CHAPTER 1

Question 1

Homeostasis

Answer 1

Maintenance of internal conditions, stability via negative feedback loop.

Question 2

Negative Feedback

Answer 2

Initiation of responses that counter deviations of a variable from normal range

Question 3

What is the main goal of homeostasis?

Answer 3

To maintain optimal conditions for cellular function

Question 4

What are the four components of Negative Feedback?

Answer 4

• Set point (target)
• Sensors/receptors (monitor the controlled variable)
• Comparator (input fro receptors determine when deviations occur initiating response)
• Effectors (restore set point to its normal level)

Question 5

Two major functional compartments of body fluid

Answer 5

Intracellular Fluid (ICF)- 60% of vol
& 
Extracellular Fluid (ECF)- 40% of volume

Question 6

What are the two components that make up the extracellular fluid and their proportion?

Answer 6

Interstitial Fluid (80% of ECF)

Plasma (20% of ECF)

Question 7

Concentration of Na+, K+,CI- and Protein in ICF

Answer 7

Sodium- low
Potassium- high
Chloride- low
Protein- high

Question 8

Concentration of Na+, K+,CI- and Protein in interstitial fluid?

Answer 8

Sodium- high
Potassium- low
Chloride- high
Protein- should be zero! (Do not want protein here)

Question 9

Concentration of Na+, K+,CI- and Protein in plasma

Answer 9

Sodium- high
Potassium- low
Chloride- low
Protein- low

Question 10

Active Transport uses __

Answer 10

ATP

Question 11

Primary vs Secondary Active Transport

Answer 11

Primary- membrane proteins that directly couple ATP hydrolysis to movement

Secondary- movement of two solutes together, energy is used to develop a driving force for one solute which is then used to power the transport of another.

Question 12

What were the four examples of primary active transport?

Answer 12

Ca2+/ATPase
H+/ATPase
H+/K+ATPase
MDR (multi-drug resistance) transporters

Question 13

Na2+/K+ATPase

Answer 13

• example of primary active transport
• 3 sodium in, 2 potassium out
• Accounts for high sodium outside the cell and high potassium inside the cell.

Question 14

Ca2+/ATPase

Answer 14

• example of primary active transport

- plasma mean-brand and endoplasmic reticulum; functions to keep low intracellular calcium

Question 15

H+/K+ATPase

Answer 15

• example of primary active transport
• hydrogen out the cell for potassium in
• acidic gastric juice in stomach

Question 16

MDR transporters

Answer 16

• example of primary active transport
• extrude molecules from cell
• expressed in the liver, kidney and BBB

Question 17

H+-ATPase

Answer 17

• example of primary active transport

- inside cells, acidified lysosomes

Question 18

What are the two types of Secondary active transport?

Answer 18

Cotransporters (symporters)- same direction

Exchangers (antiporters)- opposite directions

Question 19

Passive Transport

Answer 19

• does not require ATP

- only occurs along favorable electrochemical gradient

Question 20

What is the driving force for diffusion?

Answer 20

Permeability

Question 21

Membrane permeability is proportional to ________ and inversely proportional to ___________.

Answer 21

Lipid solubility

Molecular size

E.g. gases move easily because lipid soluble and small!

Question 22

Simple Diffusion

Answer 22

(passive transport)

Along concentration gradient

Question 23

Facilitated diffusion

Answer 23

(passive transport)

-faster than simple diffusion; saturation of the transport at high solute concentration

Question 24

Ficks Law of Diffusion

Answer 24

Net flux per unit area is a factor of PERMEABILITY of the solute and the concentration difference of that solute across the membrane.

(Basically: 1. is it even permeable? 2. Does it favor the concentration gradient?)

Question 25

Permeability is the driving force of _______

Answer 25

Diffusion

Question 26

What are three examples of gated ion channels?

Answer 26

Voltage-gated
Ligand-gated (chemicals)
Mechanical forces (e.g. stretch-activated)