Download UCCS Physiology Exam #4: Kidney Function and Regulation and more Exams Physiology in PDF only on Docsity!
UCCS Physiology Exam #4 Questions
And Correct Answers
General Functions of the Kidneys. - Answer Regulation of Extracellular Volume and Blood Pressure Regulation of Osmolarity Maintenance of Ion Balance Homeostatic regulation of pH Excretion of wastes Production of Hormones. Basic Kidney Anatomy - Answer Paired Kidneys - filtered plasma into urine Paired Ureters - Kidneys to Bladder Urinary Bladder - Store urine before micturition Excretion Males - Penis Females - Posterior clitorus, anterior vagina. Describe where the kidneys are located in the body, as well as their functional layers. - Answer Retroperitoneum Nephron is the function unit of the kidney. Outer Cortex is 80% nephrons (cortical nephrons) Inner Medulla contains 20% of the nephrons (juxtamedullary nephrons) What is the vascular pathway to the kidneys? - Answer Afferent arteriole, Glomerulus, Efferent arteriole, peritubular capillaries, vasa recta What are the tubular elements in regards to kidney anatomy? - Answer Bowmans Capsule - primary plasma filtration happens here (The pairing of this and the glamourous is the renal corpuscle. Cortex Proximal Tubule Ascending/Descending Loop of Henle medulla
Distal Tubule Collecting Ducts - converge and drain into the renal pelvis (medulla) Distal Nephron - distal tubule and collecting ducts Juxtaglomerular Apparatus - passes between afferent and efferent arterioles to allow paracrine communication Basic overview of kidney function. - Answer Filter Fluid from blood into lumen of nephron Occurs at the renal corpuscle Filtered plasma called filtrate - excreted unless needed to be reabsorbed Reabsorption Fluid that has been filtered gets returned to the blood via peritubular capillaries Secretion Material from blood into lumen of nephron Occurs with peritubular capillaries How do the nephrons modify osmolarity and fluid volume? - Answer Filtrate is almost identical plasma at the renal corpuscle 180 L/day, 300 mOsm About 70% of filtrate is reabsorbed by the proximal tubules Solutes and water 54 L/day remains, 300 mOsm Filtrate in the loop of Henle More solute is reabsorbed than water, diluted 18 L/day remains, 100 mOsm Distal tubule and collecting duct Some reabsorption and secretion 1.5 L/day remains, 100 - 1200 mOsm depending on hydration state
Surface area in glomerular capillaries Permeability inside slits GFR is controlled primarily by regulating blood flow through the renal arterioles. Resistance Afferent = Opposite (higher resistance = Lower GFR and vise versa) Efferent = Same (Higher resistance = Higher GFR) 80-180 MAP, and this stays constant Describe the autoregulation mechanisms associated with GFR. - Answer Myogenic response Intrinsic ability of vascular smooth muscle to respond to pressure changes Similar to autoregulation in other systemic arterioles Tubuloglomerular feedback Paracrine feedback macula densa detects NaCl in filtrate Granular Cells secrete the enzyme RENIN Hormones: Alter filtration coefficient Resistance in arterioles as well Describe Reabsorption in the kidneys. - Answer Transepithelial Through Membranes Paracellular - Transportation via Gap Junction Active Transport of Na+ Creates electrical gradient Anions in Na+ create osmotic Gradient H20 leaves behind higher concentration of cations EXCHANGERS - NHE and pumps (Na+, K+, ATPase
What are some examples of active and passive transport in the kidneys? - Answer Secondary Active: Symport with Na+ glucose, amino acids, and organic molecules Passive: Urea
Endocytosis happens with plasma proteins: Receptor-mediated endocytosis Digested by lysosomes Amino acids returned to circulation
Describe Saturation in Renal Transport - Answer Renal Threshold - the plasma concentration at which a substance first shows up in urine. (ex. glucose) Glucose Urea peritubular capillary pressures favor reabsorption
Describe Secretion and the chemicals involved - Answer Active movement from extracellular fluid to nephron
K+ and H+
Increasing secretions increases nephron excretion
Describe Renal Handling. - Answer What percent of the filtered load is excreted?
Low K+ 2% Normal K+ 10%-20% High K+ 150%
Clearance can help measure GFR
IV
Ingestion Normal Metabolism
Loss Urine Feces Breathing and Sweating Diarrhea, Vomiting, excessive sweating
Kidneys conserve water (cannot restore)
Describe how osmolarity changes as fluid flows through the nephron. - Answer Descending Limb: Concentrates Fluid (Higher Osmolarity) Ascending: Removal of solute (Ions) (Osmolarity Drops) Collecting Duct: Membrane Permeability depends on presence of hormones
Describe how the renal medulla concentrates Urine. - Answer Low Osmolarity is High Water High Osmolarity is Low Water Diuresis is removal of water
Fluid in descending loop of Henle loses water by osmosis to the medulla
Cells in thick
portion of the ascending limb of the loop are impermeable to water and actively transport Na+ out of the lumen into the medulla Fluid leaving loop of Henle is more dilute (100 mOsm) than fluid entering (300 mOsm)
Distal nephron: water permeability is under control of hormones Permeable to water, filtrate becomes concentrated
Collecting duct - can reabsorb additional solute, filtrate can become even more dilute
What effect does Vasopressin (ADH) have on reabsorption? - Answer Acts on collecting duct Graded effect: Matches bodies need Stimulates aquaporin to reabsorb water
Blood Volume and Osmoreceptors will activate ADH secretion
ALSO ADH has a circadian rhythm so you don't pee when you sleep.
Describe how vasopressin acts on the collecting duct. - Answer Binds to membrane receptor
Angiotensin Converting Enzyme (ACE) converts angiotensin I to angiotensin II
Stimuli: Granular cells are sensitive to Blood pressure Sympathetic stimulation for cardiac center. Paracrine feedback from macula densa cells.
What is the function of aldosterone in the RAS pathway? - Answer controls sodium balance made in adrenal cortex
reabsorption of Na+ and secretion of K+
Targets P cells and holds EnAC and ROMK channels open longer which increases Na+ K+ and ATPase activity in collecting duct
Low BP = Aldosterone and more angiotensin II
ACTIVE WITH HYPERKALEMIA (TOO MUCH K+)
Describe how Aldosterone acts on P cells. - Answer Combines with cytoplasmic receptor Transcription in receptor nucleus Translation and Synthesis make new protein channel Aldosterone modulates further pumps Increased Na+ and more Secreted K+
What are the effects of ANG II? - Answer Increases BP in several different ways.
Increase vasopressin stimulate thirsts potent vasoconstrictor receptors in heart emit sympathetic response enhance proximal tubule Na+ absorption
Drugs: ACE inhibitor, ARBs, and renin inhibitors
BP has a DIRECT effect on granular cells for renin secretion
Describe the function of Natriuretic Peptides - Answer Natriuresis: Na+ excretion Originates from cardiac stretch (Hypothalamus adh, kidney gfr, adrenal aldosterone, less sympathetics)
Atrial Natriuretic Peptide (ANP) produced in atrial myocardial cells
Brain Natriuretic cells - ventricular myocardial cells
Decrease blood volume by dilating arterioles, increasing GFR, decrease NA+ reabsorption, and suppressing RAS
What are some pathologies associated with a K+ imbalance. - Answer Hypokalemia - Heart and Respiratory weakness
Hyperkalemia - arrhythmias in T wave
Other disturbances arise from kidney disease, diarrhea, diuretics.
Kidneys reabsorb bicarb to act as an extracellular buffer.
What happens with acidosis and alkalosis? - Answer acidosis: H+ secreted and HCO3 an K+ are reabsorbed (Type A intercalated discs)
alkalosis: vise versa (Type B intercalated discs)
Describe the difference between metabolic and respiratory disturbances. (acidosis and alkalosis) - Answer Respiratory: acidosis: hypoventilation - increase pco2 ph decreases alkalosis: hyperventilation - pco2 drops - ph increases
Metabolic: acidosis: too much H+, pH drops alkalosis: loss of H+ through vomit, or too many antacids
Describe the different sections of the digestive system: - Answer Mouth: Oral Cavity Chewing Salivary Glands Stomach - Fundus Body Antrum Small Intestine - Duodenum, Jejunum, Ileum Large Intestine Ascending, Transverse, Descending Anus
What are the layers of the walls of the GI tract? - Answer Rugae Villa and Plicae Gastric Glands, Crypts, and submucosal glands.
Mucosa (Lamina Propria and Peyers patches)
Submucosa is connective tissue
Muscularis externa
Serosa
Digestion Function and process - Answer Digestion Absorption Secretion Motility
Challenges Autodigestion Mass Balance Defense
We secrete more than we take in!
What are the different kinds of GI tract contractions? - Answer Tonic - minutes Phasic - seconds
Move food, and make it into uniform particles
Migrating motor complex
Parietal Cells secrete HCL
Chief Cells Secrete Pepsinogen (Pepsin) and gastric lipase
paracrine Enterochromaffin cells secrete Histamine Parietal cells secrete intrinsic factor D cells secrete somatostatin
How does the stomach prevent autodigestion? Explain all the items secreted in the stomach - Answer Mucosal Bi Carb Layer Mucus cells secrete mucus and bi carb
Mucus Surface cell - Mucus - Physical Barrier
Mucus Neck cell - Bi Carb - Buffers gastric acid to prevent ulcers
Parietal Cells - HCl and Intrinsic factor - activates pepsin kills bacteria. also digest B
ECF - Histamine - more gastric secretion
Chief Cells - Pepsin(ogen) Gastric Lipase - Proteins and Fats
D cells - SS
G cells - Gastrin
Describe the integration of the cephalic and gastric phase. - Answer Food or Cephalic phase stimulates gastrin production
Gastrin Stimulates acid secretion through parietal cells or through histamine indirectly
Acid Secretes pepsinogen
SS is an inhibitory module that stops acid and pepsin release
Describe the anatomy of the small intestine. - Answer Segmental and peristaltic contractions
Ensure that small intestine is not overwhelmed by chyme
Need to complete digestive process and allow for absorption
Villi, Crypts, brush border
absorbed nutrients go to intestinal ET
Circulatory system or portal system
Fats use lymphatic system to enter the circulatory system
What are some intestinal secretions that promote digestion? - Answer Digestive Enzymes
pancreatic lipase break fats down into monoglycerides and fatty acids stored in micelles
monoglycerides and fatty acids move out via diffusion
cholesterol is transported to cells
absorbed fats combine with protein and cholesterol in small intestine to form chylomicrons
chylomicrons are removed by lymphatic systems
Explain digestion and absorption of a carbohydrate. - Answer only absorbed as monosaccharides. pancreatic enzymes and brush border enzymes
polymers and disaccharides get broken down into monosaccharides. (glucose, galactose, fructose)
SGLT, GLUT2, GLUT
Amylase begins in mouth
disaccharides
Maltose - Maltase - 2 glucose
Sucrose - Sucrase - fructose and glucose
Lactose - Lactase - glucose and galactose
Describe how a protein is digested. - Answer Two groups of enzymes: Endopeptidases (proteases) Zymogens: pepsin (stomach) and trypsin, chymotrypsin (pancreas)
Exopeptidases Aminopeptidases and carboxypeptidases
Peptide Absorption: amino acids Some larger peptides can be digested fully intact
Absorbed 3 ways Di and Tri with PepT1 and H+ Amino Acids with cotransport of H+ small peptides are carried around the cell intact by transcytosis.
Describe what is absorbed in the small intestine. - Answer Nucleic acids are digested into bases and monosaccharides
Intestine absorbs vitamins and minerals
Fat-soluble vitamins are absorbed with fats
Water-soluble vitamins are absorbed by mediated transport Vitamin B 12 absorbed in the ilieum when
