Chapter 11 Flashcards
Muscle Organization and Function
Muscle organization affects power, range, and speed of muscle movement
Organization of Skeletal Muscle Fibers
4 patterns of fascicle organization:
- parallel
convergent
pennate
circular
Parallel Muscles
fibers parallel to the long axis of muscle
- biceps brachii
Convergent Muscles
A broad area converges on attachment site (tendon, aponeurosis, or raphe)
Muscles fibers pulled different directions, depending on stimulation
ex. pectoralis muscles(have multiple actions)
Pennate Muscles: refer the fiber
Unipennate:
- fibers on 1 side of tendon
- ex. extensor dia
Bipennate:
- fibers on both sides of tendon
- ex. rector femoris
Multipennate:
- tendon branches within muscles
- ex. deltoid
Circular Muscles
also called sphincters
- open and close to guar entrances of body
- ex. obicularis oris, obicularis circular
Skeletal Motion
Skeletal muscles attach to skeleton, produce motion
type of muscle attachment affects power,range, and speed of muscle movement
Levers
each bone is a level(a rigid, moving structure)
- and each joint a fulcrum (a fixed point)
Muscles provide applied force (AF):
- required to overcome resistance (R)
Functions of a Level
to change
- direction of an AF
- distance and speed of movement produced by an AF
- effective strength of an AF
3 classes of levers
first class
second class
third class
First class levers
seesaw example
center fulcrum between applied force and resistance
force and resistance are balanced
head to neck. cervical
Second class levers
wheelbarrow is an example
center resistance (in center) between applied force and fulcrum
a small force moves a large weight
Ankle
Dorsey flexion and plant flextion
Third-class level
Most common levers in the body
Center applied force between resistance and fulculm
Greater force moves smaller resistance
maxmizes speed and distance traveled
(most common type in the body) elbow
