(B2) Ventilation and Gas Exchange in the Lungs Flashcards
What system are the lungs a part of?
The respiratory system
Where do most living organisms gain their energy from?
Aerobic respiration
What does aerobic respiration produce?
ATP
Equation of Respiration
Oxygen + Glucose –> Carbon Dioxide + Water + Energy (ATP)
Where does respiration take place?
Mitochondria
What is ventilation?
Breathing
What is inhalation?
Drawing air in
What is exhalation?
Pushing air out
What is the difference between breathing and respiration?
Breathing is the process of inhaling and exhaling air whilst respiration is a chemical process that takes place in the cell which breaks down glucose to create energy
Parts of the Lungs
- Nose
- Mouth
- Larynx and Pharynx
- Lungs
- Diaphragm
- Trachea
- Right and Left Bronchus
- Bronchiole
- Alveoli
Role of the Nose
The nose is where the respiratory system starts, and it helps breathing using the hairs and mucus to stop large air impurities from entering the respiratory system
Role of the Mouth
A secondary inhaler and exhaler
Role of the Pharynx
Connects the nose and mouth to the larynx, separating the pathway from the digestive system from the lungs
Functions of the Larynx
1) A passageway for air
2) As a valve to close off the air passageway from the digestive system
3) As a voice box
Role of the Trachea
A tube which allows to pass beyond the larynx to the left and right bronchus
What is the chest (thoracic) cavity?
The space in your chest that contains the lungs, heart and trachea
What is the diaphragm?
a large, dome-shaped muscle which is the main muscle of respiration that contracts
Function of the diaphragm
To help expand and contract the lungs, forcing air in and out
Function of the Lungs
To exchange carbon dioxide for oxygen and each lung is enclosed off separately within two membranes like a ballon inside a bag which is inside another bag
Left Bronchi
A passageway for air to reach the lungs, the left bronchus has a sharper bend than the right bronchus due to the presence of the heart and major blood vessel below it
Right Bronchi
A passageway for air to reach the lungs
Bronchioles
Each bronchus subdivides and then subdivides again into smaller and smaller branches to make the bronchioles
*like tree branches
Role of the bronchioles
To deliver air that has been warmed to body temperature, moistured and filtered to the alveoli
What is alveoli?
Tiny air sacs which are the “leaves” of the respiratory system, they are at the end of the bronchioles
Role of the alveoli
Where gas exchange occurs (fresh oxygen, O2 is exchanged for carbon dioxide, CO2)
What are the alveoli surrounded by?
Capillaries
Why are the alveoli surrounded by capillaries?
For faster diffusion
What are intercostal muscles?
Muscles on the ribcage that contract and relax to push air in and out of the lungs
What happens to the diaphragm during inspiration?
Contracts, flattens and moves down
What happens to the diaphragm during expiration?
Relaxes, forms a dome (pushed by the organs beneath)
What happens to the intercostal muscles during inspiration?
Contracts, pulling the ribcage upwards and outwards
What happens to the intercostal muscles during expiration?
Relaxes to let the ribcage fall downwards and inwards
What happens to the volume of the chest cavity during inspiration?
Increases
What happens to the volume of the chest cavity during expiration?
Decreases
What happens to the pressure of the chest cavity during inspiration?
Decreases below atmospheric/air pressure
What happens to the pressure of the chest cavity during expiration?
Increases above atmospheric/air pressure
What is the end result of inspiration?
Air moves into the lungs, down the pressure gradient
What is the end result of expiration?
Air moves out of the lungs, down the pressure gradient
Structure of the trachea and bronchus (left and right)
- Lined with ciliated (hairy) epithelium
- Supported by c shaped rings of cartilage
- Interspersed with goblet cells to secrete mucus
Structure of the bronchioles
- Smooth muscles tissues to contract and restrict the airways
- Elastic fibres
How is diffusion in the alveoli maximised?
- Large surface areas
- The wall of alveoli is 1 cell thick to minimize distance
- Moist alveoli walls to maximize dissolved gases
- Capillaries are close and surround the alveoli, blood is constantly flowing there so to maintain the concentration gradient between the alveoli and the capillary
What is diffusion (concentration) gradient?
A concentration gradient exists when there is a region of high concentration leading to a region of low concentration.
In the alveoli a gradient is maintained between the concentration of oxygen in the alveoli and the concentration of oxygen in the lung capillaries
What is the pleural membrane?
Two layers of serous membrane which enclose and protect the lungs
Role of the Plural Membrane
Provides protection and a smooth, lubricating elastic surface for the lungs to move during breathing
What is a spirometer?
An apparatus that measures the breathing rate
How does a spirometer work?
When someone breathes out into the tank the mobile upper half which is full of oxygen will rise and when someone breathes in from the tank the static lower half which is full of water will fall.
A trace marker is attached to the mobile upper half
What is the tidal volume?
The amount of air moving in and out of the lungs during the resting breathing rate
What is the inspiratory reserve volume?
How much extra air that can be breathed in during forced inspiration
What is the expiratory reserve volume?
How much extra air that can be breathed out during forced expiration
What is residual volume?
The volume of air that remains in the lungs even after maximum respiration
What is vital capacity?
The largest possible volume change in the lungs (from maximum inspiration to maximum expiration
What is the total lung capacity?
Residual volume + vital capacity, the maximum capacity of the lungs
Why does the rate of oxygen consumption increase during excercise?
There is a need for more energy so there is more respiration in the mitochondria. There is also a need to get rid of lactic acid.
