muscles

Cardiac muscle tissue- only found in the heart, involuntary, and its striated (striped) tubular and branched structure

skeletal muscle tissue-attached to tendons which attach to bones, voluntary, contains many nuclei, and its striated and tubular.

 smooth muscle tissue, Attached to internal organs like the stomach, esophagus, and blood vessels, its involuntary

muscle contraction causes the movement of bones at a joint. Muscles pull on the origin tendon (attached to the stationary bone) and insertion tendon (on moving bone). Muscles shorten when they contract and expand when relax, this means that muscles come in pairs because every action of one muscle has another muscle doing the opposite action (antagonistic pairs)

the flexor is the muscle that contract to bend a joint, (the extensor would relax) like bicep

the extensor is the muscle that contract to straighten a joint, (flexor relaxes  like tricep

support the body, move bones, maintain body temp, protect internal organs, and movement

• Muscle- contains everything 
• muscle fibre bundle- numerous muscle fibres 
• muscle fibre, myofibrils, myofilaments

a muscle fibre membrane that reduces friction

myofilaments contain two types of filaments a thin filament and a thick filament.Each contains their own specific protein structure responsible for muscle contraction. The filament proteins are actin and myosin

• actin- thin, surrounding myosin, anchored at Z line
• myosin-  Thicker, inside actin, has a myosin head made of proteins

produce striations when overlap

muscles shorten by actin sliding over the myosin. The myosin head attaches to the actin using calcium. the myosin head flexes backward to pull the actin filament. Atp provides energy to release the myosin head and reposition it before each flex. Then the myosin attaches to the actin farther along the filament to keep moving it after it splices atp into adp so the atp doesn't prevent the bonding

a single contractile unit which is composed of myofilaments

each actin is anchored to a Z line in the sarcomere. As actin is pulled by myosin the actin drags the z line with it. The z line is found on both sides and as their pulled inwards causing the space between the z-line to shrink contracting the muscles. eventually myosin will hit the z-line and contraction can't go further

muscle contract bu the myosin head fail to detach because of the lack of atp so the muscles stay contracted (happens when die)

lack of 02, atp and calcium also a build up of lactic acid. (lactic acid is atp made with no O2

calcium ions are from the sarcoplasmic reticulum and their used to help the myosin bind to the actin

• atp can not be stored in the muscles so
• anaerobic - which is turning sugar into lactate to form atp from adp

or

aerobic- glucose is oxidized to make atp or creatine phosphate provides a phosphate to adp creating atp and creatine.

a compound that contains creatine and phosphate and can be broken down to give the phosphate attached to the creatine to adp to form atp and creatine.

• first- creatine phosphate to make atp
• second- oxidizing glucose into atp
• third- lactic acid where atp is formed with no o2

• latent period- pause between nerve impulse and muscle contraction
• contraction period-when actin and myosin filaments slide over one another (shortening sacromere)
• relaxation period- actin and myosin disengage and the sacromer returns to its original shape

constant muscle contraction caused by bacteria keeping muscles flexed.

amount of nerve stimulation on a muscle before relaxing phase is complete

slow twitch- contract and break down atp slowly, they are very efficient and produce energy aerobically. They are usually red in colour and used for endurance. Small amount of mitochondria

fast twitch- break down atp very fast because they are used for rapid generation of power, they produce atp anaerobic meaning that they can fatigue faster (less efficient) and are white. lots of mitochondria