Exercise 12 Microscopic Anatomy And Organization Of Skeletal Muscle

Question 1

Describe muscle fibers

Answer 1

Long, large, cylindrical cells
Soft and fragile

Question 2

Plasma membrane of the muscle fiber is called

Answer 2

Sacrolemma

Question 3

Describe myofibrils

Answer 3

Long, rod shaped organelles that nearly fill the sarcoplasm

Question 4

Describe myofilaments

Answer 4

Threadlike structures complexed of 2 contractile proteins called actin and myosin

Question 5

Function of actin and myosin

Answer 5

Slide past each other during muscle activity to allow contraction of the muscle cell

Question 6

What is the actual contractile unit of muscle

Answer 6

Sacromeres
They extend from the middle of one I band to the middle of the next (I to I)

Question 7

Thick filament is surrounded by … … filaments, each thin filament is surrounded by … … filaments

Answer 7

6 thin
3 thick

Question 8

At each junction of A and I bands, the sacrolemma indenTs into muscle cells forming a…

Answer 8

Transverse tubule (t tube)

Question 9

Terminal cisterns are aka

Answer 9

Cross channels

Question 10

What is the elaborate smoother endoplasmic reticulum called

Answer 10

Sarcoplasmic reticulum (SR)

Question 11

What are triads

Answer 11

Terminal cisterns of SR surrounds the t tubules

Question 12

Describe the endomysium

Answer 12

Delicate, areolar connective tissue sheath
between individual muscle fibers

Question 13

Collagenic membrane that covers fascicles

Answer 13

Perimysium

Question 14

Describe EPImysium

Answer 14

Dense irregular connective tissue that bound together large numbers of fascicles
Sheaths entire muscle

Question 15

Difference between tendons and aponeroses

Answer 15

Tendons are cordlike
Aponeuroses are sheet like

Question 16

Function of tendons and aponeuroses

Answer 16

Attaches muscles to each other or indirectly to bones

Question 17

All functions of tendons (4)

Answer 17

*Attach muscles to each other or indirectly to bone
*Provide durability
Conserve space
Provide route for entry n exit of nerves and blood vessels that serve the muscle fibers

Question 18

What is neuromuscular junction

Answer 18

Junction between axon of motor neuron and a muscle fiber

Question 19

Function of motor neurons

Answer 19

Stimulate nerve impulses to allow voluntary movement of skeletal muscle cells

Question 20

What is motor unit made of

Answer 20

Neuron and muscle fiber

Question 21

What is synaptic cleft

Answer 21

Small fluid filled gap that separate neuron and muscle fiber

Question 22

What is within axon terminals

Answer 22

Many mitochondria and vesicles containing neurotransmitter, acetylcholine (ACh)

Question 23

What is muscle fascicle

Answer 23

Bundle of skeletal muscle fibers running parallel to each other, enveloped by perimysium

Question 24

what makes the H zone unique

Answer 24

only myosin is present

Question 25

what makes the i band unique

Answer 25

only actin is present