respiratory

• The four steps to get oxygen to cells are:

  • Ventilation
  • Diffusion at the respiratory surface
  • Circulation
  • Diffusion at the tissues
• Ventilation is the movement of air or water through a specialized gas exchange organ (lungs or gills).
• Diffusion at the respiratory surface requires blood for the oxygen to diffuse from the water or air from, and the carbon dioxide to diffuse out of the body.
• Circulation is the transport of dissolved O2 and CO2 throughout the body (with nutrients, wastes, and other molecules) via the circulatory system.
• Diffusion of the tissues involves oxygen moving from the blood to the tissues, and carbon dioxide moving out of the tissues into the blood.
• Animals need to respire and circulate blood to get oxygen for cellular respiration and to get rid of carbon dioxide.
• The partial pressure is the pressure of a particular gas in a mixture of gases, while the total pressure is the sum of the partial pressures of all the gases in the mixture.
• The partial pressure of oxygen and carbon dioxide determines the movement of the gases via diffusion.
• Water breathers have to overcome the lower concentration of oxygen in their environment and the viscosity of water, making it harder to ventilate their respiratory surfaces.
• Fick's Law states that an increased surface area, greater partial pressure difference between the gases on either side of the barrier, and a smaller barrier distance will increase diffusion rate.
• Some adaptations that fish gills have to make gas exchange more efficient include an increased surface area for diffusion with gill filaments and gill lamellae along with a countercurrent exchange system.
• Parts of the mammal respiratory system include the trachea, bronchi, bronchioles, and the lung.
• Gas exchange in mammals occurs between the alveoli of the lungs and the capillaries.
• Some adaptations of the mammal respiratory system to make gas exchange more efficient include increased surface area with alveoli and negative pressure ventilation.
• Gas exchange is easier for terrestial animals than aquatic animals since there is a higher concentration of oxygen in air and air is less viscous than water.
• In mammals, breathing is done through negative pressure ventilation, where the oxygen is inhaled and then exhaled by the contraction and relaxation of the diaphragm and rib muscles.
• In birds, air flow in one direction through the lung which maximizes gas exchange and they also have counter current gas exchange to increase efficiency.
• The main components of blood are plasma which is an extracellular matrix and the remainder is formed elements.
• Formed elements are composed of platelets, white blood cells, and red blood cells.
• Hemoglobin is used to transport oxygen across the circulatory system by binding to it with the iron ion found in its heme groups.
• Hemoglobin delivers oxygen to the tissues.
• Carbon dioxide reacts with water to form carbonic acid to dissociate into bicarbonate. Hydrogen ions that increase breathing rate. Protons on hemoglobin then bind with bicarbonate to reform carbon dioxide, then it is exhaled from the lungs
• Decreases in pH make hemoglobin more like to unload oxygen. Temperature also increases the rate of oxygen unloading. This is useful when exercising due to increased rates of cellular respiration.