Unit 11 - Muscular System

Question 1

What does the muscular system refer to

Answer 1

Skeletal muscle system

Question 2

What are muscles in the muscular system primarily attached to

Answer 2

Bone

Question 3

How do muscles produce movement

Answer 3

By contracting

Question 4

What are muscles important for

Answer 4

• locomotion
• maintaining body posture

Question 5

What are skeletal muscle cells called

Answer 5

Fibers

Question 6

Fasicle

Answer 6

Group of fibres

Question 7

Whole muscle

Answer 7

Group of fascicles

Question 8

CT components of skeletal muscle

Answer 8

1. Fascia
2. Tendons and aponeuroses

Question 9

What is fascia

Answer 9

CT surrounding muscles or other organs

Question 10

Epimysium of fascia

Answer 10

Surrounds entire skeletal muscle

Question 11

Perimysium of fascia

Answer 11

Surrounds fascicles within skeletal muscle

Question 12

Endomysium of fascia

Answer 12

Surrounds each muscle fiber (cell) within skeletal muscle

Question 13

What are tendons and aponeuroses

Answer 13

Extensions of epimysium, perimysium and endomysium

Question 14

What do tendons and aponeuroses anchor

Answer 14

Muscle to bone (periosteum), cartilage, fascia

Question 15

Tendon

Answer 15

Rope like bundle of dense regular CT
- ex. Calcaneal (Achilles) tendon

Question 16

Aponeurosis

Answer 16

Flat sheet of dense regular CT
- ex. Epicranial aponeurosis (scalp)

Question 17

What kind of cells is skeletal muscle fiber made of

Answer 17

Large, cylindrical and multinucleate cells

Question 18

Parts of skeletal muscle fibres

Answer 18

1. Sarcolemma
2. T-tubules
3. Sarcoplasm
4. Myofibrils
5. Sarcoplasmic reticulum

Question 19

Sarcolemma

Answer 19

Cell membrane

Question 20

T-tubules

Answer 20

Continuations of Sarcolemma that extend deep into fibre (cell)

Question 21

Myofibrils

Answer 21

• intracellular structures
• within each fibre there are several hundreds to thousands
• composed of sarcomeres

Question 22

Sarcomere structure

Answer 22

• composed of proteins
• made of 2 types of myofilaments
  1. Thin myofilaments
  2. Thick myofilaments

Question 23

Thin myofilaments

Answer 23

• formed by 3 proteins involved in contraction
  1. Actin
  2. Tropomyosin
  3. Troponin

Question 24

Thick myofilaments

Answer 24

• formed by a protein called myosin
• attached to Z discs by titin
• create dark and light bands (striations) of the sarcomere

Question 25

Myosin

Answer 25

- has rod-like tail with 2 globular heads

Question 26

What does myosin do at rest

Answer 26

Head extends towards actin

Question 27

What does myosin do during contraction

Answer 27

Head attaches to actin to shorten the sarcomere

Question 28

What does the banding pattern of thick myofilaments consist of

Answer 28

1. A band 2. H zone 3. I band 4. Z discs 5. M line

Question 29

A band

Answer 29

Dark band that is length of thick myofilament

Question 30

H zone

Answer 30

Lighter area at center of A band

Question 31

I band

Answer 31

Light band consisting of thin myofilaments

Question 32

Z discs

Answer 32

- in center of I band - connected to thick myofilaments (via titin) and thin myofilaments - connection point between adjacent sarcomeres - sarcomeres join end to end (at Z discs) to form a Myofibril

Question 33

Sarcoplasmic reticulum

Answer 33

- is smooth endoplasmic reticulum - triad is formed from 2 enlarged areas of Sarcoplasmic reticulum (terminal cisternae), and a T-tubule that runs in between them

Question 34

Ways muscle produce movement

Answer 34

1. Leverage system 2. Pulling on bones when they contract 3. Using group action

Question 35

Lever system

Answer 35

- bone/muscle interaction at a joint

Question 36

Parts of lever system

Answer 36

1. Levers = bone 2. Fulcrum = joint

Question 37

Effort

Answer 37

Contraction of agonist

Question 38

Resistance

Answer 38

opposes movement

Question 39

What needs to happen for movement to occur

Answer 39

Effort has to be greater than resistance

Question 40

Origin

Answer 40

Attachment of tendon to stationary bone

Question 41

Insertion

Answer 41

Attachment of tendon to moveable bone

Question 42

Agonist

Answer 42

Major muscle producing the movement

Question 43

Synergists

Answer 43

Help the agonist action and prevent undesirable motions caused by the agonist

Question 44

Antagonist

Answer 44

Produces opposite action of agonist - contraction inhibited when agonist contracts

Question 45

Flexion of forearm

Answer 45

Agonist= biceps brachii Antagonist= triceps brachii Synergist= brachialis, brachioradialis Lever= radius (insertion of agonist) Fulcrum= elbow joint Effort= muscle contraction Resistance= weight of object + forearm

Question 46

Extension of forearm

Answer 46

Agonist= triceps brachii Antagonist= biceps brachii