The Structure and Functions of the Cardio-Respiratory System

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Created by
Emilia Lombardi

Cards (12)

  • Structure of the cardiovascular system:
    • Atria are where the blood collects when it enters the heart.
    • Ventricles pump the blood out of the heart to the lungs or body.
    • Septum separates the right-hand and left-hand side of the heart.
    • Tricuspid valve located between right atrium and ventricle and opens due to a build up of pressure in the right atrium.
    • Biscupid valve located between the left atrium and ventricle and opens due to a build up of pressure in the left atrium.
    • Semilunar valves stop the backflow of blood into the heart.
  • Pathway of Blood in the heart:
    1. Left atrium
    2. Left ventricle
    3. Body
    4. Vena cava
    5. Right atrium
    6. Right ventricle
    7. Pulmonary artery
    8. Lungs
    9. Pulmonary vein
  • Functions of the cardiovascular system:
    • Deliver oxygen and nutrients to the body.
    • Remove the waste products such as carbon dioxide and lactic acid.
    • Protection against disease and infection.
    • Maintain body temperature.
  • Blood Pressure:
    A blood pressure reading consists of two values:
    • Systolic value - blood pressure while heart is squeezing.
    • Diastolic value - blood pressure while heart is relaxing.
    Average blood pressure for an adult is 120/80mmHg.
    Blood pressure is determined by Q (cardiac output) and the resistance to the blood flow (R).
  • Heart's performance as a pump:
    The heart's function is to pump blood and circulate it around the body. We assess the heart's performance by calculating cardiac output.
    Q = HR x SV
  • Cardiovascular system and exercise:
    Heart rate is measured in bpm During exercise, the HR increases so that enough blood is taken to working muscles to provide them with enough nutrients and oxygen.
    • Maximum HR = 220 - age
    Stroke volume increases during exercise which means more blood is pumped out the heart each time it contracts.
    At rest, a person's cardiac output is approximately 5 litres per minute, while during exercise it can increase to 30 litres per minute.
  • Pathway of air into the lungs:
    1. Air enters the body through the mouth/nose.
    2. It then enters the trachea.
    3. The trachea divides into two bronchi. One bronchus enters each lung.
    4. Each bronchus branches into smaller tubes called bronchioles. Air travels through the bronchioles.
    5. At the end of the bronchioles, the air enters one of millions of alveoli where gaseous exchange takes place.
  • Inspiration:
    The diaphragm contracts and moves downwards. Intercostal muscles contract and move the ribs upwards and outwards. Increases the size of the chest and decreases air pressure inside it which sucks air into the lungs.
    When exercise begins, inspiration can be assisted by the pectoral muscles and the sternocleidomastoid which help to lift the ribs out even further.
  • Expiration
    The diaphragm relaxes and moves back to its domed shape. Intercostal muscles relax so the ribs move inwards and downwards under their weight. Decreases the size of the chest and increases air pressure in the chest so air is forced out of the lungs.
    During exercise, this passive process of relaxation becomes active as the abdominal muscles pull the ribs downwards and inwards even further.
  • Gaseous Exchange:
    Occurs in the alveoli in the lungs and takes place by diffusion (the movement of gas from an area of high concentration to an area of low concentration).
    Capillaries surround the alveoli in the lungs. Both the capillaries and alveoli walls are very thin (one cell thick). They are made up of semi-permeable membranes which allow oxygen and carbon dioxide to pass through them.
  • Lung Volumes and Exercise:
    • Tidal volume - the amount of air breathed in with each normal breath.
    • Inspiratory reserve volume - the maximum amount of additional air that can be taken into the lungs after a normal breath.
    • Expiratory reserve volume - the maximum amount of additional air that can be forced out of the lungs after a normal breath.
    • Residual volume - the amount of air left in the lungs after a maximal out breath.
    During exercise, tidal volume increases as the depth of breathing increases and the rate of breathing does too.
  • Cardio-respiratory system and exercise:
    Works together to get oxygen to the working muscles and remove carbon dioxide from the body. During exercise, muscles need more oxygen to contract and they produce more carbon dioxide as a waste product.
    • Tidal volume and frequency increases - gets more oxygen into the lungs and more CO2 out.
    • HR increases - increases the rate that the oxygen is transported from the blood to working muscles and CO2 is transported from working muscles to the lungs.