Skeletal muscle

Question 1

Types of muscle

Answer 1

akeletal, cardiac and smooth

Question 2

Muscle contractions occur through the interaction of two proteins:

Answer 2

actin and myosin

Question 3

Muscle is derived from what germ layer?

Answer 3

mesoderm

Question 4

Muscle cells are called

Answer 4

myofibre

Question 5

myoblasts fuse to form ___

Answer 5

myotubes

Question 6

What are satellite cells

Answer 6

stem cells that can undergo proliferation in response to muscle damage

Question 7

How many nuclei in skeletal muscle cells?

Answer 7

multi-nucleated

Question 8

location of skeletal muscle cell nuclei

Answer 8

perpheral

Question 9

Shape of skeletal muscle cells

Answer 9

long, cylindrical and of uniform diameter

Question 10

Why are skeletal muscle cells striated?

Answer 10

due to ordered arrangement of actin and myosin filaments

Question 11

contraction of which muscle is under voluntary control?

Answer 11

skeletal

Question 12

3 layers of connective tissue in skeletal muscle

Answer 12

1. endomysium
2. perimysium
3. epimysium

Question 13

endomysium

Answer 13

fine layer of CT surrounding each myofibre

Question 14

perimysium

Answer 14

bundles fibres into a collection called a fascicle

Question 15

epimysium

Answer 15

bundles fascicles into a whole muscle (continuous with tendon)

Question 16

functions of skeletal muscle CT

Answer 16

transfers forces from myofibres to tendon. Carries within it the blood vessels and nerves that supply the muscle

Question 17

Duchenne’s muscular dystrophy

Answer 17

• x-linked degenerative disease
• caused by defect in dystrophin gene
• muscle degeneration, immobility, resp failure
• more liely to develop OCD, autism, hyperactivity

Question 18

Each myofibre consists of numerous ____

Answer 18

myofibrils

Question 19

___ is the functional unit of individual myofibrils

Answer 19

sarcomere

Question 20

a single sarcomere extends from where to where?

Answer 20

from one Z disc to the next

Question 21

Each sarcomere consists of overlapping ___ filaments and ___ filaments

Answer 21

Each sarcomere consists of overlapping ACTIN (THIN) filaments and MYOSIN (THICK) filaments

Question 22

Sliding filament theory

Answer 22

• filaments do not change length during contraction

- contractions occur when filaments slide past eachother

Question 23

Sarcomere shortens in length in response to

Answer 23

ncrease in Ca++ released from SR in response to depolarization of membrane

Question 24

Myasthenia gravis

Answer 24

autoimmune disorder caused by reduction in percent of functional ACh receptors

• binding of antibodies against ACh receptors
• weakening of actie muscels in face, eyes, tongue

Question 25

Define muscle atrophy

Answer 25

decrease in size in individual muscle cells that occurs as a result of disuse or damage to nerve that innervates the muscle

Question 26

Muscle hypertrophy

Answer 26

increase in size of individual muscle cells that can occur as a result of exercise

Question 27

muscle that forms the walls of the heart

Answer 27

cardiac muscle

Question 28

cardiac muscle cells connected end to end by ___

Answer 28

intercalated disks

Question 29

disks are sites of attachment of cells to eachother (_____) and communication between cells (____)

Answer 29

disks are sites of attachment of cells to eachother (DESMOSOMES) and communication between cells (GAP JUNCTIONS)

Question 30

up to 40% of volume of cardiac muscle is made up of

Answer 30

mitochondria

Question 31

Nuclei of cardiac muscles

Answer 31

1 or 2 per cell, centrally located

Question 32

What are the names of the modified muscle fibres in CT that conduct impulses within the heart?

Answer 32

Purkinge fibres

Question 33

Shape of smooth muscle

Answer 33

spindle

Question 34

nuclei in smooth muscle

Answer 34

single elongated nucleus

Question 35

smooth muscle is found where?

Answer 35

in walls of hollow structures (GI tract, respiratory tract, and circulatory system)

Question 36

Slow, sustained and involuntary contractions of smooth muscle are regulated by ____

Answer 36

autonomic nervous system