Muscles

Question 1

Muscle

Answer 1

-well developed properties of contraction
-movements of various parts of the body (movement/contractions of organs inside body)
-develops from embryonic mesoderm
3 types: skeletal, cardiac, smooth

Question 2

Muscle cell Development

Answer 2

1. Myoblasts - differentiate from mesoderm
2. Myoblasts line up, fuse together, form myotubes
3. myotubes are elongated, multinucleate cells
4. myotubes create proteins (muscle fibers/cells) to from contractile elements of skeletal muscle
5. Satellite cells - mesenchyme-derived myogenic stem cells remain along muscle fibers
6. Satellite cells quiescent reserved myoblasts

Question 3

Muscle Terminology

Answer 3

-Sarcolemma = plasma membrane, extends into interior muscle fiber as tubular invagination (T tubules - transverse)
-Sarcoplasm = cytoplasm
-sacroplasmic reticulum = smooth endoplasmic reticulum sores intercellular calcium
-muscle fiber = muscle cell
-myofibrils = long contractile elements
sarcomere = individual contractile unit found each myofibril

Question 4

skeletal muscle

Answer 4

-pink/red due to blood supply and presence of myoglobin (transport oxygen)
-Three types:
1. Red (slow, type 1)
2. intermediate (type 2a)
3. white (fast, type 2b)
-innervation of muscle fibers appears to influence fiber type

Question 5

Skeletal muscle

Answer 5

-collagenous connective tissue
1. epimysium - surrounds entire muscle
2. perimysium - surrounds bundles of muscle fibers (fascicles)
-reticular connective tissue
1. endomysium - surrounds each muscle cell and includes basal lamina

Question 6

Skeletal muscle morphology

Answer 6

-fibers are long cylinders
-multinucleated
-nuclei located peripherally
-muscle fibers appear striated (striped) when seen longitudinally due to light and dark bands result from specific orientation of contractile proteins