Excretory System

Question 1

What type of waste is eliminated in excretory system?

Answer 1

nitrogenous waste (urea/uric acid)

Question 2

cnidaria excretion

Answer 2

diffusion into surrounding water

Question 3

annelids

Answer 3

two nephridia in each body segment; urea passed from small capillaries to nephridia; waste exits worm through nephridia and holes (pores) in the skin

Question 4

arthropods

Answer 4

Malphighian tubules are bathed in blood (open circ. system), uric acid collects in the tubules from blood and empties into the digestive tract

Question 5

What happens to urea without water?

Answer 5

It crystallizes into uric acid which is excreted with the solid waste.

Question 6

transfer of urine in humans

Answer 6

Kidney –> Ureter –> Bladder –> Urethra

Question 7

nephron

Answer 7

tiny tubule that filters blood within the kidney

Question 8

passage of blood/filtrate through structures

Answer 8

Blood in through afferent arteriole (type of renal artery) –> Glomerulus (collection of capillaries –> blood leaves through efferent arteriole, filtrate goes through Bowman’s capsule (surrounding glomerulus) into… –> proximal convoluted tubule –> descending loop of Henle –> ascending loop of Henle –> distal convoluted tubule –> collecting duct –> ureter…

Question 9

What word should we associated with kidney (r….)?

Answer 9

renal!

Question 10

glomerulus

Answer 10

cluster of capillaries that physically squeezes blood through a “sieve,” resulting in cleaned but much thicker blood and filtrate (urea + water + glucose, salt, amino acids) FILTRATION

Question 11

Bowman’s capsule

Answer 11

This is where the filtrate gathers after going through the glomerulus “sieve.”

Question 12

proximal convoluted tubule

Answer 12

REABSORPTION – salt, water, amino acids, glucose re-enter blood; Now it is called URINE and has lost 75% water.

Question 13

descending loop of Henle

Answer 13

goes from outer region of kidney (cortex) into medulla; walls of this part are water-permeable but not salt-permeable; MEDULLA has high salt concentration, so water from urine is drawn out into medulla because of this concentration gradient – now urine has lost 94% of water

Question 14

regions of kideny

Answer 14

cortex (outer) & medulla

Question 15

ascending loop of Henle

Answer 15

salt-permeable, so the salt from urine goes into medulla, leaving only 4% of the original salt behind

Question 16

distal convoluted tubule

Answer 16

salt is pumped out and water follows, leaving only 3% of original water left and negligible amount of salt (filtration and reabsorption) + SECRETION: Hydrogen and Potassium ions are actively pumped into urine for release.
ALDOSTERONE

Question 17

collecting duct

Answer 17

extends deep down into the medulla
It is here where the amount of water loss can be controlled. Up to 75% of the remaining water CAN be lost, but levels of ADH control permeability of the duct’s walls
If ADH levels are low, then less water loss, and vice versa.
IN ADDITION, some urea is lost into medulla at the bottom to maintain high ion concentration of medulla.

Question 18

ADH

Answer 18

antidiuretic hormone, secreted by posterior pituitary gland

Question 19

aldosterone

Answer 19

produced in adrenal cortex, increases sodium and water reabsorption in distal convoluted tubule

Question 20

kidney enzymes to control blood pressure

Answer 20

kidneys release renin –> produces angiotensin II –> increases blood pressure and aldosterone amounts, therefore increasing blood volume and therefore pressure