Ch 9 - Musculaar System - road map

Endomysium

1 - this is the thin layer of ECM that surrounds skeletal muscle fibers

Fascicle

2 -  a group of 10 to 100 muscle fibers bundled together

Perimysium

3 -  connective tissue that surrounds a fascicle

Epimysium

4 -  all of the fascicles in a muscle are surrounded by this layer of CT

Fascia

5 - the most superficial connective tissue sheath of the epimysium 

Tendons

 Attach muscle to bone 

(or another part that the muscle moves)

Parallel muscle

Evenly spaced fascicles, tendon about the same width as muscle 

Convergent muscle

Large at one end uniformly tapers to a single tendon

Ex. pectoralis major

Pennate

 looks like one side of a Feather because of the way that fibers and fascicle attach to the tendon at an angle

Unipennate

 single tendon,  fascicles feather out from only one side ex.  flexor pollicis

Bipennate

Single tendon, vesicles feather out from both sides ex. Rectus femoris 

Multipennate

Made of several tendons,  physical attachments look like several feathers attached to each other

ex. Deltoid 

Naming muscles based on function (5)

muscles named based on functions include flexors, extensors,  levators,  adductors and abductors

Flexors

Function for flexing, Decreases angle between bones

Extenders

Function for extension, Increase the angle between bones

Levator

Any muscle that functions to raise or elevate a body part ex. the muscle that lifts the eyelid or the one that lifts the upper lip

Adductor

Pull towards the body, primarily in legs

Abductors

Pulls away from the body, primarily in legs

Actions

Body movements produced by skeletal muscles because of their ability to generate muscle tension

Prime mover

Also called Agonist, muscle that provides most of the force required for a given movement, opposite to antagonist

Antagonist

Usually on the opposite side of joint from Agonist partner,  opposes and slows action to prevent hyperextension and make movements more graceful

Agonist

Also called Prime Movers, muscle that provides most of the force required for a given movement, opposite to antagonist

Synergist

muscles that work together with Agonist,  guide movement making it smoother

Fixators

Hold bone in place, anchoring function, do not move, 

makes movements more efficient and reduces risk of injury

Origin

Part muscle attaches to that is fixed

Ex.  the bicep attaches to the scapula which remains stationary

Origin and insertion can switch for muscles that act on more than one joint

Insertion

Part muscle attaches to that moves

Ex.  bicep connects to the radius which moves

Origin and insertion can switch for muscles that act on more than one joint

Lever system (components)

Four components

1.  Lever =  bones

2.  Load =  weight of body part being moved

3.  Force =   tension generated by the muscles, applied to lever to move the load

4.  Fulcrum =  joint where movement occurs

Fulcrum

Joint where movement occurs

First class lever

Seesaw, load joint then Force

Joint between tension generated by muscle and weight of body part

Ex. atlanto-occipital joint (neck joint)

Second class lever

Weight of body part between joint and tension generated

 load in middle force applied to one side and Fulcrum is on the other

Uncommon, usually only in toes, ex. the ankle joint (talocrural joint)

Third class lever

Tension generated between joint and weight of body 

Force in the middle of load on one side fulcrum on the other ex.Elbow joint