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OCR A AS level biology module 3 > 3.1- exchange surfaces and breathing > Flashcards

3.1- exchange surfaces and breathing Flashcards

1
Q

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

A

size, SA to V ratio and level of activity

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2
Q

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

A

Cytoplasm very close to the outside
short diffusion pathway

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3
Q

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

A

Large, SA is larger than their volume

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4
Q

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

A

Small, smaller SA compared to their
volume.

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5
Q

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

A

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

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6
Q

what does metabolic activity require?

A

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

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7
Q

name the needs for energy in a active organism

A

movement and for warmth

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8
Q

name the 3 features of a good exchange surface plus examples

A
  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.
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9
Q

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

A

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

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10
Q

what protects the lungs?

A

ribcage

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11
Q

what are the ribs held together by?

A

intercostal muscles

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12
Q

how is ventilation produced?

A

through the action of the intercostal muscle and diaphragm.

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13
Q

how small are alveoli?

A

100-300 micrometers

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14
Q

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

A

surfactant

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15
Q

name the thin barriers that reduce diffusion distance in gaseous exchange

A
  • alveolus wall one cell thick
  • capillary wall one cell thick
  • both walls have squamous cells (thin)
  • capillaries in close contact with alveolus walls.
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16
Q

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

A

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.

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17
Q

what happens to the diaphragm during inhalation?

A

The diaphragm contracts and moves down.

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18
Q

what happens to the diaphragm during exhalation

A

diaphragm relaxes and moves up

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19
Q

what happen to elastic fibres during inspiration?

A

stretch

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20
Q

what happen to elastic fibres during exhalation

A

recoil to push air out

21
Q

what are some requirements of an effective airway?

A
  • Be large for sufficient airflow without constriction.
  • be supported to prevent collapsing when the air pressure is low.
  • be flexible
22
Q

what are airways lined with also its function?

A

ciliated epithelium (helps keep lungs healthy, and move mucus

23
Q

what do goblet cells release ?

A

mucus

24
Q

describe structure of trachea and bronchi

A

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

25
Q

why is the cartilage in the trachea c- shaped

A

flexibility and space for food to pass.

26
Q

describe the strucutre of brioncholes

A

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

27
Q

role of smooth muscles

A

constrict air ways

28
Q

how do we measure lung volumes

A

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

29
Q

what absorbs the CO2 after exhalation in a spirometer.

A

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

30
Q

name precautions that must be taken before using a spirometer.

A
  • individual must be healthy
  • soda lime is fresh
  • no air leaks
  • mouth piece is sterilised
  • water chamber is not overfilled
31
Q

definition of vital capacity

A

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

32
Q

what are the factors that affect vital capacity

A
  • size of a person
  • age and gender
  • level of regular exercise
33
Q

definition of residual volume

A

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

34
Q

volume of tidal volume

A

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

35
Q

how do we measure oxygen uptake in a spirometer?

A

the gradient of decrease in volume

36
Q

how do bony fish absorb the oxygen dissolved in water ?

A

they use their gills

37
Q

how many pairs of gills do most fish have

A

5

38
Q

what do each gills in a bony fish consist of ?

A

2 rows of gill filaments attached to a bony arch.

39
Q

how do gills in a fish gain a large SA?

A

through the folding of the many secondary lamellae.

40
Q

definition of counter current flow

A

when 2 fluids flow in opposite directions

41
Q

how do bony fish keep water flowing over the gills

A

by using a buccal-opercular pump.

42
Q

describe the ventilation in bony fish

A
  • 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.
43
Q

what type of circulatory system do insects have
?

A

they have an open circulatory system.

44
Q

what role does the body fluid obtain in insects ?

A

both the blood and tissue fluid.

45
Q

insects possess what type of air filled system

A

tracheal system

46
Q

how does air enter through the tracheal system in insects

A

pores called spiracles

47
Q

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

A

trachae

48
Q

What are the ends of tracheoles filled with?

A

tracheal fluid

OCR A AS level biology module 3 (3 decks)

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