Week 3 Flashcards
What is the origin
The fixed point of attachment
Whats the insertion
Moveable point of attachment,usually distal to the origin
Whats a flexor
Muscles whose lines of action cross the anterior side of a joint
Eg.biceps brachili, triceps brachili
Whats an extensor
Muscles who’s lines of action cross the posterior side of a joint
What is a lever
A lever is a rigid structure of the moves on a fixed point called a fulcrum
What does an applied force result in
It results in an exerted force
What do lever systems change
The direction of an applied force
The distance and speed of movement produced bu the applied force
The magnitude of the exerted force relative to the applied force
Parallel muscles
The muscle fibre bundles are parallel to the long axis of the muscle
-attach to skeleton with little or no tendon
Eg sartorius muscle
Pennate muscles
The muscle fibre bundles are shorter than the muscle and run at an angle to the principal axis of the muscle
-attach to skeleton via and external tendon
Eg rectus femoris muscle (bipennate)
Function consequences of gross muscle architecture
Pennate muscles have a cross sectional area that is higher than thay of the parallel fibred muscle so has more force
Paralled fibred muscles can undergo longer length chanhes and can shorten more quickly
Whats fascicles
The muscles fibre bundles
Circular muscles
The muscle fibre bundles are concentrically arranged around an opening
They control the diameter od body openings or hollow organs
Moment equation
Moment=force x distance
Work equation
Work=force x distance
Power equation
Work/time
Muscle actively shorten=_________
Concentric contraction
Muscles as motors generate_____
Positive work and positive power
Muscles as brakes absorb_______
Absorb energy and generate negative power
Muscle actively lengthens=
Eccentric contraction
When muscles are brakes
Muscles as struts generate______
Force wirhout shortening (isometric contraction)
What is the heirarchal organisation in skeletal muscles
Whole muscle (connective tissue)
Muscle fibres
Myofibrils
Sarcomeres
Describe muscle fibres
10-100um
Often run full length
Bundles (fascicles)