Excretion

Question 1

urinary system functions (4)

Answer 1

• metabolic wastes excretion
• water-salt balance
• pH balance
• hormone secretion (renin/erythropoietin)

Question 2

urea

Answer 2

breakdown of amino acids in liver

- get rid of ammonia (very toxic)

Question 3

uric acid

Answer 3

breakdown of nucleotides (crystallized uric acid in joints causes gout, but also serve as antioxidant)

Question 4

creatinine

Answer 4

made by muscle cells from breakdown of creatine phosphate

Question 5

anatomy of kidney (3 regions)

Answer 5

• outer: renal cortex
• middle: renal medulla
• inner chamber: renal pelvis

Question 6

nephrons

Answer 6

filters of kidney

Question 7

glomerulus

Answer 7

knot of capillaries inside glomerular capsule (Bowman’s)

• pores produce blood filtrate
• podocytes connect capsule epithelium to capillary endothelium

Question 8

proximal convoluted tubule

Answer 8

epithelial layer w/border of microvilli to allow reabsorption of filtrate components in tube lumen

Question 9

loop of nephron

Answer 9

• descending limb: allow water to leave

- ascending limb: pushes out salt

Question 10

distal convoluted tubule

Answer 10

epithelial cells rich in mitochondria

- supply energy used in movement of molecules from blood to tubule (tubular secretion)

Question 11

collecting ducts

Answer 11

several nephrons share a collecting duct

- carry urine to renal pelvis

Question 12

urine formation - 3 steps

Answer 12

• glomerular filtration
• tubular reabsorption
• tubular secretion

Question 13

step 1 glomerular filtration

Answer 13

• water/small molecules move (glomerulus -> caspule)
• large molecules/formed elements remain in blood
• filtrate enters nephron
• blood pressure drives filtration

Question 14

step 2 part 1: stubular reabsorption

Answer 14

• reabsorbed filtrate components: most h20, nutrents, required salts (ions)
• nonreabsorbed filtrate: some h20, nitrogenous waste, excess salts

Question 15

step 2 part 2: tubular secretion

Answer 15

remove substances (drugs, H+, creatinine) by active tarnsport

Question 16

osmoregulation

Answer 16

constant blood pressure (volume) and osmolarity (solute concentration)

Question 17

low blood pressure would trigger…

Answer 17

reabsorption of salt and water from nephrons (water increases blood volume)

Question 18

1. renin activates ___

Answer 18

angiotensin hormone

Question 19

2. angiotensin signals…

Answer 19

secretion of aldosterone from adrenal gland

Question 20

3. aldosterone

Answer 20

promotes excretion of K+ in urine and reabsorption of Na+ via pump (ATP powered)

Question 21

4. Cl- ions follow Na+ passive transport and then..

Answer 21

increased salt drives osmosis (more water reabsorbed by capillaries)

Question 22

atrial natriuretic hormone (ANH)

Answer 22

secreted by heart when blood volume increases

inhibits renin

Question 23

renin

Answer 23

secreted by kidneys, initiates hormone cascade to regulate water-salt balance + blood pressure

Question 24

erythropoietin

Answer 24

secreted by kidneys, stimulate rbc production in bone marrow when blood oxygen is low

Question 25

alcohol as a diuretic

Answer 25

inhibits ADH secretion -> excess urination + dehydration (hangover)

Question 26

caffeine as a diuretic

Answer 26

increases glomerular filtration rate + decreases reabsorption of Na+ ions

Question 27

juxtaglomerula apparatus

Answer 27

part of nephron; monitors blood pressure