Module 8: The Muscular System Flashcards Preview

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Flashcards in Module 8: The Muscular System Deck (42):
1

3 types of muscle

Skeletal
Smooth
Cardiac

2

Functions of muscles (4)

Produces movement
Maintains posture
Stabilizes joints
Generates heat

3

Produces movement

Skeletal muscles - walk, blink, turn around, chew, laugh etc
Smooth muscles line blood vessels and transport blood
Cardiac muscle operates as a pump for the blood

4

Maintains posture

Skeletal muscles defy gravity by making adjustments that allow us to sit or stand erect

5

Stabilizes joints

Skeletal muscles hold bones together and assist in stabilizing and strengthening joints

6

Generates heat

Muscle activity of ALL muscles general heat (skeletal muscles generate the most)

7

Coverings of skeletal muscle

-covered by fascia (layers of fibrous connective tissue)
-fascia extends beyond muscle and turns into the tendon
- Epimysium of fascia is the layer that attaches to the muscle
-Muscle fibers (cells) are grouped into fascicles (bundles)
-Perimysium surrounds each bundle
-Endomysium surrounds each muscle fiber

8

Structure of muscle fiber (cell)

-Elongated cells with hundreds of nucleoli
-Plasma membrane called sarcolemma
-Cytoplasm called sarcoplasm
-Each fiber is made of many myofibril which consist of myofilaments
-Sarcoplasmic reticulum surrounds each myofibril
-each myofilament is made of thin (actin) and thick (myosin) filaments
-Myfilaments arranged in sarcomeres (give muscle striated look)
- T tubules carry nerve stimulus into muscle fiber

9

Sliding filament mechanism

sliding of the thin filaments toward the center of the sarcomere causes the unit to shorten
Contracting muscles:
-nerve impulse stimulates sarcolemma
-t tubules allow stimulus to reach sarcolemma
-myosin heads make contact with actin to form temporary cross bridges
-myosin heads rotate, pulling actin inwards

10

Motor neuron

transmits nerve impulses from the brain and spinal cord to the skeletal muscles

11

Motor unit

a single motor neuron and the muscle fibers it stimulates

12

Neuromuscular Junction (NMJ)

The area where the motor neuron meets the muscle fibers
Structures include: plasma membrane @ end of neuron, Synaptic cleft (space between end of neuron and sarcolemma/plasma membrane of muscle fiber), sarcolemma/plasma membrane and its receptor sites
The neuron releases chemicals that diffuse across NMJ and stimulate the muscle fiber

13

Action potential

electrical impulse resulting from stimulation of the neuron to move along the neuron towards the axon terminal with vesicles (containing ACh, acetylcholine)

14

Acetylcholinesterase

NMJ enzyme that breaks down ACh

15

What happens to the electrical signal in the sarcolemma

-signal travels along sarcolemma
-travels through T tubules and then stimulates the sarcoplasmic reticulum to release Calcium
-Calcium floods the sarcomeres and allows interaction of actin, myosin and ATP to cause muscle contraction
-Calcium is pumped back into the sarcoplasmic reticulum, away from actin and myosin causing muscle relaxation

16

All or none principle

The muscle fibers are either ON (contracting completely) or OFF (relaxing)

17

Isotonic contraction

Muscles shorten and movement occurs
ex. lifting object, walking, swimming,

18

Isometric contraction

Muscles DO NOT shorten and NO movement occurs
ex. pushing against a wall with arms, holding a book in your palms, TRYING to lift a piano

19

Tone

in skeletal muscles, when there are always some muscle fibers contracted (not the whole muscle, just some fibers)

20

3 types of muscle metabolism

Muscles require lots of ATP to contract
Aerobic metabolism
Anaerobic metabolism
Metabolism of Creatine Phosphate

21

Aerobic metabolism

In presence of oxygen
Fuels such as glucose and fatty acids are completely broken down by Aerobic Respiration
Glucose + oxygen = CO + H2O + ATP
(lots of ATP, 38 ATP per glucose)
*Provides the most ATP

22

Anaerobic Metabolism

In absence of oxygen
Anaerobic Respiration partially breaks down glucose to produce lactic acid and a small amount of ATP
Glucose = lactic acid + ATP
*Takes the shortest amount of time

23

Metabolism of Creatine Phosphate

Creatine phosphate is a high energy compound stored in muscle
Creatine phosphate + ADP = creatine + ATP

24

Oxygen debt

additional oxygen that is required after a physical activity to restore resting conditions
O2 needed to convert lactic acid into glycogen

25

Labored breathing

continues after the activity has stopped until oxygen debt has been brought back to equilibrium

26

Skeletal muscle origin

the end of the muscle that is attached to the STATIONARY bone (not easily movable)

27

Skeletal muscle insertion

the end of the muscle that is attached to the other bone (easily movable)

28

Prime mover

the main muscle in a particular movement
ex. during bicep curls, biceps are the prime mover

29

Antagonist muscle

a muscle that opposes the action of another muscle

30

Synergist muscle

help the prime mover by stabilizing joints or preventing awkward movement

31

naming of muscles is based on:

location
shape
relative size
direction of muscle fibers
number of origins
location of attachments
action

32

Location of muscle

Adbominis (abdomen)
Carpi (wrist)
Femoris (femur)
Oculo (eye)
Oris (mouth)
Pectoralis (chest)
Temporalis (temporal bone)

33

Shape of muscle

Deltoid (triangle)
Latissimus (wide)
Orbicularis (circular)
Serratus (serrated)
Teres (long and round)
Trapezius (trapezoid shape)

34

Relative size of the muscle

Brevis (short)
Longus (long)
Maximus (large)
Minimus (small)
Minor (small)
Vastus (huge)

35

Direction of muscle fibers

Oblique (diagonal)
Orbicularis (circular)
Rectus (straight)
Transverse (cross)

36

Number of origins

May be named according to the number of sites the muscle is anchored to
Ex. Bicep (2)
Tricep (3)
Quadriceps (4)

37

Action

Abductor (moves away from the midline of the body)
Adductor (moves towards the midline of the body)

38

Superficial muscles for chewing

Masseter
-raises the mandible (lower jaw bone)
-responsible for mastication(chewing)

39

Superficial muscles for movement of head, pectoral girdle, upper arm

Sternocleidomastoid (sides of neck)
Trapezius (moves shoulder blade and the head)
Deltoid (abducts the arm to a horizontal position)
Pectoralis major (large anterior muscle in upper ches)
Latissimus dorsi (lateral and dorsal, extends and adducts the arm)

40

Superficial muscles of the abdominal wall

External Oblique
Rectus Abdominis (holds contents of the abdominal cavity in place)

41

Superficial muscles in the arms and hands

Biceps brachii (anterior upper arm)
Triceps brachii (posterior upper arm)
Flexor carpi or extensor carpi (move wrist and hand)

42

Superficial muscles in the legs and feet

Gluteus maximus (straightens leg)
Gluteus medius (raises leg sideways to horizontal position)
Adductors (medial part of thigh, bring down leg from a horizontal position)
Quadriceps Femoris (main extensor of the lower leg)
Hamstring group (includes semitendinousus, biceps femoris, semimembranosus)
Sartorius (strap like muscle from hip to inside of knee)
Gastrocnemius (plantar flexor)
Tibialis anterior (used for inversion of foot)
Peroneus (connects fibula to foot bones; pointing your toes)