Chapter 40: Osmoregulation

Question 1

Osmoregulation

Answer 1

o Regulation of solute concentrations in blood stream
o Regulation of water in result of the concentrations in the blood stream
- Regulations of important ions (sodium, potassium, calcium)

acid-base balance

Question 2

Osmoconformers

Answer 2

organisms that maintain a tissue osmolarity similar to their environment

Environment determines a lot of features for the salt concentration, osmotic pressure, etc.

Example: leopard shark

Question 3

Osmoregulators

Answer 3

do lots of work to maintain osmolarity different from their environment

example: Whitemouth croaker

Question 4

Marine fish environment

Answer 4

Lives in hypertonic environment

Must excrete solutes

Constantly gaining electrolytes via diffusion

Must retain H20

Question 5

Freshwater fish

Answer 5

Lives in hypotonic environment

Water constantly going in to dilute its salty body

Must excrete H20

Must retain solutes

Question 6

Lifestyle strategies to multiple different life stages

Answer 6

Lifestyles can include water changes for some organism
Sea bass in seawater vs. freshwater

Moving into freshwater, active transporter grabs things to transport into membrane

Question 7

Lifestyle strategies to multiple different life stages

Answer 7

Lifestyles can include water changes for some organisms

Sea bass in seawater vs. freshwater

Moving into freshwater, active transporter grabs things to transport into membrane

Question 8

Insect osmoregulatory organs

Answer 8

goes from midgut to hindgut

includes malpighian tubules, hemolymph, and midgut & hindgut

Question 9

Malpighian tubules

Answer 9

: specialized process of secretion
* Actively transport ions and other solutes from hemolymph into tubules; creates concentration gradient, driving water out of tubules to hindgut
* Moves particles out of tissues (from hemolymph) to be excreted

Question 10

Hemolyph

Answer 10

passes blood in insect, insect blood; balances water and ions
o Have nitrogenous waste, electrolytes, and water in pre-urine
o Has digested food go through hindgut with these
o Will produce final urine and feces, with electrolytes and water excreted out

Question 11

midgut

Answer 11

absorbs nutrients from insect’s diet

Question 12

hindgut

Answer 12

responsible for reabsorption of water and ions from feces before excreted

Question 13

Terrestrial animal osmoregulatory organs unique ability

Answer 13

highly concentrated urine; lose water by evaporation from gas-exchange and other surfaces

Question 14

Mammalian urinary system

Answer 14

Relies on functional units in the kidneys called nephrons
 Maintain salt, water balance
 Excrete nitrogenous wastes
 **occasionally reabsorbs water, but not common

Most nephrons in cortex, some extend to medulla

Question 15

Process of urination release

Answer 15

 Kidney -> ureter -> bladder -> urethra

Question 16

Nephrons

Answer 16

multicellular structure that filters out the stuff unwanted, keeps the wanted materials

Question 17

Three major functions of nephrons

Answer 17

filtration, reabsorption, and secretion

Question 18

Filtration

Answer 18

The first step in urine formation is filtration, which occurs in the glomerulus, a network of small blood vessels within the nephron.

Blood is delivered to the glomerulus via the afferent arteriole and exits via the efferent arteriole.

As blood flows through the glomerulus, water and solutes are forced through the capillary walls and into the Bowman’s capsule, a hollow structure that surrounds the glomerulus.

This forms a filtrate that contains water, ions, and small molecules, but not larger molecules like proteins and blood cells.

Question 19

Reabsorption

Answer 19

After filtration, the filtrate passes through the renal tubule, where selective reabsorption occurs.

This is the process by which the nephron reabsorbs useful substances such as glucose, amino acids, and ions back into the bloodstream.

Reabsorption occurs via active and passive transport mechanisms, and it is regulated by hormones such as antidiuretic hormone (ADH) and aldosterone.

By reabsorbing useful substances, the nephron helps to maintain the body’s fluid balance and prevent the loss of important nutrients.

Question 20

Secretion

Answer 20

The final step in urine formation is secretion, which involves the active transport of certain substances from the blood into the renal tubule.

This includes the secretion of hydrogen ions (H+) and potassium ions (K+) to regulate the body’s acid-base balance, as well as the secretion of certain drugs and toxins.

Secretion occurs in the proximal and distal convoluted tubules, and it is also regulated by hormones such as aldosterone and atrial natriuretic peptide (ANP).

Question 21

What do nephrons do together?

Answer 21

o Interacts heavily with blood supply

the three major functions of nephrons work together to regulate the composition of body fluids and remove waste products from the body.

The kidneys are vital organs that play a critical role in maintaining homeostasis and ensuring the proper functioning of the body’s organs and tissues.

Question 22

Glomerular Filtration

Answer 22

Phorocyte’s prevent bursting (from fluid pressure)

Some fluid leaks out from blood, carrying solutes

Blood cells and platelets kept in capillaries

Everything else for the most part filtered into space between glomerulus and bowman’s capsule

Question 23

What does filtration stricly rely on?

Answer 23

blood pressure to push fluid and solutes into space!

Question 24

Human Example of Nephrons

Answer 24

o Room being reorganized when going after college
 Filtration: all your things thrown into a box, no matter what it is from your room
 Reabsorption: going through the boxes and keeping certain items you really need/means a lot to you, other things lead to disposal
 Secretion: thing you decide to keep is thrown out by someone else anyways (that sucks)

Question 25

Tubule structres

Answer 25

Important in reabsorption

lumen, epithelial cells, microvillie

Question 26

Lumen

Answer 26

where filtrate flows through

Question 27

epithelial cells

Answer 27

line lots of cavities, make up tubule

Question 28

microvilli

Answer 28

contacts lumen, Moving filtrate’s wanted items through epithelial cells to be reabsorbed back into blood

Question 29

Reabsorption process of Na/K pump

Answer 29

toward blood supply, because you want sodium to pump back into blood

Pumps potassium in other direction; Active transport

Creating low sodium concentration in epithelial cells/proximal tubule

Glucose is able to be reabsorbed when moved along with sodium; Flows down concentration gradient back into blood ; Chloride vitamins can also be a secondary messenger transport and then facilitated diffusion to be moved back into blood

Reabsorption happening for the most part from ATP from Na/K pump

Question 30

Selective permeability in Loop

Answer 30

Permeability of tubule changes from descending limb -> loop of henle -> ascending limb (ascending Becomes a saltier area from sodium and chlorides leaving the area)

Three regions in loop of henle

Question 31

Materials in reference to Reabsorption

Answer 31

o Water and solutes filtered are returned to blood and reabsorbed
o 100% of glucose
o Most Na, Cl, proteins, carbs, Ca2+, vitamins, etc. reabsorbed in proximal tube
o 50% of urea reabsorbed to balance osmotic pressures
o Alterations to the rest of items reabsorbed further downstream

Question 32

Materials in reference to Secretion

Answer 32

o Elimination of Waste products
o Transport out blood and into kidney tubules for elimination
o Mostly K+ and H+
 Affect muscle and nervous system cells ability to repolarize and depolarize, causing (in worst cases) cardiac arrest

Question 33

ADH

Answer 33

anti-diuretic hormone: causes tubules cells to insert aquaporins channels into their plasma membranes, making it easier to absorb water

Question 34

Water rentention with ADH

Answer 34

o In the presence of ADH, aquaporins are inserted into collecting duct

Happens into distal tubule and collecting duct primarily; Water conserving method, allows to reabsorb water; Released when plasma osmolarity increases
o Negative feedback loop
o Higher concentrations connect to osmoreceptors in hypothalamus, causing thirst; drinking water creates negative feedback and back into loop with sensor

Question 35

What happens when water is unavailable?

Answer 35

posterior pituitary gland senses this and will have increased ADH secretion, opening up more channels to reabsorb water from urea if needed

focusing on “as needed” areas in reabsorption

Question 36

High ADH level

Answer 36

collectin duct highly permeable to water

Question 37

Low ADH level

Answer 37

collecting duct not permeable to water

Question 38

Aldosterone

Answer 38

o Targets kidneys
o Increases reabsorption of Na+ and H20 across the distal convoluted tubule
o Increases secretion of K+ into the tubule
o Occurs when blood pressure low, K+ high
 Reabsorbing water and sodium brings blood pressure back up

Question 39

Nitrogenous Wastes

Answer 39

break down of nucleic acids and amino acids (NH3)

Amino and nucleic acids -> catabolism -> ammonia by-product

Question 40

Organisms with nitrogenous waste of Ammonia

Answer 40

bond fish, aquatic invertebrates

Question 41

Organisms with ammonia coverted to urea

Answer 41

amphibians, cartilganegous fish

conversion to urea lowers toxicity of waste hanging out in body

Question 42

Organisms with ammonia converted to uric acid

Answer 42

takes more energy

birds, reptiles, insects