Module 3 Sedtion 1 - Ventilation In Mammals

Question 1

Ventilation consists of two stages…

Answer 1

Inspiration
Expiration

Question 2

Inspiration and expiration are controlled by the movement of

Answer 2

The diaphragm, internal and external intercostal muscles and ribcage

Question 3

What always happens in the process of ventilation

Answer 3

Anatomical change - Volume change - Pressure change - Movement

Question 4

What is the anatomical change of inspiration

Answer 4

External intercostal and diaphragm muscles contract
Ribcage moves upward and outward
Diaphragm flattens

Question 5

What does the anatomical change cause

Answer 5

Volume change

Question 6

What is and what causes the volume change in inspiration

Answer 6

• 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)

Question 7

What does the volume change cause

Answer 7

Pressure change

Question 8

What is and what causes the pressure change in inspiration

Answer 8

Pressure decreases (below atmospheric pressure), this is because the volume of the thorax has increased

Question 9

What does the pressure change cause

Answer 9

Movement

Question 10

What is the movement in inspiration and what causes it

Answer 10

The movement is air flowing into the lungs, caused by the pressure change

Question 11

What type of process is inspiration

Answer 11

Active process (requires energy)

Question 12

What is the anatomical change of expiration

Answer 12

External intercostal and diaphragm muscles relax
Ribcage moves downward and inwards
Diaphragm becomes curved again

Question 13

What is the volume change in expiration and what is it caused by

Answer 13

• Volume decreases
• caused by ribcage moving downward and inward and diaphragm becoming curved again

Question 14

What is the pressure change in expiration and what is it caused by

Answer 14

Air pressure increases, caused by the volume in thorax decreasing

Question 15

What is the movement in expiration

Answer 15

Air flows out of the lungs

Question 16

What is tidal volume

Answer 16

The volume of air in each breath

Question 17

What is vital capacity

Answer 17

The maximum volume of air that can be breathed in or out

Question 18

What is breathing rate

Answer 18

How many breaths are taken - usually in a minute

Question 19

What is oxygen consumption / oxygen uptake

Answer 19

The rate at which an organism uses up oxygen

Question 20

What can be used to investigate breathing

Answer 20

Spirometer

Question 21

What is a spirometer

Answer 21

A machine that gives readings of tidal volume, vital capacity, breathing rate and oxygen uptake

Question 22

What is the chamber of a spirometer filled with

Answer 22

Oxygen, chamber also has a moveable lid

Question 23

Where does the person breathe through

Answer 23

A tube connected to the oxygen chamber

Question 24

What happens to the lid of the chamber as the person breathes in and out

Answer 24

The chamber lid moves up and down

Question 25

How are the movements recorded

Answer 25

By attaching a pen to the lid of the chamber, which writes on a rotating drum crating a spirometer trace

Question 26

What is an alternative method to record results for a spirometer

Answer 26

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

Question 27

Why does the total volume of gas in the chamber decrease over time

Answer 27

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