Module 3 Sedtion 1 - Ventilation In Mammals Flashcards
Ventilation consists of two stages…
Inspiration
Expiration
Inspiration and expiration are controlled by the movement of
The diaphragm, internal and external intercostal muscles and ribcage
What always happens in the process of ventilation
Anatomical change - Volume change - Pressure change - Movement
What is the anatomical change of inspiration
External intercostal and diaphragm muscles contract
Ribcage moves upward and outward
Diaphragm flattens
What does the anatomical change cause
Volume change
What is and what causes the volume change in inspiration
- Volume increases
- caused by the ribcage moving upwards and outwards and diaphragm flattening
- as a result of the external intercostal and diaphragm muscles contracting (anatomical change)
What does the volume change cause
Pressure change
What is and what causes the pressure change in inspiration
Pressure decreases (below atmospheric pressure), this is because the volume of the thorax has increased
What does the pressure change cause
Movement
What is the movement in inspiration and what causes it
The movement is air flowing into the lungs, caused by the pressure change
What type of process is inspiration
Active process (requires energy)
What is the anatomical change of expiration
External intercostal and diaphragm muscles relax
Ribcage moves downward and inwards
Diaphragm becomes curved again
What is the volume change in expiration and what is it caused by
- Volume decreases
- caused by ribcage moving downward and inward and diaphragm becoming curved again
What is the pressure change in expiration and what is it caused by
Air pressure increases, caused by the volume in thorax decreasing
What is the movement in expiration
Air flows out of the lungs
What is tidal volume
The volume of air in each breath
What is vital capacity
The maximum volume of air that can be breathed in or out
What is breathing rate
How many breaths are taken - usually in a minute
What is oxygen consumption / oxygen uptake
The rate at which an organism uses up oxygen
What can be used to investigate breathing
Spirometer
What is a spirometer
A machine that gives readings of tidal volume, vital capacity, breathing rate and oxygen uptake
What is the chamber of a spirometer filled with
Oxygen, chamber also has a moveable lid
Where does the person breathe through
A tube connected to the oxygen chamber
What happens to the lid of the chamber as the person breathes in and out
The chamber lid moves up and down
How are the movements recorded
By attaching a pen to the lid of the chamber, which writes on a rotating drum crating a spirometer trace
What is an alternative method to record results for a spirometer
Spirometer can be hooked up lot a motion sensor - this will use the movements to produce electronic signals, which are picked up by a data logger
Why does the total volume of gas in the chamber decrease over time
Because air that’s breathed out is a mixture of O2 and CO2. The CO2 is absorbed by the soda lime - so there is only oxygen in the chamber the subject inhales from. As the oxygen gets used up by respiration, the total volume decreases
