Smooth Muscle

Question 1

tunica media

Answer 1

smooth muscle

Question 2

tunica intima

Answer 2

endothelium that lines the lumen of vessels

Question 3

tunica adventitia

Answer 3

collagen fibers

Question 4

multi motor unit example

Answer 4

fine touch in finger

Question 5

single motor unit example

Answer 5

visceral smooth muscle, organs, airways, blood vessels

Question 6

is smooth muscle singler or multi nucleated?

Answer 6

single

Question 7

Is the contraction speed faster or slower compared to skeletal muscle?

Answer 7

slower

Question 8

is the contraction time slower or longer compared to skeletal muscle?

Answer 8

longer

Question 9

are the smooth muscle cells organized in sarcomeres?

Answer 9

no

Question 10

calcium in smooth muscle contraction (5)

Answer 10

1-calcium enters through channels in caveloi
2- stretch
3- neurotransmitter/hormonal (g coupled)
4- CICR, calcium induced calcium release (at SR)
5- SORE, store operated calcium entry (when SR is depleted)

Question 11

smooth muscle contraction

Answer 11

calcium enters
binds calmodulin
activates MLCK (myosin light chain kinase) by phosphorylation
conformational change increases ATPase activity and crossbridge cycling occurs

Question 12

smooth muscle relaxation

Answer 12

opposite of contraction
low levels of calcium
increased myosin phosphatase activity

Question 13

role of endothelium in vascular smooth muscle relaxation

Answer 13

ach binds muscarinic R
Nitric oxide made by eNOS and arginine
NO activates guanylyl cyclase
cGMP inhibits Ca entry and activates MLC phosphatase

Question 14

modulation of blood flow

Answer 14

phosphodiesterases inhibit the degradation of cGMP to GMP
viagra does this
vasodilation (relaxation)

Question 15

if the alpha 2 receptor is on the post synaptic neuron does it cause vasoconstriction or vasodilation

Answer 15

constriction

Question 16

sympathetic alpha 1 receptor

Answer 16

NE
PLC>IP3
increase myosin and actin interation
vasoconstrict

Question 17

sympathetic beta 2 R

Answer 17

Epi or NE
Adenylyl cycl>cAMP>inhibition of MLCK

vasodilation or bronchodilation if found in lungs

Question 18

parasym effect on vasculature

Answer 18

ACh
GPCR
NO
Dilation 
(also receptors on smooth muscle that cause contraction generally see dilation though

Question 19

what would you observe if with Ach if endothelium was damaged?

Answer 19

vasoconstriction

Question 20

parasympathetic smooth muscle in bronchioles

Answer 20

Ach MR
IP3
bronchoconstriction

Question 21

what does stretch cause

Answer 21

increase contraction

Question 22

high CO2

Answer 22

vasodilation

Question 23

high H+

Answer 23

vasodilation