muscle 8

Question 1

why does sympathetic activity increase heart rate and contractibility

Answer 1

sympathetic activity wants a more powerful and frequent pulse

Question 2

what does below 90 bpm indicate

Answer 2

parasympathetic output

Question 3

what does above 90 bpm indicate

Answer 3

sympathetic output

Question 4

what receptors are activated by NE released from sympathetic neurone

Answer 4

beta1 adrenergic receptors

Question 5

How does smooth muscle layers run

Answer 5

In several directions

Question 6

Why does smooth muscle use less energy to generate and maintain force than skeletal?

Answer 6

It has a much slower myosin ATP

Question 7

How is smooth muscle contraction initiated?

Answer 7

Electrically or chemically

Question 8

What is smooth muscle controlled by?

Answer 8

Autonomic nervous system

Question 9

Is smooth muscle uninucleated or multinucleated

Answer 9

Uninucleated

Question 10

What is absent in smooth muscle?

Answer 10

Troponin and T tubules

Question 11

What are the 6 locations of smooth muscle?

Answer 11

Vascular
Gastrointestinal
Urinary
Respiratory
Reproductive
Ocular

Question 12

What is smooth muscle categorized by (3)

Answer 12

Location
Contraction pattern
Communication with neighboring cells

Question 13

Are unitary smooth muscles good at communicating? What is it referred to?

Answer 13

Yes
Referred to as visceral smooth muscle

Question 14

What makes up the walls of most visceral organs?

Answer 14

Unitary (single unit) smooth muscle

Question 15

Are multi unit smooth muscle good at communicating? Why or why not?

Answer 15

No they are not because they are not electrically coupled.

Question 16

Where is multi unit smooth muscle

Answer 16

Iris and eyeball
Male reproductive tract
Uterus (except just prior to labour)

Question 17

what is smooth muscle usually innervated by

Answer 17

autonomic nervous sytem

Question 18

where do APs usually occur in smooth muscle

Answer 18

unitary smooth muscle

Question 19

what propagates action potentials in unitary smooth muscle

Answer 19

Ca instead of Na

Question 20

why is repolarization slower in cardiac muscle/smooth muscle than skeletal

Answer 20

Ca channels inactivate slowly

Question 21

are some smooth muscles spontaneously activated

Answer 21

yes

Question 22

when do slow wave potentials fire action potentials

Answer 22

when they reach threshold

Question 23

what do pacemaker potentials do

Answer 23

always depolarize thresholds

Question 24

do action potentials occur in multiunit smooth muscles

Answer 24

no

Question 25

what does multiunit smooth muscle experience for contraction

Answer 25

graded potentials

Question 26

what are spontaneous AP in smooth muscle (2)

Answer 26

slow wave potential
pacemaker potential

Question 27

do spontaneous APs happen in unitary or multiunit smooth muscle

Answer 27

unitary