Muscles And Membranes

Question 1

Cells are defined by

Answer 1

Cell (plasma) membrane

Question 2

What is a prokaryote cell?

Answer 2

No nucleus or organelles, eg bacteria

Question 3

What is a eukaryote cell?

Answer 3

Has a nucleus and organelles

Question 4

What is the purpose of membranes?

Answer 4

To separate cells and organelles, and enable different environments on either side of the membrane

Question 5

What are membranes made of?

Answer 5

Phospholipid bilayer

Question 6

What are channels?

Answer 6

Holes that allow specific substances to freely move
- bidirectional
-passive
-diffusion and concentration driven

Question 7

What is gating?

Answer 7

Voltage/chemical/physical changes that cause channels to open or close

Question 8

What are aquaporins?

Answer 8

Channels that allow water to cross membranes, abundance in tissues w water transport

Question 9

What are carriers?

Answer 9

Transfer substances from one side of membrane to the other. Substances binds to one side, not bidirectional. Some passive, some active

Question 10

What is Na+K+ATPase?

Answer 10

Ion pump that moves 3 Na+ to outside of cell, 2 K+ to inside of cell, uses ATP

Question 11

What is diffusion?

Answer 11

Random movement of substance from high concentration to low concentration.

Question 12

What is a concentration gradient?

Answer 12

Difference in concentrations across membranes/through solvents

Question 13

How does water diffusion work?

Answer 13

Water follows high salt concentration

Question 14

What creates electrochemical potential?

Answer 14

Movement of charged particles across membranes, oowers biological processes

Question 15

Origin vs insertion

Answer 15

Origin is closest to spine, insertion is distal (close to joint to allow broad range of motion

Question 16

Isometric vs isotonic

Answer 16

Force generated w/out changing length
Vs
Length change w steady force

Question 17

Concentric vs eccentric

Answer 17

Tension during shortening
Vs
Tension during lengthening

Question 18

Efferent vs afferent nerves

Answer 18

Motor nerve coming from spine
Vs
Sensory nerve returning to spine

Question 19

What is a motor unit?

Answer 19

Motor nerve and all the muscle fibres it innervates (all fibres contract synchronously)

Question 20

Does motor unit size match its function?

Answer 20

Yes. Large units are used for force (lots of fibres all at once) and small units are used for precision (fewer fibres innervated by one nerve)

Question 21

Where do alpha motor neurons innervate muscle fibres?

Answer 21

Neuromuscular junctions (or motor end plates)

Question 22

Steps for twitching a muscle

Answer 22

1. Motor nerve conductions
2. Ca influx at terminal
3. Acetylcholine vesicles move to nerve end
4. ACh release into synaptic cleft
5. ACh activates receptor on MEP
6. Action potential propagated in musc membrane
7. ACh turnover