Nervous System

Question 1

2 Parts of PNS

Answer 1

1. Somatic Nervous System
2. Autonomic Nervous System

Question 2

Purpose of Somatic Nervous System

Answer 2

controls skeletal muscles

Question 3

Purpose of Autonomic System

Answer 3

controls everything somatic doesn’t

Question 4

2 Parts of Autonomic Nervous System

Answer 4

Sympathetic

Parasympathetic

Question 5

Sympathetic

Answer 5

Fight or Flight

See the Bear

Question 6

Parasympathetic

Answer 6

Rest and Relax

See the Beer

Question 7

2 Hormones Important to Sympathetic

Answer 7

Epinephrine and Norepinephrine

• hormones when released from adrenal medulla as endocrine hormones (most epinephrine)
• released from nerves as neurotransmitters (mostly norepinephrine)

Question 8

What makes up the Input region of a nerve?

Answer 8

Soma and Dendrite

• comprised of ligand gates
• gates open when ligand binds to a receptor
• influx or efflux of ions
• changes resting potential (-70mV)

Question 9

Resting Potential

Answer 9

-70

Question 10

What happens during depolarization?

Answer 10

influx of K+, becomes less negative and the current spreads

Question 11

Importance of Axon Hillock

Answer 11

• where soma meets axon
• where Na+ gates start
• no ligand gates
• beginning of voltage gates

Question 12

When do Na+ gates open?

Answer 12

when threshold potential is reached

Question 13

At what voltage do Na+ gates open?

Answer 13

When voltage drops to -50, Na+ rushes in.

Question 14

Why doesn’t Na+ go towards the soma?

Answer 14

Because that is where the relatively (+) came from

Question 15

Describe Na+ propagation.

Answer 15

• Na+ propagates toward the right, down the axon towards the terminal knob.
• Opens up more Na+ gates along the way allowing more charge to enter
• gates switch at terminal knob

Question 16

Terminal Knob

Answer 16

• Ca+ voltage gates begin and start to open at -50 as well
• Ca+ enters cell because higher [] outside
• Ca+ binds vesicles (containing NT) causing it to fuse with terminal knob
• vesicle becomes part of plasma membrane
• NT is exocytosed into synaptic cleft

Question 17

Where is threshold potential reached?

Answer 17

axon hillock

Question 18

-70 to -50

Answer 18

Na+ ligand gates on soma and dendrites

Question 19

@ -50

Answer 19

Na+ voltage gates open

Question 20

At Top

Answer 20

K+ at top of hill that open

Question 21

What drives sodium?

Answer 21

electro-chemical drive

Question 22

What causes repolarization?

Answer 22

K+ voltage gates, at rest- more K+ inside

Question 23

Equilibrium Potential of K+

Answer 23

-90

Question 24

When does K+ stop movement?

Answer 24

at -90

Question 25

What does K+ want to do at resting potential?

Answer 25

leave cell

Question 26

What reestablishes the chemical gradient in neuron?

Answer 26

Na+/K+ pump (uses 1 ATP per pump)

Question 27

What is resting potential of Na+?

Answer 27

+60

Question 28

At resting potential, describe leakiness of cell.

Answer 28

cell is more leaky to K+ than Na+ because resting potential of Na+ is +60 (why it rushes in)

Question 29

What is responsible for the resting membrane potential?

Answer 29

leaky K+ gates

Question 30

3 Fates of Neurotransmitter

Answer 30

1. Reuptake 2. Broken down by enzyme in cleft 3. can diffuse away

Question 31

Which enzyme breaks down acetylcholine in cleft?

Answer 31

acetycholine esterase

Question 32

What is the main parasympathetic neurotransmitter?

Answer 32

Acetylcholine

Question 33

Relationship of Acetylcholine and muscles

Answer 33

Acetylcholine binds to muscle receptor in T-tubule which is contiguous with sarcoplasmic reticulum and SR depolarizes to allow intracellular [Ca+] to rise

Question 34

Hyperpolarization

Answer 34

takes resting potential from -70 to -90 which is much more stable because it is further from action potential

Question 35

Hypopolarization

Answer 35

ready to fire might sit at -60 rather than -70 rapid action potentials to fix: give drug that hyperpolarizes

Question 36

Constipation: hyper or hypo?

Answer 36

hyper (decreased peristalsis because cells are more stable)

Question 37

Diarrhea: hypo or hyper?

Answer 37

hypo

Question 38

What nerve innervates the heart? What type of nerve is it?

Answer 38

Vagus nerve- parasympathetic

Question 39

What happens in neuron when you have opposing electro-chemical gradients?

Answer 39

Example: Top of Hill: cell is (+) with a lot of Na+ in cell; drive is for Na+ to leave cell but there is more Na+ outside cell Nernst Equation- reconciles electrical and chemical gradients that are going in opposite directions

Question 40

Nernst Equation

Answer 40

Delta G = -NFE = -RTlnKEq -NFE is charge N = # of electrons F = Faraday's Constant = 10\*5 E = EMF (what charge differential is) If differential charges go up, linear increase of electrical gradient

Question 41

Chemical Gradient

Answer 41

Delta G = -RTlnKEq if KEq is outside vs. inside, increases logarithmically

Question 42

If chemical separation of [100] to [1], increases chemical drive by

Answer 42

2

Question 43

If 100:1 charge difference, increases ion drive by

Answer 43

100

Question 44

Which is more powerful: electric gradient or chemical gradient?

Answer 44

electric gradient is more powerful than chemical gradient but chemical gradient can overcome electrical gradient 63:1

Question 45

Which nerve connects the lower brain to the diaphragm?

Answer 45

Phrenic Nerve (requires no higher thinking)