Lecture 11

Front 1

Motor recruitment

Back 1

Progressively activating more and more motor units

Front 2

Small motor units contain?

Back 2

Few muscle fibers and are type 1 (slow,Oxidative, red)

Front 3

Large motor units contain?

Back 3

Large number of muscle fibers, type 2, (fast, glycolic, white)

Front 4

Muscle tone

Back 4

At any time some fibers in a muscle are contracted while others are relaxed. Essential for posture and balance.

Front 5

Muscle twitch

Back 5

Response of a whole muscle to a single stimulus

Front 6

Latent period

Back 6

Few milliseconds the muscle does not contract. Covers time of the action potential, calcium release from sarcoplasmic reticulum and molecular events before power stroke of myosin

Front 7

Treppe

Back 7

Muscle stimulated repeatedly, allowing sufficient time for relaxation between stimuli, responds with a series of separate twitches that progressively increase up to a max value after a few seonds. Caused by calcium buildup in sarcoplasm

Front 8

Tetanus

Back 8

Skeletal muscle stimulates so frequently it cannot relax after previous twitch. Contractions merge not a sustained contraction. Characterizes most of contractions made by muscles during voluntary activity.

Front 9

Isotonic contraction

Back 9

Muscle shortens and tension remains constant

Front 10

Isometric contraction

Back 10

Muscle length does not change but tension developed increases sharply

Front 11

Smooth muscle

Back 11

Cells are considerably shorter than skeletal muscle fibers. Each fiber has 1 nucleus. Contains actin and myosin. Lack striations,not well organized. Lack T-Tubules, troponin and tropomyosin. Contacts slower than skeletal muscle but greater degree of shortening and large movement can be produced.

Front 12

Types of smooth muscle

Back 12

Multi unit smooth muscle and visceral smooth muscle.

Front 13

Multi unit smooth muscle

Back 13

Cells are not well organized. Occurs as separate fiber rather than sheets. Separate fibers may contract independently. Contractions initiated by signals from nerves in autonomic nervous system. Iris of eye, walls of blood vessels, large passage ways of lungs, arrector pili muscle

Front 14

Visceral smooth muscle

Back 14

Single unit. Cells arranged in wrap around sheets. Found in walls of hollow organs such as stomach, intestine urinary tract, reproductive tract and small blood vessels. Cells are in close contact and can stimulate each other via gap junctions.

Front 15

Peristaltic movements

Back 15

Wave like movements in visceral smooth muscle. Can force the contents of hollow organs in particular direction.

Front 16

Pacemaker cells

Back 16

Self initiates Repeated waves of excitation. Creates rhythmicity in visceral smooth muscle

Front 17

Calmodulin

Back 17

Mediates excitation contraction coupling in smooth muscle. Calcium binding protien

Front 18

Controls smooth muscle contraction

Back 18

Nervous input from autonomic nervous system

Hormones and related substances in circulation

Substances produced withing a metabolizing tissue cam cause smooth muscle to relax.

Stretching

Front 19

Intercalated disc

Back 19

Connect cardiac muscles end to end in branching networks. Contains gap junctions to spread electrical excitation.

Front 20

Muscle Orgin

Back 20

The end of the muscle which does not move

Front 21

Muscle instertion

Back 21

The end the muscle attached to the moving skeletal unit.

Front 22

Kinesiology

Back 22

Study of different types of muscles, lever systems and their movements

Front 23

Out force

Back 23

Generated by the lever. Move hand lift weight

Front 24

In force

Back 24

Force the muscle applies to lever to accomplish movement

Front 25

Back 25

First class lever

Front 26

First class lever examples

Back 26

Lifting the head

Straightening arm at the elbow

Movement of foot around fulcrum of ankle

Front 27

Back 27

Second class lever i.e wheelbarrow

Front 28

Back 28

Third class lever

Front 29

Third class lever examples

Back 29

Most common in body

Flexing forearm at elbow

Front 30

Formula for muscle amplification

Back 30

Front 31

Flexor

Back 31

Decrease angle of joint

Front 32

Extensor

Back 32

Increase angle of joint

Front 33

Abductor

Back 33

Moves bone away from midline

Front 34

Adductor

Back 34

Moves bone closer to midlie

Front 35

Supinator

Back 35

Turn palm upward or anteriorly

Front 36

Pronator

Back 36

Turns palm downward or posteriorly

Front 37

Satellite cells

Back 37

Stem cells that repair damaged muscle fibers. Quiescent myoblast.

Front 38

Muscular hyperplasia

Back 38

Increase in number of muscle fibers in a muscle. Humans skeletal muscles have very limited ability to form new fibers

Front 39

Muscular hypertrophy

Back 39

Increase in size of muscle fiber. Due to production of myofibrils, mitochondria and sarcoplasmic reticulum

Front 40

Muscular atrophy

Back 40

Wasting away of muscle fibers

Front 41

Myasthenia gravis

Back 41

Autoimmune disease where patient develops antibodies against acetylcholine receptors in neuromuscular junction

Front 42

Duchenne muscular distrophy

Back 42

Causes muscular atrophy. Hereditary disease. Mutation in general for dystrophin. Localized in sarcolemma. Integral for anchoring certain integral membrane glycoproteins which may control calcium flow into muscle