Biological level
What are the thick filaments made up of
A protein called myosin
What type of control is skeletal muscles under?
Conscious control
Diaphragm
Origin: Cartilage of ribs 7-12, xiphoid process, lumbar vertebrae
Insertion: Anterior longitudinal ligament
Action: Expands thoracic cavity, compresses abdominal cavity
Innervation: Phrenic nerve
Explain what the first step in muscle contraction is
A nerve impulse must be sent to the muscle
Define elevation
Upward movement of a structure
What are the thin filaments made up of
A protein called actin
What are the 3 types of muscle tissue found the in the body?
Skeletal, smooth, and cardiac
Internal intercostals
Origin: Superior border of ribs 2-12
Insertion: Inferior of ribs above (1-11)
Action: Depresses ribs (forced expiration)
Innervation: Intercostal nerves
Explain when a muscle would relax
It would relax once the calcium ions return to the sarcoplasmic reticulum
Define depression
Downward movement of a structure
Z lines connect what
Parallel bands of thin filaments
What muscle tissue makes up 40% of the bodies weight, are attached to the skeleton by tendons, and made of fibrous connective tissue?
Skeletal muscles
External intercostals
Origin: Lower border of ribs 1-11
Insertion: Upper border of ribs below (2-12)
Action: Elevates ribs (normal inspiration)
Innervation: Intercostal nerve
Explain what specifically produced a muscle contraction
The movement of the many actin filaments together
Define dorsiflexion
Flexion superiorly occurring at the subtalar (ankle) joint (movement of the toes "up")
Thick filaments are held together by what
The M line
What type of control are smooth and cardiac muscles under, and what does this mean?
Involuntary control, it means that contraction of the muscle happens without a conscious decision
Sternocleidomastoid
Origin: Sternal end of clavicle and manubrium
Insertion: Mastoid region of skull
Action:
Bilateral- neck flexion
Unilateral- turns face to opposite side
Innervation: Accessory nerve (CM XII)
Explain all of the things acetylcholine does during the movement of a muscle
Acetylcholine is released from the motor nerve ending; it then binds to receptors on the muscle cell, opening sodium channels and allowing sodium to flow inside the sarcoplasm
Define ulnar deviation
Medial movement of the wrist towards the ulna
What happens to the lines as a muscle contraction occurs
The Z lines move closer together towards the center of the sarcomere
What muscles under a microscope are striated in appearance and what muscle(s) are free of striations.
Skeletal and cardiac muscles appear to be striated, while smooth muscle is free of striations
Flexor hallucis longus
Insertion: Inferior surface of distal phalanx of digit 1 (great toe)
Action: Flexion of digit 1, inversion and plantarflexion of foot
Innervation: Tibial nerve (deep peroneal branch)
Explain what the cross bridges do during muscle movement
In the presence of calcium ions, portions of the myosin filaments called cross bridges bend backward and attach to actin filaments, after attaching the cross bridges bend forward and the actin filament is pulled along, the cross bridges attach and detach some 50 to 100 times as the thin filaments are pulled to the center of a sarcomere
Define radial deviation
Lateral movement of the wrist towards the radius