Muscle Tissue

Question 1

What are muscle tissues specialized for and what are the three types?

Answer 1

• contraction
• skeletal, cardiac, and smooth

Question 2

What do muscle cells consist of?

Answer 2

• muscle cells (fibers)
• connective tissue elements (holds them tgthr and provides structure)
• blood vessels (capillaries) (travel thru muscle cells and provide nutrients)
• nerve/nerve endings (provide electrical basis for us to contract. Tell ourselves to contract or not)

Question 3

Skeletal Muscles

Answer 3

Question 4

Cardiac Muscles

Answer 4

Question 5

Smooth Muscles

Answer 5

Question 6

Functions of skeletal muscles

Answer 6

• produce movement of the skeleton
• maintains posture and body position (contracting even tho we aren’t doing anything)
• guards orifices (eyeball, mouth, anus, urethra)
• supports soft tissue
• maintains body temperature

Question 7

Muscles attach to other structures with tendons

Answer 7

• when attaching to bone, the tendon is woven into the periosteum of bone to form a strong bond

Question 8

Muscle fibers (cells)

Answer 8

• long, cylindrical, and multinucleated
• form a syncytium = single cell/cytoplasmic mass formed by fusion of cells
• muscle fiber = muscle cells

Question 9

Sarcolemma

Answer 9

• plasma membrane of muscle cells

Question 10

Sarcoplasm

Answer 10

• the cytoplasm of the muscle cells

Question 11

Myofibrils

Answer 11

• contractile fibers

Question 12

Where are nuclei found in a muscle cell?

Answer 12

• inside the sarcolemma

Question 13

T-tubules

Answer 13

• invagination of sarcolemma
• transmit membrane depolarization throughout sarcoplasm

Question 14

Sarcoplasmic reticulum

Answer 14

• muscles smooth ER

Question 15

Picture of skeletal muscle

Answer 15

Question 16

What are myofibrils made of?

Answer 16

• sarcomeres: smallest functional unit of a muscle fiber
• they repeat
• differences in the distribution of thick and thin filaments give them a banded appearance
• thick and thin = slide past each other to produce contractions

Question 17

Muscles are controlled by what?

Answer 17

• controlled by nerves in the CNS
• axon terminals connect to muscles at neuromuscular junctions
• look at slide for picture

Question 18

Motor unit

Answer 18

• a motor neuron, its axon, and all skeletal muscle fibers that it innervates
• few fibers innervated by single neuron = delicate movements, fine control. EX: playing piano
• more fibers innervated by single neuron = gross movements, less control. EX: expanding our spine to stand up
• picture = few fibers

Question 19

Atrophy

Answer 19

• muscles not repeatedly stimulated by a motor neuron lose tone and mass due to loss of contractile proteins

Question 20

Hypertrophy

Answer 20

• muscles that are repeatedly stimulated to produce near-maximum tension develop more myofibrils and mitochondria = enlargement

Question 21

Muscle organization

Answer 21

Question 22

Muscle organization pt. 2

Answer 22

Question 23

Muscle organization pt. 3

Answer 23

Question 24

Muscle organization pt. 4

Answer 24

Question 25

Muscle terminology

Answer 25

• origin: usually remains stationary
• insertion: usually moves
• action can be describes with regard to either the region affected by movement, or the joint involved
• flexion of forearm (region affected by movement)
• flexion of the elbow (joint that’s involved)