EXAM 2- cell wall

Question 1

what type of calcium channels in the heart

Answer 1

L-type

same structure as fast Na+ channels but slower

open after depolarization causing plateau

Question 2

cardiac channel blocker in the heart

Answer 2

dihydropyridine

Question 3

GABA receptors

Answer 3

Cl ion into the neurons

hyperpolarize/suppress activity in excitable cells

alcoholics takes place of GABA

take Cl permeability way leads to seizures

Question 4

nACh receptor

Answer 4

2 Ach binding sites
negative AA pore
Na flows in, some Ca, some K out

Question 5

hypocalcemia causes

Answer 5

Trousseau sign
tetany of skel. muscles due to increased activity of the motor neuron

more positive membrane potential

Question 6

pressure sensitive channels

Answer 6

Na+
pressure leads to widening of cell walls and Na influx leads to action potential to the brainstem

baroreceptors of arteries

Question 7

mACh receptor

Answer 7

muscarinic
natural inhibition of HR
antagonist of catecholamine

GPCR alpha subunit to K+ channel

Question 8

antimuscarinic drug

Answer 8

atropine

alpha subunit no longer active, K channel closes, increasing Vrm, action potential firing

Question 9

what would HR be if no mACh

Answer 9

HR 110

Question 10

vagus nerves innervating the SA and AV node

Answer 10

Ach released by vagus nerve to mAch on the SA and AV node

increased K permeability and decreased HR

Question 11

Voltage gated Na channel

Answer 11

fast
H gate open during resting
M gate opens during activation

Na into cell

Question 12

what drugs affect Na voltage gated channels

Answer 12

local anesthetics

lidocaine, bupivicaine

Question 13

Voltage gated K channel

Answer 13

one gate opens inside during depolarization

k flows out of cell

Question 14

Myelin glial cell of the PNS

Answer 14

Schwann cell

grows and wraps in a spiral around neurons causing water to get squeezed out… lipid compound/good insulator

PNS= everything out the spinal cord

Question 15

Myelin glial cell of the CNS

Answer 15

oligodendrocyte

can’t regenerate after adulthood

Question 16

what type of conduction does myelin allow

Answer 16

saltatory conduction jumping from one node of ranvier to the next- high density Na channels

Question 17

3 reasons for myelin

Answer 17

increase speed
increased efficency (less energy)
protective

Question 18

why are myelinated neurons harder to block

Answer 18

nodes of ranvier has higher density of Na channels

Question 19

Multiple sclerosis

Answer 19

demyelination of motor neurons

normally fast Na channels and voltage gated K channel removed under myelin

BUT now they only have Na/K pumps and Fast K channels at the node of Ranvier… Na gets pumped right back out

Question 20

3 demyelinating diseases

causes

Answer 20

MS, optic neuritis, Gullain-Barre(transiet eventually goes away… ex covid)

genetics, infection, autoimmune, vaccines

Question 21

what is a a gap junction

Answer 21

2 connected connexons

cell to cell communication
faster than NMJ

Question 22

how to form one connexon

Answer 22

6 connexins

Question 23

gap junction locations in the body and what factors the speed of movement

Answer 23

• ionic pores
• smaller ions move faster
• lots of gap junctions makes faster movement
• lots Na and some Ca movement through the pores
• bidirectional

myocardium, smooth muscle

Question 24

Calcium effect on membrane potential

Answer 24

blocks LEAKY Na entry not fast Na channels

Question 25

Magnesium effect on membrane potential

Answer 25

hyperpolarize
decrease electrical activity
same as calcium