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A & P 2150 Final
The last of the information for the final exam.
| Question | Answer |
|---|---|
| kidneys are (___) organs | homeostatic |
| filters and maintain body fluids | kidneys |
| the kidneys filter how many liters of fluid/day? | ~200 |
| retain important molecules removes toxins, waste, excess ions regulates fluid volume, pH, salts have endocrine function | kidneys |
| what does the kidneys produce? | renin (regulates b.p.) - erythropoietin (stimulates R.B.C. production |
| metabolizes vitamin D to active form | kidneys |
| What shape and size is the kidneys? | bean-shaped-size=bar of soap |
| The kidneys are (____), which means they are a free floating organ, but they get (____). | -retroperitoneal -some protection from the rib cage |
| What is the renal hilus? | vertical cleft on medial surface of kidney. Entry site for: blood vessels, lymphatics, nerves. |
| What is a strong barrier on the kidneys surface? | renal capsule |
| a fatty mass that cusions the kidneys | adipose capsule |
| dense fibrous connective tissue - anchors kidneys | renal fascia |
| outer granular tissue of the kidneys | renal cortex |
| reddish-brown, cone shaped masses or medullary (renal pyramids) appear striped due to parallel bundles of tubules | Renal medulla |
| cortical tissue between pyramids positive pyramid = lobe | renal columns |
| funnel-shaped tube continuous w/ ureter at hilus | renal pelvis |
| branches into major clyces - divide into minor calyces - enclose papillae/apex of pyramid | renal pelvis |
| collect urine-pelvis-ureter-bladder | calyces |
| urine propelled by peristalsis of (____). | calyces, pelvis, and ureter. |
| deliver 25% of total cardiac output/min | Renal Arteries |
| What does the renal arteries divide into? | -5 segmental artieries (enter at hilus) -Divide into lobar arteries -Divide into interlobar arteries (between pyramids) -Divide into arcuate arteries -Divide into cortical radiate arteries -Fan out in cortical tissue |
| (____) trace path of arterial supply in reverse but no lobar or segmental veins. | Veins |
| Kidneys have a nerve network or renal plexus controlled by? | sympathetic fibers |
| 1 million per kidney | nephrons |
| what is the nephrons function? | to form urine |
| several nephrons connect up to? | 1 collecting duct. |
| What does a nephron consist of? | -a glomerulus -a renal tubule - end is cup-shaped called glomerular (bowman's) capsule - completely surround glomerulus -glomerulus and glomerular capsule=renal corpuscle |
| Endothelium of glomerulus is? | fenestrated - leaky |
| Because the endothelium of the golmerulus is leaky, what does this allow? | -allows large volumes of fluid to filter from blood into glomerular capsule -this filtrate is unprocessed urine -gets processed in kidney tubules to urine |
| In the edothelium of glomerular capsule the (____) is simple squamous epithelium. | outer parietal layer |
| In the endothelium of glomerular capsule the (____) has unique epithelia cells-octopus like-podocytes | inner visceral layer |
| -legs of octopus have extensions (pedicles) -interdigitate with pedicles of adjacent podocytes -between pedicles are filtration slits or slit pores | the inner visceral layer of the endothelium of glomerular capsule |
| -Cuboidal epithelial cells -Actively reabsorb solutes -secrete molecules -have dense microvilli | PCT |
| -simple squamous epithelia -freely permeable to water | Loop of Henle (thin segment) |
| -Cuboidal -No microvilli -Secrete solutes into filtrate -little solute reabsorption | Loop of Henle (thick segment) and DCT |
| -85% of nephrons in the kidney | Cortical neprhons |
| -located in cortex-except for tip of loop of Henle | Cortical nephrons |
| -located close to medulla -loop of Henle goes deep into medulla -very long thin segments -role is to concentrate urine | juxtamedullary nephrons |
| -arise from interlobar arteries -feed the glomerulus --has high b.p. --easily forces fluid and solutes out of glomerulus | afferent arterioles |
| drain glomerulus | efferent arterioles |
| -arise from efferent arterioles draining glomeruli -cling to renal tubules -adapted for absorption -low pressure -porous -readily absorb solutes and water | Peritubular capillaries |
| have an important role in forming concentrated urine | efferent nephrons from juxtamedullary nephrons that form a vasa recta |
| glomerulus produces a filtrate, what reclaims most of that filtrate? | peritubular capillaries and vasa recta |
| a portion of the DCT is nestled between the afferent and efferent arterioles of glomerulus. | juxtaglomerular apparatus |
| in walls of arterioles are (____) | juxtaglomerular cells |
| what are the juxtaglomerular cells and what do they do? | -large smooth muscle cells containing renin -sense blood pressure in afferent arterioles |
| (____) acts to increase blood pressure. | renin |
| Renin converts angiotensin into (1), then (2) converts angiotensin I into (3). It acts to (4) which (5) or as a (6) which (7). | 1. Angiotensin I 2. ACE 3. Angiotensin II 4. Stimulate the adrenal cortex to release aldosterone 5. stimulates renal tubule to reclaim more Na from filtrate 6. Vasoconstrictor 7. constricts efferent arteriole |
| When angiotensin II acts as a vasoconstictor and constricts the efferent arteriole what happens? | dec blood flow out of the glom. which increases glom. hydrostatic pressure, whic increases GFR. |
| -columnar cells in distal tubule next to JG cells -Are chemoreptors and sense filtrate flow -Act to regulate rate of filtration in kidneys | Macula Densa |
| chemoreceptors that respond to changes in the NaCl content of the filtrate | Macula Densa |
| What is unprocessed filtrate? | like plasma but no proteins |
| As unprocessed filtrate flows thru the tubules? | most water, nutrients, and ions are reclaimed. Also all glucose. Urine is waste and XS substances. |
| What does the urine formation process include and how is it regulated? | 1. glomerular filtration 2. tubular reabsorption 3. tubular secretion Regulated by renal and hormonal controls |
| Characteristics of glomerular filtration | a. passive b. non-selective c. due to hydrostatic pressure which is high ~55 mm Hg |
| The rate of glomerular filtration is dependent of (____). | forces that increase filtration verses forces that decrease it. |
| Forces that increase glomerular filtration | glomerular hydrostatic pressure |
| forces that decrease glomerular filtration | -osmotic pressure of blood -hydrostatic pressure in glom capsule |
| The net effect of the forces of glomerular filtration determines that the overall filtration pressure is? | 55mmHg - (30mmHg and 15mmHg) = 10mmHg |
| A net filtration pressure of (1) produces a glomerular filtration rate of (2). | 1. 10mmHg 2. ~180L/day |
| What stops glomerular filtration? | A 15% drop in glomerular pressure |
| regulates diameter of afferent arterioles | renal autoregulation |
| smooth muscle contracts when stretched | Myogenic regulation |
| During myogenic regulation, if b.p. increases and vessels stretch, then what happens? | vasoconstriction-decrease flow-maintain GFR. |
| During myogenic regulation, if b.p. decreases which causes decreased blood flow, then what happens? | vasodilation-increases flow-maintain GFR. |
| Macula densa cells detect filtrate flow and osmotic levels | Tubuloglomerular feedback |
| Due to the tubuloglomerular feedback mechanism, if a large volume of filtrate is produced or high osmolarity is reached, what happens? | this causes the M.D. cells to release a vasoconstrictor chemical that causes intense constriction of the afferent arteriole. This constriction hinders blood flow into the glomer., which decreases the NFP and GFR, allowing more time for filt. processing. |
| Due to the tubuloglomerular feedback mechanism, if a low volume of filtrate is produced or low osmolarity is reached, what happens? | ATP release is inhibited causing vasodilation of the afferent arterioles. This allows more blood to flow into the glomerulus, thus increasing the NFP and GFR. |
| -vasoconstriction restores GFR -Aldosterone lowers osmolarity | Renin-angiotensin mechanism |
| regulates renal flow only during extreme stress e.g. shock | Sympathetic nervous system |
| -vasoconstriction -shunts blood to vital organs -reduces fluid loss -helps maitain b.p | Sympathetic nerves |
| Tubular reabsorption occurs in the? | PCT |
| -mostly transcellular -sodium most abundant ion in filtrate -actively transported from tubule cell by sodium/potassium ATPase pump --produces electrochemical gradient that pulls sodium into cell from filtrate. | Tubular reabsorption-PCT |
| Inside of the tubule cell is left with a? | small negative charge |
| (____) follows salt | water |
| Because water follows salt, it is reabsorbed by (1), and it is called (2). | 1. diffusion (osmosis) 2. obligatory water reabsorption |
| What types of molecules does the gradient caused by the sodium/potassium pump draw across tubule cells? | glucose, amino acids, lactate, vitamins |
| How does the sodium/potassium pump draw some molecules across tubule cells? | The carrier that transports sodium across luminal membrane is a symport, hence it will also transport another molecule in the same direction. |
| In the loop of Henle, water is (1). Water can leave the (2). Solutes (NaCl) can leave the (3) via (4). | 1. reabsorbed by osmosis 2. descending limb only. 3. ascending limb only. 4. a sodium/potassium/2chloride symporter |
| What is the job of the vasa recta? | to maintain salt concentration in the kidney |
| Na/Cl symporters reabsorb Na and Cl in the? What is also reabsorbed? | DCT and collecting ducts Water |
| In the DCT most reabsorption is regulated by? Water is controlled by? Na reabsorption controlled by? When? | hormones ADH released from posterior pituitary when blood is too concentrated. aldosterone from adrenal cortex when low blood volume, low blood pressure, or low Na in cell fluids. |
| Some substances move from blood of peritubular capillaries-tubule cells-into filtrate. | Tubular secretion |
| Most secretion occurs in the? | PCT |
| Examples of substances of tubular secretion? | H, K (controlled by aldosterone), creatine, ammonium ions, penicellin, Phenobarbital. |
| Secretion is important for? | excreting xs K ions, controlling blood pH. |
| How much of filtrate is reabsorbed by PCT? | 65% |
| The concentration of body fluids is measured in? | milliosmols (mOsm) |
| What is a milliosmol? | number of millimoles of a substance dissolved in 1 liter water. |
| Kidneys must keep solute concentration of body fluids around? | 300 mOsm |
| Kidneys regulate urine concentration via the? | countercurrent mechanism |
| what are the basics of the countercurrent mechanism of the kidney? | -filtrate flowas in one direction through long loop of henle -blood flows in opposite direction through vasa recta -this countercurrent establishes and maintains an osmotic gradient. |
| What causes water to leave the descending limb of the loop of henle? | -high osmolarity of interstitial fluid --from NaCl exiting ascending limb --from urea exiting lower collecting duct |
| In the presence of (____) more NaCl is reabsorbed from DCT and collecting ducts. | aldosterone |
| Due to the countercurrent mechanism, what is the molality of the filtrate at the base of the loop of Henle? | 1200 mOsm |
| the vasa recta is different from a normal capillary bed running thru an organ because? | a normal capillary bed would remove an osmotic gradient, but the vasa recta helps to maintain osmotic gradient. |
| The desceding limb of vasa recta? | loses water and gains salt so blood becomes more salty or more concentrated. |
| The ascending limb of the vasa recta? | gains water and loses salt so blood becomes less salty or less concentrated. |
| Approximately how much intracellular fluids do we have? | 25-30L |
| Approximately how much extracellular fluids do we have? | 15-20L |
| Approximately how much total body fluids do we have? | 50L |
| examples of extracellular fluids | 1. plasma 2. Interstitial fluid (IF)-i.e. fluid between cells -Includes: lymph, CSF, eye fluids, synovial, serous, hormone secretion, and GI secretion |
| Body fluids are either (1) or (2). | electrolytes or nonelectrolytes |
| -no electrical charge -mostly organic molecules-e.g. glucose, lipids, creatine, urea -covalently bonded-do not dissociate in solution | Nonelectrolytes |
| -electrically charged -include inorganic acids, bases, and some proteins | electrolytes |
| electrolyte concenctrations are expressed in? | milliequivalents/liter=the number of electrical charges in 1 liter of solution. |
| how many milliequivalents/liter is Na if the concentration is 3300mg/L? | 143 mEq/L |
| in extracellular fluids, the major cation is (1) and the major anion is (2)? | 1. Na 2. Cl |
| How much is our water intake per day? -What percent from water/liquids? -What percent from food? -What percent from cellular metabolism? | ~2.5L per day -60% -30% -10% |
| How and what percent is our water output? | -evaporation from lungs and skin 28% -perpiration 8% -feces 4% -urine 60% |
| (____) in hypothalamus trigger thirst. | osmoreceptors |
| How is our water balance regulated? 1-4 | -osmoreceptors in hypothalamus trigger thirst -kidneys increase or decrease fluid loss -body temperature regulates perspiration -diet provides very small changes in water loss via feces except during GI infection-diarrhea-vomiting |
| refers to salts in body fluids - e.g. NaCl, CaHPO4 | electrolyte balance |
| essential for: -neuromuscular excitability -secreation -membrane permeability -controlling fluid movement | electrolyte balance |
| How do salts enter and exit the body? | enter the body in fluid and food; exit the body in perspiration, feces, and urine. |
| What is the role of sodium? | -sodium salts are 90-95% of all solutes in ECF i.e. NaHCO3, NaCl -contribute 280 mOsm of total 300 mOsm in ECF. -normal plasma concentration is 142-143 mEq/L -sodium is primary controller of ECF volume (water follows salt) |
| Regulation of Na levels: -PCT reabsorbs (1) -Loop of Henle reclaims (2) -DCT and collecting ducts (3) -Na lost in xs perspiration | 1. 65% of Na in renal filtrate 2. 25% 3. reclaim remaining 10% only if Aldosterone is present. |
| What is the role of Atrial natriuretic peptide in regulation of Na levels? | -promotes Na excretion -inhibits Na reabsorption in collecting ducts -Inhibits release of ADH, renin, and aldosterone |
| Main intracellular cation | potassium (K) |
| What cation can be extremely toxic | K+ = Kevorkian |
| How much K is reabsorbed by nephron? | 85% |
| how much K is lost in urine regardless of need? | 15% |
| (1) increases K secretion in (2) | 1. aldosterone 2. cortical collecting ducts-i.e. as Na reabsorbed, K is excreted |
| 99% of body's Ca is in what form? | is in bones in salt form - CaPO4 |
| Why is calcium needed? | -blood clotting -cell membrane permeability -muscular contractions -neurosecretion |
| how is Ca regulated? | by parathyroid hormone (PTH) and calcitonin |
| -activated osteoclasts to breakdown bone and release Ca2+ into blood -increases intestinal absorption of Ca -increases reabsorption in renal tubules | PTH |
| -released by thyroid gland when blood Ca increases -Encourages bone deposition of Ca | Cacitonin |
| bone formin, decreases blood Ca2+ levels | Calcitonin |
| second most abundant intracellular cation | Magnesium |
| What is magnesium neededed for? | carbohydrate and protein metabolism -cardiac function -neurotransmission -neuromuscular activity -cofactor for ATP |
| What is the cofactor for ATP? | Magnesium |
| 1. How much Mg is in bone? 2. How much of filtered Mg is excreted? 3. The control of magnesium is? | 1. 50% 2. 3-5% 3. poorly understood |
| What is the major anion? | chloride |
| what helps Na maintain osmotic pressure? | chloride |
| how much of filtered Cl is reabsorbed? | 99% |
| How is Cl reabsorbed and transported? | in PCT Cl reabsorbed passively (paracellular) in DCT Na and Cl transport is coupled |
| arterial blood pH is? | 7.4 |
| venous blood and ISF pH is? | 7.35 |
| ICF pH is? | 7.0 |
| why is ICF ph 7.0? | due to acidic metabolites and Carbon dioxide |
| H concentration in blood is regulated by? | -chemical buffer systems -respiration -kidneys -proteins -HCO3 |
| what is the formula for pH? | pH = -log[H+] |
| acids are? | proton donors |
| bases are? | proton acceptors |
| what happens when you increase H? decrease? | -increase acidity, lower pH -decrease acidity, greater pH |
| What are the 3 chemical buffer systems in the body? | 1. Bicarbonate 2. Phosphate 3. Proteins |
| important ECF buffers | 1. Bicarbonate 2. Proteins |
| gives off H in bicarbonate buffer system? | H2CO3 (carbonic acid) |
| takes up H in bicarbonate buffer system? | HCO3 (carbonate) |
| If ECF becomes more acidic what happens? | H+ + HCO3 = H2CO3, so H+ ions are mopped up and pH will not change. |
| If ECF becomes more alkali what happens? | H2CO3 = H+ + HCO3 |
| Concentration of HCO3 in ECF is regulated by? | kidneys |
| concentration of H2CO3 in ECF is regulated by? | respiration as: CO2 + H2O = H2CO3 |
| (____) are very effective in urine and ICF | Phosphate buffers |
| what are the components of phosphate buffers? | dihydrogen phosphate - monohydrogen phosphate |
| Most plentiful and powerful source of buffers in plasma and ICF | proteins |
| proteins are made up of? | amino acids |
| Example of how amino acids (proteins) mop up H+ when levels rise? | COO- + H+ = COOH |
| Example of how amino acids (proteins) give off H+ when levels fall? | NH3+ = NH2 + H+ |
| All cases of acidosis and alkalosis are classed as either? | respirator or metabolic depending on the cause. |
| most common cause of acid-base imbalance | respiratory acidosis |
| -respiration is insufficient-e.g. pneumonia, cystic fibrosis -blood CO2 rises -pH falls | respiratory acidosis |
| -CO2 is eliminated faster than it is produced -respiration is too fast-hyperventilation -blood CO2 falls -pH rises | respiratory alkalosis |
| normal blood CO2 is? | 35-45 mmHG |
| when acid-base imbalance is not caused by CO2 levels the problem is? | metabolic |
| Which is less common, respiratory alkalosis or metabolic alkalosis? | metabolic alkalosis |
| -low blood HCO3 levels -causes-too much alcohol (metabolized to acetic acid), diarrhea (excessive loss of HCO3), too much lactic acid -blood HCO3 low -pH low | metabolic acidosis |
| -less common -causes-loss of stomach acids due to vomiting, GI cleaning, overdosing on antacids -blood HCO3 is high -pH high | metabolic alkalosis |
| causes-loss of stomach acids due to vomiting, GI cleaning, overdosing on antacids | metabolic alkalosis |
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