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Muscular Jazlynn Banuelos p.3 - Coggle Diagram
Muscular Jazlynn Banuelos p.3
Major Functions of the Muscular System
Cardiac-heart
It pumps the heart
Skeletal-movement
Movements of bones at joints, maintenance of posture
Smooth-blood
Movement of viscera, peristalsis, vasoconstriction
Skeletal Muscles
-named according to shape, size, location, action, # of attachments, direction of fibers
Extensor Digitorum
Action
-extends digits (fingers, toes)
Biceps Branchii
# of attachments & Location
-has 2 origins/heads & found in arm
Deltoid
Shape
-shaped like traingle
Sternocleidomsatoid
Attachments
-attaches to sternum, clavicle & mastoid process
Pectoralis
Size & Location
-large size, located in chest
External Oblique
Location & direction of fibers
-located outside body & fibers run at start
3 Types of Muscles
Smooth
Location
Walls of hollow viscera blood vessels
Function
Movement of viscera, peristalis and vasoconstruction
Contraction Characteristics
Involuntary- Contracts & relaxes slowly. Single unit type is self exciting rhythmic
Structure
Single nuclei, elongated w/ tapered ends, undeveloped sarcoplasmic reticulum
Cardiac
Location
Wall of heart
Function
Pumping action of the heart
Contraction Characteristics
Involuntary- Network of cells contracts as a unit; self exciting rhythmic
Structure
Branching, striated cells, single nuclei
Skeletal
Location
Skeletal muscle
Function
Movement of bones at joints and maintenance of posture
Contraction Characteristics
Voluntary- contracts & relaxes rapidly when stimulated by a motor
Structure
many nuclei, striated, more than 1 insertion/origin
Sarcomere
Function
Responsible for muscular contraction
Structure
Z line
Ends of sarcomere
I bands
Light bands. Actin filaments, anchored to Z lines
A bands
Dark bands. Overlapping thick and thin filaments
H zone
The center of the A band, consist of myosin filaments only
M line
the center of the H zone, proteins that hold myosin filaments in place
Characteristics
striated of alternating patterns
Neuromuscular Junction
A synapse between a motor neuron and a muscle fiber that it regulates
Function
Transmit motor neuron to ensure muscle contraction and voluntary movement.
Structure
motor end plate where sarcolemma is tightly packed
synaptic vessels store
Synaptic cleft- a gap between the membrane of neurons and muscle fiber
Neurotransmitters- how neurons communicate with the muscle fiber by way of chemicals
Characteristics
Only stimulated by motor neuron
Sliding Filament Theory of Muscle Contraction
-During muscle contraction, a myosin head attaches to a binding site on the actin filament, forming a cross-bridge
Action Potential in Muscle Fiber
Triggers of actions that result in contraction and relaxation of muscle fiber
Skeletal
Contracts and relaxes rapidly when stimulated by motor neuron
Cardiac
Contracts as a unit
Smooth
Slower to contract & relax, maintains contraction longer, can change length
Muscle Coverings
Fascia
Layers of dense connective tissue that surround each seperate muscle
Epimysium
layer of connective tissue around each skeletal muscle
Perimysium
extends inward from epimysium, surrounds bundles of skeletal muscle fibers
Endomysium
Covers each cell (fiber)