Topic 4

Acetylcholine is the neurotransmiter that initiates muscle contraction and Cholinesterase is the enzyme which breaks down acetylcholine and initiates muscle relaxation

Myofibril is surrounded by sarcoplasmic reticulum there each myofibril can be broken down into functional repeating segments called sarcomere sarcomere consists of actin and myosin When a nerve impulse arrives at the muscle, it causes the release of a chemical called acetylcholine This presence causes depolarization enabling calcium to be released from the sarcoplasmic reticulum The calcium binds to troponin changing its shape and so moving tropomyosin from the active site of the actin The myosin filaments can now attatch to the actin forming a cross bridge The breakdown of atp releases energy which enables the myosin to pull the actin filaments (occurs along the entire length of every myofibril in the muscle cell) When the ATP molecule binds to the myosin head, the myosin detaches from the actin and the cross bridge is broken when atp is then broken down the myosin head can again attatch to an actin biding site further along the actin filament lasts as long as adequate ATP and CA+ stores The nerve impulse stops the CA+ is pumped back to the sarcoplasmic reticulum and the actin returns to its resting position causing the muscle to lengthen and the muscle to relax Z line: where actin is A band: myosin H zone: myosin not in contact with actin

slow twitch (type 1) , fast twitch (type 2a and 2b

sarcomeres contracting bringing the Z lines together reducing the H zone while A band doesn´t change

Glycolysis, aerobic (yes oxygen), red, size small, endurance, fatigue slow

Glycolysis, anaerobic and aerobic, yes and no oxygen, intermediete, rapid movement max force, fatigue medium, red and white

anaerobic (Glycolysis + PCr No oxygen, white, size big, maximal effect, fast fatigue

isometric: contractions are contractions in which there is no change in the length of the muscle (plank) isotonic:muscle contracts while it changes lengths (push ups) isokinetic: the muscular contraction that accompanies constant velocity limb movements around a joint (riding a stationary bike) concentric: muscles shorten while generating force Eccentric: total length of muscle increases as tension is produced

process in which a muscle must relax (agonistic) on one side of a joint to allow for a muscle on the other side on the joint, the antagonistic to contract

Delayed Onset Muscle soreness there is structural damage, inflammatory reactions in the muscle from overstratching and overtraining (usually from eccentric muscle action)

removing the eccentric component of muscle actions during early training, start with low intensity, warming up before exercising, cooling down after wards

arm flexion, Moving arm forward in sagittal plane Arm extension, moving the arm backward in the sagittal plane

Abduction, moving arm away front the body in a frontal plane Adduction, moving the arm toward the body in a frontal plane (para dentro)

Internal or medial rotation, rotating the arm inward External or lateral rotation, rotating the arm outward

circumduction is rotating the arm inward

hip flexion, moving the leg forward in a sagittal plane In a hip extension, hip moves backwards in a sagittal plane

Supination, externally rotationg the forearm, palm is up pronation, internaly rotating the forearm, palm is down

dorsi flexion, poiting the toes up plantar flexion, tiptoing Inversion, sola do pé para dentro eversion sola do pé para fora

elevation of the scapula or mandible Depression of the scapula or mandible

pushing or pulling action that causes a change in state (rest/motion) of a body F=ma (N)

The rate at which a body moves from one location to another (scaler) s=distance traveled/time (m/s)

Length of a path a body follows (scaler)

length of a straight line joining the start and finish points (vector)

rate at which a body moves from one location to another with magnitude and direction making it a vector quantity V= displacement/time