What happens to lactate after anaerobic respiration?
Most of it is converted back into pyruvate. Often it is oxidised directly to CO2 and Water so oxygen uptake increases. Some is converted to glycogen.
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What is VO2?
The volume of oxygen we use in a minute.
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What does myogenic mean?
The heart can beat without external stimulus.
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Describe how the heart beats.
Impulse from the sinoatrial node causes atrial contraction. Impulses pass to the ventricles via the atrioventricular node. Impulses travel down the purkyne fibres to the apex of the heart. Impulses spread up through the ventricle walls.
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Describe the different peaks on an ECG.
P wave (atrial systole), PR (Time for the impulses to travel from the SAN to the ventrical walls), QRS (ventricular systole), T wave (repolarisation diastole)
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How can the brain speed up or slow down heart rate?
The cardiovascular control centre sends impulses down the sympathetic nerve to increase heart rate and down the parasympathetic nerve to slow heart rate. These nerves connnect to the SAN.
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How does adrenaline work?
Adrenaline has a direct effect on the SAN. It also causes dilation of the arteries suppliying skeletal muscles and constriction of the arteries supplying the digestive system.
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What is our vital capactiy?
The max volume of air we can breath in and out.
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What instrument is used to work out breathing rate/tidal volume?
Spirometer.
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How does a change in co2 concentration causing an increase in breathing rate?
Co2 dissolves in the blood creating carbonic acid. This lowers the pH. Chemoreceptors in the medulla oblongata detect the change and send impulses to the ventilation centre. Impulses are sent to the muscles that control breathing.
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How does breathing rate increase when exercise occurs?
As soon as exercise begins impulses from the mortor cotrex are sent to the ventilation centre. Stretch receptors in tendons and muscles also send impulses.
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Explain the differences between slow and fast twitch fibres?
Slow twitch- red (myoglobin), many mitochondria, little sacroplasmic reticulum, low glycogen content, numerous capillaries, fatigue respistant. Fast twitch has the opposite.
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How does moderate exercise help defend against infection?
Increases the number of natural killer cells (white blood cells), These do not use specific antigen recognition.
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How do natural killer cells work?
Target cells that are not displaying self markers and release the protein perforin which creates pores in the target cell. This allows other molecules such as protease to enter and cause apoptosis.
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How does vigourous exercise affect the immune system?
Reduces the number of natural killer cells, phagocytes, B cells and T helper cells. This reduces the number of antibodies produced.
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How does EPO work?
EPO is a peptide horomone created in the kidneys. It stimulates the formation of new red blood cells in the bone marrow. It is released when oxygen concentration in the blood falls. It increases the risk of blood clotting.
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How does testosterone work?
Testosterone is a steroid hormone which binds to androgen receptors on cell. This modifies the gene expression in the cell e.g. increasing protein synthesis in muscle cells.
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What are the dangers of using steroids such as testosterone?
hypertension, liver damage, decreased sperm production, impotence, changes in the menstural cycle.
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