Urinary System – Kidney Anatomy, Physiology & Hormonal Control

A set of 45 question-and-answer flashcards covering kidney anatomy, blood supply, nephron physiology, urine formation processes, and key hormonal regulatory mechanisms of the urinary system. These cards are intended for rapid review before an exam.

What are the three microscopic processes that together produce urine?

Glomerular filtration, tubular reabsorption, and tubular secretion.

What is the basic functional unit of the kidney?

The nephron.

Are the kidneys intraperitoneal or retroperitoneal organs?

They are retroperitoneal.

Which kidney is positioned slightly lower in the body and what organ causes this?

The right kidney; it sits lower because of the large size of the liver above it.

Through which medial indentation do the renal artery, renal vein, nerves, and ureter enter or exit the kidney?

The renal hilum.

List the three protective coverings of the kidney from innermost to outermost.

Renal (fibrous) capsule, perirenal adipose (fat) capsule, and renal fascia.

Name the three main internal regions of the kidney from superficial to deep.

Renal cortex, renal medulla, and renal pelvis (collecting sinus).

Which arteriole delivers blood to the glomerulus?

The afferent arteriole.

Which arteriole carries blood away from the glomerulus?

The efferent arteriole.

What capillary network surrounds the tubules of cortical nephrons?

The peritubular capillaries.

Which long, hair-pin-shaped vessels run alongside the loops of juxtamedullary nephrons?

The vasa recta.

In which part of the nephron does plasma filtration occur?

In the glomerulus of the renal corpuscle.

What two structures compose a renal corpuscle?

The glomerulus and the glomerular (Bowman’s) capsule.

Which modified smooth-muscle cells release renin when blood pressure is low?

Juxtaglomerular (granular) cells in the afferent arteriole.

What structure consists of macula densa plus juxtaglomerular cells?

The juxtaglomerular apparatus (JGA).

What hormone cascade is initiated by renin release from the kidneys?

The renin–angiotensin–aldosterone system (RAAS).

How does angiotensin II affect the efferent arteriole?

It constricts the efferent arteriole, raising glomerular pressure and GFR.

Which hormone increases Na⁺ reabsorption in the DCT and collecting duct?

Aldosterone.

Which cardiac hormone antagonizes RAAS by promoting Na⁺ and water excretion?

Atrial natriuretic peptide (ANP).

Which limb of the loop of Henle is highly permeable to water but not to solutes?

The descending limb of the loop of Henle.

Which limb of the loop of Henle actively transports NaCl but is impermeable to water?

Thick acending of the loop of Henle. .

What fat-soluble vitamin is converted to its active hormonal form (calcitriol) by the kidney?

Vitamin D.

Which kidney-derived hormone stimulates red blood cell production in bone marrow?

Erythropoietin (EPO).

Besides filtration, what two processes fine-tune filtrate composition before it becomes urine?

Tubular reabsorption and tubular secretion.

Which nephron segment is nicknamed the "workhorse" of the kidney?

The proximal convoluted tubule because it performs the bulk of reabsorption.

Which nitrogenous waste product derived from protein catabolism is excreted in urine?

Urea.

What sphincter located at the urethra is composed of skeletal muscle and is under voluntary control?

The external urethral sphincter.

List order of Vitamin D initiation to activation.

Integumentary, digestive, urinary

Once urine leaves kidneys,

it cannot be reconcentrated

What parts of the renal hilum, are in the entrance of the kidneys

includes the renal artery and renal nerves

What parts of the renal hilum, are in the exit of the kidneys

include the renal vein and ureter.

list flow of urine from inward to outwards

kidney, ureter, urinary bladder, urethra

List order of artieries within the kidneys starting with renal artery

renal artery, segmental artery, interlobar artery, arcuate artery, interlobular artery, afferent arterioles, glomerulus, efferent arteriole, peritubular capillaries, vasa recta

Organelles located in renal cortex

include renal corpuscles, proximal convoluted tubules, and distal convoluted tubules, part of collecting duct

organelles located in renal medulla

loop of henle and collecting duct

list path of filtrate

minor calyx, major calyx, renal pelvis, ureter, urinary bladder, urethra

Which ateriole is larger

the afferent arteriole

What in the kidney produces renin

Juxtaglomerular cells

Tubular reabsorption is characterized by?

substances being reclaimed by renal tubular structures back to peritubular capillaries

what is tubular secretion?

substances secreted from peritubular capillaries into tubular structures

filtration happens only in

renal corpuscle

99% glucose reabsorption happens in

the proximal convoluted tubule.

PCT reabsorbs…

amino acid, water, glucose, solutes (Na, K, Cl)

Pct is considered workhorse of nephron because

it reabsorbs the majority of essential nutrients and water.

when filtrate first enters loop of henle at PCT, mOsm/L measures

about 300 mOsm/L.

when filtrate is near bottom/middle of loop of Henlle, mOsm/L neasures

up to 1200 mOsm/L. (concentrated).

when filtrate is in DCT, mOsm/L measures

about 100 mOsm/L (dilute).

descending loop of henle

permeable to water

ascending loop of henle

not permeable to water, but permeable to solutes

collecting duct with ADH

small volume of concentrated urine (H2O released)

collecting duct without ADH

large volume of dilute urine (H2O retained)

hypovolemia

a state of decreased blood volume which causes lowered blood pressure

in hypovolemia…

baroreceptors detect - blood volume, causes vasoconstriction of blood vessels

in hypovolemia…

cardiac msucle cells do not secrete ANP

in hypovolemia…

in kidneys jux cells release renin that then increases aldestrone release

in hypovolemia…

pituiatary gland raises ADH secretion

muscle part of urinary bladder is

the detrusor muscle

explain trigone

area inside of urinary bladder, entry of two ureters and urethra (triangle shape)

When bladder is empty , when bladder is full, _

empty=cuboidal, full=squamous epithelium

proximal to distal order of male urethra

prostatic, membranous, spongey urethra