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Elyza Vivar Period 5 Muscular System - Coggle Diagram
Elyza Vivar Period 5 Muscular System
Major functions of the muscular system
Muscles are organs that generate force to cause all types of movement
Produces heat, posture, stability, and Mobility
Stabilize skeletal system and contract involuntary muscles that keep us alive (heart and lungs)
3 types of muscles & their functions
Skeletal
Location: Skeletal Muscles
Functions by moving bones at joints
Has striations, many nuclei, and well develops transverse tubules
Contracts rapidly when stimulated by a motor neuron
Smooth
Location: Walls of hollow organs, blood vessels
Functions by contracting blood vessels and organs
No striations has a single nucleus and lacks transverse tubules
Contracts and relaxes slowly
Cardiac
Location: Walls of heart
Functions by pumping the heart
Has striations, a single nucleolus, well-developed transverse tubules, intercalated discs
Is involuntary
Network of cells contract as a unit
Names of all the skeletal muscles
Frontalis
(raises eyebrows)
Temporalis
(closes the jaw)
Orbicularis
(closes eyes)
Zygomaticus
(raises corners of the mouth)
Buccinator
(makes up the cheek)
Orbicularis Oris
(closes lips)
Sternocleidomastoid
(Neck muscle)
Trapezius
(Upper back)
Pectoralis Major
(Chest)
Deltoid
(Shoulder)
Infraspinatus
(Upper back, surrounds trapezius)
Rhomboid Major
(Upper back, next to Infraspinatus)
Teres major
(Upper back, underneath Rhomboid major)
Abdominis
(Midline of abdomen)
Serratus Anterior
(Lateral to the Abdominis)
External oblique
(Lateral to Abdominis inferior to serratus anterior
Latissimus Dorsi
(Lower back)
Biceps brachii
(Upper arm)
Brachioradialis
(Most lateral muscle from forearm)
Flexor Carpi Radialis
(Next to Brachiorodalis)
Palmaris
(Closest forearm muscle)
Triceps Brachii
(back of upper arm)
Extensor Carpi Radialis Longus
(Later back of forearm)
Extensor Digitorum
(Closer to the midline, back of forearm)
Iliopsoas
(Inguinal area)
Adductor longus
(Near midline)
Gracilis
(Closest to the midline)
Gluteus Maximus (Rear end)
Vastus Medialis
(Inner part of thing)
Rectus Femoris
(Middle thigh muscle
Vastus Lateralla
(Outer thigh muscle)
Biceps femoris
(Back outer part of thigh)
Semitendinosus
(Back Middle thigh)
Semimembranosus
(Back inner thigh)
Tibialis Anterior
(Front of leg)
Extenso digitorum longus
(Next to Tibialis anterior)
Fibularis Longus
(Side of leg)
Gastrocemuis
(Back of lower leg)
Soleus
(Lateral to Gastrocemuis)
Neuromuscular junction
Skeletal muscle fibers contract only when stimulated by a motor neuron
each skeletal muscle fiber is connected to the axon of a motor neuron creating a synapse
A synapse between a motor neuron & a muscle fiber that it regulates
Sliding filament theory of muscle contraction
Brain send a signal along the motor neuron, inside the motor neuron are vesicles that contain acetylcholine, acetylcholine reaches the receptors on the sarcolemma which causes an impulse
The impulse travels down the membrane in to the transverse tubules which causes calcium to be released from the Sarcoplasmic reticulum.
Calcium binds to a structure on the actin that causes it to change shape.
The shape allows myosin heads to form cross-bridges between the actin and the myosin.
Energy from ATP is used to create a "power stroke" between the two filaments.The actin filament slides inwards and shortens the whole muscle.
Action potential in a muscle fiber
An action potential travels the length of the axon of a motor neuron to an axon terminal
Boldege catege calcium channels open and calcium ions diffuse into the terminal
Through the process of exocytosis, Acetylcholine is released from the Synaptic vessels.
Acetylcholine Receptors are being scattered across and they stick to the synaptic cleft, after attaching to the synaptic cleft they become ligand-gated cation channels.
After the Acetylcholine attaches to the acetylcholine receptors that contain ligand gated cation channels the channels open. This allows sodium to enter and potassium to exit.
The sodium ions are entering the muscle fibers. On the other hand, potassium ions are exiting the muscle fiber. The membrane potential is more likely to be caused negative.
Once the membrane reaches a threshold value action potential along the sarcolemma or membrane and the neurons stop the “message” to contract is when acetylcholine either diffuses away from the synapse of is broken down by the enzyme acetylcholinesterase and is broken down into Acetic Acid and Choline.
Muscle coverings(TB Fig. 8.1)
Layers of dense connective tissue called fascia separate each muscle
Fascia blends with the epimysium ,the layer of connective tissue around each skeletal muscle
Perimysium extends inwards from epimysium and surrounds bundles of muscle fibers called fascicles
Each muscle fiber (cell) is covered by a connective tissue layer called endomysium
Sarcomere
A sarcomere extends form one z line to the next striations consist of an alternating pattern of light and dark bands
I Bands
(light bands) are made up of actin filaments
Z lines
(anchor the I bands)
A bands
(dark bands) made up of overlapping thick and thin filaments
H zone
(center of the A bands) consists of myosin filaments
M line
(center of H zone) made of proteins that hold the myosin filaments in place