Module 3

Question 1

What is negative feedback

Answer 1

Change in a factor that triggers an opposite reaction
- it shuts off on its own

Question 2

What is positive feedback
Give examples

Answer 2

Change in a factor that triggers a response in the same direction
- contractions during birth
- outside factor needed to shut off

Question 3

What is feedforward regulation?
Give examples

Answer 3

Response to smthg before the reaction is even made
- saliva in the mouth
- skin detects temp change and warms body

Question 4

Ways of water loss

Answer 4

• evaporation
• sweat
• feces
• kidneys (urine)

Question 5

Distribution of body water inside and outside

Answer 5

2/3 of body water inside the cell, 1/3 outside

Question 6

The concentration of substances in the plasma and interstitial fluid is the same except plasma has …

Answer 6

Proteins

Question 7

What is
-molarity
-molality
-osmolality
Respectively

Answer 7

• one mole of solute dissolved in 1 L solution
• one mole solution dissolved in 1 kg solvent
• total molality of solution

Question 8

Direction of water flow in osmosis

Answer 8

Water flows from high to low concentration
- hypotonic to hypertonic

Question 9

Direction of solute in osmosis

Answer 9

From low to high concentration

Question 10

Difference btwn neurotransmitters and messengers

Answer 10

Neurotransmitters- communicate rapidly over a short distance
Messengers- communicate slowly over a larger distance

Question 11

What are first and second messengers

Answer 11

First messenger: comes from extracellular fluid to bind to the receptor
Second messenger: produced in the cytoplasm of the cell and is formed bc of the receptor activation from the first messenger

Question 12

Briefly explain cell signaling

Answer 12

The ligand first messenger binds to receptors which causes a change in shape. This activates JAK kinases which leads to the production of new proteins that help generate a response.

Question 13

Rate of diffusion is determined by

Answer 13

• amount of substance (concentration)
• velocity
• available openings
• solubility

Question 14

Differences btwn simple and facilitated diffusion

Answer 14

Simple: no carrier protein needed, rate of diffusion increases proportionately with amount of concentration
Facilitated: with carrier protein, after some time diffusion rate becomes constant bc there is a concentration limit.

Question 15

Difference btwn primary and secondary active transport

Answer 15

Primary needs ATP, secondary uses na/k pump. The pump needs ATP

Question 16

Net charge of cell inside and outside

Answer 16

Inside cell is negative, outside is positive bc 3 Na is pumped out, 2 K is pumped in

Question 17

What is secondary active transport

Answer 17

The transport that is made with the energy released after primary transport

Question 18

Which channel is responsible for depolarization of membrane in action potential

Answer 18

Voltage gated Na channel

Question 19

What is the value of resting membrane potential?

Answer 19

-70
Its -55 when its open

Question 20

When do voltage gated K channels open?

Answer 20

Opens when the membrane potential changes and then later repolarizes the membrane to -75, causing hyper polarization( membrane becomes more negative)

Question 21

True or false:
Voltage gated K channels operate with positive feedback

Answer 21

False,
Na channels operate with positive feedback
K channels operate with negative feedback

Question 22

What is relative refractory period?

Answer 22

Small period in which a second active potential can be produced, but the stimulus has to be greater than it usually is

Question 23

Can you have a second active potential during absolute refractory period?

Answer 23

No

Question 24

What is inhibitory post synaptic potential caused by?

Answer 24

Opening of Cl/K channels, causes hyperpolarization
- less likely to reach the threshold

Question 25

Difference between temporal and spatial summation

Answer 25

Temporal: presynaptic neurons send impulses rapidly
Spatial: presynaptic neurons send impulses at once at the same time

Question 26

Example of parasthesia

Answer 26

Spontaneous pain like needles digging into your skin