Osmoregulation

Question 1

What specific variables or factors are regulated as part of osmoregulation?

Answer 1

Osmoregulation- regulation of fluids in the body
- total water content (ECF volume)
- overall osmolarity of ECF
- concentrations of specific solutes in ECF ( important ions/electrolytes: Na+, K+, Ca2+, Cl-
- gets rid of nitrogenous waste

Question 2

What satisfies the cells?

Answer 2

Regulating the ECF
- Water flux: total water volume and concentration

Question 3

Energy?

Answer 3

• It takes more energy to reabsorb the “good”
• Osmoregulation is effective at eliminating toxins

Question 4

Excretion

Answer 4

Moves excess/unwanted things OUT of the ECF

Question 5

Secretion

Answer 5

Moves anything OUT of the ECF

Question 6

Absorption

Answer 6

Moves substances INTO the ECF

Question 7

Reabsorption

Answer 7

After moved OUT (secreted), being back in and absorb

Question 8

Filtration

Answer 8

Process of forcing solution through biological sieve

Question 9

Different types of nitrogenous waste

Answer 9

Ammonia
- easy for aquatic animals (diffusible)
- MOST efficient
- very toxic
- low energy loss

Urea
- favorable by terrestrial animals
- somewhat toxic
- med energy loss
- concentrated through urine

Uric Acid
- so insoluble it precipitates out
- NOT toxic
- high energy loss (EX- birds: white in poop)

Question 10

All freshwater organisms

Answer 10

-Very dilute, animals cannot survive
-Bodies must be more concentrated

Question 11

Marine mammals

Answer 11

Most species are at sea water concentration
EXCEPT bony fish

Question 12

Sea water concentration OUTSIDE > body fluids (shark)

Answer 12

ISOTOMIC
- Na moves in through diffusion
- Electro gradient favors Na+ ( and Cl-) influx

NaCL influx (absorption)- gills and food
NaCl efflux (excretion)- rectal gland, urine

Question 13

Sea water concentration OUTSIDE > body fluids (fresh water fish)

Answer 13

HYPEROSMOTIC - less concentrated

NaCl influx- eat/drink, gills have secondary active transport to make up for loss
NaCl efflux- prod. dilute urine to eliminate water

Question 14

Sea water concentration OUTSIDE > body fluids (Marine Fish)

Answer 14

• Draws water OUT and ions diffuse IN!
• Uses ammonia to gain energy, diffuses it after

NaCl influx- drinks seawater, food, diffusion
NaCl efflux- gills active transport + lose ions, osmosis, urine

Question 15

How co-transport of one substance down its gradient can be used to move another up its gradient.

Question 16

A substance is most likely to diffuse into a cell when

Answer 16

The concentration of the substance is greater outside the cell than inside.

Question 17

How an electrical gradient can be created across the epithelium to draw ions of opposite charge across.

Answer 17

Through ion channels