Respiration Flashcards
Why do we need to breathe?
- We need oxygen for cellular respiration which provides energy for cellular metabolism
- Carbon dioxide is a byproduct of cellular respiration but is waste
- The function of the respiration system is to take in oxygen and release carbon dioxide to the environment
What are the two main requirements for respiration?
- Large surface area: for a maximal oxygen and carbon dioxide exchange rate.
- Moist environment: to dissolve oxygen and carbon dioxide.
What are the different stages of respiration?
- Breathing: inspiration (inhaling) and expiration (exhaling)
- External respiration: exchange of gases between air and blood
- Internal respiration: exchange of gases blood and body tissues.
- Cellular respiration: energy releasing chemical reactions that take place within the cell.
What two muscles are used for breathing?
- Diaphragm
- Intercostal muscles
What are the mechanics of inhalation?
Muscles contract
- Rib cage up and outward
- Diaphragm downward
- Volume thoracic cavity increases
- Air pressure in lungs decreases
What are the mechanics of exhalation?
Muscles relax
- Rib cage down and inward
- Diaphragm upward
- Volume thoracic cavity decreases
- Air pressure in lungs increases
What happens to your breathing in the event of a punctured lung?
Creates equal pressure between the lungs and the outside environment, making it harder for air to move into lungs
What happens to your breathing at high altitudes?
The atmospheric pressure is lower and more equal to the pressure inside your lungs, making it harder for air to move in.
What is respiratory volume?
The volume of gas in the lungs at a given time during the respiratory cycle
What measures respiratory volume
A spirograph
What is a spirograph measured in?
volume per second (v/s)
What is external respiration?
The exchange of gases between the external environment and the body. Occurs between alveoli and capillaries (both of which have very thin walls)
What are the two processes of external respiration?
- Diffusion - the higher concentration of oxygen in air moves to capillaries, carrying oxygen poor blood
- Facilitated Diffusion - proteins embedded in alveoli cell membranes, moving with the concentration gradient, increasing the speed of respiration (process used 30% of the time)
What is internal respiration?
Internal respiration is the exchange of gases with the internal environment, and occurs in the tissues
Why is oxygen transported via hemoglobin instead of blood?
Because oxygen is not very soluble in blood
What is oxyhemoglobin?
An oxygen-carrying hemoglobin
How is oxygen exchanged throughout the body?
When the oxyhemoglobin is circulating through the body and passes a tissue requiring oxygen, the oxygen falls off and diffuses through the capillary wall into the tissue
How is Carbon dioxide produced in the body?
When muscles do work, they use oxygen and release CO2
How is CO2 exchanged throughout the body?
When there is a build up of carbon dioxide in the tissues, the carbon dioxide will move out of the tissues to the blood (lower partial pressure)
How do hemoglobin perform the CO2 exchange?
Hemoglobin binds to 23% of the body’s CO2 (forming carbaminohemoglobin) and carries it to the lungs, where the CO2 falls off and diffuses into the alveoli
How do bicarbonate ions perform the CO2 exchange?
CO2 combines with H2O in the plasma to form carbonic acid (H2CO3) which is very unstable and quickly breaks down to bicarbonate and hydrogen ions (HCO3- + H+). The hydrogen ions combine with hemoglobin and travel to the lungs whereas the bicarbonate ions are dissolved in blood and carried back to the lungs. At the lungs, H+ combines with HCO3-, reforming CO2 which diffuses in the alveoli Oxygen replaces H+ from the hemoglobin binding sites
What is the formula for internal respiration
HCO3- + H+ = H2CO3 = CO2 + H2O
What is a chemoreceptor?
Sensory receptors that detect certain chemical stimuli in the environment (oxygen and carbon dioxide are examples of chemical stimuli)
How is your breathing regulated when there is an excess of CO2 in your blood
Too much CO2 causes an increase the acidity of your blood, which is detected by chemoreceptors in the brain. The chemoreceptors then stimulate a nerve response to increase breathing in order to expel more carbon dioxide therefore decreasing acidity
