Muscle Tissue/muscle Physiology

Front 1

What are the four main properties of all muscle tissue?

Back 1

1. Excitability: ability to respond to certain stimuli by producing electrical signals; action potentials(impulse)
2. Contractility: ability to shorten and thicken(contract), which generates force to do work.
3. Extensibility: ability to extend(stretch) without damaging the tissue.
4. Elasticity: ability to return to original shape after contraction or extension.

Front 2

What are the functions of muscle tissue?

Back 2

- body movements
- stabilization of body position(posture)
- regulation of organ volume
- moving substances within body
- thermogenesis, i.e. heat production, to help maintain body temperature

Front 3

List the types of Muscle Tissue

Back 3

1.) Skeletal muscle
2.) Cardiac Muscle
3.) Smooth muscle

Front 4

Describe the skeletal muscle

Back 4

- Attached to tendons and bone to produce bodily movement
- Elongated cylindrical cells/fibers
- Multinucleated: can increase/decrease # of nuclei with muscle use/disuse , can increase production of enzymes and proteins as needed , can increase/decrease metabolic activity within a muscle
- Visible striations
- Voluntarily controlled (somatic nervous system)
- No junctions betweens fibers

Front 5

Describe cardiac muscle

Back 5

- Heart tissue
- Branching cells: connected by desmosomes for strength , intercalated discs or gap junctions that allow AP to spread rapidly
- Single central nucleus
- Visible striations
- Involuntarily controlled (autonomic nervous system)

Front 6

Describe smooth muscle

Back 6

- Present in walls of hollow viscera, airways, blood vessels, urinary tract, iris, etc.
- Spindle shaped cells
- Single central nucleus
- Lack visible striations
- Involuntarily controlled (autonomic nervous system)
- Gap junctions present in some smooth muscle

Front 7

List the hierarchy of the skeletal muscle structure from the smallest to the largest

Back 7

1.) Myofilament
2.) Myofibril
3.) Muscle cell/fiber
4.) Fascicle
5.) Whole muscle

Front 8

Define myofilament

Back 8

- individual proteins that provide structure to skeletal muscles; help regulate contraction
- have thin and thick filaments

Front 9

What are the types of thin filaments?

Back 9

1.) Actin: contractile protein that binds with myosin to generate muscular tension/force

2.) Tropomyosin: regulatory muscle that wraps around actin

3.) Troponin: regulatory protein bound to actin that serves as a Ca2+ receptor and the heavy that pushes tropomyosin off the active binding sites.

Front 10

What role does the tropomyosin play in relaxed muscle?`

Back 10

tropomyosin blocks the active binding sites, which prevents myosin from binding to actin

Front 11

What role does the tropomyosin play in the presence of Ca2+?

Back 11

tropomyosin is pushed off the binding sites, which allows myosin to bind with actin and produce muscular force.

Front 12

Troponin T (TnT)

Back 12

bound to tropomyosin to lock actin and tropomyosin together

Front 13

Troponin l (Tnl)

Back 13

bound to actin to lock actin and tropomyosin together

Front 14

Troponin C (TnC)

Back 14

binds with Ca2+, which triggers a deformation of the entire troponin complex that moves tropomyosin off active binding sites.

Front 15

Myosin

Back 15

- main component of thick filaments
- contractile protein that binds with actin to generate muscular tension/force

Front 16

How many thin filaments surround one thick filament?

Back 16

SIX

Front 17

Overall, what do structural filaments provide?

Back 17

- keep thick and thin filaments in the proper alignment
- give myofibril elasticity and extensibility
link myofibrils to sarcolemma and extracellular matrix

Front 18

Structural filaments contain:

Back 18

collagen, elastin, titin, nebulin

Front 19

What is the function of collagen?

Back 19

provide structure and support to muscle

Front 20

What is the function of elastin?

Back 20

provide elasticity and allows to return to original shape

Front 21

What is the function of titin?

Back 21

anchors the myosin to be centered and stabilized

Front 22

What is the function of nebulin?

Back 22

act as a ruler/guide for actin growth

Front 23

Define Myofibril

Back 23

bundle of myofilaments

Front 24

Sarcomere

Back 24

- functional unit of myofibril
- each sarcomere contains multiple thick and thin filaments

Front 25

What are the features within the sarcomere?

Back 25

- Z-disk/line: the edge
- M-line: the center
- I-band: just actin
- H-zone: just myosin
- A-band: myosin and actin overlap

Front 26

Muscle cell/fiber

Back 26

bundle of myofibrils

Front 27

(Muscle cell/fiber)

Sarcolemma

Back 27

muscle cell plasma membrane

Front 28

(Muscle cell/fiber)

Satellite cells

Back 28

regulate growth and muscular adaptations

Front 29

(Muscle cell/fiber)


Sarcoplasm

Back 29

- fluid part of a cell(cytosol)
- contains ATP, CrP, glycogen, fats, mitochondria

Front 30

(Muscle cell/fiber)

Transverse tubules

Back 30

highways for APs that run inward from sarcolemma to myofibrils

Front 31

(Muscle cell/fiber)

Sarcoplasmic reticulum

Back 31

network of longitudinal tubules that surround myofibrils and store Ca2+

Front 32

(Muscle cell/fiber)

Terminal cisternae

Back 32

enlarged portions of the sarcoplasmic reticulum for Ca2+ storage

Front 33

(Muscle cell/fiber)

Mitochondria

Back 33

aerobic factories that produce ATP using oxygen

Front 34

(Muscle cell/fiber)

Nuclei

Back 34

control centers for the muscle fiber

Front 35

Fascicle

Back 35

bundle of muscle fibers

Front 36

Whole Muscle

Back 36

bundle of fascicles

Front 37

Pennation

Back 37

the organization/shape of muscles

Front 38

Parallel Pennation

Back 38

muscle fibers arranged in parallel along the length of a muscle to produce large ranges of motion.

Front 39

(Parallel Pennation)

- Flat
- provide example

Back 39

- muscle is sheet like
- rectus abdominis

Front 40

(Parallel Pennation)

- Fusiform
- provide example

Back 40

- muscle is cylindrical and bulbous in the middle
- biceps brachii

Front 41

(Parallel Pennation)

- Strap
- provide example

Back 41

- muscle is semi-cylindrical, but not bulbous in the middle
- sartorius

Front 42

(Parallel Pennation)

- Radiate
- provide example

Back 42

- fibers originate from a broad origin and converge on a small insertion point
- pectoralis major

Front 43

(Parallel Pennation)

- Sphincter
- provide example

Back 43

- fibers are arranged in a circle to open or close a hole
- orbicularis oculi

Front 44

Pennate Pennation

Back 44

muscle fibers are arranged obliquely to the central tendon to maximize cross-sectional area and force production

Front 45

(Pennate pennation)

- Unipennate
- provide ex

Back 45

- fibers run on only one side of tendon
- tibialis anterior

Front 46

(Pennate pennation)

- Bipennate
- provide ex

Back 46

- fibers run on two sides of the tendon
- gastrocnemius, rectus femoris

Front 47

(Pennate pennation)

- Multipennate
- provide ex

Back 47

- fibers run on both sides of a branched tendon
- deltoid

Front 48

What is a Fascia?

Back 48

A sheet or band of fibrous connective tissue that is deep to the skin and surrounds muscles and other organs of the body.

Front 49

Superficial fascia
(Subcutaneous layer)

Back 49

separates muscle from skin and functions to provide a pathway for nerves and blood vessels, stores fat, insulates, and protects muscles from trauma

Front 50

Deep fascia

Back 50

holds muscles with similar functions together, allows free movement of muscles, carries nerves, blood vessels, lymph vessels, and fills spaces between muscles

Front 51

Epimysium (upon)

Back 51

covers entire muscle

Front 52

Perimysium (around)

Back 52

covers fascicle

Front 53

Endomysium (within)

Back 53

cover muscle fibers

Front 54

Tendons and Tendon sheaths are...

Back 54

extensions of connective tissue beyond muscle cells that attach muscle to bone or other muscle

Front 55

Tendon proper

Back 55

the tendon that connects skeletal muscles to bones

Front 56

Tendon sheaths (synovial sheaths)

Back 56

enclose certain tendons and allow them to slide back and forth more easily

Front 57

Nerves convey...

Back 57

sensory information to the central nervous system and convey impulses for muscular contraction

Front 58

What type of nerves convey sensory information to the central nervous system?

Back 58

afferent nerves

Front 59

What type of nerves convey impulses for muscular contraction?

Back 59

- motor neurons
- efferent nerves

Front 60

List the type of muscle receptors

Back 60

- Muscle spindles
- Golgi Tendon Organs

Front 61

Define Muscle spindles

Back 61

- provide feedback on muscle length and rate of change in length
- located on intrafusal muscle fibers
- rapid changes in length can elicit muscular contraction in the agonist muscle and reciprocal inhibition of antagonist muscles

Front 62

Define Golgi Tendon Organs

Back 62

- provide feedback on muscle tension and rate of change in tension
- located in tendinous connective tissue at ends of skeletal muscle
- when great tension is placed on a muscle, GTOs induce muscular relaxation to protect the agonist muscle

Front 63

Skeletal Muscle Fiber types are based upon:

Back 63

- location, purpose, and function of muscle
- heredity
- exercise training
- age
- innervating alpha-motor neuron

Front 64

Type llx (Fast Glycolytic)

Back 64

- large diameter
- white light pink in color
- few myoglobin, mitochondria, and blood capillaries
- a lot of glycogen and CrP in sarcoplasm
- fast form of myosin ATPase
can anaerobically generate ATP at a high rate
- fatigue easily
- speed of contraction is 5-6x faster than Type l fibers
- great for speed/power activities

Front 65

Type lla (fast oxidative glycolytic)

Back 65

- intermediate diameter
- pink in color
- great for speed/power activities
- moderate amounts of myoglobin, mitochondria, and blood capillaries
- fast form of myosin ATPase
- decent capacity for generating ATP via anaerobic and aerobic metabolism, thus split ATP at a high rate (slower than Type llx, but still fast)
- fast contraction velocity, but slower than Type llx
- More resistant to fatigue than Type llx
- good compromise for all activities

Front 66

Type l (slow oxidative)

Back 66

- small diameter
- dark pink in color
- a lot of myoglobin, mitochondria, and blood capillaries
- slow form of myosin ATPase
- can aerobically generate loads of ATP, but at a slow rate
- very resistant to fatigue
- slower contraction velocity
- great for endurance activities

Front 67

Motor neuron (axon)

Back 67

efferent nerve that conducts impulses from the spinal cord to the muscle

Front 68

Neuromuscular junction

Back 68

o Synapse: the functional junction of motor neuron and muscle cell.
o Axon terminal bulb: bulbous distal end of motor neuron, synaptic vesicles contain neurotransmitter Acetylcholine (Ach).
o Synaptic cleft: the “gap” between the axon terminal and motor end plate.
o Motor end plate: region of the muscle fiber sarcolemma that includes Ach receptors.
o Neurotransmitters (Ach): bridge the gap of the synaptic cleft.

Front 69

What are the two sequential processes that are linked together for skeletal muscle contraction?

Back 69

1.) Excitation-contraction coupling
2.) Sliding filament theory