Respiratory System

• Why do we need to breathe

  • Aerobic respiration
  • Excrete (exhalation) Carbon Dioxide (CO2)
  • Prefuse our organs
  • To survive
• Primary function of the respiratory system


  Uptake of 02 (inhalation) & elimination of CO2 (exhalation)

  Designed for gaseous exchange via diffusion

  Works in conjunction with the Cardiovascular system- transports gases in blood.

  If either function fails, oxygen cannot be delivered to the cells resulting in cell death
• Structure of the respiratory system

  upper respiratory tract:

  Nose & mouth

  Pharynx

  Sinus

  Epiglottis

  Lower Respiratory Tract:

  Larynx

  Trachea

  Carena

  Bronchi

  Lungs

  Alveoli
• External Nasal Structures


  The nose and mouth are the start of the respiratory system

  Tiny hairs called cilia warm, filter (bogeys) and moisten the inhaled air.

  Air can also enter through the mouth

  The throat (pharynx) collects air and passes it into the windpipe (trachea) via the voice box (Larynx)
• Respiration


  Right lung- 3 lobes

  Left lung- 2 lobes due to the position of the heart.
• How do we breathe?

  Breathing requires several things to happen. The intercostal muscles are the muscles between the ribs.

  When we breathe the intercostal muscles contract, the ribcage expands and the diaphragm contracts.

  This enables the lung to expand allowing air to rush into the lungs.
• Dimensions of the chest cavity


  • Breathing in requires muscular activity and chest size changes.
  • Contraction of the diaphragm flattens the dome and increases the vertical dimensions of the chest
• Trachea and Bronchial Tree


  Primary or main bronchi supply each lung

  secondary bronchi supply each lobe of the lungs (3 right & 2 left)

  Tertiary bronchi supply each bronchopulmonary segment

  Further branches called bronchioles from a bronchial tree
• Structure of a lobule


  Alveoli are tiny. There are about 500 million in your lungs.

  They are folded to have a greater surface area for gas exchange.

  The walls of alveoli are only 1 cell thick so gasses do not have far to travel when diffusing.

  Blood capillaries surround each alveolus to ensure a good supply. this is important as the blood is continuously taking oxygen away and bringing in more carbon dioxide
• Diffusion


  the net movement of particles from an area of high concentration to an area of lower concentration.
• The Respiratory Control Centre


  The brain is the control centre for our respiration (breathing): The autonomic nervous system.

  Its main function is to send signals to the muscles that control respiration to cause breathing to occur.

  It is located in the medulla oblongata and pons in the brainstem
• Hypoxia 


  Low blood oxygen
• Hypercapnia


  Excessive CO2 in the blood and tissues
• Other factors that influence respiration

  Limbic system:

  • A part of the brain which is involved with emotion and behaviour. Fight or flight
  • Anticipation of activity= leads to an increased rate and depth of respiration

  Temperature:

  • Heat leads to increased rate and depth of respiration
  • A sudden cold leads to a cease in respiration (apnoea) e.g. falling into a frozen lake.

  Pain:

  • Sudden, severe pain leads to apnoea
  • Prolonged pain leads to an increased rate of respiration

  Temperature
• Asthma

  Asthma attack

  Difficulty breathing out, wheezing & cough

  Tight chest

  Symptoms often worse at night and during exercise
• Chronic Obstructive Pulmonary Disease: COPD

  It is characterized by a blend of bronchitis, emphysema and asthma.

  symptoms: phlegmy cough, shortness of breath, recurrent infections, & wheezing.

  Exacerbation of symptoms:

  Progressive disease with acute episodes

  Reduced cavity to undertake physical exertion & has a poor quality of life.

  Coal mining, factory working, industrial occupation. Often linked with smoking.