Curriculum Portal

neurologyYou need to know

• Air enters the respiratory system through the mouth or nose and then passes through the trachea, bronchi, bronchioles, and alveoli.
• The trachea is the main airway that carries air from the mouth and nose towards the lungs.
• Rings of cartilage in the trachea help keep the airway open.
• The bronchi are the two main branches of the trachea that carry air into the lungs.
• Bronchioles are smaller airways that branch from the bronchi and carry air to the alveoli.
• Alveoli are tiny air sacs where gas exchange takes place.
• Gas exchange is the exchange of oxygen and carbon dioxide between the alveoli and the surrounding capillary blood.
• Gas exchange at the alveoli happens by diffusion, which is the movement of gases from a high concentration to a low concentration.
• Oxygen diffuses from the alveoli into the blood because oxygen concentration is higher in the alveoli than in the blood arriving at the lungs.
• Carbon dioxide diffuses from the blood into the alveoli because carbon dioxide concentration is higher in the blood than in the alveoli.
• The lungs contain millions of alveoli, which provide a very large surface area for gas exchange.
• Alveoli have moist walls that are one cell thick, which helps gases dissolve and diffuse quickly.
• Capillaries around the alveoli have walls that are one cell thick, which creates a short diffusion pathway.
• A dense capillary network around the alveoli provides a large blood supply, which helps maintain concentration gradients for diffusion.
• Oxygen combines with haemoglobin in red blood cells to form oxyhaemoglobin.
• Haemoglobin can also carry carbon dioxide in the blood.
• The three main types of blood vessel are arteries, veins, and capillaries.
• Arteries carry blood away from the heart.
• Most arteries carry oxygenated blood, but the pulmonary artery carries deoxygenated blood from the heart to the lungs.
• Arteries have thick muscular walls, elastic tissue, and a narrow lumen so they can withstand and maintain high blood pressure.
• Veins carry blood towards the heart.
• Most veins carry deoxygenated blood, but the pulmonary vein carries oxygenated blood from the lungs to the heart.
• Veins have thinner walls and a wider lumen than arteries because blood in veins is under lower pressure.
• Veins contain valves that prevent the backflow of blood.
• Capillaries link arteries and veins within body tissues.
• Capillaries have walls that are one cell thick and a very narrow lumen, which makes them efficient for exchange.
• Capillary networks provide a large surface area for the exchange of gases, nutrients, and waste products.
• Vasoconstriction is the narrowing of arterioles to reduce blood flow to an area.
• Vasodilation is the widening of arterioles to increase blood flow to an area.
• During exercise, vasodilation increases blood flow to the working muscles.
• During exercise, vasoconstriction reduces blood flow to less active areas such as the digestive system.
• The vena cava returns deoxygenated blood from the body to the right atrium.
• The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
• The pulmonary vein carries oxygenated blood from the lungs to the left atrium.
• The aorta carries oxygenated blood from the left ventricle to the body.
• The heart is made of cardiac muscle, which contracts to pump blood around the body.
• The heart has four chambers called the right atrium, right ventricle, left atrium, and left ventricle.
• The atria are the upper chambers of the heart and they receive blood returning to the heart.
• The ventricles are the lower chambers of the heart and they pump blood away from the heart.
• The right side of the heart pumps deoxygenated blood to the lungs.
• The left side of the heart pumps oxygenated blood to the rest of the body.
• Heart valves open when pressure behind them is greater than pressure in front of them.
• Heart valves close to prevent backflow of blood.
• The cardiac cycle is one complete heartbeat.
• The cardiac cycle includes diastole, atrial systole, and ventricular systole.
• During diastole, the heart relaxes and the chambers fill with blood.
• During atrial systole, the atria contract and push blood into the ventricles.
• During ventricular systole, the ventricles contract and eject blood into the pulmonary artery and aorta.
• The right and left atria contract at the same time during atrial systole.
• The right and left ventricles contract at the same time during ventricular systole.
• The pathway of blood is vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, and aorta.
• Blood is oxygenated in the lungs before returning to the left atrium.
• Heart rate is the number of beats per minute.
• Stroke volume is the volume of blood pumped out of the heart with each beat.
• Cardiac output is the volume of blood pumped out of the heart each minute.
• Cardiac output is calculated using the formula `Q = \text{stroke volume} \times \text{heart rate}`.
• If stroke volume increases and heart rate stays the same, cardiac output increases.
• If heart rate increases and stroke volume stays the same, cardiac output increases.
• A fitter performer usually has a lower resting heart rate and a larger stroke volume than a less fit performer.
• A larger stroke volume allows a fitter performer to maintain the same cardiac output with fewer heart beats.
• An anticipatory rise is an increase in heart rate before exercise begins.
• Heart rate increases during exercise to meet the greater demand for oxygen by the working muscles.
• During steady-state exercise, heart rate levels off when exercise intensity remains constant.
• When exercise intensity increases, heart rate rises to a higher level.
• Recovery period is the time taken for heart rate to return towards resting level after exercise.
• A fitter performer usually has a shorter recovery period than a less fit performer.
• Ventilation is the process of breathing in and out.
• Inhalation is also called inspiration, and exhalation is also called expiration.
• Breathing mechanics depend on the movement of the intercostal muscles, ribs, and diaphragm.
• During inhalation at rest, the intercostal muscles contract and the ribs move up and out.
• During inhalation at rest, the diaphragm contracts and flattens.
• During inhalation at rest, thoracic volume increases and pressure inside the lungs decreases, so air moves into the lungs.
• During exhalation at rest, the intercostal muscles relax and the ribs move down and in.
• During exhalation at rest, the diaphragm relaxes and returns to a dome shape.
• During exhalation at rest, thoracic volume decreases and pressure inside the lungs increases, so air moves out of the lungs.
• During exercise, the pectorals and sternocleidomastoid assist inspiration so the lungs can expand more.
• During exercise, the abdominal muscles contract to pull the rib cage down more quickly and force air out faster.
• A spirometer is used to measure lung volumes and breathing rate.
• A spirometer trace is a recording of breathing over time.
• Tidal volume is the volume of air breathed in or out in one normal breath.
• Inspiratory reserve volume is the additional volume of air that can be inhaled after a normal inhalation.
• Expiratory reserve volume is the additional volume of air that can be exhaled after a normal exhalation.
• Residual volume is the volume of air that remains in the lungs after a maximal exhalation.
• A spirometer trace can be used to identify tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume.
• Breathing rate can be calculated from a spirometer trace by counting the number of breaths in a known time period.
• During exercise, tidal volume increases because breathing becomes deeper.
• During exercise, breathing rate increases because breaths are taken more frequently.
• During exercise, inspiratory reserve volume and expiratory reserve volume decrease as tidal volume increases.
• On a spirometer trace, the onset of exercise is shown by waves becoming taller and closer together.

• Trace the pathway of air from the mouth or nose to the alveoli.
• Explain gaseous exchange at the alveoli using diffusion, large surface area, thin moist walls, and capillary supply.
• Compare arteries, veins, and capillaries by linking their structures to their functions.
• Interpret redistribution of blood during exercise by applying vasodilation and vasoconstriction to working and non-working areas.
• Trace the pathway of blood through the heart, lungs, and body in the correct order.
• Explain the stages of the cardiac cycle from a named starting point.
• Calculate cardiac output from heart rate and stroke volume.
• Interpret heart rate graphs by identifying anticipatory rise, steady state, changes in intensity, and recovery.
• Explain inhalation and exhalation at rest and during exercise using the actions of the intercostal muscles, ribs, diaphragm, and accessory muscles.
• Interpret spirometer traces by identifying lung volumes, calculating breathing rate, and showing the onset of exercise.