LEC 3 Exam.txt

Digestion.

Mucosa

• • Ingest
  • Digest
  • Absorb
  • Eliminate
  Food is broken down physically and chemically (enzymatic hydrolysis) into smaller diffusible molecules (nutrients).

• • Carbohydrates
  • Fats
  • Amino Acids
  • Water
  • Minerals
  • Vitamins

Hard palate

• • It is the 3rd layer from the lumen and is called the Muscularis.
  • It is composed of an inner layer of circular muscle, and an outer layer of longitudinal muscle.

Stratified squamous for abrasion resistance in the esophagus, and simple columnar for absorption and secretion in the remainder.

Papillae

• • Circumvallate
  • Foliate
  • Filliform
  • Fungiform
  Only Filliform do not have taste buds.

Ankyloglossia is cause by too short lingual frenulum.

Intrinsic muscles have their origin and insertion in the tongue itself. Extrinsic muscles insert into the tongue, but have their origin in some other structure, for example the hyoid. Intrinsic muscles provide a high degree of maneuverability. Extrinsic muscles are important during deglutination (swallowing) and speech.

• • Parotids (enzymes only)
  • Submandibulars (enzymes & mucus)
  • Sublinguals (mucus only)
  ~1 liter per day.

32

Esophagus

First third: Striated, second third: mixed, last third: smooth only.

Cardiac

An enlargement of the esophageal hiatus that can allow parts of the lower esophageal sphincter and some of or all of the stomach up into the thoracic cavity.

Fundus – above the cardiac sphincter, body – main bulk part, and pylorus – in the vicinity of the pyloric sphincter to the duodenum.

Rugae

Chief, parietal and endocrine

A secretion of the parietal cells of the stomach (along with HCl), that binds to vitamin B₁₂, protecting it from the digestive environment of the stomach until it can be absorbed via the small intestine.

Certain drugs, some water, alcohol and some short-chain fatty acids found in butter or milk fat.

Duodenum (10 inches), followed by the jejunum (8 feet), then the ileum (12 feet).

Villi

Villi are modifications (projections) of the mucosal layer of the small intestine. Intestinal digestive enzymes are produced in the brush border cells toward the top of the villi. The presence of villi and microvilli increases the surface area of the small intestine.

Cecum, colon, and rectum

Ileocecal valve.

Mesentery

Ascending colon, transverse colon, descending colon, and sigmoid colon.

Pouch-like rings in the large intestine formed by the taeniae coli and circular muscles.

It is most often found just behind the cecum or over the pelvic rim. It is attached to the cecum of the large intestine near the ileocecal valve.

Liver

Common bile

• • Liver cells detoxify various substances.
  • Liver cells secrete about a pint of bile a day.
  • Liver cells carry on numerous important steps in the metabolism
  • of all three kinds of foods—proteins, fats, and carbohydrates.
  • Liver cells store several substances —iron, for example, and
  • vitamins A, B12, and D.
  • The liver produces important plasma proteins and serves as
  • a site of hematopoiesis (blood cell production) during fetal
  • development.

• • Bile salts
  • Bile pigments
  • Cholesterol

Store bile

Caused by an obstruction of bile flow to the duodenum. Since it is denied this exit route from the body through feces, an excess of bile pigments (with yellow hues) enters the blood and is deposited in tissues.

Pancreas

Digestive enzymes

Laryngeal

Peristalsis

Gastric inhibitory peptide

• • Hormonal via fats and other nutrients entering the duodenum, which causes the intestinal mucosa to secrete the hormone gastric inhibitory peptide (GIP) which decrease peristalsis in the stomach.
  • Nervous via receptors in the duodenal mucosa which sense both acid and stretch and via the vagus nerve also decrease peristalsis in the stomach.

Hydrolysis

Emulsified.

Amylase

Digestive enzymes catalyze the hydrolysis of food molecules. Note: where they work, extracellular, is not a “type” of reaction.

pH and temperature.

• • Protein – amino acid
  • Carbohydrate – glucose
  • Triglyceride - fatty acids and glycerol.

Water, mucus, amylase, lipase, and sodium bicarbonate.

• Gastric juice contains:
  • Water, mucus, pepsin (chief cells)
  • Acidic Mucus (mucosal neck cells)
  • Pepsinogen, i.e. enzymes of gastric juice (chief cells)
  • Hydrochloric acid & Intrinsic Factor (parietal cells)
  • Gastrin, and ghrelin (GHRL) – a hormone that stimulates the hypothalamus to secrete growth hormone and increase appetite (endocrine cells)

Trypsin, trypsinogen, enterokinase, chymotrypsin, nuclease, and amylase.

cholesterol, products of detoxification, and bile pigments

Digestive

Cephalic, Gastric and Intestinal

CCK and secretin

Inhibits gastric secretion and motility. Enhances insulin secretion.

Chylomicrons - another form of micelles that are formed by the Golgi apparatus after absorption.

Defecation

Hepatitis

Degeneration of the liver whereby damaged liver tissue is replaced by fibrous or fatty connective tissue.

Kidney

Renal artery

Bladder.

Ureters, urinary bladder, and urethra.

Process (maintain homeostasis of) blood and form urine as a waste to be excreted.

The renal cortex is the outer region of the kidney. The medulla is the inner region of the kidney.

1/5

External sphincter muscle of the bladder

Glomerulus

Juxtaglomerular apparatus

Filtration, reabsorption, and secretion

Fluid out of the capillary

Active and passive transport

Water, sodium and chloride

ADH

Water

Kidney stones

Cystitis

Edema

The ureter attaches to the bottom of the bladder and then runs at an angle for about 2 cm through the bladder wall and opens at the lateral angles of the trigone (floor) of the bladder. The ureter’s oblique angle through the bladder wall causes the ends of the tube to close and act as valves when the bladder is full, thus preventing backflow of urine.

Mucous transitional epithelium that forms folds called Rugae. Because of the folds and the extensibility of transitional epithelium, the bladder can distend considerably.

The bladder serves as a reservoir for urine before it leaves the body and, aided by the urethra, it expels urine from the body.

• 1. Renal corpuscle
  3. Bowman capsule
  5. Proximal convoluted tubule
  7. Loop of Henle
  9. Distal convoluted tubule
  11. Collecting duct

Filtration, tubular reabsorption, and tubular secretion.

Glomerular filtration rate is directly proportional to the effective filtration rate. When the GFR is low, filtration decreases.

A decrease in blood pressure tends to produce a decrease in both the glomerular pressure and the glomerular filtration rate.

Sodium ions (Na+) are pumped from tubule cell to interstitial fluid, increasing Na+ concentration to a level that drives diffusion of Na+ into blood. As Na+ is pumped out of the cell, more Na+ passively diffuses in from filtrate to maintain equilibrium of concentration. Enough Na+ moves out of the tubule and into blood that an electrical gradient is established (blood is positive relative to filtrate). Electrical attraction between oppositely charged particles drives diffusion of negative ions in filtrate, such as chloride (Cl–), into blood. As ion concentration in blood increases, osmosis of water from the tubule occurs. Thus active transport of sodium creates a situation that promotes passive transport of negative ions and water.

A type of active transport in which the proximal tubules absorb nutrients from the tubule fluid, notably glucose and amino acids, into peritubular blood.

The transport maximum of a substance is the maximal capacity for moving any substance limited by availability of carriers.

Many pores, or fenestrations, are present in the glomerular endothelium.

Peritubular blood supply; vasa recta, or “straight arteriole.”

• Intraperitoneal
  • Liver
  • Stomach
  • Transverse Colon
  • Small intestine
• Retroperitoneal
  • Pancreas
  • Duodenum
  • Rectum (Titi: colon)
  • Kidneys (urinary, not gastrointestinal)

• 1. Store bile that enters it by way of hepatic and cystic ducts.
  3. Concentrate held bile five- to ten-fold.
  5. Eject bile into duodenum when digestion occurs in the stomach and intestines.
• Bile salts and lecithin, components of bile, facilitate the emulsification of fats for digestion.

• Cholecystectomy

• Gall Stones or infection…

• CCK (cholecystokinin) and Secretin

• It, and lecithin (both phospholipids), mechanically break up large drops into smaller ones by forming micelles around smaller drops. These phospholipids are arranged so that their water-loving heads are outward, which also makes the smaller fat droplets water soluble.

• 1. Starch (polysaccharide or carbohydrate) digestion begins to some degree in the mouth where it is mixed with saliva containing amylase, which can hydrolyze them into disaccharides. But the time available to salivary amylase before it is destroyed by stomach acids and enzymes make this function relatively unimportant.
  3. Therefore, it is mostly pancreatic amylase that completes the hydrolysis to disaccharides in the intestine.
  5. There, “brush border” enzymes, sucrase, lactase, and maltase bond to the disaccharides and further hydrolyze them into monosaccharaides (mostly glucose)where they can be immediately absorbed, e.g. contact digestion.

• Proteins, large molecules of amino acids are
  1. Hydrolyzed into intermediate compounds called Peptides & Proteoses by an army of proteases:
     • Pepsin in gastric juice.
     • Trypsin & Chymotrypsin in pancreatic juice.
     • Peptidases from the intestinal brush border
  3. Finally, more unique proteases - depending on the type of peptide bond to be broken will further hydrolyze these intermediate compounds into amino acids.
  5. As with sodium and glucose, these are absorbed into the blood via sodium cotransport into the intestinal epithelium and then passively into the capillaries.

• • Starting with polysaccharides which contain many saccharide groups (C₆H₁₀O₅) we have:
    • Starches
    • Glycogen
    Disaccharides:
    • Sucrose
    • Lactose
    • Maltose
    Finally Monosaccharides:
    • Glucose
    • fructose
    • Galactose

• Sodium (Na⁺) cotransport.

• 1. Mucosa Mucus, enzymes & ectopic hormones
  3. Sub Mucosa Blood & Lymphatic vessels, with nerves in Connective tissue
  5. Thick layer of Muscularis consisting of 2 layers
     • Inner Circular, which becomes a sphincter in some locations, and serves both Peristalsis and Segmentation
     • Outer Longitudinal

• 1. Cephalic triggered by sight, smell, taste or thought. Vagal nerve impulses also stimulate endocrine G cells in gastric mucosa to secrete gastrin, which stimulates gastric secretion.
  3. Gastric stretch reflexes in stomach release 2/3 of the gastric juice. Products of protein digestion that have reached the pyloric portion of the stomach stimulate its mucosa to secrete gastrin where after circulating to the gastric glands greatly accelerates the secretion of gastric juice, high in pepsinogen and HCl.
  5. Intestinal has both a brief excitatory phase, and an inhibitory phase for gastric secretions. Chyme with fats, carbohydrates and acid in the duodenum inhibit gastric secretions via GIP, secretin, and CCK. Also, the enterogastric reflex, which reduces gastric peristalsis, may also inhibit gastric secretions.

Formed by gastric mucosa in presence of partially digested proteins, when stimulated by the vagus nerve, or when the stomach is stretched.

Stimulate secretion of gastric juice rich in pepsin and hydrochloric acid.

Formed by intestinal mucosa in presence of glucose, fats, and perhaps other nutrients.

Inhibits gastric secretion; stimulates secretion of pancreatic juice low in enzymes and high in alkalinity (bicarbonate); stimulates ejection of bile by the gallbladder.

Formed by intestinal mucosa in presence of glucose, fats, and perhaps other nutrients.

Inhibits gastric secretion and motility; enhances insulin secretion by pancreas.

Formed by intestinal mucosa in presence of fats, partially digested proteins, and acids.

Stimulates ejection of bile from gallbladder and secretion of pancreatic juice high in enzymes; opposes the action of gastrin, raising the pH of gastric juice.

• Titi:
  1. Cardius portion: mucus & HCl
  3. Pyloris
  5. Parietal HCl (needed to activate pepsinogen) and Intrinsic Factor, that binds with vitamin B₁₂ to protect it from digestive juices until it reaches the SI.
  7. Endocrine
  9. Mother & Stem Cells
  BOOK:
  1. Mucus – digestive enzymes and HCl
  3. Chief – enzymes of gastric juice
  5. Parietal – HCl & Intrinsic factor
  7. Endocrine – ghrelin (GHRL) a hormone that stimulates the hypothalamus to secret growth hormone and increase appetite, as well as gastrin.

• • Cardius – near heart and esophagus at the LES or Lower Esophageal Sphincter.
  • Fundus – dome shape to the left of esophageal opening
  • Body – middle with three layers of musculature: oblique, circular and longitudinal.
  • Pylorus – near the opening to the duodenum, lined with “Rugae” and aligned toward the pyloric sphincter.

• Heartburn is the backward flow of stomach acid up into the esophagus. Hiatal Hernia is a weakening of the LES (lower esophageal sphincter) such that part or even all of the stomach can protrude into the thoracic cavity. This condition also causes GERD. Causes are:
  • Smoking
  • Obesity
  • Spicy Food
  • Coffee

• • Duodenum, 25 cm (10”)
  • Jejunum, 2.5 m (8’) – primary site of absorption & digestion
  • Ileum, 3.5 m (12’) – absorbs vitamins & electrolytes

• 1. Cecum, 5-8 cm 0 blind pouch
  3. Ascending Colon
  5. Hepatic or Right Colic Flexure
  7. Transverse Colon
  9. Splenic or Left Colic Flexure
  11. Descending Colon
  13. Sigmoid Colon
  15. Rectum, 7-8”
  17. Anal Canal, 1”, with 2 sphincters

• • Left
  • Right
  • Caudate (posterior next to inferior vena cava)
  • Quadrate (anterior, next to gallbladder)

• • Hepatic Artery
  • Hepatic Portal vein
  • Bile Duct

• Blood flows FROM portal triad TO central vein.

• Bile flows from hepatocytes in the liver lobule through Bile Canaliculi to the Bile Ducts in the Portal Triad to:
  • Left & Right hepatic Ducts to
  • Common hepatic Duct where it meets bile from delivered from or to) the
  • Cystic Duct, then joins the
  • Common Bile Duct, which joins the Pancreatic Duct the form the
  • Hepatopancreatic Ampulla before emptying into the duodenum through the
  • Major Duodenal Papilla.

• These are Inorganic catalysts which speed up the digestion process.

• Digestive enzymes are secreted by Acinar cells in the form of zymogens or inactive enzymes and contain:
  1. Proteases for proteins
  3. Lipases (for fat digestion)
  5. Amylases (pancreatic for carbohydrates)
  Duct cells secrete a watery, bicarbonate-rich solution to neutralize the acidity of chime.

• Weakening or stretching of the LES (lower esophageal sphincter), which is intrinsic to the esophageal hiatus through the diaphragm. This can allow part or all of the stomach up into the thoracic cavity.

• Erosion of the stomach wall. Most ulcers are caused by an infection with spiral-shaped bacterium Helicobacter pylori, NOT excess stomach acid.

• Varicose veins of the anus.

• Excess water absorption leading to dry packed feces.

• Decreased water and electrolyte absorption in the SI resulting from increased motility.

• Inflammation of the covering of the organs of the abdominal cavity.

• Primary – regulation of
  • Blood Volume, i.e. BP
  • Chemical makeup of blood
  Secondary
  • Metabolism of Vitamin D
  • Production of Renin, which is released by JG (Juxtaglomerular cells) by detection of the increased reabsorption of Na⁺ & Cl^-, resulting from decreased arterial BP. Renin sets in motion the release of a vasoconstrictor to raise BP.
  • Production of EPO (erythropoietin) to stimulate RBC generation.
  • Gluconeogenesis from amino acids and possibly fatty acids. Though primarily a liver process, it does occur in the cortex of the kidneys.

• • Renal papilla of medullary pyramid.
  • Minor Calyces
  • Major Calyces
  • Renal Pelvis.
  • Ureter
  • Bladder
  • Urethra

• • 95% water
  • 5% solutes
    • Uric acid from nucleic acid breakdown.
    • Creatinine from skeletal muscles
    • Urea from protein catabolism
    • Ions: Na⁺, K⁺, Cl^-, Ca, Mg, and HCO₃^-

• 1. Abdominal aorta
  3. Renal arteries
  5. (5) Segmental arteries
  7. Lobar and then Interlobar arteries
  9. Arcuate arteries, which arch over the base of the renal pyramids
  11. Interlobar radiate arteries to Renal Cortex
  13. Afferent arterioles (larger lumen than efferent)
  15. Glomerulus
  17. Efferent arterioles
  19. Peritubular capillaries or vasa recta
  21. Interlobular veins, etc. (Note: there are no "lobar" or "segmental" veins)

• • Bowman Capsule plus the Glomerulus

• It is THE site of:
  • Filtration
  • Reabsorption
  • Secretion
• It is composed of:
  • The Renal Corpuscle (Bowman Capsule & Glomerulus)
  • PCT (Proximal Convoluted Tubule)
  • Loop of Henle
  • DCT (Distal Convoluted Tubule)
  • CD (Collecting Ducts)

• • Filtration
  • Reabsorption
  • Secretion

• • The primary driving force behind filtration is Hydrostatic pressure specifically of the Glomerulus. But the Glomerular osmotic Pressure and Capsular (Bowman) Hydrostatic Pressure have an impact on the Effective Filtration Pressure
  • The smaller lumen of the Efferent Arteriole (compare to the Afferent Arteriole boosts the pressure in the Glomerulus to about 80 mm Hg.

• • Major portion of water & electrolytes and (normally) all nutrients are reabsorbed in the PCT.
  • Na⁺ is reabsorbed via active transport (requires ATP). It has the following effects:
    1. Creates an electrical gradient, which passively pulls negative ions such as chloride (Cl^-) and phosphate (PO₄^-3)
    3. As the ions concentration increases in the Interstitial fluid and peritubular blood, an Osmotic gradient is also created, which creates an obligatory reabsorption of water.
    5. Along with the active transport of Na⁺, glucose and amino acids bind to the Na⁺ and are reabsorbed via sodium cotransport

• • The ability to move glucose back into the peritubular blood from the nephron is limited by the number of cotransport carriers; in this case sodium. This limit is the transport maximum.
  • It is the highest concentration of a substance before it cannot be reabsorbed due to limited protein carriers and it appears in the blood (should be urine).
  • Normal blood glucose is 70-110 mg/Dl. Tmax or saturation is 180 per Titi, but about 300 per book.

• Albumin, the most abundant plasma protein, never normally leaves blood plasma. But with Hypoalbuminemia – holes in damaged glomeruli, it is secreted in the urine and results in low oncotic pressure (protein osmosis gradient) resulting in widespread edema because of water leaving the blood stream.

• Is a general term referring to kidney disease; especially inflammatory conditions. More specifically is Pyelonephritis (pelvis nephritis), or inflammation of the renal pelvis.

• • Cannot eliminate UREA, a nitrogen–containing waste product from the catabolism of proteins. Diagnosed via high BUN (blood urea nitrogen) Renal failure can be acute or chronic.
  • See also AZA…EMIA - nitrogen on the blood.

• An inflammation of the urethra that is commonly the result of a bacterial infection, often gonorrhea. Nongonococcal infections are usually Chlamydia. Males suffer more often than females.

• • Titi: “Toxins of meat digestion”. Book indicates that it is essentially high UREA in the blood.
  • An indication of some failure of the kidneys.

• Ultrasonic waves via “Lithotriptor” to dissolve kidney stones.

• the most common form of kidney disease. It may be caused by a delayed immune response to a streptococcal infection – the same mechanism that causes damage to heart valves in rheumatic heart disease. For this reason, it is sometimes called postinfectious glomerulonephritis.

• Infection of the urinary bladder. (It is a “cyst” like the gallbladder.)

• Or Kidney Stones, these are crystallized mineral chunks that develop in the renal pelvis or calyces.

• Presence of proteins (especially albumin) in the urine. It abnormally leaves the blood through damage glomeruli and is not reabsorbed by the kidney tubules.

• ”Milky urine” from pus

• Reduced urine formation. Titi: less than 1 liter/day

• Glucose in the urine; a sign of diabetes mellitus.

• Involuntary voiding of urine. Usually from loss of nervous control (stroke or accident), e.g. neurogenic bladder.

• NO urine. From dehydration, renal failure or obstruction.

• Medical condition in which ketone bodies are present in the urine. It is seen in conditions in which the body produces excess ketones as an alternative source of energy. It is seen during starvation or more commonly in type I diabetes mellitus. Production of ketone bodies is a normal response to a shortage of glucose, meant to provide an alternate source of fuel from fatty acid.

• • Blood in urine – likely cause: cancer.
  • It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract (kidneys, ureters, urinary bladder, prostate, and urethra), ranging from trivial to lethal. If white blood cells are found in addition to red blood cells, then it is a signal of urinary tract infection.

• Unusually large amounts (or frequent) urination.

• Painful urination, usually indicative of an infection

• 1. The inner-most layer of the bladder is the mucosa, which is composed of transitional epithelial cells, which are extensible. In addition to this capability, the mucosa is formed into Rugae, or folds, that give it further ability to stretch. There is a submucosal layer as well.
  3. The 2nd layer is a thick Muscularis of smooth muscle with bundles running in all directions. It is often called detrusor muscle.
  5. The 3rd layer is an adventitia of connective tissue.
  7. the outermost layer is the serosa, a retroperitoneum, lying under the parietal peritoneum.

• • a.k.a. urination or voiding the bladder. 200 ml triggers stretch receptors, which signal the micturation center of the PONS, an ANS controlled parasympathetic outflow to the bladder to relax the internal (smooth) urinary bladder sphincter and contraction of the detrusor muscle.
  • Our (somatic) control of the external (skeletal) sphincter is the check on this autonomic response.