Osmotic Regulation

Question 1

What are osmoconformers?

Answer 1

organisms whose body fluid is the same osmolarity as their environment

Question 2

What type of organisms are osmoconformers typically?

Answer 2

most marine invertebrates

Question 3

What exactly is osmolarity?

Answer 3

total number of solute particles in a solution

Question 4

What are osmoregulators?

Answer 4

organisms whose body fluid is not the same as their environment

Question 5

What type of organisms are osmoregulators?

Answer 5

most marine vertebrates and everyone else

Question 6

Why is it hard to maintain osmolarity?

Answer 6

because our cells are constantly breaking down amino acids, so ammonia is formed (which is toxic)

Question 7

What do organisms that live in the water do to get rid of the ammonia?

Answer 7

they use gills and do diffusion to get the ammonia out of the body

Question 8

What do mammals, fish, and amphibians do to the ammonia?

Answer 8

ammonia is converted to urea in the liver and is excereted via the kidneys

Question 9

What is a disadvantage to converting ammonia to urea?

Answer 9

it requires a lot of water

Question 10

What do reptiles, birds, and insects do to the ammonia?

Answer 10

they convert ammonia to uric acid in order to save water

Question 11

What is a disadvantage to converting ammonia to uric acid?

Answer 11

high energy cost

Question 12

What is the purpose of bird and mammal kidney?

Answer 12

to produce urine more concentrated than body fluids

Question 13

What transports the blood to the kidney?

Answer 13

renal artery

Question 14

What are the three levels of the kidney (start from the top)?

Answer 14

1. renal cortex
2. renal medulla
3. renal pelvis

Question 15

What part of the kidney conducts the filtration?

Answer 15

nephron

Question 16

What are the two types of nephron?

Answer 16

juxtamedullary and cortical

Question 17

What kind of urine do freshwater fish make and why?

Answer 17

they make dilute urine because they use the kidney to excrete excess water not waste (they remove waste by passive diffusion)

Question 18

What kind of urine do marine fish make and why?

Answer 18

they make concentrated urine because they use the kidney to excrete ions

Question 19

What does the juxtamedullary nephron do?

Answer 19

it is used to increase concentration of urine (which is why it is longer)

Question 20

What does the cortical nephron do?

Answer 20

i is used for reabsorption and secretion (which is why it’s smaller)

Question 21

What is the path of the blood to urine?

Answer 21

renal artery
kidney
glomerulus
collecting duct
ureter
bladder
urethra

Question 22

Through which arteriole is blood coming in through?

Answer 22

afferent arteriole

Question 23

What is the glomerulus?

Answer 23

a ball of capillaries used for filtration

Question 24

How does filtration occur in the glomerulus?

Answer 24

pressure in the capillaries releases the blood and big stuff into the efferent arteriole while the filtrate is released into the bowman’s capsule

Question 25

How does the filtrate leave the bowman's capsule?

Answer 25

through the renal tubule

Question 26

Why are blood and renal tubes still intertwined?

Answer 26

this helps diffusion of particles out of the loop of henle and beyond

Question 27

Walk through the path of the filtrate?

Answer 27

1. filtrate goes from the renal tube to the proximal tube 2. filtrate goes down the descending loop of henle 3. then, it does up the acceding loop of henle 4. then the filtrate travels to the distal tubule 5. and then the filtrate travels down the collecting duct to get excreted

Question 28

In what parts of the nephron is water reabsorbed into the capillaries?

Answer 28

proximal tubule, descending loop of henle, distal tubule (if you have to), and collecting duct

Question 29

Why does water leave the nephron at various places?

Answer 29

this is because in these places, there is more solute outside the nephron, so water follows the solute

Question 30

Where does reabsorption of molecules happen and what molecules are reabsorbed?

Answer 30

it happens in the proxminal tubule and glucose and amino acids are reabsorbed by the body (capillaries)

Question 31

How does secretion occur?

Answer 31

1. unwanted molecules are actively transported from blood to nephron and this occurs in the distal convoluted tubule

Question 32

What is excretion?

Answer 32

when the filtrate goes through the collecting duct and is concentrated into the urine

Question 33

What organisms have the loop of henle?

Answer 33

mammals and birds

Question 34

What is the point of the loop of henle?

Answer 34

it is to create a gradient to up the concentration of urine

Question 35

Why doesn't the loop of henle actually achieve its point?

Answer 35

the solution coming out of the loop is actually more dilute than the solution going into the loop

Question 36

What is the countercurrent exchange in the loop of henle?

Answer 36

1. as the filtrate goes through the descending loop of henle, water moves out of the loop and into the environment 2. as the filtrate goes through the ascending loop of henle, sodium and chlorine ions move out of the loop of henle using active transport

Question 37

What happens as we go *deeper* through the environment of the loop of henle?

Answer 37

the osmolarity increases (more concentration of stuff)

Question 38

How does filtrate turn into urine?

Answer 38

as the filtrate move through the collecting duct, more water is reabsorbed into the blood and filtrate becomes urine as concentration increases

Question 39

Why is urine acidic?

Answer 39

-bicarbonate is naturally needed in the blood to maintain pH, so it gets reabsorbed in the proximal convoluted tubule -but H+ is also naturally secreted from the body to the distal tubule in order to maintain pH -so, we took away the buffer and added acid, so urine is acidic

Question 40

What dies ADH regulate?

Answer 40

blood osmolarity, blood pressure, and volume

Question 41

What does your body do when it recognizes there isn't enough water in your blood?

Answer 41

1. hypothalamus triggers thirst 2. hypothalamus releases ADH 3. ADH causes kidneys to reabsorb more water

Question 42

How does ADH cause kidneys to reabsorb more water?

Answer 42

ADH adds aquaporins in the distal tubules and collecting ducts

Question 43

What happens when ADH levels are high?

Answer 43

blood pressure increases and blood volume increases, because theres more water going through the arteries so its thicker