Week 4

Question 1

Where do Parasympathetic nerves originate?

Answer 1

Cranial Nerves (3, 7, 9, 10)
Sacral spinal cord (S2-S4)

Question 2

Where do Sympathetic nerves originate?

Answer 2

Thoracic spinal cord (T1-T12)
Lumbar spinal cord (L1-L2/3)

Question 3

Where is the ggl in Parasympathetic system? Length of Pre/Post ggl fibers.

Answer 3

Near or within the organ.
Long Preggl
Short Postggl

Question 4

Where is the ggl in Sympathetic system? Length of Pre/Post ggl fibers.

Answer 4

Close to the spinal cord
(Pre/Para-vertebral)
Short Preggl
Long Postggl

Question 5

Preganglionic Axon Transmitter in Parasympathetic & Sympathetic?

Answer 5

Acetylcholine
ACh

Question 6

Preganglionic Receptor in Parasympathetic & Sympathetic?

Answer 6

Nicotinic Acetylcholine Receptor
nAChR

Question 7

Postganglionic Axon transmitter in Parasympathetic

Answer 7

Acetylcholine
ACh
(VIP, NO)

Question 8

Postganglionic receptor in Parasympathetic

Answer 8

Muscarinic (1-5)
mAChR

Question 9

Postganglionic Axon transmitter in Sympathetic

Answer 9

Norepinephrine
NE
(ACh)

Question 10

Postganglionic receptor in Sympathetic

Answer 10

Adrenergic receptors
(a1/2 & B1/2/3)

Question 11

Elimination of transmitters in Parasympathetic

Answer 11

ACh esterase
Reuptake of Choline
Diffusion

Question 12

Elimination of transmitters in Sympathetic

Answer 12

NE Reuptake
(Degradation in the cytoplasm)
Diffusion

Question 13

Modulation in Parasympathetic

Answer 13

Blocking ACh release
Blocking Choline reuptake
Blocking ACh esterase

Question 14

Modulation in Sympathetic

Answer 14

Membrane NE transport inhib
NE vesicle carrier inhibition
Blocking NE synthesis

Question 15

What enzyme converts NE to E? What does it depend on?

Answer 15

N-methyl-transferase
Adrenal steroid hormone dependent

Question 16

What are the only 2 sources of NE in Humans?

Answer 16

Directly from Adrenal Medulla
Conversion of NE to E

Question 17

What receptor is used for Vasoconstriction? What transmitter is it sensitive to?

Answer 17

a1
NE > E

Question 18

What receptor is used for Vasodilation? What transmitter is it sensitive to?

Answer 18

B2
E > NE

Question 19

3 only similarities of SM and Skeletal?

Answer 19

Thin & Thick filaments
ATP cycle
I.C Calcium is critical cont. regulator
EVERYTHING ELSE IS DIFFERENT

Question 20

Morphology of SMC

Answer 20

Uninucleated
Not striated
No Z lines
No T tubules

Question 21

What are the Thin & Thick filaments anchored to?

Answer 21

Dense Bodies

Question 22

What junctions interconnect SMCs?

Answer 22

Gap Junctions

Question 23

3 Ways to increase I.C Calcium in SMCs

Answer 23

DEPOLARIZATION
- From neighboring cells through gap junctions.
- Neural Stimulation (transmitter)
- Mechanical Activation (mechanosensitive channels)

Question 24

Bayliss effect on Mechanosensitive channels

Answer 24

Stretching - Channel opens - Depolarization - Contraction

Question 25

SM Action potential VS neural AP

Answer 25

Smaller amplitude Lasts much longer Different ion channels

Question 26

What channels cause the Depolarization phase in SMC

Answer 26

L-type voltage gated Ca Channels

Question 27

What channels cause the Repolarization phase in SMC

Answer 27

Voltage gated late K Channel

Question 28

What channels cause the Plateau phase in SMC

Answer 28

Ca activated K Channel

Question 29

Can TTX inhibit SMC AP? And what else?

Answer 29

No Ca Channel inhibitors

Question 30

2 mechanisms to increase IC Ca in SMC

Answer 30

Depolarization Ligand binding to a membrane receptor (a1 adrenergic receptor)

Question 31

Thin myofilament made of:

Answer 31

SMC actin Tropomyosin

Question 32

Thick myofilament made of: (Types)

Answer 32

Myosin Heavy Chain Light Chain (2 per heavy chain)

Question 33

What does phosphorylation of MLC do?

Answer 33

Allows actin-myosin binding in response to Ca influx (Ca-Calmodulin)

Question 34

What mediates MLC phosphorylation?

Answer 34

MLCK Myosin light chain Kinase

Question 35

3 Mechanisms to terminate Ca signal in SMC

Answer 35

Membrane Ca ATP-ase (Pump) Membrane Na/Ca antiporter SR Ca ATP-ase (pump)

Question 36

How can SMC contraction happen independent on Ca?

Answer 36

Rho-GTP which activates Rho-Kinase

Question 37

What does Rho-Kinase do?

Answer 37

It phosphorylates MLC to MLC-P It means less Ca is needed to induce the same contraction. So increased Ca sensitivity

Question 38

Mechanisms to induce SM relaxation

Answer 38

cAMP (B2-adrenergic R) cGMP (NO-dependent act.)

Question 39

How does cAMP induce SM relaxation?

Answer 39

It induces MLCK-P (Decreases calcium sensitivity)

Question 40

How does cGMP induce SM relaxation (3) ?

Answer 40

Activation of Phosphatase Phosphorylation of IP3R Inhibition of Ca entry into the cell

Question 41

Multiunit SM

Answer 41

Each SMC has its own innervation Functions tightly regulated Neural control of regulation e.g: int eye muscles, Ductus deff.

Question 42

Single unit SM

Answer 42

Gap junctions bw cells Spontaneous contractions Basal activity Neural signals only modulate activity eg: GI tract, vascular SM

Question 43

SM contraction Characteristics

Answer 43

Contraction requires much less ATP vs Skeletal Slow actin-myosin cycle in the cell Actin-myosin cross bridges