Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
What is the purpose of autoregulation of GFR and RBF via tubuloglomerular feedback? What does it do? Describe how it works and all the components involved. |
Why: prevent extreme changes in excretion despite changes in aterial blood pressure (which changes renal blood flow)
What: Can change GFR through modifying efferent arteriolar resistance and can change RBF through modifying afferent arteriolar resistance.
How: Involves the juxtaglomerular complex consisting of the macula densa of the distal tubule and the juxtaglomerular cells of the arterioles. Two components: afferent arteriolar feedback and efferent arteriolar feedback. Both done trhough macula densa. Check out diagram |
|
|
What are Two Mechanisms of Autoregulation? |
1) Tubuloglomerular feedback 2) |
|
|
What is the micturition reflex and how does it work? |
Refers to the contraction of the bladder and relaxation of bladder neck and external urinary sphincter to release urine out of bladder, through urethra and out of the body.
initiated by the detruser muscle and triggered by sretching of bladder wall muscle. Contraction of bladder reinforces the reflex= brief positive feedback loop and relaxation of internal sphincter (inhibits sympathetic and activiates parasympathetic). Inhibition of external sphincter allows urination to occer. Micturition reflex is facilitated or inhibited by higher brain centre function. |
|
|
What is the vesicouretal reflex? |
contraction during micturition closers off ureters to prevent reflux/backflow of urine |
|
|
What are routes for water loss? Water intake? |
1) Skin (insensible) 2) Through Respitory Tract and lungs (insensible) 3) Feces 4)Urine 5) Sweating (can be heavily regulated depending on exercise level)
|
|
|
Which system relates arterial blood pressure to the sodium potassium pump. Describe how this mechanism works.
2) What factor inhibits this system when blood pressure is high? |
1) The renin/angiotensin/aldosterone system. When ABP is low, renin is secreted by the juxtaglomerular cells, which stimulates secretion of angiotensin which stimulates secretion of aldosterone form adrenal gland. Aldosterone stimulates Na+/K+ pump in nephron. Cl- ions follow Na+ into the bloodstream and H2O follows, increasing blood volume.
2) Atrial natriuretic factor.
3) Dehydration- ADH opens up aquaporins in the distal tubule (more permeable) for water to be reabsorbed into the bloodstream |
|
|
How do kidneys regulate acid/salt balance? |
Excretion of acid: eg) HCO3- and certain other types of acids (sulphuric, phosphoric, yric) and also H+ directly. |
|
|
How do kidneys regulate erythrocyte production? |
they secrete ertythropoietin (hormone) -90% produced by kidney and 10% by liver -stimulates production of RBC from stem cells of bone marrow -hypoxia promotes erythropoietin release |
|
|
Regulation of Vitamin D Production |
Kidney produces active form 1,25-dihydroxyvitamin D3 |
|
|
What is the special importance of the efferent arteriole? |
It regulates the hydrostatic pressure of both the kidney capillary beds (peritubular and glomerular) |
|
|
What are the two types of nephrons? Which nephrons lie deep in the renal cortex, near the medulla? |
cortical: short loops of hele juxtamedullary: deep in the renal cortex near the medulla, long loops of Hnle,
|
|
|
Name some hormones which decrease GFR. What do they do? |
norepinephrine, epinephrine, endothelin
They lead to vasoconstriction or renal blood vessels, lower RBF and GFR. norepinephrine is a peptide which is released during vascular damage |
|
|
Active transport in Tubular Reabsorbtion |
-sodium potassium ATPase -Hydrogen ATPasr -Hydrogen-potassium ATPase -calcium ATPase |
|
|
What is the role of the Na+/K+ pump ATPase in sodium reabsorption? Which side of the nephron is it located o n? |
Pumps Na+ out of the tubular epithelium cells and into the interstitium. This induces a concentration gradient and a membrane potential (-70 in epithelial cells). So, Na+ can flow down its concentration gradient from the lumen into the epithelial cells. This is facilitated by the brush border in between lumen and epithelial cells (increases S.A) and abundant sodium carriers (facilitated diffusion). |
|
|
Describe Proximal Tubular Reabsorption |
this part of the nephron is extremely metabolically active with lots of mitochondria -65% of Na+ and H2O are reabsorbed -many sodium co-transporters, glucose, amino acids and other solutes reabsorbed
2nd half of proximal tublue: sodium reabsorbed with chloride ions |
|
|
What type of substances are secreted in the proximal tubule? |
metabolic acids and bases: bile salts, creatinine, oxalate, urate... drugs and toxins para-aminohippuric acid (PAH) ==> 90% clearance rate |
|
|
Differences between the thin and thick loop of Henle segments |
thin descending: metabolically inactive, no brush border, highly permeable to H2O
thick ascending: metabolically active (many mitochondria), low permeability to H2O, reabsorption of 25% of ions (Na+, K+, Cl-) occurs here. Secretion of H+ also occurs. |
|
|
NKCC2 (Na/K/Cl) |
co-transporter which transports all three of these ions from the apical side of the Loop of Henle (lumen) to the basolateral side. -Several Loop diuretics inhibit this transporter in order to preserve solutes in tubule to ultimately limit the reabsorption of water and have dilute urine. |
|
|
NCC Cotransporter |
sodium chloride transporter in the early distal tubule. early distal tubule forms part of the juxtaglomerular complex which provides feedback on GFR and bloodflow |
|
|
Describe the two distinct portions of the second part of the distal collecting tubule and cortical collecting dunct |
1) principal cells: reabsorb sodium, chloride and water and secrete potassium into lumen
2) intercalated cells: reabsorb potassium and HCO3 -, secrete H+, |
|
|
Two pathways for kidney infection |
1) Hematogenous infection (bacteria like staph)--> pylonephritis 2) vesicoureteral reflux--> ascending infection (urethritis of cystitis)
|
|
|
3 categories of acute renal failure |
1) prerenal acute renal failure: decreased blood flow to kidneys 2)intrarenal acute renal failure: problems with the kidney itself 3)postrenal acture renal failure: problems with urinary collecting system |
|
|
oliguria anuria |
low urine output cessation of urine output |
|
|
Hypertrophy Sclerosis
|
1) Increase in volume of an organ or tissue due to the enlargement of its component cells 2) Hardening of tissue and other anatomical features usually caused by the replacement of organ-specific tissue by connective tissue
|
|
|
Vicious Cycle of Chronic Renal Disease |
boo |
