Kidney Review Answers

Kidney Review

1.      The kidneys produce 2 hormones, ____renin_____ and ___erythropoeitin_____.

2.      The outer region of the kidney is the renal ____cortex___. The inner layer is the renal medulla__ composed of renal ____pyramids_____. These are separated by regions of cortex called renal ___columns___.

3.      Urine flows from the renal papilla to a ___minor __ ____calyx_____, into a ___major___ ___calyx______, into the space inside the kidney called the renal ____pelvis___, and then into the ureter____ and to the bladder. It exits the body via the ___urethra____.

4.      Blood flows from the renal artery into the ____segmental_ (or lobar) arteries, then the interlobar___ arteries, then the arcuate artery along the top of the pyramid, and into the tiny ___cortical____ ____radiate______ arteries.

5.      Blood flows from the cortical radiate arteries into the ___afferent___ arteriole and through the ________glomerulus___ where filtration occurs. The filtered blood then enters the ___efferent____ arteriole and exits the kidney via the venous system.

6.      Between the efferent arteriole and the cortical radiate vein are networks of capillaries called ___peritubular_ capillaries and __vasa_ recta____.

7.      The functional unit of the kidney is called the __nephron_ which consists of the renal tubule and ___renal_ corpuscle_, which consists of the ____glomerulus_ and ___Bowman’s____ capsule.

8.      The renal tubule collects filtrate from the glomerulus. It consist of the proximal___ convoluted tubule, the __nephron__ loop___ (aka loop of Henle), the _____distal______ ___convoluted_____ tubule, and the _____collecting____ duct in the center of each pyramid. Around the renal tubule are _____peritubular__ capillaries that absorb water and solutes.

9.      Blood pressure in the glomerulus is ___high______, which pushes ____filtrate___ into ____Bowman’s__ ____capsule______.  All glomeruli are in the renal ___cortex_______. Some nephrons, called ___cortical nephrons, have short loops surrounded by __peritubular__ capillaries. Some are near the medulla and have loops that enter the medulla. These are called ___juxtamedullar___ nephrons, and their loops are surrounded  by vasa_____ ____recta_____.

10.   The kidneys filter ____180___ L of blood daily, but produce only ___1.5__ L of urine. There are 3 processes in urine formation: glomerular ____filtration__ when plasma is forced out of the blood to produce filtrate, tubular _____reabsorption_____ which returns filtrate components to the blood, and tubular ____secretion______ when substances diffuse out of capillaries, into interstitial fluid, and into the tubule.

11.   If glomerular filtration rate(GFR) is too high it causes ____dehydration___ and depletion of _____electrolytes___. If it’s too low, waste reabsorption leads to ______uremia_________.

12.   ___Myogenic____ feedback refers to constriction of arterioles to protect glomerulus from high pressure.

13.   Angiotensin_ II is a vasoconstrictor that raises bp by 3 mechanisms. 1) by enhancing reabsorption of ____Na__ and ___H2O__ in peritubular capillaries. 2) Stimulates production of aldosterone from the adrenal glands that stimulates water and NaCl reabsorption in the DCT and collecting duct, and 3) stimulates the posterior pituitary_ to release ___ADH__ which promotes water reabsorption in the _____collecting______ ____duct_________ and stimulates thirst.

14.    Tubular reabsorption of sodium__ is coupled to reabsorption of other materials. This creates an osmotic gradient for water_ which is reabsorbed through ___aquaporins____ in the ___PCT___ and sometimes the ____collecting___  ______duct________.

15.   Most reabsorption occurs in the _______PCT____. In the descending limb of the nephron loop, ____H2O_____ can leave but _____salt_____ can’t. The opposite occurs in the ____ascending____ loop. 4 hormones regulate this reabsorption: ADH____ regulates water,  ____ANP_____ and  aldosterone_ regulate sodium, and ____PTH___ regulates calcium.

16.   Most tubular secretion occurs in the ___proximal___ __convoluted__ ___tubule____.

17.   The osmolality of plasma is maintained at ____300__ mOsm. The kidney has a gradient of 300- ____1200___ mOsm. Water passes freely from the _____descending____ limb into the hyperosmotic interstitial fluid. In the ___ascending_____ limb, which is ____impermeable_____ to water, NaCl is reabsorbed from the tubule.

18.   Chemicals that enhance urine output are called ___diuretics____. There are 4 types.  ____ADH___ inhibitors (like ___alcohol_______), Na reabsorption inhibitors, ____loop_ diuretics that prevent osmotic gradient formation, and ____osmotic____ diuretics like excess glucose.

19.   Urine is clear. Infection may cause it to be ____cloudy_____. The yellow color is from ____urochrome____ and may vary due to foods, blood, etc. The pH changes according to ____diet_____.

20.   The bladder is lined with ____transitional_____ epithelium. It has 3 layers of smooth muscle called the ____detrusor_____ muscle.

21.   Clinically, kidney stones are called ___renal___ ____calculi____

22.   The urethra has 2 ___sphincters___ - one voluntary and one involuntary.

23.   Urination is known as ______micturition_ and is stimulated by bladder stretch.