Respiratory System

• We breathe to clear carbon dioxide from our systems and to transport oxygen into our cells to allow them to function
• The respiratory system includes specialized components such as structures and tissue that make up the lungs and other respiratory organs. It requires a trigger to start functioning, which in this case is the autonomic nervous system.
• The autonomic nervous system is a control system for vital functions in the brain, which is working without the consciousness of a person
• Hemoglobin is a protein that carries oxygen from your lungs to the rest of the body (including vital organs), and transports CO2 from around the body to the lungs.
• The autonomic nervous system sends a signal to the muscles around the lungs, causing them to create space for the lungs to expand.
• Air travels from the nose and mouth, through the trachea and into the bronchioles and alveoli, causing the lungs to inflate.
• At the point of maximum inflation, the air sacks are full of oxygen while the capillaries are full of CO2.
• The basic law of diffusion states that both gasses want to move to an area with a lower concentration of their gas, causing the CO2 to move into the lungs and the oxygen to move into the hemoglobin in the capillaries.
• The bloodstream transports the hemoglobin with oxygen around the body.
• The autonomic nervous system causes the muscles around the lungs to deflate, causing the lungs to compress and the CO2 gets pushed out.
• The cycle repeats about 15-25 times a minute.
• Respiration is the process of gas exchange in your alveoli (external respiration) and cells (internal respiration)
• Ventilation is the process of air moving in and out of the lungs, and the movement of muscles needed to do this
• Boyle's Law states that pressure (P) is directly proportional to the inverse of volume (1/V). Therefore high volume = low pressure, and low volume = high pressure.

  
• Inhalation is an active process, which means muscles are actively working.

  1. Intercostal muscles contract, pushing the ribcage up and outwards
  2. Diaphragm contracts and moves down
  3. The volume of the thoracic cavity increases as it expands into the extra space, decreasing the pressure in the lungs
  4. Air flows into the lungs to equalize the pressure inside the lungs to that outside the lungs
• Exhalation during rest is a passive process, which means muscles are relaxed.

  1. Intercostal muscles and diaphragm relaxes, and the diaphragm moves upward
  2. The ribcage moves down and in
  3. The volume of the lung cavity decreases, which increases the pressure in the lungs, which becomes more than the external pressure
  4. Air is released to equalize the pressure within the lungs with that outside
• Internal/cellular respiration is when cells release carbon dioxide and take in oxygen from the blood through hemoglobin
• External respiration is when the lungs take in oxygen from the atmosphere and release CO2
• Active exhalation is an active process, which means the muscles are actively working.

  1. During exercise, cellular/internal respiration increases, resulting in an increase of CO2 released by the cells
  2. Therefore, the stomach muscles contract more to make the lung cavity even smaller, allowing more air and CO2 to be exchanged
• The nose is used to breathe and contains mucus and hair to filter out bacteria. Leads to the nasal cavity
• The nasal and oral cavity filters and warms the air being inhaled

  
• Mouth is used to breathe and leads to the oral cavity
• The epiglottis is a movable "lid" above the larynx that prevents food and water from going into the lungs

  
• The pharynx carries food, fluid, and air from the nasal/oral cavity to the esophagus/trachea

  
• The larynx is the voice box and is located at the entrance to the trachea.

  
• The trachea carries air in and out of the lungs and is protected by cartilage rings.

  
• The left/right bronchis branch off of the trachea and distributes the air through the lungs and into the bronchioles

  
• Bronchioles are at the end of a bronchis and carry the air from the bronchis to the alveoli

  
• Alveoli are air sacks at the end of each bronchiole. They are wrapped in capillaries with red blood cells that contain a special protein called hemoglobin. They collect oxygen from the bronchioles and release CO2 during respiration
• The diaphragm is a muscle under the lungs that contracts to create space for the lungs to expand during ventilation

  
• The thoracic cavity is the space in your chest that houses your lungs and heart as well as other organs
• Intercostal muscles is a group of muscles behind the ribs that help form and move the chest wall

  
• Lungs are a pair of organs in the body that supply oxygen to the body and remove CO2 from the body