Histology Of Muscle Tissue

Front 1

Skeletal

Back 1

Long cylindrical cells, striated, peripheral nuclei, voluntary

Front 2

Cardiac

Back 2

Branched cells, striated, 1-2 centrally locates nuclei, involuntary

Intercalated discs- desmosomes & gap junctions

Front 3

Smooth

Back 3

Spindle- shapes cells, non- striated, 1 centrally located nucleus, involuntary

Front 4

excitability

Back 4

Car carry an action potential (change of charge across the cell membrane)

Front 5

Contractility

Back 5

Ability to contract (shorten) when stimulated by action potential

Front 6

Extensibility

Back 6

Ability to stretch or extend

Front 7

Elasticity

Back 7

Ability to return to original length and shape

Front 8

Functions of muscle tissue

Back 8

Produce body movements

stabilizing body positions

storing and moving substances with in the body

generating heat

Front 9

What element is important in directly triggering contraction?

Back 9

Calcium (Ca++)

Front 10

Aponeurosis

Back 10

Broad, sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone

Front 11

What would happen to skeletal muscle if the epimysium were destroyed?

Back 11

Muscles would lose their integrity during powerful movements, resulting in muscle damage

Front 12

Describe how tendons facilitate body movement

Back 12

When a muscle contracts, the force of movement is transmitted through the tendon, which pulls on the bone to produce skeletal movement

Front 13

What are the five primary functions of skeletal muscle?

Back 13

1) Produce movement of the skeleton

2) maintain posture and body position

3) support soft tissues

4) encircle openings of the digestive, urinary, and other tracts

5) maintain body temperature

Front 14

Role of voltage gated sodium channels

Back 14

Followed by the influx of Na+, transmits an action potential after the membrane has sufficiently depolarized

Front 15

The delayed opening of potassium channels allows what to happen?

Back 15

Allows k+ to exit the cell, to depolarize the membrane

Front 16

AcH definition

Back 16

AcH is the neurotransmitter that binds at the neuromuscular junction to trigger depolarization

Front 17

Action potential travels where to do what?

Back 17

Action potential travels along the sarcolemma to trigger calcium release from SR

Front 18

I’m relaxed muscle, the myosin- binding site on actin is blocked by___

Back 18

Tropomyosin

Front 19

According to the sliding filament model, binding sites on action open when

Back 19

Calcium ion levels rise

Front 20

During muscle contraction, the cross bridge searches when

Back 20

The myosin head binds to an ATP molecule

Front 21

Thick and thin filaments are organized into functional units called

Back 21

Sacromeres

Front 22

Hypertrophy

Back 22

An increase in the # of myofibrils in existing cells causes muscles to grow bigger.

Use muscle more than normal

Front 23

Muscle tension

Back 23

The force generated by the contraction of the muscle (or shortening of the sarcomeres)

Front 24

In order to contract, every skeletal muscle fiber must be innervated by what?

Back 24

Every skeletal muscle fiber must be innervated by the axon terminal of a motor neuron in order to contract.

Front 25

Why does summation occur at the molecular level?

Back 25

Summation occurs because the second stimulus triggers the release of more Ca++ ions.

Front 26

What determines the amount of tension produced by a muscle?

Back 26

The number of cross-bridges formed between actin and myosin determines the amount of tension produced by a muscle.

Front 27

A motor unit is formed by what?

Back 27

A motor unit is formed by a motor neuron and all of the muscle fibers that are innervated by that same motor neuron

Front 28

Muscle tone

Back 28

Muscle tone is the constant low-level contractions that allow for posture and stability

Front 29

Slow oxidative (SO) fibers

Back 29

SO fibers use aerobic metabolism to produce low power contractions over long periods and are slow to fatigue.

Front 30

Fast oxidative (FO)

Back 30

Anaerobic respiration Fast oxidative fibers have fast contractions and primarily use aerobic respiration. Can fatigue more quickly (so).

Front 31

Fast Glycolytic (FG)

Back 31

Fibers have fast, higher tension contractions and primarily use anaerobic glycolysis. Fatigue more quickly

Front 32

Creatinephosphate

Back 32

Creatine Phosphate provides about the first 15 seconds of ATP at the beginning of muscle contraction

Front 33

Anaerobic glycolysis

Back 33

Anaerobic Glycolysis produces small amounts of ATP in the absence of oxygen for a short period

Front 34

Aerobic Metabolism

Back 34

Aerobic metabolism utilizes oxygen to produce much more ATP, allowing a muscle to work for longer periods

Front 35

Muscle Fatigue

Back 35

Muscle Fatigue, occurs when muscle can no longer contract. An oxygen debt is created as a result of muscle use.

Front 36

Muscle fatigue is caused by

Back 36

Exhilaration of energy reserves and buildup of lactic acid levels

Front 37

Atrophy

Back 37

Loss of muscle mass due to the breakdown of structural proteins

Front 38

Intercalated disc

Back 38

Slows the cardiac muscle cells to contract in a wave-like pattern so that the heart can work as a pump

Front 39

What is the purpose of gap junction in cardiac muscle?

Back 39

Intercalated discs contain gap junctions for depolarization between cells

Front 40

What is the purpose of desmosomes?

Back 40

Desmosomes act to hold the fibers together when the heart contracts

Front 41

How is contraction in each cardiac muscle fiber triggered?

Back 41

Contraction in each cardiac muscle fiber is triggered by calcium ions.

Calcium ions come from SR and through voltage gated calcium channels in the sarcolemma.