Download Level 4 Physiology

By: Jose L. Barba
Upper Arm Muscles and their
Function

Deltoid-allows
abduction flexion and
extension of the arm.

Tricep brachiiallows extension of
the forearm and the
shoulder.

Bicep brachii-
allows the arm to
bend around the axis
of the elbow joint.
 Brachialis-Flexes
the elbow joint.
Upper Back Muscles and their
Function

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Trapezius-elevates,
depresses, retracts,
and rotates the
scapula.
Teres majormedially rotates and
adducts humurous
Rhomboid major-
holds and retracts
scapula on ribcage.
 Latismus dorsiadducts, extends and
internally rotates arm.
Thorax Muscles and Functions

Pectoralis majoradducts and
medially rotates the
humurous

Pectoralis minorstabilizes the
scapula
Function of Skeletal Muscle


Movement-attached
to bones.
Heat productionReaction during
muscle contraction
produce heat.


Posture-continous
partial contraction of
skeletal muscle.
Posture allows
standing, sitting,
maintaining balance
while walking.
Compare and Contrast Functions
Upper arm
Upper back
Chest
Supports lower arm
Supports shoulders
and lower back
Supports arm
movement and
rotation
• Allows movement
to lower arm
• Has more
movement and
rotation compared
to upper back or
chest
• Stabilizes upper
body
• Upper back allows
the movement of
the arm and chest
by maintaining
balance in the
upper body
• Allows good
posture
• Stabilizes scapula
• Assists movement
in the arms
Smooth Muscle
Smooth muscle lines the inside and
transport nutrients/waste.
 Also lines all “tubes” of the body
 Contracts longitudinally and in circular
motion. Ex: digestive tract, arteries and
veins, reproductive and urinary parts.

Cardiac Muscle


Found in the heart
More dense muscle
fibers than other muscle
groups


Cardiac muscle cells
contract to provide cells
with blood
Blood has nutrients for
cells to be healthy
Fxn of Cardiac Muscle
Microscopic Skeletal Muscle
Structure
What does the Cross Bridge Cycle
do?
The Cross Bridge Cycle is the process that
the human body does in order to contract
the muscles. There are twelve steps that
take place in your muscles. These steps
are to be done every time a person
flexes/contracts their muscles.
The Cross Bridge Cyle
Steps for the Cross Bridge Cycle
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1. Neuron action potential arrives at end of motor neuron.
2. Acetylcholine (Ach) is released.
3. Ach binds to receptors on motor end plates.
4. Sodium ions (Na + Red) rush into muscle fibers.
5. Muscle action potential sweeps into T tubules.
6. Sarcoplasmic reticulum releases calcium (Ca +)
7. Ca + binds to tropomyosin to shift and expose myosin
binding site
9.Myosin pivots, pulling actin
10. Myosin Pivots, pulling actin filaments
11. Myosin releases from actin due to calcium reduction
12. Myosin re-extends into “ready” position