Urinary System

Question 1

How does urinary system maintain body’s internal environment?

Answer 1

• regulate body water volume and solute concentration in that water
• regulate ion concentration in extracellular fluid
• maintain long term acid base balance
• excrete metabolic wastes
• produce erythropoietin and renin
• convert vitamin D to active form
• carry out gluconeogenesis

Question 2

Erythropoietin and renin

Answer 2

• produced by kidneys
• EPO regulates RBC production (erythropoiesis)
• renin regulates blood pressure

Question 3

Hormone that regulate RBC production

Answer 3

• erythropoietin
• increase RBC production

Question 4

Hormone that regulate blood pressure

Answer 4

• renin produced by kidney

Question 5

Renin-angiotensin-aldosterone system

Answer 5

• angiotensin is released by liver
• decrease in blood volume and blood pressure enhance renin secretion by kidney
• renin enhances angiotensin to be converted to angiotensin I
• adrenal glands release aldosterone
• aldosterone act on kidneys to reabsorb NaCl and H2O into blood

Question 6

function of vitamin D

Answer 6

• promote calcium reabsorption in the gut
• bone mineralization
• converted to active form by urinary system

Question 7

Ureters

Answer 7

• transport urine from kidneys to bladder
• paired tubes

Question 8

Urinary bladder

Answer 8

• temporary urine storage

Question 9

Urethra

Answer 9

• urine from bladder to body exterior

Question 10

Kidney shape and location

Answer 10

• bean shaped
• between dorsal body wall and parietal peritoneum

Question 11

renal pelvis

Answer 11

• area at the center of kidney
• urine funneled into ureter after leaving nephrons through collecting ducts

Question 12

major calyx

Answer 12

• through which urine flows into renal pelvis

Question 13

functional units of kidneys

Answer 13

• nephrons

Question 14

renal corpuscles and tubules

Answer 14

• corpuscles are in the cortex
• tubules begin in cortex, pass into medulla and return to cortex

Question 15

Renal corpuscles

Answer 15

• nephron filtration unit
• has glomerulus and Bowmans capsule
• capsule is continuous with renal tubule

Question 16

type of capillaries in glomerular endothelium

Answer 16

• fenestrated (very porous)

Question 17

filtrate in glomerulus

Answer 17

• raw material renal tubules process to form urine
• usually gotten rid of cells and proteins

Question 18

layers of glomerular capsule

Answer 18

• external parietal layer: simple squamous epithelium; contribute to structure; doesn’t filter
• visceral layer: cling to capillaries; has podocytes

Question 19

Function of podocytes

Answer 19

• in the visceral layer of glomerular capsule
• prevent plasma proteins from entering urinary filtrate

Question 20

major parts of renal tubule

Answer 20

• proximal convoluted tubule
• nephron loop (formerly loop of Henle)
• distal convoluted tubule
• they drain into collecting duct

Question 21

2 types of cells in collecting duct

Answer 21

• principal cells and intercalated cells
• principal - maintain water and Na+ balance
• intercalated - acid base balance

Question 22

2 major groups of nephrons

Answer 22

• cortical nephrons: located entirely in cortex, short loop
• juxtamedullary nephrons: long loop, originate close to cortex-medulla junction, concentrated urine

Question 23

cell population in juxtaglomerular complex

Answer 23

• macula densa cells: chemoreceptors; minitor NaCl content of filtrate entering DCT
• granular cells: mechanoreceptors; sense blood pressure in afferent arteriole

Question 24

urine formation formula

Answer 24

urine = glomerular filtration - tubular reabsorption + tubular secretion

Question 25

glomerular filtration

Answer 25

- in renal corpuscle - get rid of cells and proteins

Question 26

tubular reabsorption

Answer 26

- from filtrate back into blood - takes place in renal tubules and collecting ducts - reclaims glucose, amino acids, salts, water and other

Question 27

tubular secretion

Answer 27

- from blood into filtrate - in tubule and collecting duct

Question 28

substances reabsorbed in PCT

Answer 28

- sodium ions - nutrients (glucose, amino, vitamins, ions) - water - lipid-soluble solutes - urea - Cl-, K+, Mg2+, Ca2+, HCO3-

Question 29

substances reabsorbed in loop

Answer 29

- water - Na, Cl, K ions - Ca, Mg ions

Question 30

stuff reabsorbed in DCT

Answer 30

- Na, Cl, Ca ions

Question 31

substances reabsorbed in collecting ducts

Answer 31

- Na, K, Cl, HCO3 ions - water - urea

Question 32

What controls reabsorption in DCT and collecting duct

Answer 32

- hormones

Question 33

ADH and tubular reabsorption

Answer 33

- ADH inhibits urine output (diuresis) - urea/H2O @ collecting duct - overhydration decreases ADH production in posterior pituitary -> collecting ducts become impermeable to water

Question 34

Aldosterone and tubular reabsorption

Answer 34

- controls Na+ reabsorption (increase) / conserves it in blood - decreased BV/BP (or hyperkalemia) cause adrenal cortex to release aldosterone - Na+ @ distal DCT and CD (K+ secretion)

Question 35

ANP (atrial natriuretic peptide)

Answer 35

- secreted by heart - decrease BV/BP - reduces blood Na+

Question 36

PTH and tubular reabsorption

Answer 36

- act on DCT - increase Ca2+ reabsorption

Question 37

main site of tubular secretion

Answer 37

- PCT

Question 38

What is tubular secretion important for?

Answer 38

- disposal of substances bound to plasma proteins - eliminate unwanted substances reabsorbed by passive processes (urea and uric acid) - ridding of K+ (secreted back into tubules in DCT and CD due to aldosterone) - controlling blood pH

Question 39

chemical composition of urine

Answer 39

- 95% water - urea - uric acid and creatinine (nitrogenous wastes)