Control of Breathing: Lecture 3 Flashcards
If we hae an unchanged/equal metabolic rate and we pick up our breathing what will happed?
hyperventalating aka breathing to much
- O2 will increase
- CO2 will decrease
if the ventilation is unchanged/equal and we increase metabolic rate without picking up our breathing what will happen?
hypoventilation aka not breathing enough
- O2 will decrease
- CO2 will increase
What will happen to O2 and CO2 when we increase metabolic rate and pick up our breathing aka increase ventilation?
O2 and CO2 will remain steady
Where is breathing generated?
level of the medulla, in the brain stem
What are the 2 groups in the medullary respiratory centre called?
- Dorsal respiratory group (DRG)
- Ventral respiratory group (VRG)
What kind of neurons do the dorsal respiratory group and the ventral respiratory group both control?
Inspiratory neurons
Which respiratory group controls expiratory neurons?
ventral respiratory group
Why do we need more neurons for inspiration?
because we have to activate our inspiratory muscles, we need to tell the diaphragm what to do via the phrenic nerve
Where is the Pre-Botzinger complex?
within the medulla
What does the Pre-Botzinger complex do?
generates the respiratory rhythm
- size and frequency of the breath
What are the 3 types of receptors that control the respiratory pattern?
- Mechanoreceptors
- Metaboreceptors
- Pulmonary receptors
What do mechanoreceptors do?
detect changes in pressure or displacment of a structure and sends this information to the medulla
What are examples of changes that the mechanoreceptos would pick up on?
- lung and chest wall
- peripheral muscles
What do metaborcepetors do?
detect local changes in metabolic byproduct concentration and sends this information to the medulla
What are examples of changes that the metaborcepetors would pick up on?
- changes in lactate or hydropgen
What do pulmonary receptors do?
dectects chnage in the strecth of the lung
What are chemical controls/chemoreceptors?
sense fluxations of O2 and CO2 in the blood to maintain our breathing
What are the 2 types of chemoreceptors?
- Peripheral receptors
- Central Medullary receptors
What are the 2 peripheral chemoreceptors?
- Carotid
- Aortic
True or False
The carotid and aortic chemoreceptors both respond to changes in the arterial blood gas concentration or partial pressures and send signals to the medulla
True
Which body plays a larger role and is more sensitive?
carotid
True or False
The carotid body is much more dominant, aka its more important
True
The peripheral carotid chemoreceptor is predominantly for a sensor for what?
Oxygen
How much can we increase and decrease PO2 with almost no change in our minute ventilation?
+20 or -40 mmhg of PO2
When would the carotid peropheral chemoreceptor become active?
after the arterial PO2 reaches about 60 or lower, sending a signal to increase our breathing
True or False
When the PaO2 decreases the receptors increase their rate of discharge
True
True or False
When the rate of firing (excitatory stimuli) increases our ventilation increases, meaning what exactly?
True, meaning increased ventilation is directly proportional to ventilation
What kind of feedback is being used with the peripheral chemoreceptors?
Negative feedback, bring us back to breathing aka back to homeostasis
If we have an increase of H+, can that also stimulate the carotid chemoreceptor?
yessir
What are the 2 scenarios where there is an increase of H+ in the cell?
- Diarrhea
- loss of lactic acid or HCO3- - Maximal exercise
- where H* exceeds HCO3- buffering capacity
Where are central chemoreceptors located?
in the medulla
What do central chemoreceptors do?
- sense changes within the brain’s extracellular fluid or the cerebral spinal fluid
- respond to changes of H+ (pH) in the medulla
Can hydrogen pass the blood-brain barrier?
no, not alone as a hydrogen moelcule
Can carbon dioxide pass the blood-brain barrier?
yes, it can
When the cerebrospinal fluid senses hydrogen where is the hydrogen coming from?
it is the hydrogen from the arterial CO2
The CO2 in the blood leads to increased what?
ventilation via the bicarbonate equilibrium
The central chemoreceptors respond to what?
CO2 fluctuations, via an increased Hydrogen in the cerebral spinal fluid
Low O2 is sensed by which sensors?
carotid peripheral chemoreceptors
High CO2 is sensed by which sensors?
central chemoreceptors
