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Biology A Level > Exchange Surfaces > Flashcards

Flashcards in Exchange Surfaces Deck (18):
1

Ventilation

Breathing movements
Ensures O₂ in alveolus is higher than in blood and
CO₂ in alveolus is lower than in blood

2

Alveoli comprised of

Squamous epithelium

3

Alveolus walls contain _______ _____ which _______ ______ ___________ and ______ __ ____ ___ ___

Elastic fibres
Stretch during inspiration
Recoil to push air out

4

Airways are lined with ________ __________ which have ____ ____ __________

Ciliated epithelium
Hair like extensions

5

Bronchioles have ______ ______ and _______ ______ instead of _________

Smooth muscle
Elastic fibres
Cartilage

6

Smooth muscle is

Involuntary muscle which contracts without thought
Constricts airways making lumen narrower and constricting air flow to alveoli if there are harmful substances

7

Elastic fibres

Deform and recoil to original size
Elongate smooth muscle again, as they recoil, the muscle relaxes

8

Spirometer

Measures movement of air in and out
Air floats on tank of water
Air out, lid goes down
Air in, lid goes up
CO₂ exhaled passes through soda lime so only measures O₂

9

Spirometer precautions

Healthy subject
Fresh soda lime
Sterilised mouthpiece
No overflow of water
No air leaks

10

Vital capacity

Maximum air moved in, in 1 breath
Deep breath
Expiring all air

11

Tidal volume

Air moved in and out with 1 breath at rest

12

Breathing rate

Number of breaths per minute
=Volume change/time

13

Oxygen uptake

Volume of O₂ absorbed in 1 minute

14

In insects, air enters via

Spiracles then tracheae then tracheoles filled with tracheal fluid

15

In insects, gas exchange is between

Air in tracheole and fluid

16

Bony flap

Operculum

17

Mouth

Buccal cavity

18

What is countercurrent flow?

Blood flows through capillaries opposite to flow of water over lamellae