A+P

• Health

  A state of physical, emotional and social well-being and the absence of disease and infirmity
• Fitness

  The ability to meet the demands of the environment
• High cholesterol

  Cholesterol builds up in arteries which leads to high blood pressure as a more powerful contraction from the heart is required. A blood clot can form preventing blood flow leading to a heart attack.
• Stroke Volume

  The volume of blood pumped out by the ventricles in each contraction
• Cardiac output

  The volume of blood pumped out the ventricles per minute
• Cardiac output litres/min


  Heart rate x stroke volume
• Maximal intensity exercise 


  Exceeding 85% of your maximum heart rate
• Anticipatory Rise

  An increase in heart rate just before taking part in exercise - caused by increased activity of the sympathetic nervous system. The sympathetic nervous system causes the adrenal glands to release adrenaline.
• Redistribution of blood flow

  Vascular shunting. The brain requires the same amount of oxygen at rest and during exercise. Eating before exercising causes cramps and stomach pain due to the conflict between the demands of the digestive system and the muscles.
• Process of Vascular shunting

  Increase in CO2 and lactic acid detected by chemoreceptors, vasomotor is stimulated and signals for a redistribution of blood flow, vasodilation and vasoconstriction occur and pre-capillary sphincters adjust blood flow into the capillaries.
• Chemoreceptors


  Detect a change in blood acidity, located in the wall of arteries. Nerve impulses are sent to the medulla oblongata activating the sympathetic nervous system - impulses send to the SAN
• Vasomotor


  Located in the medulla oblongata and is responsible for the regulation of heart rate, blood pressure and the redistribution of blood flow
• The cardiac conduction system


  A group of cells found in the wall of the heart. Responsible for the electrical impulses that cause the heart to contract and pump blood towards arteries. The heart is myogenic - it is capable of generating its own impulses.
• Cardiac conduction system - electrical impulses 


  Begins in the SAN - atria contract passing blood into the ventricles, AVN (delay of 0.1s while the atria contract and empty), Bundle of His (septum), Purkinje fibres - ventricular contraction
• Baroreceptors

  Detect an increase/decrease in blood pressure by detecting the stretching of the arterial wall. An increase in arterial pressure sends impulses to the medulla oblongata activating the parasympathetic nervous system - impulses are sent to the SAN for contractions to decrease. The set point increases during exercise.
• Proprioceptors


  Located in muscles, joints and tendons. During exercise they detect an increase in muscle movement.
• Transportation of oxygen


  Oxygen attaches to haemoglobin forming oxyhaemoglobin - transported to the muscles via blood plasma. Due to low pressure of oxygen at the muscle tissues the oxygen releases and diffuses into muscle cells. Myoglobin is present in muscle cells and stores oxygen allowing it to be used quickly for energy production.
• Dissociation Curve


  Explains how different partial pressures of oxygen enable haemoglobin to transport and release oxygen to active muscle tissues. Low PO2 at the tissues so oxygen diffuses in - percentage saturation is 50%. At the lungs there is a higher PO2 so oxygen diffuses into the blood stream - percentage saturation at the lungs is 100%
• Bohr Shift

  During exercise oxygen dissociates from haemoglobin faster that at rest. The line shifts to the right during exercise - at the muscle tissue more oxygen dissociates from haemoglobin than it would at the same percentage saturation of oxygen at rest. Caused by an increase in body temperature and partial pressure of CO2, and a decrease in pH.
• Venous return

  The flow of blood back to the heart via the veins and vena cava. Venous return increases during exercise. Aided by smooth muscle, gravity and the suction pump of the heart.
• Venous return mechanisms - Skeletal Muscle Pump

  Muscles contracting and relaxing are constantly changing shape, causing muscles to press on nearby veins, creating a pumping action (pushes blood back towards the heart)
• Venous return mechanisms - The respiratory pump


  Breathing in and out causes contractions in many muscles as well as the diaphragm. This causes a constant change in pressure of the thoracic cavity, compressing the veins and causing venous return.
• Venous return mechanisms - Pocket valves

  Veins are full of pocket valves - as blood passes through they close in order to prevent back flow of blood.
• Starlings law

  States that stroke volume increases in response to an increase in venous return. Increase in venous return - greater diastolic filling of the heart occurs - cardiac muscle is stretched - more powerful contraction occurs - increased ejection fraction.
• Systolic blood pressure


  The pressure of the blood against the wall of the arteries as the heart contracts
• Diastolic Blood pressure


  The pressure of the blood in the heart as it relaxes and refills
• Cardiovascular drift 


  When exercising for longer than 10 minutes at a steady state, in a warm environment, heart rate will begin to rise. Stroke volume decreases due to a reduction of fluid in the blood plasma so venous return decreases - heart rate must begin to rise in order to maintain cardiac output.
• Arterio-venous oxygen difference - A-VO2 diff


  The difference in the volume of oxygen between the arteries and the veins. Arteries carry a higher volume of oxygen than veins as they supply the muscles with oxygen. Increases during exercise.
• Diaphragm


  Inhalation - contracts and flattens. Exhalation - relaxes and becomes dome shaped.
• Spirometer trace during exercise


  Tidal volume and minute ventilation increase. Inspiratory reserve volume and expiratory reserve volume decrease. Residual volume stays the same
• Gas exchange 


  At the alveoli - CO2 diffuses out of the blood and O2 diffuses into the blood. At muscle tissues - O2 diffuses out of the blood and CO2 + lactic acid enter the blood.
• Tidal volume 


  Volume of air inspired or expired per breath.
• Inspiratory Reserve Volume

  The volume of air that can be forcibly inspired after a normal breath.
• Expiratory Reserve Volume

  Volume of air that can be forcibly expired after a normal breath.
• Residual Volume

  The volume of air that remains in the lungs after maximal exhalation.
• Minute Ventilation

  The volume of air inhaled or exhaled from the lungs per minute.
• Pulmonary ventilation regulation - Neural and Chemical

  The medulla oblongata contains the inspiratory centre and expiratory centre and signals for an increased breathing rate and depth. Chemoreceptors detect an increase in CO2 - impulse sent to medulla oblongata - SNS is activated - nerve impulse sent via the phrenic nerve to the inspiratory nerve - breathing rate is increased.
• Stretch receptors 


  Found in the lungs. Prevent lungs from over inflating by sending signals to the expiratory centre in the medulla oblongata. Breathing rate and depth decrease
• Smoking and its effect on the respiratory system


  Irritation of the trachea, damaged cilia, carbon monoxide exposure (causes rapid fatigue), damaged alveoli, bronchoconstriction
• Slow twitch muscle fibres


  Contracts slowly, darker in coulor due to a high oxygen supply and contain myoglobin.