chapter 15 quiz #2 Flashcards
What is the respiratory control centre?
The medulla oblongata
What is the role of the respiratory control centre?
Send signals to muscles that cause breathing to occur.
What are the two regions in the medulla that control breathing?
The ventral respiratory group and the dorsal respiratory group.
What does the ventral respiratory group control?
Expiratory breathing movements
What does the dorsal respiratory group control?
Inspiratory breathing movements.
Other than expiration and inhalation, what air movements does the medulla oblongata control?
- Coughing
- Sneezing
- Swallowing
- Vomiting
What controls the respiratory rate?
The pons, under the medulla oblongata
Why does inspiration occur?
Increased firing in inspiratory nerves (phrenic and intercostal) and an increase of motor units to intercostal and diaphragm muscles causing contraction.
Why does expiration occur?
Impulses along inspiratory nerves cease.
What is the pleura?
The thin membrane between the rib cage and the lungs which helps the two slide against each other.
Where are the lungs located?
Within the sealed thoracic cavity.
In the respiratory system, where is there a continuous column of air?
From the pharynx to the alveoli in the lungs.
What sends signals via the vagus nerve for the respiratory centre to stop inhalation impulses?
Stretch receptors in the alveoli walls.
What does the respiration centre detect?
Whether lungs are full or empty, to activate phrenic nerve to stimulate diaphragm .
What elements stimulate activity in the respiratory centre?
CO2 and H+, not oxygen
What is a carotid?
In arteries that carry blood to head and neck.
What is the carotid sensitive to?
H+, CO2 and O2 levels in blood.
What are the aortic bodies sensitive to?
Blood O2 and CO2 levels, pH of blood.
What is a chemoreceptor?
A sensitive cell responsive to chemical stimuli.
What are the two types of chemoreceptors?
Central: in medulla oblongata. Peripheral: carotid and aortic bodies.
What is the role of the central chemoreceptors?
Sensitive to pH of environment.
If the aortic bodies sense low oxygen concentration, what happens?
Breathing becomes faster and deeper.
What happens when there are higher concentrations of CO2 and H+ in blood?
Breathing becomes faster and deeper.
What cells influence respiration rate?
Carotid and aortic bodies.
What is the order of nerves from respiratory centre to throat?
Respiratory centre (medulla oblongata), phrenic nerve, intercostal muscle/diaphragm, alveoli stretch receptors, vagus nerve.
What directions do the phrenic and vagus nerves go?
Phrenic: from brain, vagus: to the brain.
What is the role of the phrenic nerve?
Contracts muscles for breathing.
What is the role of the vagus nerve?
Relaxes muscles for breathing.
What is the formula for Carbaminohemoglobin?
HbCO2
What is the role of HbCO2 and percentage CO2?
Carrier of CO2 in blood, 10%
What is the formula for oxyhemoglobin?
HbO2
What is the role of HbO2 and percentage O2
Main carrier of O2 in blood, 2.95%
What is the formula for reduced hemoglobin?
HbH
What is the role of HbH?
Formed when Hb picks up excess H+ ions in blood.
What is the formula for bicarbonate ion?
HCO3
What is the role of HCO3 cand percentage of CO2
Main carrier of CO2, 85%
5% of CO2 and 5% of O2 in blood is found where?
plasma
Where does H+ in blood come from?
Dissociation of H2CO3 (carbonic acid).
What do you call the exchange of gases between air in alveoli and blood in pulmonary capillaries?
External respiration.
Describe external respiration in lungs?
CO2 leaves blood, O2 enters blood.
What are the 4 chemical equations for external respiration?
Hb + O2 → HbO2
HbCO2 → Hb + CO2
HCO3- + H+ → H2CO3 →(carbonic anhydrase)→ H2O + CO2
HbH → Hb + H+
What is the role of carbonic anhydrase?
Speeds up breakdown of carbonic acid.
When do hemoglobin have a higher affinity for O2?
In lower temp
How does CO2 leave blood?
carried in plasma as HCO3, diffuses into lungs
How does O2 enter blood?
O2 diffuses from lungs to plasma and then to RBC
What do you call the exchange of gas between blood in systemic capillaries and the tissue fluid?
Internal respiration
What happens in the internal respiration of the tissue?
O2 leaves blood, CO2 enters blood.
What are the 4 chemical equations for internal respiration?
- HbO2 → Hb + O2
- Hb + CO2 → HbCO2
- CO2 + H2O →(carbonic anhydrase)→ H2C03 → HCO3- + H+
- Hb + H+ → HbH
How does CO2 enter blood in the tissues?
Combines with hemoglobin or combines with water in plasma to form carbonic acid H2C03 which dissociates to H+ and HCO3
Why does O2 enter tissues?
Because they have a higher temperature so Hb connects to it less
