Respiration 1 Flashcards
What is internal respiration?
Cellular processes within the cells
What is external respiration?
Ventilation
Exchange and transport
What mechanism of transport does respiration rely on?
Diffusion (high to low conc)
Which side of the respiratory system is under high pressure?
Left
What is pulmonary diffusion?
Exchange of gases within the lungs
Describe the overall respiratory system
O2 moves down a conc gradient into the blood ->
O2 binds to haemoglobin ->
Oxyhaemoglobin is pumped round systemic circulation ->
O2 moves down conc gradient into capillary membrane and tissues ->
CO2 is carried into the blood as a bicarbonate to the right side of the heart
What are the 2 sections of the lungs?
The conducting zone
The respiratory zone
What is in the conducting zone?
Nose
Nasopharynx
(Mouth) Oropharynx
Pharynx
Larynx
Trachea
Bronchial Tree
What is in the respiratory zone?
Alveolar ducts and sacs
Alveolar air spaces
What is the function of the conducting zone?
Filtering
Warming
Humidifying
Describe the structure of bronchial wall
Reinforced with rings of cartilage
Smooth muscle around the lumen
Epithelial cell layer
Goblet cells
Mucus glands
Elastic tissue in walls of airways
What is the respiratory epithelium composed of?
Ciliated epithelia
Goblet cells
Sensory nerve endings
Where does the respiratory epithelium end?
At the alveolar ducts
Function of nerve endings in the respiratory epithelium
Identify noxious substances
Describe the structure of bronchioles
Thick smooth muscle
Lack cartilage
Lined by respiratory epithelium
Describe the structure of alveoli
Large surface area
Extremely thin walls
In close arrangement of capillary network
What is the air blood barrier?
A ‘sandwich’ created by flattened cytoplasm of type 1 pneumocyte and the capillary wall
What is the function of a type 1 pneumocyte?
The site for gas exchange
What is the function of a type 2 pneumocyte?
Responsible for production of surfactant
What are the 2 ventilation processes?
Inspiration
Expiration
What is the pressure gradient during inspiration?
P atmos > P alv
What is the pressure gradient during expiration?
P alv > P atmos
What is quiet inspiration?
Involving the primary muscles of inspiration (diaphragm and external intercostal muscles)
- Increases thoracic and lung volume
Explain Boyle’s law
Increase in volume = reduction in pressure
What is forced inspiration?
Accessory muscles are used
Scalene in neck contracts and pulls the sternum and ribcage up and out causing chest expansion
What type of process is quiet expiration?
Passive process using elastic recoil
What type of process is forced expiration?
An active process where internal intercostal muscles contract the ribcage
What is the function of the Pleura?
Prevents lungs from sticking to chest wall
Enables free expansion and collapse of lungs
Where is the first pleural membrane?
Outside the lungs
Where is the second pleural membrane?
Lines inside the chest wall
What is the pressure in a pleural membrane?
Slightly subatmostpheric to allow lungs to expand
What happens to the lungs at rest?
Inward and outward forces balance
Lungs have an inward space which pulls inner membrane forwards
Chest wall expands outwardly
What causes pneumothorax (collapsed lung)?
Imbalance of pressures
Air can enter intrapleural space so outward effect is lost and elastic nature of lungs takes over
