Gas Exchange

• external respiration - exchange of O2 and CO2 between the organism and its environment.
• for diffusion to be effective, gas-exchange regions must be?

  Thin, moist, relatively large
• Effectiveness of oxygen diffusion to the body is enhanced by what process?

  Vascularization
• Cutaneous respiration - direct diffusion of gases throughout the integument
• Gills or branchia (external) - for aquatic animals
• Papulae (dermal branchiae or skin gills)- Extension of the fluid

  filled coelom.
• branchial tufts (gills) - in marine worm
• Appendages called parapodia also serves as an external respiratory surface such as those in ragworms
• When a fish ventilates its gills, as the operculum expands and closes and pulls water across gills, is the mouth open or closed?

  open
• When a fish ventilates its gills, as the operculum is open and pushes water across gills, is the mouth open or closed?

  Closed
• Countercurrent flow creates a partial pressure gradient that favors the diffusion of O2 from water to blood along the entire length of the capillary
• Countercurrent - allows the most efficient extraction of O2 from water to blood across the lamellae, compared to same current flow

  
• Lungs (invaginated) – allows for ventilation of air
• Label the following. A frog ventilates its lungs by positive pressure

  breathing wherein pressure is greater inside the lungs, than

  outside the body.

  A) Buccal Cavity

  
• Mammals ventilate their lungs by negative pressure breathing which is generated by contraction of the diaphragm that allow airs to flow in lungs.
• Tidal Volume - the volume of air an animal inhales and exhales with each breath at rest
• What is the average tidal volume in resting humans in mL?

  500
• Vital capacity - the maximum tidal volume during forced breathing
• Label the following.

  A) Nasal cavity

  B) Larynx

  C) Trachea

  D) Bronchus

  E) Bronchiole

  F) Alveoli

  
• Gases (O2 and CO2) diffuse from a locationof higher concentration → to one of lower concentration.
• Label what's needed.

  A) Pulmonary

  B) Oxyhemoglobin

  C) Bicarbonate ion

  D) Carbaminohemoglobin

  
• Hemocyanin (invertebrates) – copper containing
• Most animals transport most of the O2 bound to special proteins called respiratory pigments
• Hemoglobin (vertebrates) – iron containing
• What converts CO2 to carbonic acid in red blood cells?

  Carbonic anhydrase
• Label the following.

  A) 70%

  B) Hydrogen ion

  C) Bicarbonate ion

  D) 5%

  E) Plasma

  F) 25%

  G) Carbaminohemoglobin