Topic 11 Muscular system

Question 1

Describe the organization of the skeletal muscle from cell (skeletal muscle fibre) to whole muscle

Answer 1

First cells are called** fibres **
and the GROUP of fibres are called fascicles **
and the GROUP of fascicles are called whole muscle**

Question 2

fibres

Answer 2

the cells of the skeletal muscle

Question 3

Fascicles

Answer 3

groups of fibres

Question 4

Whole muscle

Answer 4

groups of fascicles

Question 5

Name the connective tissue layers that surround each skeletal muscle fibre, fascicle and whole muscle

Answer 5

Fascia = Connective tissue

1. Epimysium (connective tissue) = surround entire muscle
2. Perimysium (connective tissue) = surround dascicles
3. Endomysium (connective tissue) = surround each muscle fibre

Question 6

Epimysium

Answer 6

a type of connective tissue that surrounds entire muscle

Question 7

Perimysium

Answer 7

a type of connective tissue that surrounds the fascicles

Question 8

Endomysium

Answer 8

a type of connective tissue that surrounds each muscle fibre

Question 9

Define tendon and aponeurosis

Answer 9

Well, the tendons and aponeuroses are extensions of the epi, peri and endomysium and they anchor muscles to bone (periosteum), cartilage, skin or fascia of other muscles

tendons = rope like e.g achilles
aponerosis = sheet like

Question 10

describe the components within a skeletal muscle fibre

Answer 10

Large multinucleated cells
Parts of these cells :
1) sarcolemma = cell membrane
2) sarcoplasm = cytoplasm
3) myofibrils = intracellular strucutres (organelles)
- within each fibre there are several hundreds to thousands
- composed of sarcomeres (contractile units of muscle fibres)

4) T Tubules = continutations of sarcolemma that extend deep into fibre (cell)
- directly encircle myofilaments of myofibrils at junction A and I bands (2/sarcomere)

5) Sarcoplasmic reticulum = smooth ER
- forms a triad = 2 enlarged areas of SE (terminal cisternae) and T - tubule

Question 11

Sarcolemma

Answer 11

Cell membrane of the large multinucleated cells of the skeletal muscle fibre

Question 12

Sarcoplasm

Answer 12

Cytoplasm of the large multinucleated cells or skeletal muscle fibre

Question 13

Myofibrils

Answer 13

Part of the large multinucleated cells of skeletal muscle fibre
- intracellular structures (organelles)
- within each fibre contains several hundreds - thousands
- composed of sarcomeres

Question 14

define sarcomere

Answer 14

composed of proteins

Question 15

describe the arrangement and composition of the following components of a sarcomere

Answer 15

Sarcomeres are made up of proteins and they contains 2 types of myofilaments (which are proteins)
1) thin filaments
- made of actin (functions in contraction)
- tropomyosim and troponin (help regulate contraction (regulatory proteins)

2) thick filaments
- composed of myosin (functions in contraction)
- attached to z discs by titin
- has rod-like tail with 2 gobular heads (heads extend toward actin and attaches to it - forming a cross bridge)
-
the myofilaments creat dark and light bands (striations) of the sarcomere
Banding pattern:
1) A band
2) H zone
3) I band
4) Z discs
5) M line
- sarcomeres join end to end (at Z discs) to form myofibrils

Question 16

Banding patterns of myofilaments

Answer 16

the myofilaments create dark and light bands (striations) of the sarcomere)
the banding pattern includes
1) A band
2) H zone
3) I bands
4) Z discs
5) M line

Question 17

A band

Answer 17

dark = length of thick filament - myosin and actin (with troponin and tropomyosin)

Question 18

H zone

Answer 18

Lighter band at the centre of A band - myosin only

Question 19

I band

Answer 19

light = actin (with troponin and tropomyosin) + titin

Question 20

Z discs

Answer 20

in the centre of I band
actin and titin attach (sticking out)
connect sarcomeres between 2 Z discs = 1 sarcomere

Question 21

M line

Answer 21

where myosin tails (thick myofilaments) attach to eachother (center of sarcomere)

Question 22

T - tubules

Answer 22

continuations of sarcolemma that extend deep into fibre (cell)
- directly encircle myofilaments of myofibrils at junction of A and I bands (2/sarcomere)

Question 23

Sarcoplasmic reticulum

Answer 23

Smooth ER
triad = 2 enlarged areas of SR (temrinal cisternae) and T - tubule

Question 24

What forms a triad?

Answer 24

2 enlarged areas of the sarcoplasmic reticulum (terminal cisternae) and t-tubule

Question 25

Pulling on bones when they contract involves?

Answer 25

origin and insertion

Question 26

Define origin

Answer 26

attachment of tendon to stationary bone

Question 27

Define insertion

Answer 27

Attachment of tendon to movable bone

Question 28

Using a group action involves

Answer 28

agonist, synergist and antagonist

Question 29

Define Agonist

Answer 29

Major muscle production the movement

Question 30

Define Antagonist

Answer 30

produces opposite action of agonist (= contraction inhibited when agonist contracts)

Question 31

Define synergist

Answer 31

help the agonist action and prevent undesireable motions caused by the agonist

Question 32

Lever systems involves

Answer 32

• bone/muscle interaction at a joint
  parts: lever and fulcrum
  a) lever = bone
  b) fulcrum = joint
• also involves effort, resistance (EFFORT MUST BE greater than resistance to get movement)

Question 33

define lever

Answer 33

Bones and muscles interactions at a joint = lever system
lever = bone

Question 34

define fulcrum

Answer 34

bones/muscles interaction at a joint
fulcrum = joint

Question 35

define effort

Answer 35

involved in lever systems
contraction of agonist
THE EFFORT must be greater than resistance to get movement

Question 36

define resistance

Answer 36

involved in lever systems
opposes movement
the effort must be greater than resistance to get movement

Question 37

With the flexion and extension of forearm use origin, insertion, agonist, antagonist, synergist, lever, fulcrum, effort, resistance to describe how muscles produce movement

Answer 37

**flexion of forearm **
agonist = biceps brachii
antagonist = triceps brachii
synergist = brachialis + brachioradialis
lever = radius (inserotion of agonist)
fulcrum = elbow joint
effort = muscle contraction
resistance = weight of forearm

**example 2 extension of forarm **
- agonist = tricepts brachii
- antagonist = biceps brachii

Question 38

describe the ways that muscles are named and give examples of each

Answer 38

**1) the action they perform **
- a) flexors
- b) extensors
- c) abductors
- d) adductors

**2) shape of muscle **
e.g 1: deltoid = triangular shape
e.g 2 trapezius - trapezoid shaped (no two sides parallel)

3) origin and insertion
e.g sternocleidomastoid
- origin: sterno = sternum, cleido = clavicle
- insertion: mastoid = mastoid process of temporal bone

**4) location **
e.g tibialis anterior (where you whack yuorself in shins)

**5) Relative size **
e.g gluteus
- maximus
- medius
- minimus

**6) direction of fibres **
e.g 1 rectus abdominis - rectus = straight ||
e.g 2 external obliques \ //

**7) number of origins **
e.g 1: bicep brachii = 2 origins on scalpula
e.g 2 triceps brachii = 3 origins on scalpula and humerus
e.g 3 quadriceps femoris = 4 origins on ilium, femur