Body Systems L21 Notes Flashcards
What are the two types of breathing control?
Subconscious
Conscious
Give an example of when subconscious breathing occurs
- Subconscious
» Until something goes wrong
-> Dyspnea Eg. High altitude
Give an example of when conscious breathing occurs
- Conscious
|»_space; Scuba diving, partners -> Snorers.
What are the tasks of breathing control?
- Establish automatic rhythm
- Adjust rhythm -> Accommodate
- > Metabolic
- > Mechanical
- > Episodic Non-Ventilatory Behaviours
Give examples of -> Metabolic -> Mechanical -> Episodic Non-Ventilatory Behaviours changes which need to be accommodated by breathing control
Metabolic >> Arterial Blood gases & pH Mechanical >> Postural changes Episodic Non-ventilatory Behaviours >> Speaking, sniffing, eating etc.
Describe the normal rates of O2 absorption as a result of breathing control
- Rates:
O2:
»_space; Rate -> absorption matched to delivery
Describe the normal rates of CO2 absorption as a result of breathing control
CO2:
|»_space; Rate -> generation matched to removal.
Describe the two conditions involved in maintenance of balance in regards to breathing control
- Maintenance -> Balance:
Local:
» Changes -> Blood flow & oxygen delivery
Central:
» Changes -> Depth & rate of respiration
What are local factors involved in maintenance of balance of breathing control?
Local:
|»_space; Changes -> Blood flow & oxygen delivery
What are central factors involved in maintenance of balance of breathing control?
Central:
|»_space; Changes -> Depth & rate of respiration
What are the two complexities regarding the control of breathing?
- Complexities:
No single pacemaker generating basic breathing rhythm
No single muscle devoted -> pumping of air
What three locations are involved in local control of gas transport?
Active tissue
Lung perfusion
Alveolar ventilation
Describe local control of gas transport in active tissue
- P(O2) & P(CO2) -> Active Tissue
- Incr. P(CO2)
Vasodilation
»_space;Incr. Blood Flow
i) Decr. P(O2)
»_space; Incr. Delivery -> O2
ii) Incr. Removal -> CO2
Describe local control of gas transport in lung perfusion
- Lung Perfusion:
- Decr. P(O2)
Vasoconstriction
»_space; Decr. Blood Flow
Directs blood -> Areas of higher P(O2)
Describe local control of gas transport in alveolar ventilation
- Alveolar Ventilation:
- Incr. P(O2)
Bronchodilation
»_space; Incr. Air Flow
Directs airflow -> Areas of higher P(CO2)
»_space; Improves efficiency -> Gas transport
What are the aims of the central control of ventilation?
Aims -> Maintenance of arterial P(CO2) & P(O2)
Describe the process of central control of ventilation
• Central Control -> Ventilation: Aims -> Maintenance of arterial P(CO2) & P(O2) 1. -> Detection >> Change -> arterial P(CO2) & P(O2) Central & Peripheral Chemoreceptors Mechanoreceptors 2. Send impulses / signals -> Central Controller Respiratory Centres >> Pons >> Medulla 3. Send impulses / signals -> Effectors >> Muscles of Ventilation Initiate change
Name the major types of receptors involved in control of breathing
Central Chemoreceptors
Peripheral Chemoreceptors
Mechanoreceptors
Describe the effects of the central chemoreceptors
1. Central chemoreceptors >> Medulla Change -> pH Hypercapnia No effect of hypoxia
Where are the central chemoreceptors located?
- Central Chemoreceptors:
Location:
Just beneath ventral surface of medulla
»_space; Close -> Entry of VIII & XI cranial nerves
What are the central chemoreceptors stimulated by?
Stimulated
Acidic pH / High P(CO2) -> within CSF
Describe the response of the central chemoreceptors to incr. P(CO2)
Incr. P(CO2)
Decr. pH
» Incr. ventilation
> Decr, P(CO2)
Describe the response of the central chemoreceptors to CO2 passing the blood-brain barrier
CO2 crosses blood-brain barrier
» Lipid soluble
Decr. pH -> CSF
( CSF weakly buffered )
Describe the response of the central chemoreceptors to decr. O2
Decr. O2
|»_space; No effect -> Central chemoreceptors
Describe the effects of the peripheral chemoreceptors
2. Peripheral chemoreceptors >> Aortic & carotid body Hypoxia Hypercapnia Change -> pH
Where are the peripheral chemoreceptors located?
Location:
Outside Brain
Name the components of the peripheral chemoreceptors
Carotid body
Aortic bodies
Describe the location of the carotid body of the peripheral chemoreceptors
Bifurcation of carotid arteries
Describe the location of the aortic bodies of the peripheral chemoreceptors
Above & Below aortic arch