Chapter 9: Muscles And Muscle Tissue Flashcards Preview

Advanced Anatomy & Physiology > Chapter 9: Muscles And Muscle Tissue > Flashcards

Flashcards in Chapter 9: Muscles And Muscle Tissue Deck (42):
1

What are the 3 types of muscle tissue?

1. Skeletal
2. Cardiac
3. Smooth

2

Describe Skeletal Muscle Tissue

• Striated
• Location: Attached to skin and bone
• Voluntary

3

Describe Cardiac Muscle Tissue

• Striated
• Location: Heart
• Involuntary

4

Describe Smooth Muscle Tissue

• No Striations
• Location: Walls of hollow organs
• Involuntary

5

What are the 4 main characteristics of muscle tissue?

1) Excitability (responsiveness)
2) Contractibility
3) Extensibility
4) Elasticity

6

Excitability (responsiveness)

Ability to receive and respond to stimuli

7

Contractibility

Ability to shorten forcibly when stimulated

8

Extensibility

Ability to be stretched

9

Elasticity

Ability to recoil to resting length

10

What are the 4 main functions of the muscle?

1. Produce movement
2. Maintain posture
3. Stabilize joints
4. Generate heat as they contract

11

What are the 3 features of the Skeletal muscle anatomy?

1) Nerve and blood supply
2) CT sheaths
3) Attachments

12

Nerve and Blood Supply

• Each muscle receives a nerve, artery, and veins--> cellular respiration

• Contracting muscle fibers require huge amounts of oxygen and nutrients

13

CT Sheaths

• Every skeletal muscle (and muscle fiber) is covered in CT

• Support cells and reinforce whole muscle

- Sheaths from external to internal (3)

14

What are the 3 Sheaths of CT?

1) Epimysium
2) Perimysium
3) Endomysium

15

Epimysium

Dense irregular CT surrounding entire muscle

16

Perimysium

Fibrous CT surrounding fascicles

17

Endomysium

Fine areolar CT surrounding each muscle fiber (cell)

18

Attachments

• Muscle spans joints and attach to bones

- Muscles attach to bone in a least (2) places:
• Insertion
• Origin

19

Insertion

Attachment to movable bone

20

Origin

Attachment to immovable or less movable bone

21

Sarcolemma

Muscle fiber plasma membrane

22

Sarcoplasm

Muscle fiber cytoplasm

23

Myofibrils

Densely packed, rodlike elements

24

Muscle tension

The force exerted on load or object to be moved; produced by contraction

25

What are the 2 types of contractions?

1) Isometric
2) Isotonic

26

Isometric Contraction

No shortening; muscle tension increases but does not exceed load

27

Isotonic Contraction

Muscle shortens because muscle tension exceeds load

28

Why does the force and duration of a contraction vary?

In response to stimuli of different frequencies and intensities

29

Motor Unit

Consists of the motor neuron and all muscle fibers it supplies

30

Muscle twitch

Simplest contraction resulting from a muscle fiber's response to a single action potential from motor neuron

31

Why do graded muscle responses vary?

The various strength of contractions are for different demands

32

How do muscles graded in response to change change in stimulus frequency?

- Single stimuli= single contractile (i.e muscle twitch)

- Multiple stimuli= multiple contractiles from same fiber

33

How does stimulus strength change to muscle response?

Recruitment (or multiple unit stimulation )

34

Recruitment (or multiple unit stimulation )

Stimulus is sent to more muscle fibers, leading to more precise control

35

What are the 3 types of stimulus in recruitment?

1) Sub threshold
2) Threshold
3) Maximal

36

Sub Threshold stimulus

Stimulus not strong enough, so no contractions seen

37

Threshold stimulus

Stimulus is strong enough to cause first observable contraction

38

Maximal stimulus

Strongest stimulus that increases maximum contractile force

39

Describe the asynchronous contraction of motor units in muscles?

Tag team back-and-forth, contracting and relaxing

40

Muscle tone

Constant, slightly contracted state of all muscles

41

ATP supplies the energy needed for the muscle fiber to:

- Move and detach cross bridges
- Pump calcium back into SR
- End the action potential moving through the muscle

42

What are the 3 mechanisms in which ATP is regenerated quickly?

1. Direct phosphorylation of ADP by creatine phosphate (CP)
2. Anaerobic pathway; glycolysis and lactic acid formation
3. Aerobic respiration