Notes 17

Question 1

What is osmoregulation?

Answer 1

The process by which animals control solute regulation and balance water gain and loss.

Question 2

What is osmolarity?

Answer 2

the number of moles of solute per litre of solution. Seawater is saltier than blood

Question 3

What is a hyperosmotic solution?

Answer 3

solution with higher concentration of solutes

Question 4

What is a hypoosmotic solution?

Answer 4

solution with lower concentration of solutes

Question 5

What are osmoconformers?

Answer 5

lets water flow freely in and out of its body. Internal osmolarity = external osmolarity

Question 6

What are osmoregulators?

Answer 6

Keeps internal osmolarity constant

Question 7

What are stenohalines? (aquatic environments)

Answer 7

Very sensitive to changes in external osmolarity

Question 8

What are euryhalines? (aquatic environments)

Answer 8

Can tolerate large fluctuations in external osmolarity

Question 9

T or F: All creatures in aquatic enviornments are euryhaline, but only some are osmoconformers and osmoregulators.

Answer 9

True

Question 10

Many marine invertebrates are ____. Many marine vertebrates are ____. For osmoregulators the marine environment is a ____ environment

Answer 10

Many marine invertebrates are osmoconformers. Many marine vertebrates are osmoregulators. For osmoregulators the marine environment is a dehydrating environment

Question 11

How does osmoregulation occur in marine fish?

Answer 11

Gains water and salt ions from drinking seawater. Excrete salt ions from gills, and have osmotic water loss through gills and other parts of body surface. Also, excrete salt ions and small amounts of water and minimal urine.

Question 12

How does osmoregulation occur in freshwater?

Answer 12

Gains water and ions in food, take in salt ions through the gills and excrete salt ions and large amounts of water in dilute urine from kidneys as well as have osmotic water gain through body surface.

Question 13

T or F: Fish can change physical shape when in differnet types of water.

Answer 13

True. For eels they are tiny in freshwater, largest in the estuary (mix of salt and fresh), and just an egg in marine. For salmon they are eggs in freshater, smolt in estuary, and bigger in marine.

Question 14

What is smoltification?

Answer 14

physiological and anatomical changes to the osmoregulatory system

Question 15

What are the specialized cells called transport epithelia?

Answer 15

one or more layers of epithelial cells that are specialize for moving particles (solutes) in a specific direction. Can face the outer environment in organisms with simple body plans. Can line channels that lead to
an opening E.g., nasal ducts in sea birds

Question 16

What are the waste products of the body?

Answer 16

Mostly a byproduct of breakdown of proteins and nucleic acids. Usually Nitrogenous molecules. Ammonia (NH3) is very toxic → NH4+ interferes with biochemistry of the body

Question 17

How are ammonia, urea, and uric acid produced?

Answer 17

Ammonia:Directly produced waste. Only used in animals which excrete directly into surroundings e.g., bony fish.
Urea: Requires ATP and enzymes. Has to be dissolved in water; so causes water loss e.g., mammals, amphibians
Uric Acid:Requires even more ATP and enzymes. Conserves water e.g., birds, reptiles, insects

Question 18

How does the body filter and excrete waste?

Answer 18

1. Filtration: driven by blood pressure. Large cells in blood cannot go through membrane, but water and small solutes can (→ filtrate)
2. Reabsorbtion: a selective process (facilitated by epithelium via active transport) recovers usefu moleculesfrom the filtrate and passes them into the blood
3. Secretion: Nonessential molecules left in the filtrate OR actively transported out of the blood
4. Excretion: Processed filtrate is released from the body as urine

Question 19

How big is a kidney?

Answer 19

10cm (about the length of a popsicle stick)

Question 20

What are the structures of the kidneys?

Answer 20

Renal cortex – outer layer of kidney
Renal medulla – inner layer of kidney
( both contain excretory tubes)

Renal artery – brings blood that requires filtration to the cortex and medulla
Renal vein – takes filtered blood and recovered substances to the rest of the body
Renal pelvis – collects waste fluid as urine, and carrries it out of the kidney

Question 21

How many nephrons are in one kidney?

Answer 21

1 million per kidney (2 mill in total)

Question 22

How much blood flows through your kidneys daily?

Answer 22

1600L

Question 24

T or F: Only 5% of nephrons are cortical (shorts)

Answer 24

False. 85% of the nephrons are cortical (short). The rest are juxtamedullary – essential for water conservation – produces urine that is hypoosmotic to body fluids

Question 25

What are the parts of nephron organization?

Answer 25

Glomerulus: ball of capillaries branching from the afferent arteriole Bowman’s capsule: a swollen end of the tube system that surrounds the glomerulus Filtrate is formed when the blood pressure forces fluid component from blood into the lumen of Bowman’s capsule. Filtrate passes through the proximal tubule, the loop of Henle, and the distal tubule. Reabsorption happens in the proximal tubule, the loop of Henle and distal tubule. The distal tubule empties into a collecting duct, which empties into the rental pelvis and from there to the ureter.

Question 26

In the kidneys,1600 L of blood produces 180 L of filtrate via the _____ in both kidneys. The 180 L of filtrate has to get processed to ____ ____ ____ and leave behind 1.5 L of urine per day.

Answer 26

In the kidneys,1600 L of blood produces 180 L of filtrate via the glomeruli in both kidneys The 180 L of filtrate has to get processed to re-absorb key molecules and leave behind 1.5 L of urine per day.

Question 27

What happens in step 1 of the filtering process in the kidneys?

Answer 27

Na+ is actively transported out of proximal tubule into interstitial fluid. This drives passive transport of Cl- out Water then follows by osmosis H+ is secreted by the transport epithelium into the lumen of the tubule, along with ammonia (NH3), which traps the H+ as ammonium ion (NH4+).

Question 28

What happens in step 2 of the filtering process in the kidneys?

Answer 28

Water reabsorption happens via osmosis as the filtrate travels down the loop of Henle. Descending limb is permeable to water; via aquaporin proteins that provide channels for transport. Descending limb is impermeable to salts and other solutes

Question 29

What happens in step 2 of the filtering process in the kidneys?

Answer 29

Ascending limb is impermeable to water. Ascending limb has ion channels. In thin region NaCl filters out via diffusion. In thick region NaCl filters out via active transport NaCl transport is necessary to maintain osmolarity of medulla.

Question 30

What happens in step 4 of the filtering process in the kidneys?

Answer 30

The distal tubule regulates K+ and NaCl concentration of body fluids. pH regulation also at play through section of H+ and reabsorption of HCO3-

Question 31

What happens in step 5 of the filtering process in the kidneys?

Answer 31

The distal tubule empties into the collecting duct which carries the filtrate to the penal pelvis. More reabsorption of water and solute/concentration of urine

Question 32

What happens in the first downward part of the kidney?

Answer 32

As filtrate travels through the nephron, osmolarity increases along the descending arm of the loop of Henle. This is facilitated by the fact that the tube is impermeable to solutes. Medulla has higher osmolarity so water diffuses out via osmosis; allowing body to reabsorb water.

Question 33

What happens in the first upward part of the kidney?

Answer 33

As filtrate travels back up, water is conserved, because tube is impermeable to water. Filtrate has high osmolarity; so in first section salts diffuse out → this helps the medulla maintain high osmolarity. In upper part of ascending arm, salts are pumped out via active transport.

Question 34

What happens in the second downward part of the kidney?

Answer 34

Water is reabsorbed as filtrate moves down the collecting duct; concentrating the urine. Salts also reabsorbed.

Question 35

A desert animal would have what length of "loop of henle"?

Answer 35

Longer

Question 36

How do bats kidneys adapt?

Answer 36

Vampire bat drinks blood at night – so much volume that it gets too heavy to take off and fly back to roost. (Solution – excrete large volumes of very dilute urine as you feed). At night – processing proteins in the blood creates large quantities of urea, but they do not have drinking water in the cave to dilute it (Solution – excrete highly concentrated urine)

Question 37

What hormones regulate the kidneys/osmotic balance?

Answer 37

Main hormone regulating osmotic balance is antidiuretic hormone (ADH) (aka vasopressin). ADH signals are triggered by osmolarity of blood. ADH sends signals to receptor molecules on the membrane of the collecting duct. these then facilitate reabsorption of water

Question 38

How do hormones balance kidney/osmotic levels?

Answer 38

Blood osmolarity increases after sweating. Osmoreceptors in the hypothalamus trigger the release of ADH from the posterior pituitary. ADH goes to the collecting duct in the distal tubule where water reabsorption reduces blood osmolarity. THe hypothalamus generates thirst and drinking water then reduces blood osmolarity.