Internal/external Respirations Flashcards
What is external respiration?
External respiration is the exchange of gases that takes place in the lungs. Oxygen in inhaled air is exchanged for carbon dioxide, which is then exhaled.
Alveoli= high concentration of oxygen
Pulmonary capillaries= high concentration of carbon dioxide
How are gases exchanged?
Gases are exchanged by diffusion. Gases flow from areas of high concentration to areas of low concentration with the concentration gradient.
What are three ways that carbon dioxide is transported in external respiration?
1) dissolved in plasma (5%)
2) bound to hemoglobin molecules. The complex is called carbaminohemoglobin (20%)
3) as bicarbonate ions (75%)
How do bicarbonate ions form to transport carbon dioxide in external respiration?
Bicarbonate ions form when carbon dioxide enters plasma and combines with water to form carbonic acid. Takes place in red blood cells catalyzed by carbonic anhydrase enzyme. The carbonic acid disassociates into hydrogen and bicarbonate ions.
How is oxygen transported in the blood in external respiration?
1) dissolved in plasma (2%)
2) bound to hemoglobin molecules in red blood cells. Complex is called oxyhemoglobin (98%)
What are three characteristics of hemoglobin in external respiration?
A hemoglobin molecule has 4 polypeptide chains joined by 4 heme groups that contain iron.
A single hemoglobin can carry 4 oxygen molecules.
Hemoglobin is a quaternary structure protein.
What is the effect of pH and temperature on hemoglobin in external respiration?
As temperature increases, hemoglobin binds less readily with oxygen.
As pH decreases, hemoglobin binds less readily with oxygen.
Lungs= temperature decreased and pH increased
Tissues= temperature increased and pH decreased
How is hemoglobin a buffer?
Hemoglobin prevents pH from changing by absorbing excess hydrogen ions as a result of the disassociation of carbonic acid. When hemoglobin combines with hydrogen it is called reduced hydrogen.
What is internal respiration?
Internal respiration is the exchange of gases in the tissues. By diffusion, oxygen moves from capillaries into the tissue fluids. Carbon dioxide moves from the tissue fluid into capillaries.
Systemic capillaries= high concentration of oxygen
Tissues= high concentration of carbon dioxide
How does blood become oxygenated?
Each air sacs (alveoli) is surrounded by capillaries. Blood enters through the pulmonary artery, and oxygen from inhaled air moves from the alveoli to the blood through diffusion in the capillaries. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.
What happens to blood when it enters and leaves capillaries?
When blood enters capillaries blood pressure is higher and oxygen and nutrient leave the blood. As blood descends down the capillary blood pressure decreases and osmotic pressure constant and blood absorbs carbon dioxide and waste to be exhaled in the lungs.
What is osmotic pressure?
Osmotic pressure is the inflow of water into a capillary caused by the plasma protein and osmotic concentration gradients on the inside of the capillary as opposed to the interstitial fluid.
What is hydrostatic pressure?
Hydrostatic pressure is the force exerted by fluid pressing against a walls. In capillaries, hydrostatic pressure is the same way as blood pressure.
What is interstitial fluid?
Interstitial fluid is found in the spaces around cells and allows for transportation, regulation of homeostasis, and exchange of materials.
Does osmotic pressure and hydrostatic pressure drive blood in or out of capillaries?
Osmotic pressure drives blood into capillaries from the interstitial fluid (reabsorption)
Hydrostatic pressure drives blood our of capillaries and into the interstitial fluid (filtration)
