2. muscular system

Question 1

muscular system

Answer 1

• refers to skeletal muscle system
• primarily attached to bone
• produce movement by contracting - byproduct = heat

Question 2

skeletal muscle

Answer 2

• cells called fibres
• fascicle = group fibres
• whole muscle = group of fascicles

Question 3

CT components of skeletal muscle

Answer 3

• fascia = CT

- tendons and aponeuroses

Question 4

fascia = CT

Answer 4

epimysium - surrounds entire muscle
perimysium - surrounds fascicles
endomysium - surrounds each muscle fiber

Question 5

tendons and aponeuroses

Answer 5

• extensions of epi, peri, and endomysium
• anchors to bone (periosteum), cartilage, skin, or fascia
• tendon=rope-like
  eg. achilles tendon
• aponeurosis=sheet like
  eg. galea aponeurotica-epicranial aponeurosis

Question 6

skeletal muscle fiber structure

Answer 6

large multinucleate cells
parts: 
sarcolemma
sarcoplasm
myofibrils 
T-tubules
sarcoplasmic reticulum

Question 7

sarcolemma

Answer 7

cell membrane

Question 8

sarcoplasm

Answer 8

cytoplasm

Question 9

myofibrils

Answer 9

(intracellular structures)

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

Question 10

sarcomere structure

Answer 10

composed of proteins
-made of 2 types of myofilaments:
thin and thick

Question 11

thin filaments

Answer 11

composed of:

• actin-functions in contraction
• tropomyosin
• troponin- regulate contraction (regulatory proteins)

Question 12

thick filaments

Answer 12

composed of:
-myosin-functions in contraction
attached to Z discs by titin
has rod-like tail with 2 globular heads
*head extends toward actin and attaches to it -forming a cross bridge
*the myofilaments create dark and light bands (striations) of the sarcomere
*sarcomeres join end to end (at Z discs) to form myofibrils

Question 13

thick filaments banding pattern:

Answer 13

A band
H zone
I band
Z discs 
M line

Question 14

A band

Answer 14

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

Question 15

H zone

Answer 15

lighter band at centre of A band- myosin only

Question 16

I band

Answer 16

light-actin (with troponin and tropomyosin) and titin

Question 17

Z discs

Answer 17

in center of I band

• actin and titin attach
• connect sarcomeres: between 2 z-discs = 1 sarcomere

Question 18

M line

Answer 18

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

Question 19

T-tubules

Answer 19

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

Question 20

sarcoplasmic reticulum

Answer 20

smooth ER

-triad - 2 enlarged areas of SR (terminal cisternae) and T-tubule

Question 21

how muscles produce movement

Answer 21

1. pulling on bones when they contract
2. using group action
3. lever systems

Question 22

pulling on bones when they contract

Answer 22

• origin=attachment of tendon to stationary bone

- insertion=attachment of tendon to movable bone

Question 23

using group action

Answer 23

• agonist=major muscle producing the movement
• synergists=help the agonist action and prevent undesirable motions caused by the agonist
• antagonist=produces opposite action of agonist (contraction inhibited when agonist contracts)

Question 24

lever systems

Answer 24

-bone/muscle interaction at a joint
*parts:
-levers=bone
-fulcrum=joint
*effort must be great than resistance to get movement
page 3 has examples

Question 25

naming of skeletal muscles

Answer 25

1. action they perform (in anatomical position)
2. shape of muscle
3. origin and insertion
4. location
5. relative-size
6. direction of fibres
7. number of origins

Question 26

action they perform (in anatomical position)

Answer 26

a. flexors
- decrease angle b/w 2 bones
eg. biceps brachii
b. extensors
- increase angle (back to anatomical position after flexion)
eg. triceps brachii
c. abductors
- move limb away from midline
d. adductors
- move limb toward midline

Question 27

shape of muscle

Answer 27

eg. deltoid
- triangular shape
eg. trapezius
- trapezoid shape (no two sides parallel)

Question 28

origin and insertion

Answer 28

eg. sternocleidomastoid
* origin
- sterno=sternum
- cleido=clavicle
* insertion
- mastoid=mastoid process of temporal bone

Question 29

location

Answer 29

eg. tibialis anterior

Question 30

relative size

Answer 30

eg. gluteus
* maximus
* medius
* minimus

Question 31

direction of fibers

Answer 31

eg1. rectus abdominis
* rectus=straight ll
eg2. external obliques \ //

Question 32

number of origins

Answer 32

eg1. biceps brachii
* 2 origins on scapula
eg2. triceps brachii
* 2 origins on scapula and humerus
eg3. quadricips femoris
* 4 origins os coxa and femur