BREAKDOWN OF MUSCLE

WHOLE MUSCLE - MUSCLE IS COVERED BY EPIMYSIUM

FASCICULUS - FASCICULUS IS COVERED BY PERIMYSIUM

MUSCLE FIBER - A SINGLE MUSCLE FIBER IS COVERED BY ENDOMYSIUM

MYOFIBRIL:

SARCOLEMMA: Aids the transmission of action potential from the motor neuron to the muscle fibers.

ACTIN: Found within the sacromere on the z disk which create the sliding filaments when connected to the myosin.

SATELLITE CELLS: Facilitate growth, development and adaptation to injury, immobilisation and training of the muscle fibers.

SARCOPLASMIC RETICULUM: Loops around the myofibril and stores calcium which is need to create sliding filaments.

MYOSIN: Two protein strands twisted together one end folded into a globular head

TRANSVERSE TUBULES: Allows waste products to move in and out of the myofibril, makes the myofibril respon to sarcolemma developments.

THE MOVEMENT OF BLOOD THROUGH THE HEART

1. Deoxygenated blood arrives via the superior and inferior vena cava. 
2. The blood moves into the right atrium and passes through the tricuspid valve.
3. The blood then moves into the right ventricle which then passes through the pulmonary valve.
4. Blood then arrives in the pulmonary artery which carries the deoxygenated blood to the lungs.
5. The lungs cause gaseous exchange to occur which removes the carbon dioxide from the blood and refuels it with oxygen. 
6. The newly oxygen rich blood then returns to the heart via the pulmonary vein.
7. The blood passes into the right atrium and through the mitral valve.
8. Blood arrives in the right ventricle and then passes through the aortic valve.
9. Once through the aortic valve, the oxygen rich blood arrives in the aorta which delivers the blood to the organs and tissues through arteries. 
10. Once the oxygen rich blood has been sapped by the organs and tissues, the process will start over again and the veins will carry the deoxygenated blood back to the heart.

BLUE = DEOXYGENATED BLOOD

RED = OXYGENATED BLOOD

ITALICS = SYSTEMIC CIRCULATION

NORMAL = PULMONARY CIRCULATION

VEINS, ARTERIES & CAPILLARIES

VEINS = BRINGING DEOXYGENATED BLOOD BACK TO THE HEART AND LUNGS

ARTERIES = BRING OXYGENATED BLOOD TOWARDS THE REST OF THE BODY

CAPILLARIES = TINY VESSELS WHICH CONNECT VEINS WITH ARTERIES, FACILITATE GASEOUS EXCHANGE TO OCCUR AND THE REMOVAL OF WASTE PRODUCTS.


CAPILLARIES

Precapillary sphincters: Maintain and controls blood flow from the arterioles into the capillaries.

Thoroughfare channel: Allows blood to freely move through the arteriole to the venule.

Vascular shunt: The distribution of blood to the working muscles around the body.

Metarterioles: Connect the venules and arterioles together.


VEINS AND ARTERIES

Veins carry oxygenated blood from the lungs back into the heart, this is the pulmonary circulation. However in the systemic circulation they carry deoxygenated blood from the rest of the body back to the heart.

Arteries carry deoxgenated blood from the lungs back into the heart, this is the pulmonary circulation. However in the systemic circulation they carry oxygenated blood from the heart to the rest of the body.


COMPOSITION OF VEINS & ARTERIES

Tunica interna - Thin inner layer of the vein and artery.
Tunica media - Thin middle layer of the vein and artery.
Tunica exertina - Thick outer layer of the vein and artery.
Endothelium cells- Layer of cells within the vein and artery.
Valve - controls blood flow within the vein and artery.
Lumen- the space or hole in the vein and artery which allows the flow of blood.

COMPOSITION OF CAPILLARIES

Endothelium cells - the layer of cells within the capillary.

SLIDING FILAMENT THEORY

ROLE OF CALCIUM IN THEORY

- When binding with the troponin, calcium changes its shape which in effect removes the blocking of tropmyosin which allows the myosin heads to attach to the actin.

- Calcium levels vary depending on the action - when muscle goes to rest the myosin head needs to deattach from the actin filament therefore calcium levels drop to allow the myosin head to move back to its original position.

SLIDING FILAMENT THEORY

- The sliding filament theory occurs in the sarcomeres, which run laterally along the myofibril.

- Each sarcomere is made up of two filaments, actin and myosin.

- When we decide to move, calcium attaches onto the troponin of the actin, this then changes shape causing topomyosin to move around allowing the myosin head to attach onto the actin.

- The attachment of the myosin head onto the actin is called a 'CROSS BRIDGE'.

- Once the connection is complete, the ATP allows the myosin head to push the actin, this is called the power stroke and causes the sarcomere to shorten.

- To disconnect the cross bridge, ADP allows the myosin head to return to its original position, this is called the recovery stroke.

- If there is still enough calcium the process will keep going until the calcium is transported back into the sarcopaslmic reticulum, therefore causing the muscle to relax.

NEUROMUSCULAR CONTROL

ACTION POTENTIAL released into AXON TERMINAL

Provokes SODIUM CHANNELS to open which release sodium particles into the AXON TERMINAL.

This then causes DEPOLARIZATION to occur which causes CALCIUM CHANNELS to open, thus releasing CALCIUM into the AXON TERMINAL.

CALCIUM then binds with VESICLES which then move to the front of the PRE-SYNAPTIC MEMBRANE.

Once the VESICLES reach the PRE-SYNAPTIC MEMBRANE, the vesicles release the CALCIUM into the SYNAPTIC CLEFT.

The Vesicles carrying the CALCIUM and SODIUM cross the SYNAPTIC CLEFT until they reach the ACH RECEPTORS at the muscle fiber front called the MOTOR END PLATE.

This then opens ION CHANNELS within the ACH RECEPTORS and allows both SODIUM and POTASSIUM to pass through.

The SODIUM pass through whilst POTTASIUM moves way from the muscle fiber, thus causing DEPOLARIZATION in the fiber.

DEPOLARIZATION spreads through the muscle fiber and across the sarcolemma.

The DEPOLARIZATION causes CALCIUM to appear in the muscle fiber, which is therefore used for contractions etc.