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