Lecute 7: Body Fluids Flashcards Preview

Mammalian Biology > Lecute 7: Body Fluids > Flashcards

Flashcards in Lecute 7: Body Fluids Deck (24):
1

How is the Total Body Water monitored?

By homeostatic mechanisms

2

What are organs bathed in?

External fluid

3

what does the external fluid do for organs?

provide nutrients

4

What is ICF?

Interstitial fluid is the fluid inside cells

5

What is ECF?

Extracellular fluid is comprised of plasma, interstitial fluid and other ECF

6

What are the body fluid compartments seperated by?

A selectively permeable membrane

7

What determines the composition of each fluid?

The properties of the membranes

8

What is osmosis?

The movement of water molecules from a high concentration to low concentration through a selectively permeable membrane

9

The membrane is permeable to water but not to -insert word here-

Sodium (Na+) and Chloride (CL-)

10

What does water follow?

Water follows the solute (Na+)

11

What is the osmolarity of biological solutions dictated by?

The total number of osmotically active particles present

12

How do epithelial sheets move water between different body fluid compartments?

By first transporting solutes like sodium (Na+) so that water follows

13

What is the molarity for a substance that doesn't ionise or dissociate? Give an example

The molarity and osmolarity are equal. Osmolarity = Molarity e.g. Glucose

14

What's the molarity for substances that do ionise or dissociate? Give an example

Osmolarity = ~2x Molarity e.g. NaCL = Na+ and CL-

15

Hypotonic and its consequence

There is a higher concentration of particles on the inside of the cell than the outside. The cell will take in water and possibly burst

16

Hypertonic and its consequence

There is a higher concentration of particles on the outside of the cell and a lower concentration on the inside. The cell will shrivel up

17

Isotonic and its consequence

The concentration of particles are equal on both sides. There is no net movement of water and the cell will not shrink or burst

18

Describe the steps of the sodium-potassium pump

Na+ binds to pump, stimulates phosphorylation, proteins change conformation and expell Na+, K+ binds and releases phosphate, original conformation of protein restored, K+ released and Na+ sites are receptive, repeat.

19

Symport

Movement of 2 molecules simultaneously across a membrane in the same direction.

20

Antiport

Transportation of 2 molecules in opposite directions.

21

What is the importance of the sodium-potassium pump?

It is electrogenic. It prevents cells from swelling, responsible for maintaining concentration differences and generating signals along merves and muscles.

22

Why are Ca2+ levels maintained at a very low concentration in the cytosol of mammalian cells?

Ions that are extensively used in the cell would form insoluble salts with calcium and the cell would calcify.

23

What mechanisms have cells evolved to maintain these low Ca2+ levels?

Active transport of Ca2+ out of the cell or active transport to intracellular conpartments like the ER/Mitochondria

24

Name some things that Ca2+ does

Triggers physiological processes in response to neurotransmitters, growth factors, hormones and muscle contraction