muscles and nervous system

Question 1

steps of smooth muscle contraction

Answer 1

1-bundles of myofilaments containing thin and thick filaments are anchored on cytoplasmic densities
2- these densities, in turn, are anchored on the sarcolemma
3-because the contractile filament bundles are oriented obliquely to the long axis of the cell, their contraction shortens the cell

Question 2

contraction of smooth muscles is regulated by?

Answer 2

the Ca2-calmidulin-myosin light chain kinase system.

Question 3

skeletal muscle structural unit

Answer 3

syncytium
nuclei beneath the sarcolemma
diameter 10-100 micrometers, length mm-30cm

Question 4

types of skeletal muscles

Answer 4

epimysium
perimysium
endomysium

Question 5

epimysium:

Answer 5

-surface of the entire muscle
-dense CT

Question 6

perimysium:

Answer 6

-surrounds each fascicle
-thiner but dense CT
-blood vessels and nerves

Question 7

endomysium:

Answer 7

-surrounds muscle fibre
-lamina externa plus the loose CT- reticular and elastic fibres and fibroblasts

Question 8

contractile structure of myofibril

Answer 8

-actin and myosin myofilaments
-sarcomere-functional unit
-in the sarcoplasm
-triad - 1x T-tubule + 2x SER cisternae