lecture 8 (respiratory) Flashcards
(20 cards)
what occurs during excersize?
- ventilation increases as intensity of excersize increases
- blood flow to face increases
- heart rate increases
- lactic acid generation in high levels of excersize
- warmth
what are the mechanics of breathing?
- inspiration:
external intercostal lift ribcage up and out
diaphragm moves down and flattens
what’s the first phase in ventilation?
- vigorous excersize
- abrupt change
what is the next phase?
- match the energy requirement or usage with demand
- attempt to reach steady state
how is ventilation stimulated?
- pneumotaxic and apneustic centres in Pons detect
- work through dorsal respiratory group
- act through diaphragm and intercostal muscles
what does the pneumotaxic centre do?
- coordinate ventilation
what does the apneustic centre do?
- control rate and depth of ventilation
- can override the pneumotaxic centre
why does the abrupt increase in ventilation occur?
- central command response
- instant response needed to allow match in ventilation
what does an increase in speed of excersize cause?
- greater increase in minute ventilation than increase in gradient does
what occurs with frequency vs load experiment?
- fluctuates (increases and decreases)
- increasing power output = minute ventilation follows same pattern
- lag for increasing then lag for decreasing
- co2 output similar for both
what mechanisms causes increase in ventilation?
- matching demand for oxygen
- central and peripheral chemoreceptors
- changing partial pressure of CO2 in blood affecting ventilation rate
what is active in the steady state?
- central and peripheral chemoreceptors
- fine tuning to meet demand
what is the cause of the abrupt reduction due to stopping excersize?
- takes away central command input
- slower level of reduction back to resting levels (takes time)
what occurs to oxygen levels throughout excertion?
- levels dont tend to change much
what occurs to co2 levels throughout exertion?
- reduction as maximal exertion occurs
what are the controls of ventilation?
- maintaining Po2
- changes in co2
what causes changes in CO2 levels in blood?
- increasing hydrogen ion conc so decreasing pH
- reducing ventilation rate
- higher levels of CO2
what are the chemical controls of ventilation?
- minute ventilation increasing
- rapidly produce lactic acid
- increasing ventilation rate further
- allows balancing of pH in blood
what are the effects seen when training occurs?
- increased mitochondria
- increased muscle size
what does the hypothalamus control?
- increase in body temperature
- thermoregulation
- stimulates sweating and panting
