Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Muscular System
| Term | Definition |
|---|---|
| Muscular System Functions | produces movement, maintains posture, supports soft tissue, guards entrances and exits, and generates heat |
| skeletal muscle | organs containing skeletal muscle tissue, connective tissue, nerves, and blood vessels |
| skeletal muscle structure | long, cigar shaped, can be up to 1 ft in length |
| sarcolemma | membrane surrounding muscle cells |
| microfibrils | long ribbon bundles made up of muscle cells of overlapping myofilaments |
| myofilaments | actin(thin), myosin(thick, with heads called cross bridges) |
| actin | thin |
| myosin | thick, with heads called cross bridges |
| cross bridges | heads of myosin |
| sarcomeres | alternating myofilaments |
| light band (I) | contains only actin filaments of two end to end sarcomeres |
| dark band (A) | myosin, end to end. bands give muscle its striated look |
| z line | boundary of sarcomere. dark area in midline of I band |
| m line | connects myosin |
| H zone | light central area in A band |
| myofibrils | chain of sarcomeres, they run z-line to z-line |
| neuromuscular junctions | skeletal muscles must be stimulated by nerve impulses in order to contract |
| axon | nerve fiber |
| neuromuscular junctions | formed when axon moves close to sarcolemma of individual muscle cells |
| synaptic cleft | gap between nerve and muscle |
| acetylcholine | neurotransmitter released when nerve impulse is sent down nerve fiber. |
| acetylcholine | Ach |
| action potential | electric current in muscles that rushes over the muscle cells caused by the excess Na+ |
| sliding filament theory | contraction. cross bridges attach to binding sides on actin and slide it across myosin. bridges detach and reattach to contract further. sarcomeres shorten. action potential end...cell relaxes...everything returns to normal length. |
| tendons | attaches muscles to bone, cartilage or connective tissue covering Durable-can cross bony projections and conserve space around joints |
| skeletal muscles | 700. have at least 2 points attachment. only pull. work in pairs. fibers tend to go in direction of pull. flexors on ventral, extensors on dorsal. |
| origin | attachment of muscles at fixed or relatively stationary bone |
| insertion | attachment of muscles at moveable end of bone |
| agonist | muscle whose contraction leads to a particular movement |
| antagonist | muscle whose movement opposes movement of other muscles |
| flexors | on ventral surface |
| extensors | on dorsal side |
| power and stability muscles | cross one joint. fibers run diagonally at an angle to the length |
| speed and agility muscles | cross many joints. have parallel fibers |
| small muscles | create subtle movement |
| big muscles | create gross movements |
| muscle names | come from size, shape, direction of Fibers, function/action, origin/intersection, or a combinatin of any one of these |
| frontalis | covers frontal bone. inserts at eyebrows. allows you to raise your eyebrows and wrinkle your forehead |
| orbicularis oris | circles around lips. closes mouth and pucker lips |
| buccinator | compresses cheeks to pucker lips (trumpeter) moves food back and forth over teeth from cheeks. creates sucking motion in infants |
| zygomaticus | allows you to smile. originates at zygomatic bone and inserts at corner of mouth |
| orbicularis oculi | encircles eyes. closes eyes |
| masseter | runs from zygomatic process to the mandible. closes jaw |
| sternocleidomastoid | originates at sternum or clavicle. inserts into mastoid process of temporal bone. if both sides contract, neck flexes. alone-oneside bends head toward shoulder and turns face to opposit side. |
| temporalis | elevates the mandible. originates along temporal lines of skull. inserts into mandible |
| trapezius | diamond shaped muscle on back. originates at occipital bone and thoracic vertebrae. inserts at clavicle and scapula. allows shoulder movement and head extension |
| latissimus dorsi | flat muscle covering lower back. originates on lower spine and ribs. inserts to proximal end of humerus. extends and adducts the humerus. large inswimmers |
| deltoid | triangular shaped muscle that forms rounded part of shoulder. favorite injection side for medications. originates in scapula and clavicle. inserts into humerus. abducts arm. |
| pectoralis major | fan shaped muscle covering upper part of chest. originates at scapula, clavicle, and ribs 2-6. inserts at proximal end of humerus at the greater tubercle. allows you to fles, adduct, and rotate arm |
| pectoralis minor | located beneath pectoralis major. originates from anterior ribs 3-5 and inserts into the coracoid process of scapula. depresses and protracts the shoulder |
| depresses and protracts | moves anteriorally in the horizontal plane. pulling shoulders in |
| teres major | adduction and medial rotation of shoulder. origin of inferior andgle scapula. inserts into humerus |
| muscles of rotators cuff | common sports injury site |
| supraspinatus | abducts shoulder. originates in scapula. inserts into greater tubercle of humerus |
| infraspinatus | lateral rotation of shoulder. same insertion and origin as supraspinatus. |
Created by:
cj422