M 3.1

Question 1

• Found in walls of hollow viscera, airways, blood vessels, iris and ciliary body of eye, arrector pili muscles of hair follicles
• Fibers are fusiform in shape (thickest in middle, tapered at each end) and contain one centrally positioned nucleus; not striated
• Develop from mesodermal cells that migrate to and envelop the developing gastrointestinal tract and viscera

Answer 1

Smooth Muscle Tissue

Question 2

Smooth Muscle Tissue:
- Found in walls of hollow _________, airways, blood vessels, iris and ciliary body of eye, arrector pili muscles of__________

Answer 2

viscera; hair follicles

Question 3

Smooth Muscle Tissue:
- Fibers are __________in shape (thickest in middle, tapered at each end) and contain __________ centrally positioned nucleus; not striated

Answer 3

fusiform; one

Question 4

Smooth Muscle Tissue:
- Develop from ___________cells that migrate to and envelop the developing gastrointestinal tract and viscera

Answer 4

mesodermal

Question 5

Smooth Muscle Fiber
Length: Intermediate - _____um

Answer 5

30-200 um

Question 6

Smooth Muscle Fiber
Diameter: Small - ____um

Answer 6

3-8 um

Question 7

Smooth Muscle Fiber
Structure:
- Contains ________ and ______ filaments that have no regular pattern of overlap; therefore,
does NOT exhibit _________

Answer 7

myosin; actin; striations

Question 8

Smooth Muscle Fiber
Structure:
- Actin and myosin form _______ (criss-cross) network and insert into dense bodies in the sarcoplasm
- Contains ______ central nucleus

Answer 8

lattice; one

Question 9

Smooth Muscle Fiber
Structure:
- Gap junctions couple muscle and allow _____________________ between all fibers
‣ T tubules are NOT present

Answer 9

ionic communication

Question 10

Smooth Muscle Fiber
Structure:
- Short membrane invaginations, called _________, are often frequent at the smooth muscle cell surface

Answer 10

caveolae

Question 11

Smooth Muscle Fiber
Structure:
- Very little sarcoplasmic reticulum
- Regulatory proteins: ___________ (MLCK) and ___________

Answer 11

myosin light-chain kinase; calmodulin

Question 12

Connective Tissue Components of Smooth Muscle?

Answer 12

Endomysium and less-organized CT sheaths