Cells and the internal environment

Question 1

What are the 3 major fluid compartments in the body?

Answer 1

Blood plasma, interstitial fluid, intracellular fluid

Question 2

What is the body weight % of blood plasma?

Answer 2

5%

Question 3

What is the body weight % of interstitial fluid?

Answer 3

15%

Question 4

What is the body weight % of intracellular fluid?

Answer 4

40%

Question 5

What is the body weight % of extracellular fluid?

Answer 5

20%

Question 6

What are the 3 internal environments that we absorb water from?

Answer 6

Blood vessels, stomach, intestine

Question 7

From the internal environment, where does the fluid pass through first?

Answer 7

Blood plasma

Question 8

From the blood plasma, where does the fluid pass too?

Answer 8

Lungs, kidneys, interstitial fluid

Question 9

What separates the blood plasma and interstitial fluid?

Answer 9

Two compartment capillary wall

Question 10

What separates the interstitial fluid and intracellular fluid?

Answer 10

Cell membrane

Question 11

What does the process of having a cell membrane achieve?

Answer 11

Osmotic equilibrium

Question 12

What is the general trend in extra vs intra fluids ion concentrations?

Answer 12

Extracellular has high concentrations of Na and Cl but low concentrations of K and protein. Intracellular has low concentrations of Na and Cl but a high concentration of K and protein.

Question 13

Why does intracellular fluid have a high protein concentration?

Answer 13

Enzyme reactions

Question 14

What is the composition of intra vs extra cellular fluids called?

Answer 14

Chemical disequilibrium

Question 15

Why does a chemical disequilibrium occur?

Answer 15

Differences in the composition and cell membranes permeability to molecules

Question 16

What molecule properties makes it hard to cross a membrane?

Answer 16

Large size, low lipid solubility, high charge

Question 17

What is the most important factor that affects permeability?

Answer 17

Charge

Question 18

What is a membrane impermeable to?

Answer 18

Sugars, amino acids, peptides, proteins and inorganic ions

Question 19

What is diffusion?

Answer 19

Diffusion is the process of random collisions causing molecules to move down a gradient from a high to low concentration to make an equilibrium

Question 20

What is filtration?

Answer 20

Filtration occurs under a high pressure and a porous membrane which will only allow molecules of a certain size through

Question 21

What is an example of filtration?

Answer 21

Kidney

Question 22

What is osmosis?

Answer 22

Osmosis is the movement of water across a membrane in response to a solute concentration gradient. It moves from low to high solute gradient

Question 23

What is osmotic pressure?

Answer 23

Pressure which would prevent water moving

Question 24

What is protein mediated transport?

Answer 24

PMT is where proteins act as carriers and channels to facilitate the flow of substances that cannot permeate through the lipid bilayer

Question 25

What are 2 examples of molecules which us PMT?

Answer 25

Ions and large unionised molecules

Question 26

What process happens to allow PMT

Answer 26

Facilitated diffusion down a concentration gradient. No energy is required. Active transport against a concentration gradient, ATP is used

Question 27

Describe endocytosis:

Answer 27

Endocytosis is the process of a molecule being engulfed by the cell membrane into the cell

Question 28

What 2 ways are there for endocytosis:

Answer 28

Pinocytosis - pinches off pockets

Phagocytosis - engulfing

Question 29

What is exocytosis?

Answer 29

The process of hormones and neurotransmitters leaving the cell