2 - APP - Unit 2.2 - The Muscular System Flashcards Preview

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1
Q

The Muscular System - Muscles

A

Main organ of the muscular system.
Produces nearly all movement of body (incl breathing moving fluids like blood or urine, move food through digestive system).
Provides support to the body

2
Q

The Muscular System

A

Organized system of contractile fibrous tissues that work together to produce movement.

3
Q

The Muscular System - Connective tissues

A

Organizes muscles into functional groups.
Surrounds each individual muscle
Extends inward throughout the muscle creating muscle cell bundles (= fascicles)
Surrounds each individual muscle cell
Creates supporting structure for the intricate network of blood vessels & nerves of the muscular system

4
Q

The Muscular System - Contractile tissues

A

Organized and supported by an intricate network of connective tissue.

5
Q

Structure of Skeletal Muscles - Epimysium

A

Layer of connective tissue that covers an entire muscle

6
Q

Structure of Skeletal Muscles - Perimysium

A
  • Etends in the muscles and surrounds groups of muscle cells know as fascicles
  • Covers the group of muscle cells
7
Q

Structure of Skeletal Muscles - Endomysium

A

Within the fascicle, delicate connective tissue covering each muscle cell

8
Q

Structure of Skeletal Muscles - Tendons

A

Attach muscles to bones

Connective tissue layers (epimysium?? to verify) project beyond the ends of the muscle to become the tendons

9
Q

Structure of Skeletal Muscles - Cell membrane

A

Beneath the layer of connective tissue that surrounds the muscle cell.
Within cell membrane: muscle cell highly organized

10
Q

Structure of Skeletal Muscles - Myofibril

A

Long strand of cable-like protein that contains thousands of actin and myosin filament

11
Q

Structure of Skeletal Muscles - Sarcomeres

card to be verified

A

Organized segments made of actin and myosin filament.

Gives skeletal muscle the striped or striated appearance.

12
Q

Structure of Skeletal Muscles - Transverse tubules

A
  • AKA or “T” tubules

- Important role in transmission of the stimulus of muscle cell contraction

13
Q

Structure of Skeletal Muscles - Sarcoplasmic reticulum

A
  • Network of membranous channels within the cell that surrounds each myofibril and is closely associated with the transverse tubules.
  • Releases calcium ions when impulse is transmitted through cell membrane and transverse tubules.
14
Q

Structure of Skeletal Muscles - Sarcoplasmic reticulum -In the high concentrations of calcium ions…

A

… actin filaments slide across the myosin filaments resulting in the shortening of the cell.

15
Q

Skeletal Muscle Contraction - Neuromuscular jonction

A

AKA myoneural junction
Site where muscle cell and nerve fiver meet.

  • A muscle cell has only one nerve fiber connection.
  • A motor nerve may have many branches / connect to several muscles cells
16
Q

Skeletal Muscle Contraction - Motor unit

A

Motor nerve + all the muscle cells that it controls

  • motor unit of small muscles providing intricate movement : as few as 2-3 muscle cells. Expl: control speech or eye movement
  • motor unit of larger muscles providing less intricate movement: several hundred of muscle cells. Expl: muscles of thigh or leg.
17
Q

Skeletal Muscle Contraction - Acetylcholine

A
  • Chemical neurotransmitter
  • Is released when a nerve impulse travels from the brain or spinal cord through the motor nerves and reaches the end of the nerve fiber, and bridges the gap between the nerve and the muscle cell.
  • Affects muscle cell membrane by creating an impulse that travels throughout the muscle cell.
18
Q

Skeletal Muscle Contraction -

A

Impulse created in muscle cell is transmitted through the transverse tubules until it contacts the sarcoplasmic reticulum, which releases a flood of calcium ions.
Calcium ions bond to actin filaments causing the actin and myosin filaments to slide across each other, resulting in the shortening of the cell.

19
Q

Skeletal Muscle Contraction - Adenosine Triphosphate (ATP)

A

Energy for muscle cell contraction comes from Adenosine Triphosphate (ATP) molecule.

20
Q

Skeletal Muscle Contraction - Aerobic cellular respiration

A

Taking place in the cell’s mitochondria.

Responsible for the majority of the sustained energy supply for the constant replenishing ATP.

21
Q

Skeletal Muscle Contraction - Anaerobic respiration

A

When oxygen available in aerobic respiration depletes, cells must rely exclusively on anaerobic respiration.

Glucose is broken down to make some ATP and produces a substance called pyruvic acid, which chemically degrades into lactic acid. Lactic acid is transported out of cell, to liver to be converted back to glucose.

22
Q

Terminology of the Muscular System - Irritability

A

AKA Excitability
Capacity of muscles to receive and react to stimuli.

Expl stimuli:

  • mechanical (massage)
  • electrical (currents)
  • thermal (heat)
  • chemical (acid or salt)
  • impulses of nervous origin
23
Q

Terminology of the Muscular System - Contractility

A

Ability to contract or shorten and thereby exert force

24
Q

Terminology of the Muscular System - Extensibility

A

Ability to stretch

25
Q

Terminology of the Muscular System - Elasticity

A

Ability to return to its original shape after being stretched

26
Q

Terminology of the Muscular System - Isometric contraction

A

When a muscle contracts and the ends of the muscle, or the body part affected, do not move.
expl: straining to move a heavy object that does not budge. Contraction of muscles that stabilize in an upright posture.

27
Q

Terminology of the Muscular System - Isotonic contraction

A

When a muscle contracts and the distance between the ends of the muscle changes.
Muscle contraction with movement

28
Q

Terminology of the Muscular System - Isotonic contraction - 2 types

A
  • Concentric isotonic: muscle shortens as it contracts.
    Expl: for bicep curls, the contraction that brings the bar up to the chest
  • Eccentric isotonic: muscle lengthens as it contracts.
    Expl: for bicep curls, the contraction that allows the bar to be lowered down.
29
Q

Terminology of the Muscular System - Muscle tone

A

Type of muscle contraction in healthy muscles, even when at rest.
Muscle possesses tone if firm & responding promptly to stimulation under normal condition.
Lack of tone evidenced by a condition of flaccidness.

Exercice and massage help to improve muscle tone.

30
Q

Terminology of the Muscular System - Skeletal movement produce movement by…

A

… exerting force on the tendons, which in turn pull on bones or other structures, such as skin.

31
Q

Terminology of the Muscular System - Origin

A

Muscle tendon attachement to the stationary bone

32
Q

Terminology of the Muscular System - Insertion

A

Muscle tendon attachement to the movable bone

33
Q

Terminology of the Muscular System - Belly

A

Fleshy portion of the muscle between the tendons of the origin and insertion.

34
Q

Terminology of the Muscular System - Origin/Insertion in the limbs

A

In the limbs, origin is proximal and insertion is distal.

35
Q

Terminology of the Muscular System - Most skeletal muscles are arranged in…

A

… opposing pairs at joints

Expl: Flexor-extensors, abductors-adductors, etc

36
Q

Terminology of the Muscular System - Agonist

A
  • Prime mover
  • Muscle that causes a desired action

Expl: When flexing forearm at elbow, biceps brachii is prime mover.

37
Q

Terminology of the Muscular System - Antagonist

A
  • Usually located on the opposite side of the bone or joint in relation to the prime mover.
  • Action opposite to the Prime Mover
  • Stretches and yields to the Prime Mover

Expl: When flexing forearm at elbow, triceps brachii is the antagonist
When stretching forearm at elbow, triceps brachii is the prime mover and biceps brachii is the antagonist

38
Q

Terminology of the Muscular System - Synergists

A

Serve to steady movement, preventing unwanted movements and helping the prime mover function more efficiently

39
Q

Terminology of the Muscular System - Fixators

A

Some synergist muscles in a group act as fixators.

They stabilize the origin of the prime mover so it can act more efficiently.

40
Q

Common Dysfunctions and Diseases of the Muscular System - Spasm

A
  • Sudden involuntary contraction of a muscle or group of muscles
  • Usually occurs when the nerve supplying muscle is irritated
  • Varies in duration and intensity
  • Can affect any muscle tissue including voluntary, involuntary or cardiac muscle tissue
  • Can be the result of injury, disease or emotional stress

Expl: hiccups, tics, twitches in the face, charley-horses, convulsions & muscle “splinting” associated with injuries such as sprains.

41
Q

Common Dysfunctions and Diseases of the Muscular System - Muscle strains

A

AKA pulled or torn muscles
Overstretching of the muscle and/or tendons

Most common muscle injury
80% occur in muscle belly or at the junction between muscle and tendon

42
Q

Common Dysfunctions and Diseases of the Muscular System - Muscle strain - Grade I

A
  • Over-stretching of a few of the muscle cells with minimal tearing of the muscle tissue
  • Some pain
  • No loss of function
  • No palpable or visual indications
43
Q

Common Dysfunctions and Diseases of the Muscular System - Muscle strain - Grade II

A
  • Partial tear of 1%-49% of the muscle cells
  • Considerable pain
  • Some loss function
  • Palpable thickening of the muscle tissue and may be some tissue bleeding
44
Q

Common Dysfunctions and Diseases of the Muscular System - Muscle strain - Grade III

A
  • The most severe injury
  • Tear of 50%-100% of the muscle cells
  • Severe pain
  • Total or near total loss of muscle function
  • Palpable depression and/or bunching of the muscle
45
Q

Common Dysfunctions and Diseases of the Muscular System - Hypertrophy

A
  • Increase in size of the muscle as a result of repeated forceful muscle activity
  • Increases power of muscle and metabolic support system
  • Most of enlargement due to increase in size of muscle cells rather than increase in number of muscle cells.
46
Q

Common Dysfunctions and Diseases of the Muscular System - Atrophy

A
  • Decrease in size of the muscle as a result of muscle disuse.
    If muscle cannot be contracted it rapidly degenerate and begin to waste away.
  • Degeneration due to decrease in number and size of capillaries supplying blood and nutrients to the muscle and to decrease in size of myofibrils within muscle cells.
  • If nerve supply to muscle is interfered, paralysis results and muscle atrophy progresses rapidly.
47
Q

Common Dysfunctions and Diseases of the Muscular System - Fibrosis

A

Formation of fibrous scar tissue within normal tissue

48
Q

Common Dysfunctions and Diseases of the Muscular System - Myofibrosis

A

Formation of fibrous scar tissue within normal muscle tissue

49
Q

Common Dysfunctions and Diseases of the Muscular System - Fibrositis

A

Inflammation of abnormal fibrous scar tissue

50
Q

Common Dysfunctions and Diseases of the Muscular System - Myofibrositis

A

Inflammation of fibrous scar tissue within muscles tissue Causes pain and stiffness

51
Q

Common Dysfunctions and Diseases of the Muscular System - Muscular dystrophy

A
  • Progressive degeneration of the muscular tissues
  • Group of related diseases that seem to be genetically inherited
  • Contractile cells of muscles become virtually useless.
  • Rarely causes pain. Intellect not affected.
  • Exercise & massage helpful in prolonging muscular ability and maintaining flexibility