The Respiratory System - Part 2 Flashcards
Define external respiration
gas exchange in the lungs
Define internal respiration
gas exchange in the rest of the body
What happens during external respiration?
oxygen diffuses from alveoli into blood and CO2 diffuses from blood into alveoli
What happens during internal respiration?
oxygen diffuses from blood into body tissues and CO2 diffuses from body tissues into blood
What happens during quiet respiration?
diaphragm contracts which flattens it and increases thoracic volume
What happens during quiet expiration?
no muscle contraction, decreases thoracic volume
What happens during forced inspiration?
pulls ribs up, uses extenal intercostal muscles
What happens during forced expiration?
uses internal intercostal muscles and pulls ribs down
Define atmospheric pressure
pressure from the atmosphere (760 mmHg)
Define intrapulmonary pressure
pressure inside lungs, changes with phases of breathing
What happens when intrapulmonary pressure is slightly higher than atmospheric pressure?
air will leave lungs
Define intrapleural pressure
pressure between visceral and parietal pleura, always negative making sure these two stay together
What is Boyle’s law?
pressure of gas is inversely proportional to volume
Describe the relationship between intrathoracic volume and intrapulmonary pressure during inspiration
volume increases as pressure decreases
Describe the relationship between volume and pressure during expiration
volume decreases as pressure increases
Define flow
change in pressure divided by resistance
What factors affect pulmonary ventilation?
changes in pressure and resistance, lumg compliance, and pulmonary surfactant and alveolar surface tension
Define pulmonary ventilation
amount of air going into lungs when breathing
Describe the relationship between pressure and flow
increased pressure = increased flow
Describe the relationship between resistance and flow
increased resistance caused decreased flow and vice versa
If the diameter of the bronchioles decreases then…
there is a higher resistance to inflow of air
Define lung compliance
the ease with which the lungs expand
What are the factors that decrease lung compliance?
- decreased surfactant
- lung disease decreasing elasticity
- chest wall deformity preventing lung expansion
Define alveolar surface tension
tension created at the alveolar membrane due to water molecules pulling toward each other
Surface tension increases as…
alveolar radius decreases (highest at end of expiration)
Describe negative intrapleural pressure and how it works
The pneumothorax (pleural space between visceral and parietal pleura) is forced together by negative pressure. If air gets into this space, the lung can collapse.
List the 6 respiratory volumes
tidal, inspiratory reserve, expiratory reserve, residual, total lung capacity, and vital capacity
Define spirometry
used to measure respiratory volumes
Define tidal volume
volume of air moved in and out of lungs during normal breathing (500 mL)
Define inspiratory reserve volume
volume of air that can be inhaled beyond normal resting tidal inhalation (3200 mL TV)
Define expiratory reserve volume
volume of air that can be exhaled beyond normal resting tidal exhalation (1200 mL)
Define residual volume
volume of air left in lungs after maximal expiration (1200 mL)
Define lung capacity
total amount of air in lungs during max inspiration (6000 mL)
Define vital capacity
total volume of air that you can control (4800 mL)
Define anatomical dead space
volume of air that fills the conducting zone and can’t undergo gas exchange
Define alveolar dead space
volume of air that fills the respiratory zone, but does not undergo gas exchange (this is very bad)
Define physiological dead space
anatomical dead space + alveolar dead space
What is Dalton’s law?
total pressure of gas mixture is equal to sum of partial pressures of its own individual gases
Describe the path of O2 once it leaves the alveoli
it goes into the blood and goes through the left atrium, left ventricle and into the tissues of the body
Describe the path of CO2 once it is created in the tissues
diffuses into the blood and into the right atrium and right ventricle to the lungs and goes into the alveoli. we then exhale the CO2
How is CO2 created in the body?
Created in the tissues when O2 is used to make ATP that then turns into CO2
List the alveolar partial pressure (external resp)
PO2=100 mmHg
PCO2=40 mmHg
List the blood in pulmonary capillaries partial pressure (external resp)
PO2= 40 mmHg
PCO2=45 mmHg
Describe the movement of pressure diffusion
goes from high to low pressure
List the 5 factors that affect gas movement
- partial pressure gradient
- solubility of gases
- membrane thickness
- surface area
- ventilation-perfusion coupling
Which is more soluble? CO2 or O2
CO2 is 20 times more
Define lung perfusion
proper blood flow through capillaries to alveolar tissue
Name the 3 parts of the respiratory membrane
- type 1 alveolar cells
- shared basement membrane
- capillary endothelium
Tissue partial pressure is…
PO2=40 mmHg
PCO2= 45 mmHg
Capillary partial pressure is…
PO2=100 mmHg
PCO2=40 mmHg
Define the Bohr effect
acidity created by CO2 weakens bond between Hb and O2, promotes O2 unloading
What does body temp do in relation to O2
promotes hemoglobin to release O2
What is the oxyhemoglobin dissociation curve?
shows what factors determine the rate at which hemoglobin releases oxygen
Name the two respiratory control centers
medulla oblongata and pons
What is the function of the medulla?
tells the diaphragm when to contract and relax
What is the function of the pons?
tells medulla when to tell the diaphragm what to do
What are the two groups the medullary rhythmicity center are divided into?
- Dorsal respiratory group
2. ventral respiratory group
Describe dorsal respiratory group
aka inspiratory center which contains inspiratory neurons. tells diaphragm to contract at regular intervals
Describe ventral respiratory group
aka expiratory center which contains both inspiratory and expiratory neurons. expiratory neurons stimulate internal intercostal muscles for forced expiration
What is a normal adult respiratory rate? Child’s?
12-18 / 30-60
What are the two respiratory centers in the pons?
- Apneutstic
2. Pneumotaxic
What is the function of the apneustic center?
promotes inspiration by stimulation of neurons in the medulla
What is the function of the pneumotaxic center?
ends inspiration by sending inhibitory impulse to inspiratory center in medulla
Name a neural stimuli to the respiratory centers
hypothalamic control
List the 3 chemical stimuli to the respiratory centers
Hypoxia, respiratory acidosis, respiratory alkalosis
Define hypoxia
severe decrease in PO2 which causes chemoreceptors to stimulate respiratory centers and increase ventilation
Define respiratory acidosis
decreased blood pH which causes increase in respiratory rate (RR) –this can happen from a person breathing too slowly causing more CO2, causing acidity
Define respiratory alkalosis
increased blood pH causes decrease in RR and happens when breathing too quickly
What are the central chemoreceptors in the brainstem sensitive to?
pH changes to CSF
What are peripheral chemoreceptors in carotid and aortic bodies sensitive to?
pH changes in blood
Define hyperventilation
increase in rate and depth of breathing
Hypoventilation
decrease in rate and depth of breathing
Apnea
temporary cessation in breathing
Define alveolar ventilation
exchange of gas between alveoli and external environment which happens during external respiration
Why is alveolar ventilation important?
determines the amount of oxygen in our blood and CO2 leaving our blood
