Chapter 5

Question 1

EPSPs cause ________.

Answer 1

hypopolarization

Question 2

IPSPs cause ________.

Answer 2

hyperpolarization

Question 3

Direct mechanism to mediate response of binding of neurotransmitter to receptor?

Answer 3

• involves opening of ion channels, altering membrane potential
• neurotransmitters that open Na+ channels cause an EPSP
• ” “ that open K+ or Cl- channels cause an IPSP

Question 4

Indirect mechanism?

Answer 4

• use second messengers
• when neurotransmitter binds receptor on the membrane target cell, it acts as the first messenger, activating a G protein bound to the interior of the cell
• activated G protein activates the enzyme adenylate cyclase which diffuses into cytoplasm and initiates a series of rxns that results in the production of cyclic AMP
• Cyclic AMP is the 2nd messenger which activates kinase enzymes

Question 5

Cyclic AMP?

Answer 5

common intracellular 2nd messenger for nonsteroid hormones synthesized from amino acids

Question 6

How can ACh cause different responses at different locations?

Answer 6

it binds to different receptors at different locations

Question 7

Two types of cholinergic receptors?

Answer 7

Nicotinic

Muscarinic

Question 8

What is the mechanism when ACh binds to nicotinic receptors?

Answer 8

direct mechanism that causes EPSP

Question 9

What is the mechanism when ACh binds to muscarinic receptors?

Answer 9

indirect mechanism which is generally inhibitory

Question 10

What is considered to be both a neurotransmitter and a hormone?

Answer 10

NE

Question 11

What does the adrenal medulla secrete the most of?

Answer 11

Epi 80%

Question 12

What are adrenergic receptors?

Answer 12

general group of receptors that bind with NE and Epi

Alpha
Beta 1
Beta 2
Beta 3

Question 13

What second messenger do NE and Epi act through at Beta receptors?

Answer 13

Cyclic AMP

Question 14

What second messenger do NE and Epi act through at alpha receptors?

Answer 14

Ca 2+

Question 15

What receptors have a greater affinity for NE?

Answer 15

Alpha

Beta 3

Question 16

What receptors have a greater affinity for Epi?

Answer 16

Beta 2

Question 17

What receptors have an equal affinity for NE and Epi?

Answer 17

Beta 1

Question 18

Cotransmitter?

Answer 18

chemical released from the neuron that acts cooperatively with the neurotransmitter

Question 19

What breaks down ACh? Why?

Answer 19

Acetylcholinesterase breaks it into acetate and choline

to prevent chronic stimulation of post synaptic membrane

Question 20

Where does acetate go after ACh has been broken down?

Answer 20

forms acetyl CoA and is transported back with choline to the terminal ends of the presynaptic neuron where it combines to form ACh again

Question 21

What results from activation of Beta 1 receptors?

Answer 21

• increased rate of contraction of the heart

- increased force of contraction of the atrial and ventricular myocardium

Question 22

What results from activation of Beta 2 receptors?

Answer 22

• vasodilation of arterioles supplying the heart, liver, skeletal muscles
• bronchodilation of lungs
• increased muscle and liver glycogenolysis and liver gluconeogenesis

Question 23

What results from activation of Beta 3 receptors?

Answer 23

increased lipolysis in adipose tissue

Question 24

What results from activation of alpha receptors?

Answer 24

• vasoconstriction of veins

- vasoconstriction of arterioles supplying the visceral organs, except heart and liver

Question 25

What half life is shorter, NE released from neurons or NE released from adrenal gland?

Answer 25

from neurons, 50-80% is quickly reabsorbed into the neuron

Question 26

Blood shunt?

Answer 26

prioritize blood flow based on metabolic demand

during exercise, blood is shunted away from digestive system

Question 27

What would happen if a patient is taking a beta blocker medication?

Answer 27

he would not be able to reach a target heart rate b/c the medication blocks NE and Epi from binding to Beta 1 and 2 receptors