Physiology of Respiratory System Flashcards
Where are central chemoreceptors located
Ventral surface of medulla
What is the function of central chemoreceptors
primarily sense pH changes in the central nervous system caused by alterations in arterial CO2
Chemoreceptors respond to reduced pH by sending sensory input to brain to stimulate hyperventilation
Where is the respiratory centre located
located in lower brain/upper brainstem
What does the medulla do
Sends signals to muscles
Ventral group stimulates expiratory movement
Dorsal group stimulates inspiratory movement
What does the Apneustic centre do
Sends signals for inspiration for long and deep breaths, controls intensity of breathing
Pneumotaxic centre function?
Inhibits inspiration to finely control respiratory rate
What are the three nerves involved in respiration and what do they do
Phrenic: stimulates diaphragm
Vagus: innervates diaphragm, larynx and pharynx
Posterior Thoracic nerve: stimulate intercoastal muscles around the pleura
What is the motor cortex responsible for
Responsible for initiating any voluntary muscular movement
Main functions of respiratory system
Exchange of O2 and CO2 between air and blood
Keeping body pH stable
Protection from harmful substances
Vocalisation
How does breathing occur
Volume of the thoracic cavity changes with the contraction and relaxation of muscles
The volume of lungs changes according to the thoracic cavity, which causes a change in the pressure of the lungs
Air diffuses from an area of high partial pressure to an area of low partial pressure
How does inspiration occur
air diffuses into lungs when atmospheric pressure is greater than intrapulmonary pressure
mechanism of inspiration
Diaphragm and intercostal muscles contracts
Thoracic cavity increases in size
Lung volume increases
Intrapulmonary pressure less than atmospheric pressure
Air diffuses from environment into the lung tissues via the bronchial tree, down the pressure gradient
HOW DOES EXPIRATION OCCUR
air to diffuse out of the lungs into the environment
intrapulmonary pressure > atmospheric pressure
mechanism for expiration
Diaphragm and intercostal muscle relaxes
Thoracic cavity decreases in size
Lung volume decreases
Intrapulmonary pressure > atmospheric pressure
Air (CO2) diffuses from the lung tissues into the environment down the pressure gradient
Muscles involved inactive inspiration
Scalenes Sternocleidomastoid Lasttissimus dorsi Serratus anterior Pectoralis minor
