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Biology A level > 3.1.1 exchange surfaces > Flashcards

3.1.1 exchange surfaces Flashcards

1
Q

why do organisms exchange things with their environments

A

to take in things for metabolic reactions and to excrete waste products from these reactions

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2
Q

how do we calculate surface area to volume ratio

A

SA:V = SA/V

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3
Q

why do multicellular organisms need specialised exchange surfaces

A

there is too big of a distance between most internal cells and the environment so diffusion directly would take too long
multicellular organisms have a high metabolic rate so they use up oxygen and glucose faster

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4
Q

how does a large surface area improve efficiency of an exchange surface

A

it increases the rate of diffusion as there is a bigger area for the exchange to happen so more can happen at once

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5
Q

how does thickness effect efficiency of an exchange surface

A

a thin exchange surface is more efficient as there is less diffusion distance so it takes less time to take place

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6
Q

how does a good blood supply effect efficiency of an exchange surface

A

it maintains concentration gradients making exchange more efficient

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7
Q

what are the exchange organs in mammals

A

lungs

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8
Q

what is the structure of the lungs

A

trachea branches into two bronchi one bronchus leading to each lung.
the bronchi split into smaller tubes called bronchioles which end in small sacs called alveoli.

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9
Q

what is the function of goblet cells in the gaseous exchange system

A

they secrete mucus which traps microorganisms and dust particles inhaled stopping them reaching alveoli

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10
Q

what is the function of cilia in the gaseous exchange system

A

they beat the mucus which moves it up and away from the alveoli towards the throat to avoid infections

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11
Q

what is the function of elastic fibres in the gaseous exchange system

A

allow the parts of the lung to stretch when inhaling and recoil when exhaling

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12
Q

what is the function of smooth muscle in the gaseous exchange system

A

allows the diameter of the tubes in the lungs to be controlled e.g. it relaxes during exercise making tubes wider so air moves in easier

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13
Q

what is the function of the rings of cartilage gaseous exchange system

A

it provides support. it is strong and flexible and stops the trachea and bronchi collapsing when you inhale and pressure drops

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14
Q

which parts of the lungs contain cartilage

A

trachea (large C shaped pieces)
bronchi (smaller pieces)

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15
Q

which parts of the lungs contain smooth muscle

A

trachea, bronchi and larger bronchioles

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16
Q

which parts of the lungs contain elastic fibres

A

trachea, bronchi, bronchioles and alveoli

17
Q

which parts of the lungs contain goblet cells

A

trachea, bronchi and larger bronchioles

18
Q

which parts of the lungs contain cilia

A

trachea, bronchi and larger bronchioles

19
Q

what is inspiration

A

air flowing into the lungs, it is an active process

20
Q

how does inspiration happen

A

external intercostal muscles and diaphragm contract causing the ribcage to move upwards and outwards and the diaphragm to flatten. this increases the volume of the thorax, this decreases the pressure this causes air to flow into the lungs

21
Q

what is expiration

A

air flowing into the lungs, it is an passive process but can be forced actively

22
Q

how does expiration happen

A

external intercostal muscles and diaphragm relax causing the ribcage to move downwards and inwards and the diaphragm to curve. this decreases the volume of the thorax, this increases the pressure this causes air to be forced out of the lungs
in forced expiration the intercostal muscles contract to pull the ribcage down and in

23
Q

what is the tidal volume

A

the volume of air in each breath
( average tidal volume is about 0.4dm3)

24
Q

what is the vital capacity

A

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

25
Q

what is the breathing rate

A

how many breaths are taken in a certain time

26
Q

what is the oxygen consumption/uptake

A

the rate at which an organism uses up oxygen

27
Q

what is the residual air

A

air that cant be expelled from the lungs

28
Q

how does a spirometer work

A

it has an oxygen filled chamber with a moveable lid, the person breathes through a tube connected to the oxygen chamber as the person breaths it moves up and down, these movements are recorded by a pen attached to the lid of the chamber which writes on a rotating drum or it can be hooked up to a motion sensor to create electronic signals picked up by a data logger

29
Q

how do we analyse data from a spirometer

A

breathing rate is the number of peaks in a certain time.
tidal volume is the length of the peaks is the tidal volume
oxygen consumption is the decrease in volume of gas in the spirometer chamber

30
Q

what is the structure of gills in fish

A

each gill is made up of lots of thin branches called gill filaments which give a large surface area. these are covered in gill plates which increase surface area even more
each gill is supported by a gill arch

31
Q

what is a counter current system

A

when the water flows in the opposite direction to the blood

32
Q

how does a counter current system allow for as much oxygen as possible to diffuse into the blood

A

it maintains the concentration gradient so water always has a higher oxygen content than blood so net movement is always into the blood

33
Q

how are the gills in fish ventilated

A
  1. fish opens mouth which lowers the buccal cavity floor so the volume of the buccal cavity increases decreasing the pressure inside so water is sucked in
  2. fish closes its mouth raising the buccal cavity floor decreasing volume and increasing pressure so the water is forced out across the gills
  3. each gill is protected by a bony flap called the operculum which is forces pen by the increase in pressure allowing water to lave the gills
34
Q

what are tracheae

A

microscopic air filled pipes which insects use for gas exchange

35
Q

what are spiracles

A

the pores in the insects body that air moves in and out of the tracheae

36
Q

how does gas exchange take place in insects

A

oxygen travels down the concentration gradient towards the cells and carbon dioxide moves to the spiracles
tracheae branch off into smaller tracheoles which have thin permeable walls and go to single cells. they contain fluid that the oxygen dissolves in
oxygen then diffuses into body cells and carbon dioxide diffuses out

37
Q

how do insects ventilate

A

rhythmic abdominal movement to change the volume in their bodies
large insects also use wing movements

Biology A level (13 decks)

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