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Matrix is the blood plasma- a clear light yellow fluid consisting a little over half of the blood volume. Plasma is a mixture of water (92%), proteins, nutrients, electrolytes, nitrogenous wastes, hormones and gases.
Suspended in the plasma, formed elements are cells and cell fragments including the red blood cells, white blood cells, and platelets. Term denotes that these are membrane-enclosed bodies with a definite visible structure.
Carries blood to the lungs for gas exchange and returns it to the heart.
Right half of the heart supplies the pulmonary circuit. It receives blood that has circulated through the blood and pumps it into a large artery, the pulmonary trunk.
Circulation to & from lungs
Supplies blood to every organ of the body, including other parts of the lungs and the wall of the heart itself. The left side o the heart supplies the systemic circuit. It pumps blood into the body’s largest artery (aorta).
Circulation to and from rest of the body.
Delivers blood to extremities.
Contains 5-30 mL of pericardial fluid, exuded by the serous layer of the pericardial sac. Allows the heart to beat with minimum friction.
Heart is enclosed in a double-walled sac called the PERICARDIUM.
visceral pericardium (Epicardium)
Serous membrane on the heart surface. Consists mainly of a simple squamous epithelium overlying a thin layer of areolar tissue.
parietal pericardium ( Pericardial sac)
The outer wall has a tough, superficial fibrous layer of dense irregular connective tissue, and a deep, thin serous layer. The serous layer turns inward at the base of the heart and forms the epicardium (visceral pericardium). Anchored by ligaments to the diaphragm below and the sternum anterior to it; and more loosely anchored by fibrous connective tissue to mediastinal tissue posterior to the heart.
Composed of cardiac muscle, lies between two layers, and composes most of the mass of the heart. It performs the work of the heart
Continues around the left side of the heart in the coronary sulcus. It gives off a left marginal branch that passes down the left margin of the heart and furnishes blood to the left ventricle. The circumflex branch then ends on the posterior side of the heart, where it supplies blood to the left atrium and posterior wall of the left ventricle.
1. Great vein
Collects blood from the anterior aspect of the heart and travels alongside the anterior interventricular artery. It carries blood from the apex of the heart toward the coronary sulcus, then arcs around the left side of the heart and empties into the coronary sinus.
2. Middle cardiac vein
Found in the posterior interventricular sulcus, collects blood from the posterior aspect of the heart. It, too, carries blood from the apex upward and drains into the same sinus.
3. Small Cardiac Vein
The small cardiac vein runs in the coronary sulcus between the right atriumand ventricle and opens into the right extremity of the coronary sinus.
It receives blood from the posterior portion of the right atrium and ventricle.
It may drain to the coronary sinus, right atrium, middle cardiac vein, or be absent.
A large transverse vein in the coronary sulcus on the posterior side of the heart collects blood from all 3 of the aforementioned veins as well as some smaller ones. It empties blood into the right atrium.
CAD is a narrowing of the coronary arteries resulting in insufficient blood flow to maintain the myocardium. It is usually caused by atherosclerosis, a vascular disorder in which fatty deposits form in an arterial wall, causing arterial degeneration and obstructed blood flow.
A patch of modified cardiocytes in the right atrium, just under the epicardium near th superior vena cava. This is the PACEMAKER that initiates each heartbeat and determines the heart rate
(Sinoatrial node (SA node) & atrioventricular node (AV node))
Nervelike processes that arise from the lower end of the bundle branches and turn upward to spread throughout the ventricular myocardium. They distribute the electrical excitation to the cardiocytes of the ventricles. Form a more elaborate network in the left ventricle than the right.
A cord of modified cardiocytes by which signals leave the AV node. This bundle soon forks into right & left branches, which enter the interventricular septum and descend toward the apex of the heart.
left & right
The middle layer, usually the thickest. It consists of smooth muscle, collagen, and in some cases elastic tissue. The relative amounts of muscle and elastic tissue vary greatly from one vessel to another and form a basis for the classification of vessels described. Strengthens the vessels and prevents blood pressure from repturing them, and it produces VASOMOTION, changes in vessel diameter.
Outermost layer, consisting of loose connective tissue that often merges with that of neighboring blood vessels, nerves, or other organs. It anchors the vessels and allows small nerves, lymphatic vessels, and smaller blood vessels to reach and penetrate into the tissues of the larger vessel.
The biggest arteries. Like an interstate highway, they serve only to deliver blood at high speed to the major ‘exit ramps’ that head off to individual organs. The aorta, common carotid and subclavian arteries, pulmonary trunk, and common iliac arteries are examples of conducting arteries. They have a layer of elastic tissue called the internal elastic lamina.
Smaller branches that distribute blood to specific organs, like the exit ramps and state highways that serve individual towns. Most arteries that have a specific name, are in these first 2 classes. Brachial, femoral, renal, and splenic are examples of distributing. Distributing layers normally have 40 layers of smooth muscle.
Occur in most tissues, such as skeletal muscle. Endothelial cells are held together by tight junctions, form a continuous tube. A thin protein carbohydrate layer, the basal lamina, surrounds the endothelium and seperates it from the adjacent connective tissues. Some continuous capillaries exhibit cells called pericytes, that lie external to the endothelium.
Irregular blood-filled spaces in the liver, bone marrow, spleen, and some other organs. They are twisted, tortuous passageways. Conform to the shape of the tissue. Their endothelial cells are seperated by wide gaps with no basal lamina. Even protein and blood cells can pass through these pores. This is how albumin, clotting factors, and other proteins synthesized by the liver enter the blood, and how newly formed blood cells enter the circulation from the bone marrow and lymphatic organs. Contain macrophages.
Range up to 10 mm in diameter. Most veins with individual names are in this category, such as the radial and ulnar veins of the forearm. Medium veins have a tunica media of loosely organized bundles of smooth muscle interrupted by regions of collagenous, reticular, and elastic tissue. Many medium veins exhibit infoldings of the tunica interna that meet in the middle of the lumen, forming VENOUS VALVES.
Diameter greater than 10 mm. They have some smooth muscles in all three tunics. The tunica media is relatively thin, with only a moderate amount of smooth muscle. Tunica externa is the thickest layer and contains longitudinal bundles of muscle. Large veins include the venae cavae, pulmonary veins, internal jugular veins, and renal veins.
Rises for about 5 cm above the left ventricle. Its only branches are the coronary arteries, which arise behind two cusps of the aortic valve. They are the origins of the coronary circulation.
Curves to the left like an interverted U superior to the heart. It gives off 3 major arteries (brachiocephalic trunk, left common carotid artery, and left subclavian artery.
passes downward posterior to the heart, at first to the left of the verterbral column and then anterior to it, through the thoracic and abdominal cavities. It is called the abdominal aorta below it. It ends in the lower abdominal cavity by forking into the right and left common iliac arteries.
Recieves all of the blood draining from the abdominal digestive tract, as well as from the pancreas, gall bladder and spleen. It is called a portal system because it connects capillaries of the intestines and other digestive organs to modified capillaries of the liver;thus; the blood passes through two capillary beds in series before it returns to the heart. Intestinal blood is richly laden with nutrients for a few hours following a meal. The HPS gives the liver first claim to these nutrients before the blood is distributed to the rest of the body. It also allows allows the blood to be cleansed of bacteria and toxins picked up from the intestines, an important function of the liver. Its principal veins:
Digestive venous return
Hepatic portal vein-A continuation beyond the convergence of the splenic and superior mesenteric veins. It travels about 8 cm upward and to the right, receives the cystic vein from the gallbladder, then enters the inferior surface of the liver. In the liver, it ultimately leads to the innumerable microscopic hepatic sinusoids
Lymph flows through a system of lymphatic vessels, similar to blood vessels. These begin with microscopic lymphatic capillaries, which penetrate nearly every tissue of the body but are absent from the CNS, CARTILAGE, CORNEA, BONE, AND BONE MARROW. Closed at 1 end.
Is the body’s largest lymphatic organ, measuring up to 12 cm long and weighing up to 160 g. It is located in the left hypochondriac region, just inferior to the diaphragm and posterolateral to the stomach. It is protected by ribs 10-12. Spleen fits snugly between the diaphragm, stomach, and kidney. Has indentations called gastric area and renal area. Medial Hilum penetrated by the splenic artery, splenic vein, and lymphatic vessels.
LIES DORSOLATERAL TO STOMACH, CONTAINS LYMPH NODULES
FILTERS BLOOD NOT LYMPH
STORES IRON (FE)
TRIGGERS B & T CELL IMMUNE RESPONSE
Composed of multiple tissues, meeting the criteria of an organ. Red & Yellow bone marrow.
Red bone marrow- soft loosely organized, highly vascular material. (involved in hempoiesis (blood formation) and immunity.)
Yellow- adipose (fat) tissue, can be disregarded for present purposes.
Patches of lymphatic tissue located at the entrance to the pharynx, where they guard against ingested and inhaled pathogens. Each is covered by an epithelium and has deep pits called tonsillar crypts.
3 main sets of tonsils: PHARYNGEAL TONSILS a single median on the wall of the pharynx just behind the nasal cavity. A pair of PALATINE TONSILS at the posterior margin of the oral cavity and numerous LINGUAL TONSILS, each with a single crypt, concentrated in a patch on each side of the root of the Tounge.
NK CELLS- (KILLER CELLS)- LARGE LYMPHOCYTES THAT ATTACK AND LYSE BACTERIA, TRANSPLANTED TISSUE CELLS, AND HOST CELLS. STAY ON LOOKOUT FOR ABNORMAL CELLS.
Fluid continually filters from the blood capillaries into the tissue spaces. The blood capillaries reabsorb about 85% of it. One would die of circulatory failure within hours if this water and protein were not returned to the blood stream.
a. Maintains blood volume
b. Maintains interstitial fluid composition
In the small intestine, special lymphatic vessels called lacteals absorb dietary lipids that cannot be absorbed by the intestinal blood capillaries.
Penetrate nearly every tissue of the body but are absent from the CNS, cartilage cornea, bone, and bone marrow. Closely associated with blood capillaries, but unlike them, they are closed at one end. Consists consists of a sac of thin endothelial cells that loosely overlap each other like the shingles of a roof. The cells are tethered to surrounding tissue by protein filaments that prevent the sac from collapsing.
* BLIND END VESSELS
Lymphocytes and macrophages congregate in dense masses called nodules, which come and go as pathogens invade the tissues and the immune system answers the challenge.
When a lymph node is fighting a pathogen, these nodules aquire light-staining germinal centers, where b cells multiply and differentiate into plasma cells.
Indentation called the hilum on one side. It is enclosed in a fibrous capsule with trabeculae that partially divide the interior of the mode into compartments.
consists of sinuses gorged with concentrated erythrocytes
Consists of lymphocytes and macrophages aggregated like sleeves along small branches of the splenic artery. In tissue sections, white pulp appears as an ovoid mass of lymphocytes with an arteriole passing through it. However, its 3 dimensional shape is not egg like but cylindrical.
when they encounter an enemy cell they attack it directly and destroy it with toxic chemicals. This is why immunity carried out by T cells is called cellular (cell-mediated) immunity.
helper T cells activate not only the B and Tc cells of adaptive immunity but also help to mediate the nonspecific inflammatory response. They secrete chemical that stimulates the B cell to divide still more.
Larger than B cells and have an abundance of rough endoplasmic reticulum. Develop mainly in the germinal centers of the nodules and lymph nodes
They are a connective tissue cells that secrete defensive proteins called antibodies
Instead of becoming plasma cells, some B cells become memory cells that live for months to years and respond very quickly if they ever encounter the same antigen again. This provides long lasting immunity to that pathogen
Natural killer cells included in nonspecific defense and defend equally against a broad range of pathogens
It warms, cleanses, and humidifies inhaled air; it detects odors in the airstream; and it serves as a resonating chamber that amplifies the voice.
Begins with a small dilated chamber called the vestibule just inside each nostril, bordered by the ala nasi.
Or throat, is a muscular funnel extending about 13 cm from the Choanae to the Larynx. 3 Regions: Nasopharynx, Oropharynx, Laryngopharynx
Or throat, is a muscular funnel extending about 13 cm from the Choanae to the larynx. It has 3 regions: NASOPHARYNX,OROPHARYNX, LARYNGOPHARYNX.
The NASOPHARYNX lies posterior to the Choanae and the soft palate. It receives auditory tubes from the middle ears and houses the pharyngeal tonsil. ONLY PASSES AIR AND IS LINED BY PSEDOSTRATIFIED COLUMNAR EPITHELIUM
The OROPHARYNZ- a space posterior to the root of the Tounge. It extends from the inferior tip of the soft palate to the superior tip of the epiglottis. Its anterior border is formed by the base of the Tounge and the fauces, the opening of the oral cavity into the pharynx.
The LARYNGOPHARYNX- begins at the tip of the epiglottis, passes downward posterior to the larynx, and ends where the esophagus begins at the level of cricoid cartilage.
O AND L PASS AIR, FOOD, DRINK AND ARE LINED BY STRATIFIED SQUAMOUS EPITHELIUM.
A tube about 12 cm long and 2.5 cm in diameter, lying anterior to the esophagus. It is supported by 16-20 C shaped rings of hyaline cartilage, some of which you can palpate between your larynx and sternum.
Trachea forks into left and right bronchi,
Each lung contains a branching system of air tubes called the bronchial tree, extending from the main bronchus to the terminal bronchioles.
Supported by C shaped hyaline cartilages, whereas the lobar and segmental bronchi are supported by overlapping crescent shaped cartilaginous plates, lined by a ciliated pseudostratified columnar epithelium, but the cells grew shorter and the epithelium thinner.
Conical organ with a broad, concave base resting on the diaphragm and a blunt peak called the apex projecting slightly above the clavicle. The broad costal surface is pressed against the rib cage, and the smaller concave mediastinal surface faces medially. Crowded by an adjacent viscera and therefore neither fill the entire rib cage, nor are they symmetric. Inferior to the lungs and diaphragm, much of the space within the rib cage is occupied by the liver, spleen, and stomach.
The mucus traps inhaled particles, and the upward beating of the cilia drives the debris-laden mucus toward the pharynx, where it is swallowed. This mechanism of debris removal is called mucocilairy escalator
Begins with a small dilated chamber called the vestibule just inside each nostril, bordered by the ala nasi. It is lined with stratified squamous epithelium. Has guard hairs, or vibrissae, that block insects and large airborn particles from the nose. Divided into right and left halves called nasal fossae by a wall of bone and hyaline cartilage, the nasal septum. The nasal cavity receives drainage from the paranasal sinuses.
Small area of the roof of the nasal fossa and adjacent parts of the septum and superior concha.
Odors are detected by sensory cells in olfactory epithelium
The largest, is named for its shield like shape. It broadly covers the anterior and lateral aspects of the larynx. The Adam’s apple is an anterior peak of the thyroid cartilage called the laryngeal prominence.
Inferior to the thyroid cartilage is a ring like cricoid cartilage. The thyroid and cricoid cartilages essentially constitute the box of the voice box
The superior opening guarded by a flap called the epiglottis. At rest, the epiglottis usually stands almost vertically. During swallowing, however, extrinsic muscles of the larynx pull the larynx upward toward the epiglottis, the Tounge pushes the epiglottis downward to meet it and the epiglottis closes the airway and directs food and drink into the esophagus behind it.
Protects airways during swallowing
Covered with stratified squamous epithelium, best suited to endure vibration and contact between the cords that occurs during speech. The intrinsic muscles control the vocal cords by pulling on the corniculate and arytenoid cartilages, causing the cartilages to pivot. Depending on their direction of rotation, the arytenoid cartilages abduct the vocal cords. Air forced between the adducted vocal cords vibrate them, producing a high pitched sound when the cords are relatively taut and a lower pitched sound when they are more relaxed. In adult males, the VC are longer and thicker, vibrate more slowly and produce lower-pitched sounds than in females.
Traps inhaled particles, and the upward beating of the cilia drives the debris-laden mucus toward the pharynx, where it is swallowed.
The open part of the C faces posteriorly and allows room for the esophagus to expand as swallowed food passes by. The gap is spanned by smooth muscle tissue called trachealis. Contraction or relaxation of this muscle narrows or widens the trachea to adjust airflow for conditions of rest or exercise.
Left lung only has a superior and inferior lobe & a single oblique fissure.
Left lung has an indention, where the heart presses against the medial surface; part of this is visible anteriorly as a crescent shaped CARDIAC NOTCH.
Esophageal groove-right lung
Cardiac Notch-left lung- margin of the lung
Aortic groove- left lung
Hilum-A slit called the Hilum through which the lung receives the main bronchus, blood vessels, lymphatic vessels, and nerves.
Are continuations of the airway that lack supportive cartilage and are 1 mm or less in diameter. The portion of the lung ventilated by one bronchioles is called a pulmonary lobule. Lack mucous glands and goblet cells. - smooth muscle layer
1- bronchoconstriction- narrowing
Final branches of the conducting division, there are about 65,000 of these in each lung. Gives off 2 or more smaller respiratory bronchioles
Have alveoli budding from their walls. They are the beginning of the respiratory division. Walls have scanty smooth muscle. Turns into 2-10 elongated thin walled passaged called alveolar ducts.
1) squamous alveolar cells (type I cells)
2) great alveolar cells (type II cells) – pulmonary surfactant
3) alveolar macrophages
1) squamous alveolar cells (type I cells)
Covers about 95% of the alveolar surface area. Their thinness allows for rapid gas diffusion between the alveolus and blood stream.
2) great alveolar cells (type II cells) – pulmonary surfactant
The other 5%. Although they cover less area, they outnumber the TYPE 1 CELLS. 2 functions- repair the alveolar epithelium when the squamous alveolar cells are damaged, and they secrete pulmonary surfactant (a mixture of phospholipids) and protein that coats the alveoli and smallest bronchioles and prevents them from collapsing when one exhales.
3) alveolar macrophages
Most numerous of all cells
Wander the lumens of the alveoli and the connective tissue between them. These cells keep the alveoli free of debris by phagocytizing dust particles that escape entrapment by mucus in the higher parts of the respiratory tract. In lungs that are infected or bleeding, the macrophages also phagocytize bacteria and loose blood cells.
Adheres to the mediastinum, inner surface of the rib cage, and superior surface of the diaphragm.
Pulmonary ligament-connects it to the diaphragm
Layer on the lung surface, it extends into the fissures between the lobes of the lung. At the hilum, the visceral pleura turns back on itself and forms the parietal pleura
Stiffen the thoracic cage during respiration and prevent it from caving inward when the diaphragm descends. Also contribute to enlargement and contraction of the thoracic cage.
Prime mover of pulmonary ventilation
The muscular dome that seperates the thoracic cavity from the abdominal cavity. It alone accounts for two thirds of the pulmonary airflow. When relaxed it bulges upward to its farthest extent, pressing against the base of the lungs. The lungs are then at its minimum volume. When it contracts, it tenses and flattens somewhat. This enlarges the thoracic cavity, expanding the lungs and sucking in air.
Other muscles of the chest and abdomen also aid in breathing, especially during forced respiration (taking deeper breaths than normal)
Elongated mass of neurons that extend for much of the length of the medulla near the central canal, posterior to the VRG. It is apparently an integrating center that receives input from pontine respiratory group (next); from central and peripheral chemoreceptors described shortly. Output to the VRG to modify the breathing rhythm.
Primary pacemaker of the respiratory rhythm. Elongated neural network in the medulla that issues output signals to an integrating center in the spinal cord. The left and right spinal centers output by way of the phrenic nerves to the diaphragm by way of intercostal nerves to the external intercostal muscles. Periodic output from the VRG creates the basic cycle of contraction and relaxation of these muscles causing inspiration and expiration.
Filter blood plasma; excrete toxic metabolic wastes, Regulate blood volume, pressure, and osmolality by regulating water output. Regulate electrolyte and acid base balance of the body fluids. Secrete the hormone ERYTHROPOIETIN, which stimulates the production of red blood cells and thus supports the oxygen carrying capacity of the blood. Contributes to calcium homeostasis (Vitamin D). Clears hormones and drugs from the blood. Detoxifies free radicals.
Passage of fluid from the blood stream into the nephron, carrying not only wastes but also chemicals useful to the body. The fluid filtered from the blood is called glomerular filtrate. In contrast to the blood, it is free of cells and very low in protein. After it passes into the renal tubule, its composition is quickly modified by the following processes (tubular fluid)
CREATES A PLASMALIKE FILATRATE OF THE BLOOD.
glucose, amino acids, Na+, H2O
Removes useful solutes from the filtrate, returns them to the blood
K+, toxins, drugs
Removes additional wastes from the blood, adds them to the filtrate. (to be eliminated in the urine)
Removes waste from the urine and returns it to the blood, concentrates wastes.
Consists of the glomerulus (2 layers)
The inner (visceral) layer consists of elaborate cells called podocytes wrapped around the capillaries.
The outer (parietal) layer is simple squamous epithelium.
The 2 layers are separated by a filtrate-collecting capsular space.
Layer of proteoglycan gel beneath the endothelial cells
For large molecules to pass through it is like trying to pass sand through a kitchen sponge. A few particles may penetrate its small spaces, but most are held back.
Shaped like an octopus, with a bulbous cell body and several thick arms. Each arm has an extension called foot processes.
Arises from the glomerular capsule. It is the longest and most coiled f the 4 regions and thus dominates histological sections of renal cortex.
Carries out both tubular reabsorption and secretion. It reabsorbs about 65% of the glomerular filtrate, and consumes about 6% of ones daily ATP expenditure in doing so.
1) cuboidal epithelium with microvilli
Microvilli- attests to the great deal of absorption that occurs here. It gives the epithelium a shaggy look in tissue sections.
A long U shaped portion of the renal tubule found mostly in the medulla. It begins where the PCT straightens out and dips toward or into the medulla forming the descending limb. As its deep end, the loop turns 180 degrees and forms the ascending limb, which returns back to the cortex, traveling parallel and close to the descending limb.
Function: maintain a gradient of osmolarity in the renal medulla.
DESCENDING VS ASCENDING
A device for monitoring the fluid entering the distal convoluted tubule and adjusting the performance of the nephron.
-juxtaglomerular cells - afferent arteriole
Enlarged smooth muscle cells in the afferent arteriole and to some extent in the efferent arteriole, directly across from the macula densa. When stimulated by the macula, they dilate or constrict the arterioles. JG cells also secrete renin, an enzyme that triggers corrective changes in blood pressure.
-macula densa - specialized DCT cells
Patch of slender, closely spaced epithelial cells at the end of the loop on the side facing the afferent arteriole. These cells apparently act as sensors that monitor the flow or composition of the tubular fluid and communicate with the cells described next.
Straight tubule that passes down into the medulla. It is part of the renal tubule but not part of the nephron; the nephron and collecting duct have separate embryonic origins.
Lined with simple cuboidal epithelium
Several collecting ducts converge to form a larger, short stretch called the papillary duct.
Arise from it at nearly right angles like the limbs of a pine tree. Each afferent arteriole supplies one nephron. It leads to a spheroidal mass of capillaries called GLOMERULUS
Mass of capillaries, enclosed in a nephron structure called the glomerular capsule. Is drained by an efferent arteriole
Usually leads to a plexus of peritubular capillaries
Form a network around the tubules of a nephron. These capillaries pick up the water and solutes reabsorbed by the tubules.
receive absorbed ions and nutrient molecules
secrete excess or waste
Renal medulla receives only 1-2% of the total renal blood flow, supplied by a network of vessels called the vasa recta. Efferent arterioles descend immediately into the medulla and give off the vasa recta instead of peritubular capillaries.
Arise from the abdominal aortic plexus. They control renal blood flow and the rate of urine production.
a. controls glomerular blood flow and blood pressure
b. stimulates renin release
a. mucosa – transitional epithelium
Lines the urinary tract beginning in the minor calyces of the kidneys and extending through the ureters, urinary bladder, and part of the urethra.
b. muscular layer – smooth muscle
2 layers of smooth muscle over most of the ureters length but a third layer appears in the lower ureter.
c. outer connective tissue layer
The adventitia is a connective tissue layer that binds the ureter to the surrounding tissues. It blends with the capsule of the kidney at the superior end and with the connective tissue of the bladder wall at the inferior end.
A muscle sac on the floor of the pelvic cavity, inferior to the peritoneum and posterior to the pubic symphysis. Covered by parietal peritoneum
temporary storage of urine
Unique surface umbrella cells protect it from the osmotic effect of hypertonic urine. The epithelium is better developed here than anywhere else in the urinary tract. 5-6 cells thick when the bladder is full.
2. Detrusor muscle – 3 layers of smooth muscle **
1. Begins at the urinary bladder and passes for about 2.5 cm through the prostate gland. During orgasm, it receives semen from the reproductive glands.
3. About 15 cm long, and passes through the penis to the external urethral orifice. It is named for the corpus spongiosum, an erectile tissue that surrounds it.
Male Urethra assumes an S shape
Compresses the urethra and retains urine in the blood. Since the sphincter is composed of smooth muscle, it is under involuntary control.
external urethral sphincter (skeletal muscle - voluntary)
1. Ingestion-Selective intake of food
2. digestion - mechanical and chemical- Mechanical and chemical breakdown of food into a form usable by the body.
3. absorption-The uptake of nutrients into the blood and lymph
4. compaction-Absorbing water and consolidating the indigestible residue into feces
5. defecation-Elimination of feces
1. epithelium, Lamina Propria (Loose connective tissue), Muscularis mucosae (Smooth muscle)
The epithelium is simple columnar in most of the digestive tract, but the mouth, pharynx, esophagus and anal canal differ. Muscularis mucosae tenses the mucosa, creating grooves and ridges that enhance its surface area and contact with food. This improves the efficiency of digestion and nutrient absorption.
1. connective tissue, blood vessels, glands
A thick layer of loose connective tissue containing blood vessels, lymphatic vessels, a nerve plexus, and in some places mucous glands. MALT also extends into the submucosa in some parts of the GI tract.
Consists of two layers of smooth muscle near the outer surface. Cells of the inner layer encircle the tract and those of the outer layer run longitudinally. In some places the circular layer is thickened to form valves that regulate the passage of material through the digestive tract. RESPONSIBLE FOR PRISTALSIS AND OTHER MOVEMENTS THAT MIX FOOD AND DIGESTIVE ENZYMES AND PROPEL MATERIAL THROUGH THE TRACT.
1. visceral peritoneum (serous membrane)
Composed of a thin layer of areolar tissue topped by a simple squamous mesothelium. Pharynx has no serosa
Parasympathetic- dominates the digestive tract and comes mainly from the vagus nerve, which supply all of the tract from esophagus to transverse colon. Relaxes sphincter muscles and stimulates gastrointestinal motility and secretion. Promotes digestion
Sympathetic- inhibits motility and secretion and keeps the GI sphincters contracted and closed. Inhibits digestion.
System of vessels connecting the lower digestive tract to the liver. It routes all blood from the stomach and intestines, as well as from some other abdominal viscera, through the liver before returning it to the general circulation
Connective tissue sheets that hold the abdominal viscera in their proper relationship to each other and prevent the small intestine, especially from becoming twisted and tangled by changes in body position and by its own contractions. Provide passage for the blood vessels and nerves that supply the digestive tract.
Hangs like an apron from the left inferior margin of the stomach, loosely covering the small intestine.
a. hard palate-Supported by the palatine processes of the maxillae and the smaller palatine bones. Transverse ridges that aid the Tounge in holding and manipulating food.
b. soft palate – uvula- More spongy texture and is composed mainly of skeletal muscle and glandular tissue, but no bone.
Uvula- conical medial projection visible at the real of the mouth. It helps retain food until you’re ready to swallow.
a. intrinsic - inside tongue
Contained entirely within the tongue, produce the relativity subtle Tounge movements of speech.
b. extrinsic (-glossus)
Produce most of the stronger movements of food manipulation.
Parotid- located just beneath the skin anterior to the earlobe. Its duct passes superficially over the masseter, pierces the buccinators, and opens in the mouth. MUMP
Submandibular- located halfway along the body of the mandible, medial to its margin, just deep to the mylohyoid muscle. Its duct empties into the mouth at a papilla on the side of the lingual frenulum.
Sublingual- located in the floor of the mouth. Multiple ducts that empty into the mouth posterior to the papilla of the submandibular duct.
1. Mucosa-Stratified squamous epithelium
2. Submucosa-Contains the esophageal glands, which secrete mucus.
3. Muscularis externa- composed of skeletal muscle
Lower esophageal sphincter- prevents stomach contents from regurgitating into the , thus protecting the esophageal mucosa from the erosive effect of the stomach acid.
1. Lesser / greater curvature
2. Cardia- small area within about 3 cm of the cardiac orifice
3. Fundus-domelike roof superior to the esophageal attachment
4. Body-makes up most of the stomach distal to the cardiac orifice.
5. Pyloric region-slightly narrower pouch at the distal end, it is subdivided into a funnel like antrum.
a. pyloric sphincter-regulates the passage of chyme into the duodenum
6. Rugae-when the stomach is full, the mucosa and submucosa are flat and smooth, but as it empties these layers fold into longitudinal wrinkles.
mucous cells-Secrete mucus, predominate in the cardiac and pyloric glands. In Gastric glands, they are called mucous neck cells and are concentrated in the neck of the gland.
parietal cells – HCL-Found mostly in the upper half of the gland, secretes hydrochloric acid, a digestive aid, and intrinsic factor, a glycoprotein needed for the absorption of dietary vitamin B, and an appetite regulating hormone named ghrelin. Found mostly in gastric glands, but a few occur in the pyloric glands.
chief cells – pepsinogen-Most numerous, secrete the fat digesting enzyme gastric lipase, as well as pepsinogen, the precursor of a protein digesting enzyme called pepsin. They dominate the lower half of the gastric glands but are absent from cardiac and pyloric glands.
G cells – gastrin-Secrete a hormone called gastrin, which stimulates the exocrine cells of the gastric gland to secrete acid and enzymes.
1. 2m long (in vivo, 6-7m)
2. Circular folds-Duodenum exhibits transverse to spiral ridges called circular folds. They cause the chyme to flow on a spiral path along the mucosa, slowing its progress, causing more contact with the mucosa and promoting thorough mixing, digestion, and nutrient absorption.
3. villi and microvilli
Villi-are Tounge to finger shaped projections that rise from the intestinal wall. They give the mucosa a fuzzy texture. The largest duodenum. Covered with enterocytes and goblet cells.
1. Duodenum-constitutes of the first 25 cm
a. bile duct and pancreatic duct
b. duodenal glands (Brunner’s, submucosal)- Secrete an abundance of alkaline mucus, which neutralizes stomach acid and shields the mucosa from its erosive effects.
2. Jejunum - superior left-first 40% of the small intestine beyond the duodenum. Most digestion and nutrient absorption occur here.
3. Ileum - inferior right
a. Peyer patches-prominent lymphatic nodules in clusters, which are readily visible to the naked eye and become progressively larger approaching the large intestine.
Lacteals-The core also contains an arteriole, a bed of blood capillaries, a venule, and a lymphatic capillary called a LACTEAL.
Capillaries-absorb most nutrients, but the lacteal absorb most dietary lipid.
1. Water reabsorption
2. Condenses chyme (500 ml à 150 ml per day)
3. Absorbs vitamins
4. Storage and elimination of fecal matter
a. ileocecal valve
b. vermiform appendix - lymph organ-blind tube 2-7 cm long. Densely populated with lymphocytes and is a significant source of immune cells.
4 regions of colon
1) Ascending-begins at the ileocecal valve and passes up the right side of the abdominal cavity. It makes a 90-degree turn at the right colic flexure near the lobe of the liver and becomes the TRANSVERSE COLON. This passes horizontally across the upper abdominal cavity and turns 90-degrees downward at the left colic flexure near the spleen. This is where it becomes the descending colon which passes down the left side of the abdominal cavity.
4) sigmoid-Pelvic cavity is narrower than the abdominal cavity, so the colon turns medially and downward forming a S shaped portion called the sigmoid colon.
1) internal anal sphincter - smooth muscle- under involuntary control and relaxes automatically when the rectum is distended with feces.
2) external anal sphincter - skeletal muscle- Under voluntary control and enables one to postpone defecation when appropriate.
1. No villi
2. Large intestinal glands (crypts) - goblet cells
3. Muscularis externa - taeniae coli
Concentrates the longitudinal fibers in the Muscularis externa. Ribbon like strips.
1. 4 lobes (Left, Right, quadrate, Caudate.)
2. Hilus - porta hepatis-Irregular opening between these lobes, a point of entry for the hepatic portal vein and hepatic arteries and a point of exit for bile passages.
3. Hepatic circulation
a. hepatic artery-enter the liver at the porta. These arteries deliver oxygen and other materials to the liver.
b. hepatic portal vein-receives blood from veins of the stomach, intestines, pancreas, and spleen and carries it into the live at the porta hepatis.
c. hepatic veins à vena cava-Blood from the central veins ultimately converges in the right & left hepatic veins, which exit at the superior surface of the liver and empty into the nearby inferior vena cava.
hepatic portal vein / hepatic artery à sinusoids à central vein à hepatic veins à vena cava
hepatocytes à bile canaliculi à bile ductules à bile ducts à common hepatic duct à bile duct (or cystic duct)
bile duct = common hepatic ducts (from liver) + cystic duct (from gall bladder)
1. hepatopancreatic sphincter (sphincter of Oddi)-regulates the release of bile and pancreatic juice from the ampulla into the duodenum.
1. Produces / secretes digestive enzymes
2. Produces / secretes metabolic hormones
The internal surface of a bone is lined with endosteum, a thin layer of reticular connective tissue with cells that deposit osseous tissue and others that dissolve it.
Gets it color from an abundance of red blood cells. It is best regarded as an organ. As an adult, RBM is limited to the skull, vertebral, sternum, rubs, part of the pelvic.
With age, the red bone marrow is replaced by yellow marrow, like the fat seen at the center of a ham bone. No longer produces blood, although in the event of severe or chronic anemia, it can transform back into red bone marrow.
The frontal bone extends from the forehead back to a prominent coronal suture.
Deep to the eyebrows it has a ridge called the supraorbital margin, the center of each margin is perforated by a single supraorbital foramen, which provides a passage for a nerve, artery and vein.
Also contains the frontal sinus
1) sagittal suture-Between parietal bones
2) coronal suture-At the anterior margin
3) superior and inferior temporal lines-form an arc across the parietal and frontal bones
1) Squamous suture-relatively flat and vertical. It is enclosed by the squamous suture.
3) Mandibular fossa-A depression where the mandible articulates with the cranium. (Fig. 7.5a)
4) External acoustic meatus-The ear canal
5) Styloid process-A pointed spine on its inferior surface. Provides attachment for muscles of the tongue, pharynx, and hyoid bone.
6) Mastoid process-prominent lump behind the earlobe. Filled with small air sinuses that communicate with the middle ear cavity.
1) Lambdoid suture-connects parietal bone with occipital bone
2) Foramen magnum-Most conspicuous feature of the occipital bone (rear skull). Where the spinal cord meets the brainstem. An important consideration in head injuries is swelling of the brain.
3) Occipital condyles-On each side of the foramen magnum is a smooth knob called the occipital condyle, where the skull rests on the vertebral column.
Is an anterior cranial bone located between the eyes. It contributes to the median wall of the orbit, the roof and walls of the nasal cavity, and the nasal septum.
Strongest bone of the skull and the only one that can move significantly. Supports the lower teeth, and supports facial expression.
Largest facial bones, they form the upper jaw and meet each other at the median intermaxillary suture.
Located in the posterior nasal cavity. Each one has an L shape formed by a horizontal plate and a perpendicular plate. The horizontal plates form the posterior one third of the bony palate.
Form part of the medial wall of each orbit. Smallest bone of the skull, about the size of a fingernail
Bridge of the nose and support cartilages that shape the lower portion of the nose. Only slightly larger than a fingernail.
Cranial bones are separated at birth by gaps called fontanels bridged by fibrous membranes.
Slender U shaped bone between the chin and larynx. Suspended from the Styloid process of the skull.
1. IMMOBILE OR ONLY SLIGHTLY MOBILE FIBROUS JOINTS THAT CLOSELY BIND THE BONES OF THE SKULL TO EACH OTHER.
Found only in between bones of the skull
Limited movement until about 20, when they become fixed.
Elevation refers to movement in a superior direction. For example, shrugging is an example of elevation of the scapula. 
Depression refers to movement in an inferior direction, the opposite of elevation.
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