Sternocleidomastoid
Function
Turns head
Masseter
Fuction
Closes jaw
Latissimus dorsi
Function
Adduction of arm
Trapezius
Function
Raise shoulders
Pectorals
Function
Adduction of arms
“flex”
Triceps
Function
Extend arm
Biceps
Function
Flexes elbow and supinates forearm
Deltoids
Function
Abducts arms
Rotation
Obliques
Function
Stabilize spine
Rectus abdominis
Function
Stabilize core
Vastus lateralis
Function
Extend and stabilizes knee
Quadriceps femoris
Function
Knee extension “flex”
Hip flexion
Hamstrings
Function
Flexion of the knee
Extension of hip
Tibialis anterior
Function
Dorsiflexion and inversion of the foot
Gastrocnemius
Function
Plantar flexion
Gluteus maximus
Function
Sitting and climbing
Synaptic cleft
Space between the nerve and motor end plate
Muscle contraction
Myosin heads of the thick filaments pull on the thin filaments causing you to slide towards the center
Muscle contraction requires…
Calcium and ATP
Myosin
Thick filament
Actin
Thin filament
Contains two other proteins: tropomyosin and troponin
Contains a myosin-binding site where myosin can attach
Myofibrils
Cylindrical structures that contain two types of proteins:
Actin
Myosin
Sarcoplasmic reticulum
“SR”
Fluid filled membrane enclosed tubules that store calcium for muscle contraction
Sarcoplasm
Muscle fibers cytoplasm, packed with mitochondria which produce large amounts of ATP
Transverse tubules
T-tubules
Tunnel in from the surface towards the center of the muscle fibers
Sarcolemma
Plasma membrane that covers the muscle fiber
Tendon
Dense regular connective tissue that attaches muscle to a bone
Muscle fiber
Elongated, cylindrical cells arranged parallel to each other
Endomysium
Connective tissue, surrounds each individual muscle fiber
Perimysium
Connective tissue that surrounds bundles of muscle fibers called fascicles
Epimysium
Connective tissue, wraps around the entire muscle
Skeletal muscles
structure
Skeletal muscle tissue
Nervous tissue
Blood
Connective tissue
Functions of muscular tissue
Producing contraction
Stabilize a body positions
Storing and moving substances within the body
Produce heat
Three types of muscle
Cardiac
Smooth
Skeletal
Neuromuscular junction
“NMJ”
The synapse between the neuron terminals and the motor end plate of the motor muscle fiber
4 steps that occur in the neuromuscular junction (NMJ)
1- Release of Acetylcholine (Ach)
2- Ach binds to the motor end plate opening the sodium channels and releasing Na
3- Na generates a motor action potential
4- Breakdown of Ach by an enzyme called acetylcholinesterase
Physiology of muscle contraction
1- Motor neuron is activated and releases Ach into the synaptic cleft
2- Ach diffuses across sarcolemma and binds to the binding sites and triggering action potential
3- Acetylcholinesterase breaks down the Ach
4- The muscle action potential travels down the T-tubule opening the Ca channels in this SR
5- Ca floods into the sarcoplasm and binds to the thin filaments (troponin) exposing the binding sites for myosin
6- Myosin binds to actin and power strokes towards the center (contraction)
7- Ca channels are closed in the SR and Ca is actively pumped back into the SR (uses ATP)
8- Troponin-tropomyosin complex slides back into position and blocks myosin from binding to actin
9- Muscle relaxes
Muscles involved in breathing
External intercostals
Internal intercostals
Diaphragm
Exterior intercostals
Lie superficially between ribs
They elevate the ribs during inspiration
Interior intercostals
Lie deeper than the external intercostals
They depress the ribs during forced exhalation
Diaphragm
Enlarges the thorax to trigger inspiration
Homeostasis of Ca in blood
Calcium too low:
Parathyroid gland secretes Parathyroid hormone
Calcium too high:
Thyroid gland secretes Calcitonin