respiratory system

• Respiration


  The process of taking in Oxygen and removing Carbon Dioxide
• Ventilation


  Getting air into and out of the lungs
• External respiration


  Gaseous exchange between the lungs and blood
• Internal respiration

  Gaseous exchange between the blood in the capillaries and the body cells
• Cellular respiration


  The metabolic reactions and processes that take place in a cell to obtain energy from glucose
• Passage of air

  Nose - Pharynx - Larynx - Trachea - Left and Right Bronchus - Bronchi - Bronchioles - Respiratory Bronchioles - Alveoli
• Diffusion


  The movement of gas molecules from an area of high concentration / partial pressure to an area of low concentration / partial pressure
• Structure

  Designed to help with gaseous exchange
• Gaseous exchange


  The movement of oxygen from the air into the blood, and Carbon Dioxide from the blood into the air
• Structure of the alveoli

  Big surface area, One cell thick, Good blood supply
• Inspiration


  Getting air into the lungs
• Expiration


  Getting air out of the lungs
• Lung volumes


  Movement of air into and out of the lungs
• Tidal volume


  Volume of air breathed in or out per breath
• Inspiratory reserve volume


  Volume of air that can be inspired after a maximal inspiration
• Expiratory reserve volume


  Volume of air that can be expired after a maximal expiration
• Residual volume


  Volume of air remaining in the lungs after a maximal expiration
• Minute ventilation


  Volume of air breathed in or out per minute
• Spirometer


  A device that is used to measure the volume of air inspired and expired by the lungs
• Partial pressure


  The pressure exerted by an individual gas when it exists within a mixture of gases
• Diffusion / Concentration gradient


  Difference in the partial pressure
• Diffusion pathway of oxygen

  Alveoli - blood - muscles
• Diffusion pathway of carbon dioxide

  Muscles - blood - alveoli
• Where is adrenaline found?

  Natural stimulant made in the adrenal gland of the kidney and is often referred to as the body's activator as it is released in response to exercise
• Neural Regulation / Control


  Involves the brain and nervous system
• Chemical Regulation / Control

  Involves blood acidity
• Sympathetic nervous system

  Prepares body for exercise so it will increase breathing rate
• Parasympathetic nervous system


  Lowers breathing rate
• Respiratory Centre


  Located in the medulla oblongata and controls the rate and depth of breathing, using neural and chemical control
• Inspiratory Centre


  In the Respiratory Centre - Responsible for inspiration and expiration when an increase concentration of CO2 in the blood stimulates the Respiratory Centre to increase Respiratory rate
• Expiratory Centre


  Stimulates the expiratory muscles during exercise
• Chemoreceptors


  Located in the Carotid Arteries and sense chemical changes as they detect and increase in Carbon Dioxide during exercise. It stimluates the Sympathetic Nervous System. An increase in Carbon Dioxide means an increase in Respiratory rate until blood acidity has returned to normal
• Baroreceptors


  Contain nerve endings, that respond to the stretching of the arterial wall, which is caused by the changes in blood pressure. A decrease in Blood Pressure means an increase in breathing rate
• Proprioceptors


  Sensory nerve endings which are located in the muscles, tendons and joints. They provide information about movements and body position. An increase in Muscle Movement means an increase in Respiratory rate
• The respiratory centre has 2 main areas

  1 = The inspiratory centre is responsible for both inspiration and expiration

  2 = The expiratory centre stimulates the expiratory muscles during exercise
• The inspiratory centre


  Sends out nerve impulses via the phrenic nerve to the inspiratory muscles (diaphragm and external intercostals) to cause them to contract. This stimulation acts for approximately 2 seconds then then impulses stop and passive expiration occurs due to the elastic recoil of the lungs
• The respiratory control centre

  Responds mainly to changes in blood chemistry. Has two main areas - inspiratory control centre (inspiration and expiration) and expiratory control centre (expiration during exercise)
• Inspiratory control centre (ICC) - exercise

  Blood acidity increases as a result of an increase in the plasma concentration of carbon dioxide and an increase in lactic acid production. Changes are detected by chemoreceptors which are found in the carotid artery + the aortic arch and they send impulses to the IC to increase ventilation until blood acidity is returned to normal. To achieve this, the respiratory centre sends impulses down the phrenic nerve to stimulate more inspiratory muscles - sternocleidomastoid, scalenes, pectorialis minor. As a result depth, rate and rhythm increases.
• Neural/chemical control for increased inspiration during exercise

  Receptors (baro,chemo,proprio) --> medulla oblongata --> phrenic nerve --> inspiratory muscles (diaphragm, external intercostals, sternocleidomastoid, scalenes, pectorialis minor)
• Neural/chemical control for expiration during expiration

  Receptors (chemo, proprio, baro) --> medulla oblongata --> intercostal nerve --> abdominals and intercostals