Smooth Muscle Physiology Flashcards
T/F smooth muscle has striation
False, it has no striation
Describe the arrangements of the muscle proteins in smooth muscle
Actin and myosin are not arranged to form a myofibril
T/F: Smooth muscle has T-Tubules
False
Is smooth muscle voluntary or involuntary?
Involuntary
What are the cell communications used by Smooth muscle?
Gap junctions
Describe Smooth muscle
- long spindle shaped
- one central nucleus
- no striation
The myofilaments are arranged how?
criss cross in sarcoplasm in latticework appearance
What are the anchoring sites for actin filaments in smooth muscle?
Dense bodies
What do Dense bodies resemble from skeletal muscle?
z lines
What are the two types of functional smooth muscle?
- single unit
- multi unit
Why are functional sm mm referred to as single or multi?
It refers to te number of nerve fibers require to activate the smooth muscle tissue
Which functional smooth muscle has no gap junction?
Multi unit
How many nerve fibers innervate the single unit smooth muscle?
one
What is another name for unitary smooth muscle?
visceral or syncytial
What connects unitary cell membranes at multiple points to transmit the force?
Adherent junctions
Syncytium is:
The contraction of a mass of fibers
What can unitary smooth muscle display in response to stretch?
Intrinsic or myogenic contraction
Where can you find multi unit smooth muscle?
-iris
- airways
- ciliary muscles
Are multi unit smooth muscles capable of intrinsic activity?
no, only extrinsic
Muscle fibers of a multi unit will form what?
Motor unit
What is the protein that replaces troponin in smooth muscle and activates myosin light-chain kinase?
Calmodulin
In smooth muscle, does Ca enter from internal or external stores?
External through voltage gated Ca channels
Action potential of smooth muscle is mediated by voltage gated _____ Channels
Ca
Smooth muscles are innervated by which motor neurons?
Autonomic
