain regions.

Deep structures

Pathways called white matter tracts connect areas of the cortex to each other. Messages can travel from one gyrus to another, from one lobe to another, from one side of the brain to the other, and to structures deep in the brain (Fig. 5).

Figure 5. Coronal cross-section showing the basal ganglia.

Hypothalamus: is located in the floor of the third ventricle and is the master control of the autonomic system. It plays a role in controlling behaviors such as hunger, thirst, sleep, and sexual response. It also regulates body temperature, blood pressure, emotions, and secretion of hormones.

Pituitary gland: lies in a small pocket of bone at the skull base called the sella turcica. The pituitary gland is connected to the hypothalamus of the brain by the pituitary stalk. Known as the “master gland,” it controls other endocrine glands in the body. It secretes hormones that control sexual development, promote bone and muscle growth, and respond to stress.

Pineal gland:
is located behind the third ventricle. It helps regulate the body’s internal clock and circadian rhythms by secreting melatonin. It has some role in sexual development.

Thalamus: serves as a relay station for almost all information that comes and goes to the cortex. It plays a role in pain sensation, attention, alertness and memory.

Basal ganglia: includes the caudate, putamen and globus pallidus. These nuclei work with the cerebellum to coordinate fine motions, such as fingertip movements.

Limbic system: is the center of our emotions, learning, and memory. Included in this system are the cingulate gyri, hypothalamus, amygdala (emotional reactions) and hippocampus (memory).

Memory

Memory is a complex process that includes three phases: encoding (deciding what information is important), storing, and recalling. Different areas of the brain are involved in different types of memory (Fig. 6). Your brain has to pay attention and rehearse in order for an event to move from short-term to long-term memory – called encoding.

Figure 6. Structures of the limbic system involved in memory formation. The prefrontal cortex holds recent events briefly in short-term memory. The hippocampus is responsible for encoding long-term memory.

Short-term memory, also called working memory, occurs in the prefrontal cortex. It stores information for about one minute and its capacity is limited to about 7 items. For example, it enables you to dial a phone number someone just told you. It also intervenes during reading, to memorize the sentence you have just read, so that the next one makes sense.
Long-term memory is processed in the hippocampus of the temporal lobe and is activated when you want to memorize something for a longer time. This memory has unlimited content and duration capacity. It contains personal memories as well as facts and figures.
Skill memory is processed in the cerebellum, which relays information to the basal ganglia. It stores automatic learned memories like tying a shoe, playing an instrument, or riding a bike.

Ventricles and cerebrospinal fluid

The brain has hollow fluid-filled cavities called ventricles (Fig. 7). Inside the ventricles is a ribbon-like structure called the choroid plexus that makes clear colorless cerebrospinal fluid (CSF). CSF flows within and around the brain and spinal cord to help cushion it from injury. This circulating fluid is constantly being absorbed and replenished.

Figure 7. CSF is produced inside the ventricles deep within the brain. CSF fluid circulates inside the brain and spinal cord and then outside to the subarachnoid space. Common sites of obstruction: 1) foramen of Monro, 2) aqueduct of Sylvius, and 3) obex.

There are two ventricles deep within the cerebral hemispheres called the lateral ventricles. They both connect with the third ventricle through a separate opening called the foramen of Monro. The third ventricle connects with the fourth ventricle through a long narrow tube called the aqueduct of Sylvius. From the fourth ventricle, CSF flows into the subarachnoid space where it bathes and cushions the brain. CSF is recycled (or absorbed) by special structures in the superior sagittal sinus called arachnoid villi.

A balance is maintained between the amount of CSF that is absorbed and the amount that is produced. A disruption or blockage in the system can cause a build up of CSF, which can cause enlargement of the ventricles (hydrocephalus) or cause a collection of fluid in the spinal cord (syringomyelia).

Skull

The purpose of the bony skull is to protect the brain from injury. The skull is formed from 8 bones that fuse together along suture lines. These bones include the frontal, parietal (2), temporal (2), sphenoid, occipital and ethmoid (Fig. 8). The face is formed from 14 paired bones including the maxilla, zygoma, nasal, palatine, lacrimal, inferior nasal conchae, mandible, and vomer.

Figure 8. The brain is protected inside the skull. The skull is formed from eight bones.

Inside the skull are three distinct areas: anterior fossa, middle fossa, and posterior fossa (Fig. 9). Doctors sometimes refer to a tumor’s location by these terms, e.g., middle fossa meningioma.

Figure 9. A view of the cranial nerves at the base of the skull with the brain removed. Cranial nerves originate from the brainstem, exit the skull through holes called foramina, and travel to the parts of the body they innervate. The brainstem exits the skull through the foramen magnum. The base of the skull is divided into 3 regions: anterior, middle and posterior fossae.

Similar to cables coming out the back of a computer, all the arteries, veins and nerves exit the base of the skull through holes, called foramina. The big hole in the middle (foramen magnum) is where the spinal cord exits.

Cranial nerves

The brain communicates with the body through the spinal cord and twelve pairs of cranial nerves (Fig. 9). Ten of the twelve pairs of cranial nerves that control hearing, eye movement, facial sensations, taste, swallowing and movement of the face, neck, shoulder and tongue muscles originate in the brainstem. The cranial nerves for smell and vision originate in the cerebrum.

The Roman numeral, name, and main function of the twelve cranial nerves:

Number	Name	Function
I	olfactory	smell
II	optic	sight
III	oculomotor	moves eye, pupil
IV	trochlear	moves eye
V	trigeminal	face sensation
VI	abducens	moves eye
VII	facial	moves face, salivate
VIII	vestibulocochlear	hearing, balance
IX	glossopharyngeal	taste, swallow
X	vagus	heart rate, digestion
XI	accessory	moves head
XII	hypoglossal	moves tongue

Meninges

The brain and spinal cord are covered and protected by three layers of tissue called meninges. From the outermost layer inward they are: the dura mater, arachnoid mater, and pia mater.

Dura mater: is a strong, thick membrane that closely lines the inside of the skull; its two layers, the periosteal and meningeal dura, are fused and separate only to form venous sinuses. The dura creates little folds or compartments. There are two special dural folds, the falx and the tentorium. The falx separates the right and left hemispheres of the brain and the tentorium separates the cerebrum from the cerebellum.

Arachnoid mater: is a thin, web-like membrane that covers the entire brain. The arachnoid is made of elastic tissue. The space between the dura and arachnoid membranes is called the subdural space.

Pia mater: hugs the surface of the brain following its folds and grooves. The pia mater has many blood vessels that reach deep into the brain. The space between the arachnoid and pia is called the subarachnoid space. It is here where the cerebrospinal fluid bathes and cushions the brain.

Blood supply

Blood is carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries (Fig. 10). The internal carotid arteries supply most of the cerebrum.

Figure 10. The common carotid artery courses up the neck and divides into the internal and external carotid arteries. The brain’s anterior circulation is fed by the internal carotid arteries (ICA) and the posterior circulation is fed by the vertebral arteries (VA). The two systems connect at the Circle of Willis (green circle).

The vertebral arteries supply the cerebellum, brainstem, and the underside of the cerebrum. After passing through the skull, the right and left vertebral arteries join together to form the basilar artery. The basilar artery and the internal carotid arteries “communicate” with each other at the base of the brain called the Circle of Willis (Fig. 11). The communication between the internal carotid and vertebral-basilar systems is an important safety feature of the brain. If one of the major vessels becomes blocked, it is possible for collateral blood flow to come across the Circle of Willis and prevent brain damage.

Figure 11. Top view of the Circle of Willis. The internal carotid and vertebral-basilar systems are joined by the anterior communicating (Acom) and posterior communicating (Pcom) arteries.

The venous circulation of the brain is very different from that of the rest of the body. Usually arteries and veins run together as they supply and drain specific areas of the body. So one would think there would be a pair of vertebral veins and internal carotid veins. However, this is not the case in the brain. The major vein collectors are integrated into the dura to form venous sinuses — not to be confused with the air sinuses in the face and nasal region. The venous sinuses collect the blood from the brain and pass it to the internal jugular veins. The superior and inferior sagittal sinuses drain the cerebrum, the cavernous sinuses drains the anterior skull base. All sinuses eventually drain to the sigmoid sinuses, which exit the skull and form the jugular veins. These two jugular veins are essentially the only drainage of the brain.

Cells of the brain

The brain is made up of two types of cells: nerve cells (neurons) and glia cells.

Nerve cells

There are many sizes and shapes of neurons, but all consist of a cell body, dendrites and an axon. The neuron conveys information through electrical and chemical signals. Try to picture electrical wiring in your home. An electrical circuit is made up of numerous wires connected in such a way that when a light switch is turned on, a light bulb will beam. A neuron that is excited will transmit its energy to neurons within its vicinity.

Neurons transmit their energy, or “talk”, to each other across a tiny gap called a synapse (Fig. 12). A neuron has many arms called dendrites, which act like antennae picking up messages from other nerve cells. These messages are passed to the cell body, which determines if the message should be passed along. Important messages are passed to the end of the axon where sacs containing neurotransmitters open into the synapse. The neurotransmitter molecules cross the synapse and fit into special receptors on the receiving nerve cell, which stimulates that cell to pass on the message.

Figure 12. Nerve cells consist of a cell body, dendrites and axon. Neurons communicate with each other by exchanging neurotransmitters across a tiny gap called a synapse.

Glia cells

Glia (Greek word meaning glue) are the cells of the brain that provide neurons with nourishment, protection, and structural support. There are about 10 to 50 times more glia than nerve cells and are the most common type of cells involved in brain tumors.

Astroglia or astrocytes are the caretakers — they regulate the blood brain barrier, allowing nutrients and molecules to interact with neurons. They control homeostasis, neuronal defense and repair, scar formation, and also affect electrical impulses.
Oligodendroglia cells create a fatty substance called myelin that insulates axons – allowing electrical messages to travel faster.
Ependymal cells line the ventricles and secrete cerebrospinal fluid (CSF).
Microglia are the brain’s immune cells, protecting it from invaders and cleaning up debris. They also prune synapses.

Sources & links

If you have more questions, please contact Mayfield Brain & Spine at 800-325-7787 or 513-221-1100.

Links

brainfacts.org

thebrain.mcgill.ca

updated > 4.2018
reviewed by > Tonya Hines, CMI, Mayfield Clinic, Cincinnati, Ohio

Mayfield Certified Health Info materials are written and developed by the Mayfield Clinic. We comply with the HONcode standard for trustworthy health information. This information is not intended to replace the medical advice of your health care provider.

Glands of the Abdomen – Advanced Anatomy 2nd. Ed.

Organs

The adrenal gland is a yellow, pyramid-shaped gland that sits on top of each kidney. Since they sit on top of the kidney’s superior border, the adrenals can be referred to as the suprarenal gland. The adrenal glands are connected to the kidneys via the dense fibrous capsule that firmly holds the two organs together. The adrenals are also located near the 12^th rib and the diaphragm with major arteries and veins in close proximity as they run along the posterior wall of the abdominopelvic cavity. Since it is an endocrine organ it is important that is highly vascularized, this will allow for the secreted hormones to affect the body. The adrenal gland had two key layers, the adrenal medulla and adrenal cortex.

The adrenal medulla is the deep layer of the adrenal gland. The medulla is often a grey-pink colour due to the abundance of blood vessels and connective tissues. The medulla is responsible for the secretion of two hormones. From specialized cells epinephrine, also known as adrenaline, and norepinephrine, also known as noradrenaline, are produced. Each hormone is produced by one cell with evidence showing that the two types of cells are found in different areas of the adrenal medulla and that they are independently controlled.

The adrenal cortex is the more superficial layer. It has a yellowish colour due to the stored lipids, which include cholesterol and various fatty acids. From the cortex, dozens of hormones are released that are collectively called corticosteroids. Corticosteroids are vital to survival. These corticosteroids are produced in three distinct zones on the adrenal cortex, these include the zona glomerulosa, zona fasciculata, and zona reticularis. Each zone produces specific steroid hormones that make up the corticosteroids. Transport proteins are needed to move adrenal hormones around the body. Transcortin, found in the blood bound with the corticosteroid hormones and carry them to their target organs.

Hormones

The adrenals medulla is responsible for the release of epinephrine and norepinephrine. These hormones are released by packing the hormones into vesicles that then cluster just inside the plasma membrane. From here these hormones are slowly released at low levels through exocytosis, however, if there is a sympathetic stimulus epinephrine and norepinephrine are released at a dramatically accelerated rate of exocytosis. The sympathetic nervous system involves the fight or flight mechanism, so it makes sense that the role of epinephrine and norepinephrine help the body response to a stressful situation. Epinephrine and norepinephrine have four key functions, the acceleration of ATP production, breakdown of stored fat, liberating glucose stores in the liver, and increase the rate and force of cardiac muscle contraction. This in terms of short-term stress this response means that your heart rate and pressure will increase and that you will have better muscular strength and endurance. So, if your stressful situation is running into a hungry lion or mugger you will have the surge of strength and endurance to fight your attacker or run away. The metabolic changes that epinephrine and norepinephrine cause reach their peak 30 seconds after the stimulus and persist for several minutes.

The adrenal cortex has a more complex role when it comes to the endocrine functions. It is responsible to produce corticosteroids which can be broken down into three groups that are associated with the zone that produces them. These zones are the Zona Glomerulosa, Zona Fasciculata and the Zona Reticularis.

The Zona Glomerulosa is responsible for the production of a group of hormones called Mineralocorticoids. The mineralocorticoids affect the concentration and composition of electrolytes in body fluids. The main hormone from mineralocorticoid group is Aldosterone. Aldosterone is responsible for the conservation of sodium ion and the elimination of potassium ion. The target of aldosterone is the kidneys, sweat gland, salivary gland and the pancreas. Aldosterone is also responsible for increasing a person interest in salty food by increasing the sensitivity of the salt receptor taste bud on the tongue. Aldosterone is stimulated when the sodium concentration falls, a drop in blood volume, a drop in blood pressure, or a rise in potassium concentration in the blood.

The Zona Fasciculata is responsible for the production of the group of hormones called Glucocorticoids. Glucocorticoids are a group of steroid hormones that affect glucose metabolism. When the zona fasciculata is stimulated by ACTH, a pituitary hormone, the secretion of cortisol also known as hydrocortisone. Cortisol is the primary hormone in the glucocorticoid, with corticosterone and cortisone also released in smaller amounts. Cortisol is often referred to as the stress hormone, but unlike epinephrine and norepinephrine, the stressor is not a single short-term event. In times of long-term stress, cortisol helps control blood sugar levels, regulate metabolism, reduce inflammation and assist in memory formulation.

The final zone is Zona Reticularis, this zone produces small amounts androgens. Androgens are usually associated with the reproductive organs, but small amounts are produced by the adrenal cortex. In early stages of puberty adrenal androgen stimulate the growth of pubic hair in both girls and boys. In adulthood, adrenal androgens are not important to men. However, for adult women, adrenal androgens are important to build muscle mass, blood cell formation and to support their sex drive.

Clinical application

In today’s world chronic stress is commonplace, with people stressing about finances, school, work, family and ironically health. Although cortisol can be helpful in short bouts of chronic stress, it can be damaging when high levels are maintained over a long period of time. In this short video by DNews explains the effect of long-term stress.

References

https://www.hormone.org/hormones-and-health/hormones/cortisol

Bartholomew E.F., Hutching R.T. Martini F.H., Nath J.L, Ober C.E.,Ober W.O, O’Keefe R.A,& Welch K.. (2015) Fundamentals Of Anatomy and physiology (10^th ed.) Pearson

Videos:

D News https://www.youtube.com/watch?v=8IUZjCSkbrc