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HSCI100 > Excretion > Flashcards

Flashcards in Excretion Deck (27):
1

urinary system functions (4)

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

2

urea

breakdown of amino acids in liver
- get rid of ammonia (very toxic)

3

uric acid

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

4

creatinine

made by muscle cells from breakdown of creatine phosphate

5

anatomy of kidney (3 regions)

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

6

nephrons

filters of kidney

7

glomerulus

knot of capillaries inside glomerular capsule (Bowman's)
- pores produce blood filtrate
- podocytes connect capsule epithelium to capillary endothelium

8

proximal convoluted tubule

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

9

loop of nephron

- descending limb: allow water to leave
- ascending limb: pushes out salt

10

distal convoluted tubule

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

11

collecting ducts

several nephrons share a collecting duct
- carry urine to renal pelvis

12

urine formation - 3 steps

- glomerular filtration
- tubular reabsorption
- tubular secretion

13

step 1 glomerular filtration

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

14

step 2 part 1: stubular reabsorption

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

15

step 2 part 2: tubular secretion

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

16

osmoregulation

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

17

low blood pressure would trigger...

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

18

1. renin activates ___

angiotensin hormone

19

2. angiotensin signals...

secretion of aldosterone from adrenal gland

20

3. aldosterone

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

21

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

increased salt drives osmosis (more water reabsorbed by capillaries)

22

atrial natriuretic hormone (ANH)

secreted by heart when blood volume increases
(inhibits renin)

23

renin

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

24

erythropoietin

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

25

alcohol as a diuretic

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

26

caffeine as a diuretic

increases glomerular filtration rate + decreases reabsorption of Na+ ions

27

juxtaglomerula apparatus

part of nephron; monitors blood pressure