Three muscle types

Skelatal - 2D movement, straitions

Smooth - 3D movement, no striations

Cadriac - 3D movement, no striations, intrecilated disc

- are junctions between cadiac cells to permit the rapid simultanious contraction

1) Fascia -  cover the muscles

2) Muscle - group of fassicles covered by fascia

3) fassicle - collection of muscle fibers

4) muscle fibers (cells)

5) myofibrils - actin (thin) and myosin (thick)

Muscle Cells

(components)

sarcolemma - membrane

sarcoplasm - cytoplasm

myofibril - C.T. with actin and myosin filaments

transverse tubules - tubes that transmit action potentials from motor plate to the sarcoplasmic reticulum

Sarcomere - A single unit on contraction

I band - actin only

A band - action and myosin

H zone - just myosin

M line - attachment between myosin

Z line - boundry of sarcomere, and actin attachment

Sarcomere layout

           Zline                 |         ABand       |                   Zline    

|       iBand     |      |  Hzone |     |     iBand       |    

|

MLine

Basic nuromuscluar anatomy

1) motor neuron

2) motor end plate

3) neuromuscular junction

4) synapse

5) neurotransmitter

6) motor unit

1) neuron that sends signal to motor end plate

2) a folded cell that accepts AP from motor neuron

3) connection between nuron and the motor end plate

6) motor unit - muscles triggered by a single motor neuron (usually a few)

Patterns of muscle contraction

Twitch - a single contraction that lasts only a fraction of a second

Summation - the force of many individual twitches (unable to relax between stim.)

Tetanus - lacks even partial relaxation

Muscle tone - even when muscle appears at rest, fibers undergo sustained contraction

threshold stimulus - minimal strength required to cause a contraction

all-or-none response - when the muscle fiber contacts it contacts fully every time

Types of muscle fibers

smooth muscle - hollow organs, iris, blood vessels (NO TT) - involuntary - self-exciting - slow

cardiac muscle - heart - involuntary - network of contraction, self-exciting

Skeletal - movement at joints - voluntary, contacts and relaxes rapidly

Where are the muscles?

1) temporalis

2) masseter

3) sternocleidomastoid

4) platysma

1) temporal bone - process of mandible - closes jaw

2)  zygomatic arch - lateral mandible - closes jaw

3)