Chapter 6: Muscular System

Question 1

4 Tissue Types

Answer 1

1.Epithelium
2.Connective
3.Muscular
4.Nervous

Question 2

What is the main function of muscle tissue?

Answer 2

Contraction

Question 3

How does a muscle function?

Answer 3

Muscles function like a motor, nutrients are the energy for the motors, controlled by the nervous system.

Question 4

3 Types of Muscle Tissue

Answer 4

1.Skeletal
2.Smooth
3.Cardiac

Question 5

Skeletal Muscle (Histology)

Answer 5

1. Large Cylindrical Fibers
2. Striated
3. Multinucleate (off to side)

Question 6

Cardiac Muscle (Histology)

Answer 6

1. Short
2. Striated Branched Fibers
3. Single Nucleus
4. Intercalated discs: Special junctions that conduct contractions.

Question 7

Smooth Muscle (Histology)

Answer 7

1. Small, Spindle Shaped
2. Non striated
3. Single central nucleus

Question 8

Skeletal Muscle (Characteristics)

Answer 8

1. Voluntary controlled (via nervous system)
2. Speed of contraction (Slow to Fast)
3. Rhythmic Contraction: No

Question 9

Cardiac Muscle (Characteristics)

Answer 9

1. Involuntary controlled (hormones)
2. Speed of contraction (Slow)
3. Rhythmic contraction (yes)

Question 10

Smooth Muscle (Characteristics)

Answer 10

1. Involuntary Controlled (via nervous system, hormones)
2. Speed of Contraction (very slow)
   Rhythmic Contraction (yes, in some)

Question 11

Functions of Skeletal Muscles (6)

Answer 11

1. Produces skeletal movement
2. Maintain body position
3. Supports soft tissues
4. Guard openings (mouth, eyes)
5. Maintain Body Temp (ATP powers contraction but energy escapes as heat.)
6. Stores nutrients reserves- glycogen

Question 12

3 Layers of Connective Tissue

Answer 12

1. Epimysium
2. Perimysium
3. Endomysium

Question 13

Epimysium

Answer 13

1. Separates muscle from surrounding tissue

Question 14

Perimysium

Answer 14

1. Surrounds muscle fiber bundles (fascicles)
2. Contains blood vessels and nerve supply to fascicles

Question 15

Endomysium

Answer 15

1. Surrounds individual muscle cells (muscle fibers)

Question 16

Organization of Muscle Tissue

Answer 16

1. Epimysium, Endomysium, and Endomysium come together at the end of a muscle and connects to bone (tendons)

Question 17

Skeletal Muscle Fibers

Answer 17

1. Very Long
2. Develop through fusion of embryonic cells (myoblasts)
3. Become very large
4. Contain hundreds of nuclei

Question 18

“Myo”

Answer 18

Associated with Muscle

Question 19

“Sarco”

Answer 19

Flesh

Question 20

Sarcoplasm

Answer 20

Cytoplasm

Question 21

Sarcolemma

Answer 21

Plasma Membrane

Question 22

Transverse Tubule

Answer 22

Invagination of sarcolemma

Question 23

Sarcoplasmic reticulum

Answer 23

Specialized ER that stores and releases calcium, surrounded by myofibrils

Question 24

Terminal Cisterna

Answer 24

Enlarged sacs of SR near transverse tubules

Question 25

Myofibrils

Answer 25

1. 1000 in one muscle fiber 2. Bundles of protien microfilaments 3. Structural and functional unit: Sarcomere 4. Types of protien 1. Contractile: Actin/Myosin 2. Regulatory: Troponin/Tropomyosin

Question 26

Sarcomere

Answer 26

1. Contractile units of muscle 2. Structural units of myofibrils 3. Form visible patterns within myofibrils 4. Actin-Thin filament (light) 5. Myosin- Thick Filament (dark)

Question 27

Sliding Filament Theory

Answer 27

1. Actin and myosin filaments within a sarcomere connect and slide past each other to produce muscular tension and movement. 2. Actin and Myosin do not change length they just overlap more. 3. The muscle itself shortens or contracts

Question 28

Neuromuscular junction

Answer 28

1. Association site of axon terminal of the motor neuron and sarcolemma of a muscle

Question 29

Neurotransmitter

Answer 29

1. Chemical release of nerve upon arrival of nerve impulse in the axon terminal. 2. Acetylcholine (ACh) is the neurotransmitter that stimulates skeletal muscle.

Question 30

Synaptic Cleft

Answer 30

1. Gap between nerve and muscle 2. Nerve and muscle do not make actual contact

Question 31

Twitch

Answer 31

1. Contraction and relaxation of a muscle fiber

Question 32

The all-or-none principle

Answer 32

1. As a whole, a muscle fiber is either contracted or relaxed, however the tension can differ.

Question 33

Tension of a single muscle fiber

Answer 33

Depends on... 1. Number of pivoting cross bridges. 2. The fibers resting length at the time of stimulation. 3. The frequency of stimulation.

Question 34

Incomplete Tetanus

Answer 34

1. Twitches reach maximum tension 2. If rapid stimulation continues and muscle is not allowed to relax, twitches reach maximum level of tension.

Question 35

Complete Tetanus

Answer 35

If stimulation frequency is high enough, muscles never begin to relax, and is in continuous contraction.

Question 36

Muscle Fatigue

Answer 36

1. When muscles can no longer perform required activity

Question 37

Causes of muscle fatigue

Answer 37

1. Depletion of energy (ATP) 2. Damage to sarcolemma and sarcoplasmic reticulum. 3. Low pH (Lactic acid) 4. Pain/Psychological