Exam 2 - Lecture 1

Question 1

When you deviate from resting charge, cells can be turned ____ or _____

Answer 1

on, off

Question 2

Repolarization is to reset ____

Answer 2

Fast sodium channels

Question 3

what ion has the same Voltaged-gated structure as fast Na+ channels? How do they differ?

Answer 3

Calcium (L-type), they are slower.

Question 4

Calcium channels can be blocked by ______. Where are these channels found and what are they called?

Answer 4

Dihydropyridine (DHP) calcium channel blockers, specifically found in smooth muscle and the heart. Also called L-type channels.

Question 5

Chloride permeability is adjusted to

Answer 5

Hyperpolarize or suppress electrical activity in excitable cells, typically through GABA receptors

Question 6

GABA receptors

Answer 6

Opens up chloride channels for chloride to enter the cell, make them more negative and difficult to excite.

Question 7

Process of action potential

Answer 7

initial resting state = inside pos, outside neg.

Stimulus (e.g. maybe outside electrical stimulus, cop shoots you with a taser, causing AP) causes depolarization in one area of cylinder, opening fast sodium channels, making cell more positive (depolarization), triggering more fast Na+ channels.

Causes a wave in cell of depolarization outward away from initial trigger, opening Na+ channels across the entire cell.

Na+ channels close, while slow V-G K+ opening, repolarizing the cell in the same wave direction/pattern of depolarization.

Question 8

Neurons that talk to skeletal muscles

Answer 8

Motor neurons.

Question 8

Action potential is __________ cycle.

Answer 8

Positive feedback: due to sodium coming in, causing more sodium to come in.

Question 9

Skeletal muscle tends to be

Answer 9

striated

Question 10

Process of communication between brain and skeletal muscle

Answer 10

Brain/spinal cord decides to contract muscle -> motor neuron activated (somewhere in spinal cord) -> that activation produces an action potential from brain/spinal cord to neurotransmitters that are connected to skeletal muscle inside motor neuron.

Question 11

Neuromuscular junction

Answer 11

NMJ. Area that connects neurotransmitters and receptors on the skeletal cell surface.

Question 12

What type of receptors does skeletal muscle have? Where are they also found?

Answer 12

nACh: nicotinic acetlycholine receptors, excitatory.

also found in brain, but mostly skeletal muscle cells.

Question 13

nACh have ___ binding site(s)

Answer 13

2, must be occupied simultaneously.

Question 14

Acetylcholine is a type of ______

Answer 14

neurotransmitter

Question 15

Nicotine can mimic

Answer 15

Acetylcholine being released from motor neurons.

Question 16

nACh receptor characteristics

Answer 16

Donut shaped protein in cell wall. Lined with amino acids with negative charges. These negative charges repel/prevent negatively charged electrolytes from moving through channel.

Question 17

nACh channels are specific for _________ ions

Answer 17

Positively charged. Mostly sodium current.

Question 18

Small amounts of ___ leaks out through these nACh receptor channels

Answer 18

Potassium. Mostly prevented from coming out due to sodium flowing in so fast.

Question 19

Small amounts of ____ come in through nACh receptor channels with Na+

Answer 19

Calcium. It will also depolarize the cell with Na+, but much much much less comes in. Calcium is BIG and CLUNKY.

Question 20

When nACh channels are exposed to depolarization, ______ are opened up nearby.

Answer 20

Fast Na+ channels, allowing more sodium to come in.

Question 21

Paralytics work on the

Answer 21

NMJ.

Question 22

Skeletal muscle is part of the intracellular or extracellular container?

Answer 22

Intracellular.

Question 23

mACh-R, and where are they found? What do they do?

Answer 23

Muscarinic acetylcholine receptors. Found in heart, smooth muscle, lungs. Influence hyperpolarization by opening potassium channels.

Question 24

In the heart, mACh-r are found where?

Answer 24

SA and AV node

Question 25

Vagus nerves

Answer 25

come in contact with pacing structures in the heart

Right vagus nerve = predominantly SA node, left side of heart.

Left vagus nerve = predominantly AV node, septum

They release: acetlycholine

Question 26

mACh-r are what type of receptors?

Answer 26

GPCRs

Question 27

mACh-r work by opening which channels?

Answer 27

Open K+ channels to hyperpolarize the heart, influencing pacemaker ability. They lower the Vrm.

Question 28

Heart has an abnormally large amount of _______

Answer 28

Sodium leaking in, giving pacemaker activity and generating an action potential (heartbeat)

Question 29

Acetylcholine is released from vagus nerves all the time to

Answer 29

Keep the heart rate down.

Question 30

Absence of muscarinic activity in the heart causes _____

Answer 30

HR to go up

Question 31

How does atropine work?

Answer 31

Inhibiting muscarinic activity

Question 32

Another receptor on heart that antagonizes mACh-r activity

Answer 32

Beta receptors (B-R)

Question 33

Another way to turn a neuron on

Answer 33

Physical pressure (anywhere we can sense pressure)

Question 34

Baroreceptors

Answer 34

Pressure sensor in heart

Question 35

When theres not alot of pressure on sensor, there is ______ sodium permeability

Answer 35

minimal.

(not alot of sodium going into cell, may or may not be enough to cause an action potential and send signal to brain)

Question 36

When theres a ton of pressure on sensor and sensor flattens/widens, then _________ comes in and causes an action potential to send signal to brain.

Answer 36

More sodium

Question 37

How is an action potential measured in a neuron? What about the heart?

Answer 37

Milliseconds and seconds