Smooth Muscle Flashcards
1
Q
What are the categories of smooth muscle?
A
Tonic smooth muscle
Physic smooth muscle
2
Q
What does tonic smooth muscle do?
A
Maintains tone, no action potentials
3
Q
How are phasic smooth muscle cells connected?
A
Gap junctions
4
Q
What keeps smooth muscle in the right position?
A
Intermediate filaments
5
Q
Is the length tension curve longer or shorter for smooth muscle?
A
Longer
6
Q
Why is the length tension curve longer for smooth muscle?
A
- actin filaments are very long
- myosin heads move in opposite directions
7
Q
Smooth muscle action potential
A
Influx of Ca2+
8
Q
How does a smooth muscle contraction occur?
A
- Depolarisation opens voltage gated Ca2+ channels
- Ca2+ flows in
9
Q
Neurotransmitter/hormone path way of Ca2+ release
A
- Ca2+ CPCR bind a neurotransmitter or hormone
- G protein activates phospholipase C
- IP3 is released
- binds to sacroplasmic reticulum and releases Ca2+
10
Q
Contraction of smooth muscle process
A
- Ca2+ joins with calmodulin
- forms Ca2+ calmodulin myosin light chain kinase (regulatory elements on myosin light chain head)
- phosphorylates myosin
- phosphatase dephosphorylates myosin - causes cross bridge cycling
