Topic 4 Breathing

Question 1

how should you refer to the chest?

Answer 1

thorax

Question 2

ribs

Answer 2

• bone structure that protects internal organs

Question 3

intercostal muscles

Answer 3

• muscles between the ribs

- move ribcage up and down when they contract / relax

Question 4

diaphragm

Answer 4

• sheet of tissue + muscle at bottom of thorax

- raises and lowers to change vol of thorax

Question 5

trachea

Answer 5

• windpipe that connects mouth and nose to lungs

- can only pass through here

Question 6

what happens once air passes through the nasal cavity?

Answer 6

• air is smelt /warmed/filtered/moistened

- air meets pharynx (junction at back of oral cavity)

Question 7

what is the pharynx?

Answer 7

• junction between two tubes
• epiglottis is flap that separates trachea from other tube
• below epiglottis = larynx (voice box)

Question 8

bronchi

Answer 8

• large tubes branching off trachea w/ one bronchus for each lung

Question 9

bronchioles

Answer 9

bronchi split -> smaller tubes connected to alveoli

Question 10

alveoli

Answer 10

tiny air sacs where gas exchange takes place

Question 11

pleural cavity

Answer 11

• fluid filled space between pleural membranes
• pleural fluid reduces friction and is lubrication between lungs and inside of chest
• pleural membranes form air tight seal round lungs

Question 12

what happens during inhalation?

Answer 12

1. diaphragm muscles contract so diaphragm lowers
2. external intercostal muscles contract so ribcage moves up and out
3. this increases volume inside thorax
4. decrease in air pressure
5. air enters lungs

Question 13

what happens during exhalation?

Answer 13

1. diaphragm muscles relax so diaphragm raises
2. external intercostal muscles contract so ribcage moves down and inwards
3. this decreases volume of chest cavity
4. increase in air pressure
5. air forced out

Question 14

how are alveoli adapted for gas exchange?

Answer 14

1. large sa to vol ratio -> fast rate of diffusion
2. moist surface -> gases dissolve for fast diffusion
3. lots of capillaries surround them keeps conc gradient high for fast diffusion
4. one cell thick so short diffusion distance

Question 15

CORRMMSS breathing in humans affected by exercise

Answer 15

c) intensity of exercise

O)humans of the same s) gender and age s) who are all moderately active

R) I will test a range of mild, medium and high intensity exercise each three times and find a mean

(No of star jumps)

After exercise I will count how many breaths (m1) the test subject takes in a minute (using a stopwatch) (M2) after they stop exercising

Question 16

What happens when we exercise?

Answer 16

Breathing gets deeper and quicker

Need more oxygen for respiration as muscles need more energy to contract for movement

Need to get rid of waste co2

Question 17

Why is a bell jar model not a great representation of the thorax?

Answer 17

• no ribs
• no pleural membranes/fluid
• no intercostal muscles

Question 18

What two indicators can be used to detect co2?

Answer 18

• limewater

- hydrogen carbonate indicator (yellow more co2, purple less co2)