random facts Flashcards
(29 cards)
path from nose to pharynx
external nares> nasal cavity > internal nares > pharynx
pharynx is divided into:
nasopharynx (air), oropharynx (food and air), laryngopharynx (food and air)
respiratory membrane:
allows gases to cross by simple diffusion, allows oxygen to be picked up by blood for transport and for carbon dioxide to be released into the air of the alveoli
each lung is enclosed and surrounded by a :
serous membrane called pleura
pleura consists of two layers
- visceral pleura- superficial to the lungs
- parietal pleura- outer layer that connects thoracic wall and diaphragm
pleural cavity is the…
space between the visceral pleura and the parietal pleura
pleura perform two functions:
- provide pleural fluid
- create cavities separating major organs
major mechanisms that drive pulmonary ventilation are:
- atmospheric pressure
- intra-alveolar pressure
- intra-pleural pressure
what is intra-pleural pressure?
it is the pressure within the pleural cavity- between the visceral pleura and the parietal pleura. (always remains below/negative to the intra-alveolar pressure)
describe Boyle’s law of gases
that gases in a confined space at a constant temperature - volume increases and pressure decreases and vise versa
what two muscle groups are involved in an inspiration?
diaphragm and external intercostal muscles
how does expiration occur?
passive; no energy required. Diaphragm and external intercostal muscles relax and creates higher intra-alveolar pressure than atmospheric pressure, lower volume= air removed to equalize with atmospheric pressure
major brain centres involved in pulmonary ventilation?
medulla oblongata and pontine respiratory group
medulla oblongata contains the…
dorsal respiratory group, ventral respiratory group
role of dorsal respiratory group?
constant, quiet breathing rhythm. stimulates diaphragm and external intercostal muscles to contract, resulting in inhalation. When these muscles relax, = exhalationo
role of ventral respiratory group?
stimulates the muscles involved in forced breathing to contract
pontine respiratory group located within:
pons
pontine respiratory group includes:
apneustic and pneumotaxic centre
what does apneustic centre do?
double cluster of neuronal cell bodies; stimulation of neurons in the Dorsal respiratory group, controlling mainly deep breathing
what does pneumotaxic centre do?
inhibits the dorsal respiratory group neurons, causing exhalation by allowing for exhaling and overall controlling heart rate
what happens when CO2 in blood is high?
-increased [CO2] diffuses across blood brain membrane into extracellular fluid.
- converted to carbonic acid which diffuses into extra H ions
- increase in H ions signals chemoreceptors to speed up heart rate and breathing rate by signalling diaphragm and internal costal muscles to expel excess CO2
what happens if low [CO2] in blood?
leads to low [CO2] in the brain which means less [H ] ions, causing slower pulmonary ventilation resulting in slower and shallower breathing
what is alveolar dead space?
air in alveoli that is unable to be used due to infection or lack of blood flow
what is total dead space?
represents all the air in respiratory system that is unable to be used for gas exchange (anatomical dead space + alveolar dead space)
