Physiology Lecture 2

Question 1

Distribution of H2O in the body

Answer 1

-40L
-57% of total weight
-67% found in the intracellular compartment
-33% found in extracellular compartments
-20% of that 33% is found in the blood (forms the blood plasma)
The other 80% is found between the cells (interstitial fluid)

Question 2

Distribution of Molecules in different body compartments

Answer 2

NA+ 140mmol/L in EFC, 15mmol/L in IFC

K+ 4mmol/L in EFC, 150mmol/L in IFC

Question 3

MATERIALS MOVE FROM ________ TO _________UNLESS ARE SOME HOW PREVENTED FROM DOING SO!!!!!!!!!!!

Answer 3

High concentration to low concentration

Question 4

What is diffusion?

Answer 4

Movement of particles down a concentration gradient resulting in equal distribution of particles

Question 5

What biological molecules move by simple diffusion?

Answer 5

Oxygen, nutrients, and small molecules

Question 6

As molecules become warmer, they ______.

Answer 6

Move more quickly

Question 7

With a freely permeable membrane, do molecules still move down their concentrationo gradient?

Answer 7

Yes

Question 8

What organ is reliant on diffusion?

Answer 8

Kidneys

Question 9

If a membrane is semipermeable to small molecules but not large molecules what happens?

Answer 9

There will be an equal distribution of small molecules on either side but the large molecules will stay on one side.

Question 10

Cell membrane is often referred to as the ________ and is composed primarily of ______ and _______.

Answer 10

Lipid bilayer

Lipids and proteins

Question 11

Difference between hydrophilic and hydrophobic molecules.

Answer 11

Hydrophilic

• Water loving
• Interact w/ charged (polar) molecules
• proteins, vitamins, ions, hormones
• Difficult to move across cell membrane

Hydrophobic

• Water hating
• Interact w/ uncharged (non-polar) molecules
• ETOH, fatty acids, steroids
• More easily move across cell membrane

Question 12

Would our cells work if they were either completely permeable or completely impermeable?

Answer 12

No, we want to be able to regulate what’s allowes through the membranes

Plasma membranes are leaky

Question 13

This unequal distribution of ions creates a membrane that tends to be __________ on the inside and _______ on the outside.

Answer 13

Negatively charged on the inside and positively charged on the outside

Question 14

A failure to appropriately regulate/ control/ manage transport process disrupts _______.

Answer 14

homeostasis

Question 15

Which molecules move through the membrane very rapidly?

Answer 15

Non-polar (uncharged, lipid soluble, hydrophobic)

Question 16

Increasing the lipid solubility of a molecule will _________.

Answer 16

Increase its rate of diffusion across the lipid bilayer.

Question 17

Ions are polar and thus…

Answer 17

Have difficulty moving across the membrane

Question 18

What are ion channels?

Answer 18

Openings that allow specific charged molecules to move through

Question 19

The concentration gradient also creates an __________.

Answer 19

Electrical gradient

Question 20

Ion channels allow for regulation of the movement of ions. The resulting seperation of charges creates an electrical gradient which influences ion movement in what way?

Answer 20

Pulls positive ions (+) into a cell
Pulls negative ions (-) out of the cell

Occurs because the inside of the cell is negatively charged.

Question 21

What is the electrochemical gradient?

Answer 21

It is the combination of both the electrical and concentration gradients.

Question 22

In a cell at rest, what is the Resting Membrane Potential?

Answer 22

-60 to -75 mV

Question 23

Movement through ion channels is regulated by?

Answer 23

Concentration gradient and charge

Question 24

What is mediated transport?

Answer 24

Involves using transporters to move molecules through the membrane. Transporter molecules may move molecules up or down a concentration gradient.

Question 25

Glucose is dependent on _____________.

Answer 25

Mediated transport system

Question 26

Where is GLUT4 primarily found?

Answer 26

Muscle tissue

Question 27

What is defective in type 2 diabetes?

Answer 27

Transporter

With type 2 diabetes we want to improve the functionality of glucose transporters, thus increase uptake of glucose.

Question 28

What 3 factors determine the magnitude of solute flux achieved through a mediated transport system

Answer 28

1. The number of transporters available
2. The speed at which transporters undergo conformation change and move the solutes
3. Extend to which the binding sites are saturated

Question 29

What is facilitated diffusion?

Answer 29

Net movement remains from high to low concentration but doesn’t go through the membrane on its own. It uses transporters across the membrane.

L2S52

Question 30

What is active transport?

Answer 30

Requires energy (ATP)

Molecules can move from low-to-high or high-to-low.
Involves the expenditure of ATP and specific carrier molecules or biological pumps

Question 31

Net Effect

Answer 31

A shape change in the pump occurs that extrudes 3 Na+ ions into the extracellular fluid for every 2 K+ moved into the interior of the cell

inside of cell becomes negatively charged. K+ > Na+

Question 32

T or F. Membranes are slightly permeable to NA+.

Answer 32

False.

Membranes are slightly permeable to K+ (leaky), but are relatively impermeable to Na+

Question 33

What is endocytosis?

Answer 33

Process by which a piece of the cell membrane engulfs an organism, molecule, etc. The resulting vesicle then enters the cell and is degraded

Phagocytosis

Question 34

What is exocytosis?

Answer 34

Opposite on endocytosis.

Vesicle formed inside cell, fuses with membrane releasing the contents into the extracellular space.

Example is insulin

Question 35

What is osmosis?

Answer 35

The movement of water molecules from high water conc to low water conc.

Question 36

What does adding a solute to water do in regards to its concentration?

Answer 36

Decreases the concentration of water in the solution

Question 37

Solutes that cannon cross a membrane and promote osmosis are called _______.

What are some examples?

Answer 37

osmotically active molecules

Hemoglobin in red blood cells are osmotically active

Large proteins (often carry electrical charges) are osmotically active

Question 38

The movement of water across a membrane that is permeable to water but not to solute leads to an equilibrium state ____________.

Answer 38

…involving a change in the volumes of the two compartments.

Question 39

What is osmotic pressure?

Answer 39

The force required to stop the osmotic movement of water.

Question 40

Hypertonic solution

Answer 40

blood cells have more water so they come out of red blood cells

Question 41

Hypotonicity vs Hypertonicity

Answer 41

Hypotonicity: has a lower concentration of solutes than another solution; higher concentration of water

Hypertonicity: has a greater concentration of solutes than another solution; lower concentration of water

Question 42

What is the epithelium?

Answer 42

The outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body.

Question 43

What is the endothelium?

Answer 43

is the layer of cells lining the closed internal spaces of the body such as the blood vessels and lymphatic vessels