Respiratory System

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Respiratory System
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Respiratory System

• Why do we need to breathe?
• Gas exchange system
• Requirements of respiratory membranes
• must be moist.
• Must be thin
• must be permeable to gases.

• All organisms must have a mechanism with which to
  transport gases. (circulatory system)
• Movement of gases happens by simple diffusion.

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Surface Area and other Respiratory Characteristics

• Cutaneous Respiration
• Examples
• Why are our lungs located within the chest cavity
  and rib cage?
• Moisture
• protection
• Importance of surface area.

• We have a respiratory surface area of about 60 to
  70 square meters.

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Human Respiratory Tract

• Why is it so easy for humans to choke?
• Vocal cords
• trachea
• cartilage rings
• incomplete rings
• trachea
• bronchi
• bronchioles
• alveoli
• capillaries

• Nostrils
• nasal septum
• nasal cavity
• Role of mucous membranes and hairs?
• Pharynx
• glottis
• epiglottis
• larynx
• Adams apple

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How do we breathe?

• Thoracic cavity
• pleura
• pleurisy
• diaphragm
• intercostal muscles
• Role of pressure
• inspiration
• What happens with pressure and the volume of the
  chest cavity?

• Expiration
• What happens with pressure and the volume of the
  chest cavity?

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Gas Exchange

• Where does it occur?
• What gases are exchanged?
• Simple diffusion is responsible.
• Erythrocytes
• RBCs
• Role of hemoglobin
• Structure of hemoglobin

• Oxyhemoglobin
• 4 oxygens at a time.
• Effects of CO
• Carbon dioxide is largely transported as a
  dissolved gas in the plasma although some is
  transported by hemoglobin

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Control of breathing

• Respiratory Center
• Medulla Oblongata
• Brainstem
• Peripheral Chemoreceptors
• aorta and carotid arteries
• increase in Carbon dioxide increases H ion
  concentration.

• Central chemoreceptors in the brain are sensitive
  to this.
• Increase CO2, Increase breathing rate.
• Hyperventilation

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Other mechanisms of breathing

• Gills
• Structure
• Why do fish suffocate on land?
• Countercurrent flow
• Insects
• spiracles
• tracheae
• tracheoles

• Why cant this work in us?
• Snail and Frogs
• Have lungs, but very little respiratory surface
  area.
• Cutaneous Breathing.

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