3.1- exchange surfaces and breathing

Question 1

what are the 3 main factors that affect the need for an exchange system?

Answer 1

size, SA to V ratio and level of activity

Question 2

what advantages do small organisms have compared to larger organisms when it comes to gaseous exchange?

Answer 2

Cytoplasm very close to the outside
short diffusion pathway

Question 3

how would you describe to SA:V ratio in a small organisms

Answer 3

Large, SA is larger than their volume

Question 4

how would you describe the SA:V ratio in a large organisms

Answer 4

Small, smaller SA compared to their
volume.

Question 5

how do some animals increase their SA?
Give an example of an animal that does this.

Answer 5

By adopting a different shape.
e.g. flat worm have a thin and flat body

Question 6

what does metabolic activity require?

Answer 6

energy from food and oxygen to release the energy in anaerobic respiration.

Question 7

name the needs for energy in a active organism

Answer 7

movement and for warmth

Question 8

name the 3 features of a good exchange surface plus examples

Answer 8

1. large SA:V ratio for more space for diffusion. e.g folding membranes in root hair cells.
2. thin permeable barrier. e.g. alveoli in the lungs
3. Good blood supply. helps maintain a steep conc. gradient.

Question 9

name the tissues/organs that air flows through after it reaches the nose down to the lungs hint- t,b,b,a

Answer 9

trachea(windpipe) then bronchi and bronchioles (small air sacs) finally the alveoli.

Question 10

what protects the lungs?

Answer 10

ribcage

Question 11

what are the ribs held together by?

Answer 11

intercostal muscles

Question 12

how is ventilation produced?

Answer 12

through the action of the intercostal muscle and diaphragm.

Question 13

how small are alveoli?

Answer 13

100-300 micrometers

Question 14

what must the lungs produce to reduce cohesion forces between water molecules that can cause alveoli to collapse?

Answer 14

surfactant

Question 15

name the thin barriers that reduce diffusion distance in gaseous exchange

Answer 15

• alveolus wall one cell thick
• capillary wall one cell thick
• both walls have squamous cells (thin)
• capillaries in close contact with alveolus walls.

Question 16

why is having a good blood supply in gaseous exchange important? hint- CO2 and O2

Answer 16

blood transports CO2 from tissues to lungs. ensuring conc of CO2 in the blood is higher than that in the air. making it diffuse through alveoli.

blood transports O2 from lungs to tissues. so conc is lower in blood.

Question 17

what happens to the diaphragm during inhalation?

Answer 17

The diaphragm contracts and moves down.

Question 18

what happens to the diaphragm during exhalation

Answer 18

diaphragm relaxes and moves up

Question 19

what happen to elastic fibres during inspiration?

Answer 19

stretch

Question 20

what happen to elastic fibres during exhalation

Answer 20

recoil to push air out

Question 21

what are some requirements of an effective airway?

Answer 21

• Be large for sufficient airflow without constriction.
• be supported to prevent collapsing when the air pressure is low.
• be flexible

Question 22

what are airways lined with also its function?

Answer 22

ciliated epithelium (helps keep lungs healthy, and move mucus

Question 23

what do goblet cells release ?

Answer 23

mucus

Question 24

describe structure of trachea and bronchi

Answer 24

they have similar structure. but bronchi is more narrow than trachae. also contain cartilage to prevent collapsion.

Question 25

why is the cartilage in the trachea c- shaped

Answer 25

flexibility and space for food to pass.

Question 26

describe the strucutre of brioncholes

Answer 26

narrower than bronchi, no cartilage and wall is compromised by smooth muscle and elastic fibers.

Question 27

role of smooth muscles

Answer 27

constrict air ways

Question 28

how do we measure lung volumes

Answer 28

spirometer- movement of the chamber is recorded on a datalogger.

Question 29

what absorbs the CO2 after exhalation in a spirometer.

Answer 29

a chamber of soda lime. which also allows measurment of oxygen consumption

Question 30

name precautions that must be taken before using a spirometer.

Answer 30

- individual must be healthy - soda lime is fresh - no air leaks - mouth piece is sterilised - water chamber is not overfilled

Question 31

definition of vital capacity

Answer 31

maximum air that can be moved through one breath usually 2.5-5.0 dm3

Question 32

what are the factors that affect vital capacity

Answer 32

- size of a person - age and gender - level of regular exercise

Question 33

definition of residual volume

Answer 33

air that stays in the lungs even after exhalation usually 1.5 dm3

Question 34

volume of tidal volume

Answer 34

volume of air moved in and out with each breath. usually 0.5 dm3

Question 35

how do we measure oxygen uptake in a spirometer?

Answer 35

the gradient of decrease in volume

Question 36

how do bony fish absorb the oxygen dissolved in water ?

Answer 36

they use their gills

Question 37

how many pairs of gills do most fish have

Answer 37

5

Question 38

what do each gills in a bony fish consist of ?

Answer 38

2 rows of gill filaments attached to a bony arch.

Question 39

how do gills in a fish gain a large SA?

Answer 39

through the folding of the many secondary lamellae.

Question 40

definition of counter current flow

Answer 40

when 2 fluids flow in opposite directions

Question 41

how do bony fish keep water flowing over the gills

Answer 41

by using a buccal-opercular pump.

Question 42

describe the ventilation in bony fish

Answer 42

- first buccal cavity changes volume which draws water in. - cavity closes and pushes water towards the gills. - movements of operculum reduces pressure directing the water.

Question 43

what type of circulatory system do insects have ?

Answer 43

they have an open circulatory system.

Question 44

what role does the body fluid obtain in insects ?

Answer 44

both the blood and tissue fluid.

Question 45

insects possess what type of air filled system

Answer 45

tracheal system

Question 46

how does air enter through the tracheal system in insects

Answer 46

pores called spiracles

Question 47

what is the name for the tubes that transport air in the body of an insect ?

Answer 47

trachae

Question 48

What are the ends of tracheoles filled with?

Answer 48

tracheal fluid