Homeostasis

Question 1

What is the typical magnitude of the RMP?

Answer 1

-70mV

Question 2

What is the testing membrane potential? (RMP)

Answer 2

RMP refers to the fact that the inside of the cell membrane is negatively charged compared to its external surface

Question 3

What do unicellular organisms depend on to survive?

Answer 3

The immediate external environment must provide conditions conductive to their survival.

Question 4

What must be maintained within acceptable limits for multicellular organisms?

Answer 4

The extracellular fluid (ECF) must be maintained within acceptable limits, however the external environment may vary, unlike with unicellular organisms.

Question 5

Why should the ECF remain constant?

Answer 5

Maintaining the constancy of the extracellular fluid allows multicellular organisms to explore and function in a diverse range of environments.

Question 6

What are the normal ranges of sodium in the ECF?

Answer 6

135-145mmol/L

Question 7

What are the normal concentrations of calcium in the ECF?

Answer 7

2.2-2.6mmol/L

Question 8

What are the normal concentrations of glucose in the ECF?

Answer 8

Non fasting: 3.5-6mmol/L

Fasting: 3.5-8mmol/L

Question 9

What are the normal limits of potassium in the ECF?

Answer 9

3.5-5mmol/L

Question 10

What is the normal pH range in the ECF?

Answer 10

7.35-7.45

Question 11

What is the normal core body temperature?

Answer 11

36-37.5 degrees Celsius

Question 12

Define osmolarity.

Answer 12

Osmolarity is a measure of the total number of solute particles per litre of solution.

Question 13

What are the normal ranges of osmolarity in the ECF and ICF?

Answer 13

275-300mosmol/L

Question 14

Define tonicity.

Answer 14

Tonicity specifically refers to the effect that a solution has on cell volume.

Question 15

What are the differences between hyper, hypo, and isotonic solutions?

Answer 15

Hypertonic solutions will cause cells to shrink.
Hypotonic solutions will cause cells to swell.
Isotonic solutions will cause no change in cell volume.

Question 16

What is the difference between osmolarity and tonicity?

Answer 16

Osmolarity is a property of a particular solution (in depended of any membrane). Tonicity is a property of a solution with reference to a specific membrane.

Question 17

What are the key components of a negative feedback system?

Answer 17

Sensor
Integrator
Effector(s)
Communication pathways

Question 18

What are the 2 physiological communication pathways?

Answer 18

Neuronal and hormonal.

Question 19

When would a neuronal pathway be used?

Answer 19

When conditions are changing rapidly and an immediate response is required to prevent harm.

Question 20

When would a hormonal pathway be used?

Answer 20

When a widespread, sustained response is required.

Question 21

What is feed-forward?

Answer 21

Detection or anticipation of external or internal conditions or situations that could alter a regulated variable or disrupt homeostasis if some sort of preemptive action is not taken.

Question 22

What is positive feedback?

Answer 22

A response to a stimulus that moves the controlled variable even further away from the set point.