Gas Exchange Flashcards
What is the difference between conformers and regulators?
Conformers internal environment varies with the external environment while regulators maintain internal stability even as external conditions change.
What are ectotherms?
Animals that do not have internal control of their body temperature.
What is an endotherm?
An animal that maintains a constant body temperature in the face of environmental changes.
What are the properties of oxygen in aquatic environmnet?
Lower diffusion rate and solubility and less available oxygen in a give volume of fluid.
What is Frick’s first law?
A solute will move from a region of high concentration to a region of low concentration across the concentration gradient.
What is Frick’s second law?
The amount of substance that diffuses across a surface is proportional to the area of that surface and inversely proportional to the distance across which it diffuses.
What is ventilation?
It is the active movement of respiratory medium
What is perfusion?
The flow of blood in the pulmonary capillaries which ensures gas delivery within the body.
What is internal respiration?
Use of O2 to make energy
What is the problem with a small SA: V (large animals)?
They must improve oxygen uptake so they need specialized structure such as gills or lungs
What are marine turbellarian worms?
They are among the largest aquatic animals that rely primarily on diffusion for gas exchange
What is unidirectional flow?
Medium enters at one point and exits via another
What is countercurrent flow?
Blood and water flow in opposite directions
What would happen with oxygen if blood and water are flowing in the same direction?
If the flow was concurrent, the diffusion gradient is not as efficient or disappears, which means no oxygen flow.
How does climbing perch breathe on land?
They have an accessory air-breathing organ that allows them to survive out of water for several days in moist conditions.
Describe spiracular breathing.
Tracheal system opens to air via spiracles which lead into the trachea internally to contact hemolymph
Describe the unidirectional flow in spiracular breathing.
From spiracles to abdomen and then out through different set of spiracles
What are the functions of spiracles?
Control air flow into trachea, control water loss and keeps dust out
Why can insects increase the rate of gas exchange?
Their tips of tracheoles are filled with fluid and in active tissues, fluid is replaced by air (via osmosis to tissues).
What flow is the ventilation in birds?
Unidirectional flow
How many cycles of inhalation and exhalation for each breath of air do birds do?
Two complete cycles of inhalation and exhalation for each breath of air.
What is the ventilatory surface of birds?
Lungs (parabronchi)
What are parabronchi?
Any of very many small air passages (air capillaries) in the lungs of birds
Why do birds have cross-current exchange?
Because their capillaries are perpendicular to parabronchi
What is tidal flow?
Medium enters and exits a chamber
State Dalton’s law about total pressure.
Total pressure is the sum of all the partial pressures of gaseous mixture
What are Boyle’s laws?
- Gases move from areas of high pressure to areas of low pressure
- The pressure of a gas is inversely proportional to the volume of its container
What is Henry’s law?
The partial pressure of oxygen or carbon dioxide is directly proportional to the concentration of these gases in blood
What are the three types of pressure pulmonary ventilation depending on?
Atmospheric, intra-alveolar, and intrapleural
What is intra-alveolar pressure?
Also known as intrapulmonary pressure; this is the pressure of the air within alveoli, which changes during different phases of breathing
What is intrapleural pressure?
The pressure of air within the pleural cavity, between the visceral and parietal pleurae.
What is the relationship between intrapleural pressure to intra-alveolar pressure?
Intrapleural pressure is always lower than, or negative to, the intra-alveolar pressure (and therefore, also to atmospheric pressure.
What is the purpose of intrapleural pressure?
It ensures that the lungs stay closely connected to thoracic wall and follow its movements during a breath cycle.
What happens during inhalation?
Diaphragm contracts, lung volume increases causing pressure to be more negative and allowing air to flow in
What happens during exhalation?
Diaphragm and rib muscles relax, lung volume decreases and pressure is less negative allowing air to flow out.
What is the function of red blood cells?
They carry oxygen from the lungs to the tissues
True or false? Red blood cell is not flexible and cannot pass through extremely small blood vessels.
False.
Describe the red blood cells.
It is covered with a membrane composed of lipids and proteins, lacks a nucleus, and contains hemoglobin
What is hemoglobin?
A red, iron-rich protein that binds oxygen
What are respiratory pigments?
They are metalloproteins which circulate in body fluids and undergo reversible chemical combinations with oxygen
What are the two examples of respiratory pigments?
Hemoglobin and hemocyanin
What is it called when O2 binds with hemoglobin?
Oxyhemoglobin
What is it called when O2 binds with hemoglobin?
Carbaminohemoglobin
How do oxyhemoglobin and carbaminohemoglobin in colour?
Oxyhemoglobin: bright-red coloured
Carbaminohemoglobin: burgundy coloured
How many heme units is each Hb molecule?
Each Hb molecule is 4 heme units
What does each heme has in its center?
Iron
How many oxygen molecules can each hemoglobin hold? Explain.
4 oxygen molecules since each HB molecule has 4 heme units with iron in the center and oxygen molecules reversibly with iron.
What is external respiration?
It is the exchange of gases from external environment to the circulatory media which occurs across the respiratory surfaces.
What is the partial pressure of oxygen in alveoli and in blood?
Alveoli: 104 mm Hg
Blood: 40 mm Hg
What is internal respiration?
The gas exchange that occurs at the level of body tissues
What does the oxygen dissociation curve show?
It shows how the hemoglobin saturation with oxygen is related to the partial pressure of oxygen in the blood.
True or false? The O2 capacity of blood decreases with the amount of hemoglobin in the blood.
False, it increases.
What is the sigmoid shape in oxygen-dissociation curve due to?
To the subunit cooperativity
What is subunit cooperativity?
The oxygenation of the first heme group facilitates the oxygenation of the others.
What happens as Hb molecule is oxygenated?
It undergoes conformational changes from a tense (T) state to relaxed (R) state
What does it mean pO2 is 0 in O2 dissociation curve?
No O2 bound to respiratory pigment hemoglobin (Hb)
What happens as pO2 increases in O2 dissociation curve?
More O2 bound to respiratory pigment Hb until all Hb are fully bound to O2
What is p50?
The O2 partial pressure at which 50% oxygen saturation is attained
What does a shift to the right mean?
The O2 partial pressure needed to saturate is higher, p50 is higher and O2 affinity is lower.
What is Bohr effect?
It is a decrease in the amount of O2 bound to Hb in response to a lowered blood pH resulting from an increase in CO2
When does a decrease in pH happen?
When there is an increase in H+
When does an increase in H+ happen?
When CO2 reduces O2 affinity of Hb
What affects hemoglobin-oxygen affinity?
By changes in partial pressure of oxygen, temperature, partial pressure of carbon dioxide, pH, and organophosphates.
What causes the shift to the left and right in an oxygen dissociation curve?
Shift to the left: Decreased temperature, and decreased partial pressure of carbon dioxide
Shift to the right: Increased temperature and increased partial pressure of carbon dioxide
What happens to CO2 when it is transported from tissue to blood?
10% dissolved in plasma, 30% binds to hemoglobin, and 60% converted to HCO3
True or false? Carbon dioxide is more soluble in fluid than oxygen
True
What part of hemoglobin does CO2 bind to?
Not to the heme group, but with the protein part to form carbaminohemoglobin.
True or false? The sum of all forms of CO2 in the blood is not the total CO2 in the blood.
False. The sum of all forms of CO2 in the blood is the total CO2 content of the blood.
What is the simplest type of circulatory system?
Open circulatory system
What happens in circulatory fluid in an open circulatory system?
It does not flow in vessels but rather it bathes each of the body cells in body cavity.
Is open circulatory system more or less efficient at distributing nutrients?
Tend to be less efficient at distributing nutrients but require less energy to maintain
