12 systems of the human body
Skeletal- example = bones
Cardiovascular organs- example = heart
Digestive- example = alimentary canal, like stomach and intestines
Respiratory- example = lungs
Urinary- example = organs that collect urine, like kidneys, ureters, bladder, and urethra
Reproductive- example = genital, like testes for males and uterine tubes, uterus and vagina for females
Nervous- example = brain, spinal cord, and nerves
Muscular- example = the three muscle types: skeletal, visceral, and cardiac
Endocrine- example = all ductless glands, like the testes, ovaries, pancreas, adrenals, thymus, thyroid, parathyroids, pineal, and pituitary
Integumentary- example = composed of skin and areas like hair, nails, and sweat/oil glands, also regulates body temperature
Lymphatic System = example Lymph Nodes
Immune System- example = areas that fight disease, like WBC
How many bones does the human skeleton contain? Axial? Appendicular?
206
80
126
5 part of the axial skeleton
Skull Hyoid Auditory Vertebral column Thorax
2 parts of the skull bones
Cranium (8) Facial bones (14)
8 cranium bones
Parietal (2) Temporal (2) Occipital Frontal Sphenoid Ethmoid
14 facial bones
Nasal (2) Lacrimal (2) Inferior Nasal Concha (2) Maxilla (2) Mandible Palatine (2) Zygomatic (2) Vomer
3 auditory bones
Stapes
Incus
Malleus
5 parts of the vertebral column
Cervical-7 Thoracic-12 Lumbar-5 Sacrum-1 (fused 5) Coccyx-1 (fused 4)
2 parts of the thorax
Sternum-1
Ribs-24 (12 each side)
Cartilage that connects the sternum and the ends of the ribs
Costal cartilage
Ribs 1-7 because they attach directly to the sternum
True ribs
Ribs 8-10 because they DO NOT attach directly to the sternum
False ribs
Ribs 11-12 because they attach only to vertebrae
Floating ribs
Spaces between the ribs
Intercostal spaces
2 parts of the shoulder girdle
Clavicles 2
Scapula 2
6 parts of the upper limbs
Humerus 2 Ulna 2 Radius 2 Carpals 16 Metacarpals 10 Phalanges 28
7 parts of the lower limbs
Femur 2 Tibias 2 Fibula 2 Patella 2 Tarsals 14 Metatarsals 10 Phalanges 28
4 parts of the appendicular skeleton
Shoulder girdles
Upper limbs
Pelvic girdle
Lower limbs
3 parts the hip consists of
Ischium
Ilium
Pubis
4 classifications of bones
Long (humerus of arm)
Short (carpal of wrist)
Flat (sternum)
Irregular (vertebra)
3 functional types of joints
Synarthrosis
Amphiarthrosis
Diarthrosis
Immovable Joints
Example would be the cranial sutures
Synarthrosis
Limited Movement
Example would be roots of teeth
Amphiarthrosis
Freely Moveable Joint
Example would be knee joint, shoulder joint
Diarthrosis
6 types of movement
Gliding/Plane Hinge Pivot Ellipsoid/Condyloid Saddle Ball and Socket
Sliding or gliding motion
Example: intercarpal joints of the wrist
Gliding/Plane
Permit flexion and extension
Example: elbow, knee, ankle
Hinge
Allows rotational movement around a single axis
Example: atlas and axis = atlas rotates around the dens of the axis and allows the head to rotate to either side
Pivot
Permit flexion and extension AND abduction and adduction
Example: radiocarpal joint of the wrist
Ellipsoid/Condyloid
Like the ellipsoid joint, except the two saddlelike structures fit into each other
Example: first carpometacarpal joint
Saddle
Allows the greatest freedom of motion, adds lateral and medial rotation to the ellipsoid
Example is hip joint or shoulder joint
Ball-and-socket
Moving away from the midline
Abduction
Moving toward the midline
Adduction
Circular movement of a limb
Circumduction
Straightening or increasing the joint angle
Extension
Bending or decreasing the joint angle
Flexion
Outward stress movement
Eversion
Inward stress movement
Inversion
Turning downward
Pronation
Turning upward
Supination
Forward movement; gliding motion anteriorly
Protraction
Backward movement
Moves structure back to anatomic position or even further posteriorly
Ex: scapulae and mandibles
Retraction
Lifting, raising, or movement of a part superiorly
Elevation
Letting down, lowering, or moving a part inferiorly
Depression
Flexion or bending the foot toward the leg
Dorsiflexion
Flexion or bending the foot downward toward the sole
Plantar flexion
Turning away from the regular standard or course
Deviation
Flexing toward radius
Radial deviation
Flexing toward ulna
Ulnar deviation
Turning toward midline
Internal rotation
Turning away from midline
External rotation
Hunchback
Kyphosis
Swayback
Lordosis
Curve to the right; forming a backward “C” shape
Dextroscoliosis
Curve to the left; forming a “C” shape
Levoscoliosis
The heart is a muscular pumping organ located medial to the lungs along the body’s midline in the thoracic region. The bottom tip of the heart, known as its apex, is turned to the left. The top of the heart, known as the heart’s base, connects to the great blood vessels of the body: the aorta, vena cava, pulmonary trunk, and pulmonary veins.
Cardiovascular system
Right and left ventricles separated by this
Interventricular septum
13 steps in the path of blood
IVC to the SVC of the
RT ATRIUM of the heart, through the
TRICUSPID OR RIGHT ATRIOVENTRICULAR (AV) into the
RT VENTRICLE of the heart. From here it flows through the
PULMONARY VALVE into the
PULMONARY ARTERY, which takes the blood to the
LUNG to pick up oxygen. Blood returns by way of the
PULMONARY VEIN into the
LT ATRIUM of the heart, through the
MITRAL VALVE OR LEFT ATRIOVENTRICULAR (AV) and into the
LEFT VENTRICLE of the heart, which sends oxygenated blood through the
AORTIC VALVE into the
AORTA which carries the blood to the body & flows to the brachiocephalic, carotid and subclavian arteries
Which side of the heart handles venous/deoxygenated blood? Arterial/oxygenated blood?
Right
Left
Muscular wall of the heart
Myocardium
Inner lining of the heart
Endocardium
Thin membrane that covers the heart
Epicardium
Double-walled outermost covering/sac of the heart
Pericardium
Carry blood away from the heart
Arteries
Smaller branch of artery
Arteriole
Vessel for returning blood to heart
Vein
Smaller branch of vein
Venule
Smallest vessel, connects arterioles and venules, supplies oxygen and removes waste
Capillary
Largest artery in the body
Approximately 2.5 cm
If over 5 cm, surgery candidate for aneurysm
Aorta
Largest veins in the body
Superior and inferior vena cava
2 circulation circuits
Systemic
Pulmonary
Carries oxygenated blood to organs and tissue
Systemic
Takes blood to lungs to exchange carbon dioxide for oxygen
Pulmonary
A condition in which cramping pain in the leg is induced by exercise, typically caused by obstruction of the arteries
Claudication
The blockage or closing of a blood vessel or hollow organ
Occlusion
Weakened area of an artery that is “ballooned”
If blood flows on the weakened wall it can burst
Aneurysm
Lack of normal heart rhythm
Arrythmia
Slow heartbeat, less than 60 beats per minute
Bradycardia
Rapid heartbeat, greater than 100 beats per minute
Tachycardia
Arteries that serve the heart are obstructed or narrowed, most commonly from atherosclerosis
Coronary Artery Disease
Deposits of plaque inside the arteries
Atherosclerosis
Caused by high blood pressure that forces the layers of the aortic walls to separate
Aortic dissection
Thickening of valvular tissue that results in narrow valve openings
Stenosis
Procedure in which small, selected areas of the heart are destroyed to treat tachycardia
Ablation
Group of organs working together to convert food into energy and basic nutrients to feed the entire body
Food passes through a long tube inside the body known as the alimentary canal or the gastrointestinal tract (GI tract)
Any modality can image these areas, fluoroscopic procedures too
Digestive system
8 parts in the path of food
Mouth Pharynx Esophagus Stomach Small Intestine Liver and Gallbladder Pancreas Large Intestine
Funnel-shaped tube connected to the posterior end of the mouth
Responsible for the passing of masses of chewed food from the mouth to the esophagus
Also plays important role in respiratory system as air from the nasal canal passes through this on its way to the larynx and eventually the lungs
Because it serves two different functions, contains flap of tissue known as the epiglottis that acts as a switch to route food to the esophagus and air to the larynx
Pharynx
6 primary processes of the digestive system
Ingestion of food Secretion of fluids and digestive system Mixing and movement of food and wastes through the body Digestion of food into smaller pieces Absorption of nutrients Excretion of wastes
Muscular tube connecting pharynx to stomach that’s part of upper GI tract
Carries swallowed masses of chewed food along its length
Esophagus
Muscular ring at inferior end of esophagus that closes off end of esophagus and traps food in stomach
Lower esophageal sphincter/cardiac sphincter
Muscular sac located on left side of abdominal cavity just inferior to diaphragm
In average person, size of their two fists placed next to each other
Acts as storage tank for food so body has enough time to digest large meals properly
Also contains hydrochloric acid and digestive enzymes that continue the digestion of food that began in mouth
Stomach
Long, thin tube about 1 in in diameter and about 10 ft long that’s part of lower GI tract
Located just inferior to stomach and takes up most of space in abdominal cavity
Entire thing is coiled like a hose and inside surface full of many ridges and folds used to maximize digestion of food and absorption of nutrients
By time food leaves this, around 90% of all nutrients have been extracted from food that entered it
Small intestine
Roughly triangular accessory organ located to right of stomach just inferior to diaphragm and superior to small intestine
Weighs about 3 lb and is second largest organ in body
Main function in digestion is production of bile and secretion into small intestine
Liver
Small, pear-shaped organ located just posterior to liver
Used to store and recycle excess bile from small intestine so it can be reused for digestion of subsequent meals
Gallbladder
Large gland located just inferior and posterior to stomach
About 6 in long and shaped like short, lumpy snake with its “head” connected to the duodenum and its “tail” pointing to the left wall of the abdominal cavity
Secretes digestive enzymes into the small intestine to complete chemical digestion of food
Pancreas
Long, thick tube about 2 ½ in in diameter and about 5 ft long
Located just inferior to stomach and wraps around superior and lateral border of small intestine
Absorbs water and contains many symbiotic bacteria that aid in breaking down of wastes to extract some small amounts of nutrients
Large intestine
4 main parts of large intestine
Cecum: first part of the large intestine
Colon (ascending, transverse, descending, and sigmoid)
Rectum
Anal canal: terminates at the anus, feces exit here
Consists of the upper and lower respiratory tracts
X-ray and CT best to image these areas
Respiratory system
6 parts of the upper respiratory tract
Nose Mouth Nasopharynx Oropharynx Laryngopharynx Larynx
Air enters respiratory tract, hairs filter out dust
Nose
Air enters respiratory tract
Mouth
Extend from the posterior nostril to the soft palate
Nasopharynx
Extend from the soft palate to the upper portion of epiglottis
Oropharynx
Extend from the epiglottis to the larynx
Laryngopharynx
Contain the vocal cords (voice box), connects the pharynx with the trachea
Larynx
3 parts of the lower respiratory tract
Trachea
Bronchi
Lungs
Windpipe, lies half in the neck and half in the thorax, c-shaped cartilage rings reinforce and protect the trachea
Trachea
Trachea branches into the carina/Tracheal Bifurcation, into two smaller airways, the left and right mainstem
Bronchi
Each of the pair of organs situated within the rib cage, consisting of elastic sacs with branching passages into which air is drawn, so that oxygen can pass into the blood and carbon dioxide be removed
Lungs
A membranous partition between two body cavities or two parts of an organ, especially that between the lungs
Mediastinum
Shortness of breath
Dyspnea
Bluish discoloration of the skin from deoxygenated hemoglobin in the blood
Bluish color that’s caused by an excess of oxygen starved hemoglobin molecules in the blood
Cyanosis
Absence or near absence of oxygen
Anoxia
Coughing or spitting up blood
Hemoptysis
Discomfort in breathing except in the upright position
Orthopnea
Absence of breathing
Apnea
Body’s water treatment plan
Filters the blood and collects and expels the resulting liquid waste products as urine
Consists of the kidneys, ureters, bladder, and the urethra
Ultrasound, CT and some x-ray procedures like cystograms are best to image these areas
Urinary/renal system
Bean shaped highly vascular organs located at the small of the back (posterior) on either side of the vertebral column between T12 and L3
Right one is positioned a little lower due to the liver
Kidneys
Sit on top the kidneys and affect the renal system by influencing blood pressure and sodium and water retention by the kidneys
Adrenal glands
Normally arise off the side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood
Renal arteries
3 regions of kidneys
Renal Cortex
Renal Medulla
Renal Pyramids
Outer region of kidneys, contains blood filtering mechanisms
Renal Cortex
Middle region of kidneys, contains 8-12 renal pyramids
Renal medulla
Wedge-shaped region of kidneys
Renal pyramids
Each kidney has a this part that carries urine from the kidney to the bladder
Ureters
Small duct that channels urine outside the body from the bladder
Urethra
Painful or difficult urination
Dysuria
Presence of blood in the urine
Hematuria
Excessive urination at night
Nocturia
Diminished urine output, less that 400ml in a day
Oliguria
Excessive urine production
Polyuria
Pus in the urine
Pyuria
System of sex organs within an organism which work together for the purpose of sexual reproduction
Ultrasound or MRI is the best imaging for these anatomic regions
Reproductive/genital system
3 parts of the male reproductive system
Prostate Gland
Seminal Vesicles
Testicle
Main function is to produce fluid which protects and enriches sperm
Prostate gland
Each of a pair of glands that open into the vas deferens near its junction with the urethra and secrete many of the components of semen
Seminal vesicles
Either of the two oval organs that produce sperm, enclosed in the scrotum behind the penis
Testicle
5 parts of the female reproductive system (usually ultrasound or MRI is best for imaging this areas)
Ovaries Uterus Fallopian Tubes Cervix Vagina
Produce eggs and hormones
Ovaries
Home to the developing fetus
Uterus
Narrow tubes that are attached to the upper part of the uterus and serve as tunnels for the ova to travel from the ovaries to the uterus
Best seen by hysterosalpingogram (HSG)
Fallopian tubes
Narrow neck like passage forming the lower end of the uterus
Cervix
Muscular tube leading from the external genitals to the cervix of the uterus
Vagina
Network of nerve cells and fibers that transmits nerve impulses between parts of the body
Brain and Vertebral Column
MRI, angiography, myelography are
the best to check these areas
Nervous System
Respond to stimuli and transmit responses by means of electromechanical messages
Neurons
Conduct nerve pulses away from the cell body
Axons
Conduct impulses toward the cell body
Dendrites
White, fatty, segmented covering for nerve protection
Myelin sheath
4 lobes of the cerebral hemispheres
Frontal
Temporal
Parietal
Occipital
Lobe of cerebral hemisphere that influences personality, judgement, reasoning, social behavior
Frontal
Lobe of cerebral hemisphere that controls hearing, language, comprehension, storage to recall memories
Temporal
Lobe of cerebral hemisphere that interprets sensations like pain, temperature and touch
Parietal
Lobe of cerebral hemisphere primarily to interpret visual stimuli
Occipital
Functions to maintain muscle tone, coordinate muscle movement, and control balance
Cerebellum
Downward displacement of cerebellum through the foramen magnum
Arnolds Chiari
Relays messages between parts of the nervous system
Provides pathways for nerve fibers
Serves as the origin of the cranial nerves
Brainstem
3 parts of the brainstem
Midbrain
Pons
Medulla Oblongata
Olfactory- loss of smell
CN I
Optic- blindness, usually due to a lesion
CN II
Oculomotor- drooping of the eyelid, deviation of the eyeball outward
CN III
Trochlear- rotation of the eye upward and outward
CN IV
Trigeminal- pain or loss of sensation in the face, forehead, temple, and eye, difficulty chewing
CN V
Abducens- deviation of the eye outward, double vision
CN VI
Facial- paralysis of all the muscles on one side of the face, inability to wrinkle forehead (Bell’s Palsy)
CN VII
Acoustic- deafness or ringing in the ears (tinnitus)
CN VIII
Glossopharyngeal- disturbance of taste and difficulty swallowing
CN IX
Vagus- paralysis of the main trunk of the throat on one side causes hoarseness and difficulty talking
CN X
Spinal accessory- motor, shoulder movement and head rotation
CN XI
Hypoglossal- motor, tongue movement
CN XII
Bundle of spinal nerves and spinal nerve roots, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enlargement and the conus medullaris of the spinal cord
Cauda equina (Latin for “horse’s tail”)
A tapering lower part of the spinal cord at the level of the first lumbar segment
Conus medullaris
Inner core of the vertebral disc composed of a jelly-like material that consists of mainly water, as well as a loose network of collagen fibers
Nucleus Pulposus
Tough circular exterior of the intervertebral disc that surrounds the soft inner core, the nucleus pulposus
Annulus Fibrosus
Nucleus pulposus bulging into annulus fibrosus
Bulging disk
Cover and protect the cerebral cortex and spinal column
Meninges
3 layers of meninges
Dura Mater
Arachnoid Mater
Pia Mater
Layer of meninges that lines the skill and forms folds that descend into the brain’s fissures and provide stability
Dura Mater
Layer of meninges that lies between the dura mater and pia mater
Arachnoid Mater
Innermost layer of the meninges
Rich blood supply
Pia Mater
3 layers of space to further cushion the brain an spinal cord
Epidural Space
Subdural Space
Subarachnoid Space
Space that lies over the dura mater
Epidural Space
Space situated between the dura mater and arachnoid mater
Subdural Space
Space filled with CSF, separates the arachnoid membrane and pia mater
Subarachnoid Space
Paralysis on one side of the body
Hemiplegia
Paralysis or muscular weakness affecting only one side of the body
Hemiparesis
Severe pain in a nerve or nerves
Neuralgia
Inflammation of the meninges of the brain and spinal cord caused by bacterial, viral, or fungal infection
Meningitis
Unilateral facial paralysis of sudden onset, usually not permanent
Bells Palsy
Painful disorder affecting one or more branches of the 5th cranial nerve; tingling in side of face, headaches
Trigeminal Neuralgia
Early signs progress to severe deterioration in memory, language, and motor function
Alzheimer’s Disease
Progressive demyelination of the white matter of the brain and spinal cord that results in weakness, incoordination, paresthesia, speech disturbance, and visual complaints
Multiple Sclerosis
4 main functions of muscular system (MRI best modality for these areas)
Support the body
Permit movement
Produce body heat
ALSO an integral part of internal organs, such as the heart, lungs, uterus, and intestines
3 types of muscles
Skeletal = Voluntary Visceral = Involuntary Cardiac = Involuntary
Muscle ontrolled by will
Move body parts, maintain posture, and reflex movements
Skeletal = Voluntary
Muscle not controlled by will
Found in organs like the stomach and intestine (peristalsis)
Visceral = Involuntary
Movement of heart
Controlled by autonomic nervous system and neuromuscular tissue
Cardiac = Involuntary
Muscle pain or tenderness
Myalgia
Wasting of muscle
Wasting of muscle
Complete or incomplete tear in the supporting ligaments surrounding a joint
Sprain
Injury to a muscle or tendinous attachment
Strain
Painful inflammation of one or more of the bursae
Bursitis
Controls complicated body activities by secreting chemical substances into the circulatory systems
Main components are glands and hormones
Ultrasound and MRI best imaging modalities
Endocrine
Specialized cell clusters or organs
Glands
Chemical substances secreted by the glands in response to stimulation
Hormones
7 major endocrine glands
Pituitary Gland Thyroid Gland Parathyroid Glands Adrenal Glands Pancreas Pineal Gland Thymus
Gland that is no larger than a pea and lies at the base of the brain in a depression of the sphenoid bone called the sella turcica
Controls all the other glands
Important in controlling growth and development and the functioning of the other endocrine glands
Pituitary gland
5 hormones the pituitary gland produces
GH: growth TSH: thyroid stimulating FSH: follicle stimulating (ovaries) LH: luteinizing Prolactin
Lies directly below the larynx and partially in front of the trachea
A large ductless gland in the neck that secretes hormones regulating growth and development through the rate of metabolism
Thyroid gland
4 hormones thyroid gland produces
TSH
T4 Thyroxine
T3 Triiodothyronine
Calcitonin
Gland that controls the calcium in our bodies = how much calcium is in our bones, and how much calcium is in our blood; calcium is the most important element in our bodies
Four lie on the posterior surface of the thyroid
Produces PTH: parathyroid
Parathyroid gland
Two, sit on top of the kidneys
Endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol
Found above the kidneys
Produce: Epinephrine
Adrenal/suprarenal glands
Gland that plays an essential role in converting the food we eat into fuel for the body’s cells
Produces: Insulin
Pancreas
2 main functions of the pancreas
Exocrine function that helps in digestion
Endocrine function that regulates blood sugar
It is a neuroendocrine gland
Produces: Melatonin
Involved in the reproductive system and the body’s circadian (24 hour body clock) rhythms
Gets smaller as you age, why adults don’t sleep as well as kids
Pineal gland
Located below the sternum
A lymphoid organ situated in the neck of vertebrates that produces T cells for the immune system
Becomes much smaller at the approach of puberty
Thymus
2 hormones the thymus produces
Thymosin
Thymopoietin
Enlarged thyroid gland, usually evident as swelling in the front of the neck
Goiter
Acute exacerbation of hyperthyroidism that is a medical emergency and may lead to cardiac failure
Thyroid storm
Low serum thyroid hormone, abnormally low activity of the thyroid gland
Hypothyroidism
High serum thyroid hormone, abnormally high activity of the thyroid gland
Hyperthyroidism
Associated with the pancreas, chronic insulin deficiency or resistance to insulin by the cells
Diabetes Mellitus
Abnormally low blood glucose level
Hypoglycemia
Disorder in which the adrenal glands don’t produce enough hormones
Addison’s Disease
Organ system that protects the body from various kinds of damage, such as loss of water or abrasion from outside
The system comprises the skin and its appendages (including hair, scales, feathers, hooves, and nails)
Ultrasound probably best modality for this system
Integumentary system
Redness of inflammation of the skin resulting from congestion of the superficial capillaries
Erythema
Fungal infection of the oral mucous membranes, usually in patients with a weakened immune system
Thrush
Superficial skin infections
Dermatitis
Chronic skin disease that causes dilated and inflamed surface blood vessels and reddening of the nose and adjoining tissues
Rosacea
Irregularly shaped patches of lighter or white skin caused by the loss of pigment-producing cells
Vitiligo
Network of organs, lymph nodes, lymph ducts, and lymph vessels that make and move lymph from tissues to the bloodstream
Major part of the body’s immune system
CT best modality
Lymphatic system
A colorless fluid containing white blood cells, that bathes the tissues and drains through the lymphatic system into the bloodstream
Lymph
Liquid portion of blood
Plasma
Red Blood Cells
Erythrocytes
White Blood Cells
Leukocytes
Platelets
Thrombocytes
Lymph nodes in underarm and upper chest (most common to get metastases)
Axillary
Lymph nodes in neck
Cervical
Lymph nodes in groin area
Inguinal
Lymph nodes behind the knee
Popliteal
Lymph nodes in the flood of the mouth and lower jaw
Submandibular
Lymph nodes in the clavicle area
Subclavian
Lymph nodes above the clavicle area
Supraclavicular
Lymph nodes in the abdomen area
Mesteric
Lymph nodes in the upper leg area
Femoral
Distal lymph nodes in the medial epicondyle of the humerus
Supratrochlear
Lymph nodes in the chest area
Mediastinal
11 lymph nodes
Axillary Cervical Inguinal Popliteal Submandibular Subclavian Supraclavicular Mesenteric Femoral Supratrochlear Mediastinal
Abdominal organ involved in the production and removal of blood cells in most vertebrates and forming part of the immune system
Largest structure of the lymphatic system
Initiates an immune response, filters and removes bacteria and other foreign substances from the bloodstream, destroys worn-out blood cells and serves as a blood reservoir
Left side
Spleen
Profuse nose bleed
Epistaxis
Uncontrolled bleeding
Hemorrhage
Severe itching
Pruritus
Hives
Uticaria
Defends the body against invasion by harmful organisms and chemical toxins
Made up of a network of cells, tissues, and organs that work together to protect the body
One of the important cells involved are white blood cells, also called leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances
Immune system
8 organs involved in the immune system
Tonsils and Adenoids Thymus Lymph Nodes Appendix Bone Marrow Lymphatic Vessels Spleen Peyer’s Patches
The numerous areas of lymphoid tissue in the wall of the small intestine that are involved in the development of immunity to antigens present there
Peyer’s Patches