Muscular System-Alexis Gutierrez Per.2
Major Functions of the Muscular System
3 Types of Muscles & their Functions
Names of all the Skeletal Muscles(including the facial muscles)
Sarcomere
Neuromuscular Junction(a synapse between a motor neuron and a muscle fiber that it regulates)
Sliding Filament Theory of Muscle Contraction
Action Potential in a Muscle Fiber
Muscle Coverings(TB Fig. 8.1)
Motor Neuron
T-Tubule
Vesicles
Acetylcholine
Calcium
Sarcoplasmic Reticulum
Actin Myofilament
Cross Bridges
ATP
signals are sent along motor neuron
contain neurotransmitters(acetylcholine)
reaches the receptors & causes impulse
impulses travel through the t-tubules
calcium released from sarcoplasmic reticulum
releases calcium
calcium binds to actin & changes shape
bridge between actin and myosin
energy to create "power stroke"
Myofilament
Mitochondria
Sarcoplasmic Reticulum
Transverse Tubules(T-Tubules)
Sarcolemma
Expanded light & dark bands
I-band
A-band
Thin & Thick filaments
Z-line(disc)-boundry between sarcomeres
Thin filaments
H-zone
M(middle)-line
Thick filament
Thick & Thin filaments
Spread throughout the fiber, supply energy needed for contraction
tubes that start at the surface and go into fiber,
perpendicular to filaments
network of tubes that run parallel to filaments
entire muscle fiber surrounded by srcolemma
Motor neuron- causes stimulation
Synapse- connection from muscle fiber to axon of motor neuron
Neurotransmitters- neuron communicates with the muscle fiber by way of chemicals, released by synapse
Cytoplasm- end of motor neuron contains numerous mitochondria & synaptic vesicles storing neurotransmitters
Membrane- in this area contains specialized region called the motor end plate, in which sarcolemma is tightly folded
Synaptic cleft- electrical impulse reaches the end of axon of motor neuron, synaptic vesicles release neurotransmitter into synaptic cleft, the gap between the membranes of the neuron and muscle fiber
Cardiac
Skeletal
Smooth
lack striations, elongated with tapered ends, relatively undeveloped sarcoplasmic reticulum, involuntary, single nucleus
have thick & thin filaments but are arranged more randomly
Smooth & Skeletal
Similarities
Differences
Both involve reaction between actin & myosin
Both stimulated by membrane impulses, require increase in calcium ions in cells, & use ATP energy
Both acetylcholine(ACh) & norepinephrine stimulate & inhibit smooth muscle contraction, while only ACh stimulates skeletal muscle
Hormones can stimulate or inhibit contraction of smooth muscle, but not skeletal muscle
smooth=slower contract & relax
smooth=longer contraction with same amount of ATP
smooth=change length without change in tautness
only found in heart
branching, striated,involuntary
Complex membrane junctions, called intercalated discs
Movement of bones at joints, maintenance of posture
many nuclei, striated, voluntary
Movement of viscera, peristalsis, vasoconstriction
Fascia- layers of dense connective tissue, blends with the epimysium
gives rise to tendons fused to periosteum of bones
Aponeuroses- muscles connected to each other by broad sheets of connective tissue
Perimysium extends inward from epimysium it surrounds bundles of skeletal muscle fibers, called fascicles,
each muscle cell (fiber) is covered by a connective tissue layer called endomysium
neuron sends information down an axon, away from the cell body
"spike" "impulse"
Mobility
Heat production
Less than half of energy released in reactions of cellular respiration is used to form ATP; rest becomes heat
Front
Back
Face
Torso
Lower body
Torso
Lower body
Biceps femoris; middle outer thigh
Frontalis; forehead, raise eyebrows
Temporalis; side of head, closes jaw
Zygomaticus; cheek, smile
Orbicular oculi; around eyes, blink
Masseter; jaw, prime mover of jaw closure
Buccinater; lower cheek, compresses cheek
Orbicularis oris; around mouth, pucker or kiss
Platysma; neck, tense neck
Sternocleidomastoid; neck
Trapezius; between neck & shoulder
Deltoid;shoulder
Pectoralis major; chest
Biceps branchii; upper arm
Serratus anterior; under armpit
Rectus abdominis; abs
External oblique; sides of stomach
Branchicradials; outer forearm
Flexor Carpi Radius; inner forearm
Palmaris longus; lower inner forearm
Iliopsoas; between stomach & groin
Sartorius; skinny, upper thigh to lower thigh
Adductor longus; inner upper thigh
Gracilis; inner upper thigh closer to edge
Rectus femoris; middle thigh
Vastus laterialis; outer thigh
Vaclus medicilis; lower inner thigh
Gastrochemius; calf
Soleus; lower calf
Tibialis anterior; front leg
Extensor digitorum; outer front leg
Fibularis longus; upper outer front leg
Sternocleidomastoid; neck
Trapezius; upper back
Deltoid; shoulder
Infraspinatius; middle back
Rhomboid major; under Infraspinatius
Teres major; close to armpit
Tricips branchii; arm
Latissimus dorsi; all lower back
Extensor carpi radialis longus; middle outter foreamr
Extensor digitorum; middle forearm
Gluteus maximus; butt
Semitendinosus; middle inner thigh
Semimembranosus; inner thigh
Gastrochemius; calf
Soleus; lower outer leg
Fibularis longus; lower leg close to ankle