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A & P 2150 Final

The last of the information for the final exam.

QuestionAnswer
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
Created by: dsh0819