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A Level Biology Me > chapter 7 exchange in animals > Flashcards

chapter 7 exchange in animals Flashcards

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1
Q

why do single cell organisms not need specialised exchange surfaces?

A
  • metabolic activity of single cell organisms is so low that the oxygen demand and co2 produced is so little
  • SA:V is so big that diffusion can happen at a fast enough rate to sustain metabolic demand
  • diffusion distances are very small too, so no transport system needed
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2
Q

why do multicellular organisms need specialised exchange surfaces? (3)

A

as organism gets bigger

  • metabolic demands increase
  • SA:V decreases, so can’t diffuse fast enough to sustain these increased metabolic demands
  • diffusion distance is too big to reach cell that could be deep in
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3
Q

sa and v of sphere

A 
sa = 4pi r 2
v= 4/3 pi r 3
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4
Q

what are 4 features all effective specialised exchange surfaces have?

A
  • thin and thus short diffusion distance
    this increases rate of diffusion as less distance to travel
  • High Sa: V (more efficient diffusion as more area available to diffuse into)
  • High conc gradient : GOOD BLOOD SUPPLY and VENTILLATION
    Good blood supply offers high conc gradient as low concentration of oxygen always brought back keeping gradient high

good ventilation means the gradient between blood and outside is always kept high, as highly concentrated area of co2 is moved as soon as diffuses and high o2 brought in.

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5
Q

what is ficks law

A

rate of diffusion is proportional to ==== SA* concentration gradient / diffusion distance

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6
Q

describe the way organs and pathway air takes to get to a red blood cell

A

first

  • nostril +mouth
  • nasal cavity
  • larynx
  • trachea
  • bronchi
  • bronchioles
  • alveoli
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7
Q

what is found between ribs in rib cage and in general to aid with ventilation system?

A

in between ribs are external (more outside) and internal intercostal muscles

  • there is thin layer of lubcricating fluid so that membranes slide over each other
  • also skin connecting the lungs in this fluid, and punctured lung is when this breaks
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8
Q

inspiration

active or no

A

AN ACTIVE PROCESS- energy requiring

1) diaphragm contracts, so is flattened and lowers
2) external intercostal muscles at the same time contract, pushing the rib cage upwards and outwards, whilst internal relax
3) here this causes the volume of the thorax to increase, and thus pressure to decrease
4) as there is higher pressure of the atmospheric air, air is DRAWN in through nasal cavity to equalise the pressure inside and outside

(thoracic volume , pressure)

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9
Q

Expiration

active or no

A

NOT ACTIVE, initially PASSIVE

1) diaphragm relaxes, causing it to push up to its resting dome shape
2) at same time external intercostal muscles relax moving ribs down and inwards AIDED by gravity
- as well all the elastic fibres in the alveoli of lungs elastically recoil and relax , which forces air out, again lowering volume but increasing pressure
3) thi reduces thoracic volume so increases thoracic pressure
4) as a result as higher pressure inside than out, air is forced out so pressure can be equalised

however more air can be actively pushed out…

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10
Q

how to forcefully and thus ACTIVElY expire?

A

active process requiring energy

1) here intercostal muscles internal will also CONTRACT which forcefully pushes rib cage down, reducing volume but increasing pressure even more forcing as much air out as possible
2) as well ABDOMINAL muscles contract forcing diaphragm up quickly to quickly increase pressure and force air out

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11
Q

what features of the nasal cavity makes it better for job (3)
why important it needs to make air humid

A
  • a large surface area with GOOD blood supply, which warms blood entering (better) so it can enter at same temp and humidity
  • a hairy lining, which secretes mucus in attempt to trap dust and bacteria protecting delicate lung tissue
  • MOIST SURFACES, which INCREASES humidity of the incoming air

2) here the lungs are already humid to allow gas to dissolve in and out, however if nasal cavity was dry then water would move by diffusion and escape, as a result naval cavity artificially creates similar humidity through warm blood so this doesn’t happen!!!

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12
Q

what does the trachea have structuarlly and why (£)

- incomplete?

A

1) wide tube supported by INCOMPLETE cartilage rings
- these offer support stopping from collapsing
- however incomplete so food can move by oesophagus behind expanding with no restrain (and air expanding too)

2) cillated epithelial tissue lined
- have goblet cells= sticky mucus= traps any leftover microorganisms and dust left behind from most, cilia beat and push down digestive

3) SMOOTH MUSCLE + ELASTIC + FIBRES

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13
Q

what material do trachea bronchi and alveoli have and why is this useful (3)
which ones specifically have collagen

A

1) smooth muscle (except alveoli) (especially bronchioles )
- this means amount of air can be controlled going in. when relaxed it means more air comes in and this happens during exercise etc

2 ) elastic fibres (especially alveoli)
- when breathing in these stretch and cause to expand , but in breathing out elastic recoil happens and helps push air out

3) collagen (rings) only for trachea and bronchi (not bronchioles or alveoli)
- support so don’t collapse when pressure drops, shape maintained…

4) cilliated epithelial tissue all except alveoli

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14
Q

structure of bronchi (main difference)

A
  • divides to form left and right
  • also has cartiallge rings , incomplete but SMALLER
  • again smooth muscle + elastic fibre + cilliated epithelial tissue
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15
Q

bronchioles structure

A

bronchi divide to form many small bronchioles

1) some squamous for gas exchange
2) MORE PROPORTION OF smooth muscle (to control air ). + elastic fibres + cillated epithelial

smallere loses cillated and muscle

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16
Q

alveoli structure

A

tiny air sacs , 200-300 micrometers diameter

1) consists SQUAMOUS epithelial tissue to allow for gas exchange
2) collagen, elastic fibre (especially for recoil ) , BUT NO smooth muscle

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17
Q

all 4 structures summary

A

trachea - cartillage rings , cillated, smooth muscle and elastic fibres
bronchi - same but smaller cartillage rings
bronchioles - no cartilage, smooth muscle elastic, cillated and squamous
smaller bronchioles have no ciliated
Alveoli - squamous , elastic fibre for recoil, NO muscle

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18
Q

what adaptions do alveoli have that allow them for efficient gas exchange?

what is distance in cells

A

1) High SA:V
- 300-500 million alveoli in lungs which gives rise to insane surface area, meaning diffusion rate increase
2) Small diffusion distance
- CAPILLIARY is one cell thick and so is squamous , so diffuse distance is only 2 cells and this is very small, fick law shows rate of diffusion increases as a result
3) High conc : good blood supply
- ensures fresh blood with low o2 and high co2 levels brought , fick says high conc more diffusion
HIGH conc : ventilation
- ensures diffused gases are removed and fresh air brought in, this is so conc gradients kept high for maximum diffusion

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19
Q

why are the insides of alveoli MOIST, and why is there LUNG SURFACTANT? (IMPORTANT)

A

moist so gas can diffuse directly in as needs ro be absorbed like this

surfactant ENSURES ALVEOLI REMAIN INFLATED , MAKING IT EASIER TO BREATHE!!!

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20
Q

what happens in an asthma attack briefly (2)

what effect does smoking have. to increase lung infections?

A
  • large proportion of smooth muscle found in bronchioles contract reducing amount of oxygen going in
  • a lot of sticky mucus produced, which actually blocks air from coming in if in excess

2) smoking stops cilia breathing so sticky muscus not pushed down and chance of infection increases

21
Q

again effect of surfactant on alveoli in lungs? premature baby and surfactant??

A

stops collapsing when breathing out
means they don’t stick to each other, here baby first breath much harder and surfactant saves them\

premature babies don’t have enough surfactant produced so they need artificial

22
Q

what’re 3 different ways volume of air can be measured ?

A

1) peak flow meeter ( basic asthma blow out hard as can and read)
2) vital graphs ( how quickly breathed out against a graph- forced expiratory volume)
3) spirometer - measures different aspects of lung volume

23
Q

what is measured in a spirometer or what can you see from graph
tidal, vital, IRV ERV, residual, total lung capacity

A

tidal volume - this is just the volume of air in each resting breath (volume moves in and same moves out)

2) Vital Capacity - the maximum amount of air that can be breathed in/ out. worked by deepest possible intake of air following deepest exhalation

3) IRV AND ERV
- Inspiratory reserve volume is the max air you can breathe above a normal inhalation (tidal volume)
- expiratory reserve volume is Max air you can breath out a normal breath (tidal volume )

4) residual volume - this is air left in lungs even after exhaling as much as possible, can’t be directly measured
5) total lung capacity = vital + residual

24
Q

what is breathing rate

what is ventillation rate ?

A

breathing rate = number of breaths per minute , can be found on the spirometer graph

ventialltion rate = total number of volume air breathed in a minute
- for this you need how many breaths per minute * by the amount of air breathed in per breath

=== breathing rate * tidal volume

25
Q

again go throughs seeing different component on graph

A
  • tidal volume easy, just air from inhale and exhale constant , but changes with exercise
  • Vital capacity - look for lowest exhale and highest inhale, this is that
  • redial volume - volume after lowest exhale

-irv and erv, irv is just extra air after Max tidal, and era is after lowest tidal to lowest exhale

26
Q

what happens during exercise to some rates?

how does tidal volume change

A

breathing rate increases and tidal volume, so ventilation rate increases too

here tidal volume can increase form taking 15% of vital capacity to 50%!

27
Q

how does a spirometer work?

A

1) a gas chamber filled with only oxygen is fitted with a lid that moves up and down based on how much oxygen is there
2) a mouthpiece has access to this chamber, when someone breathes in oxygen is removed from chamber , causing lid to move down , when exhale level goes up
3) attached to the lid is a pen which writes a SPIROMETER TRACE to a rotating graph, this is what we analyse
4) before breathed out air reaches chamber again carbon dioxide is removed by soda lime

this keeps happening until oxygen runs out

28
Q

how to ensure test is valid for spirometer (2)

A
  • wear a nose clip to ensure no air coming from surroundings

- machines is AIRTIGHT

29
Q

how to find volume of oxygen uptake

what to be careful of!!!

A

use the slope , but be careful if its volume of gas in or volume of gas out

30
Q

average tidal volume (normal breath)

A

500 cm 3

31
Q

what control variables need to take if measuring vital capacities, what makes a difference?

A
  • health and fitness (athlete, asthma)
  • weight
  • state you are in
  • time after woke up
31
Q

what control variables need to take if measuring vital capacities, what makes a difference?

A
  • health and fitness (athlete, asthma)
  • weight
  • state you are in
  • time after woke up
32
Q

What are the probems that insects facw that they need to overcome and solutions (how does this lead to specialised exchange system ?)

A
  • insect are very active so need a lot of oxygen
    • however if cells are exposed to air they will dehydrate quickly
      • ==as a result they have a wtwerproof exoskeleton so little gas exchange can take place
        • but waterproof stops diffusion of gas not just water ,
          - also insects dont have any PIGMENT in blood to transfer gas around
          • ==as a result insects need to develop structures specialsed in gas exchange…
33
Q

Describe quick journey of air into insect

A

Holes on abdomen / thorax called spiracles

1) air enters spiracles if opened by sphincters
2) these pass chitin ring trachea
3) which then branch to tracheoles without chitin and so exchnsge happens here as they branch to cells

34
Q

Explain the system of air travel

What is at the end of tracheoles?

A

1) spiracles on throax and abdomen controlled by sphincters . When open, gas exchnage can happen, but water loss happens too. Thus when inactive these are kept closed most of the time
2) leading away are trachea, with chitin rings. This means they dont close , but also means no gas exchange takes place here
3) these branch into tracheoles which dont have chitin. These go all the way to the cells, which means gas exchange takes place there.
4) at the end of tracheoles are TRACHEAL FLUID

35
Q

Why is tracheal fluid present in tracheoles?
What is the downside of it?
How have insects adapated to negate this when under exercise?

A

1) tracheal fluid is needed so similar to in akveloli gas can dissolve and then be absorbed

  • 2) however problem with all surfaces being lined with fluid is that it LIMITS THE SURFACE AREA FOR gas exchange
  • 3)Normally not a problem if an insect is at rest but if active snd oxygen demands high it forces ANAEROBIC RESPIRATION to cope
  • this allows to keep going but produces lactic acid . Increase of lactic acid decreases water potential here , causing TRACHEAL FLUID TO DIFFUSE IN , and thus water is lost when spiracle open…
  • however this now exposes more surface area for gas exhcngse, which is needed when ACTIVE

The overall increase of oxygen for a sacrifice of fluid is better overall in exercise

36
Q

What are disadvantages of system for insects?

A

The same air going in is same air going out and mixes, this reduces that macimum potential conc gradient and thus reduces effiency of diffusion avaialble, whereas animals dont have this

37
Q

How do having many tracheols provide efficient diffusion?

A

Many tracheoles mean huge SA:V

38
Q

For larger insects that need more energy waht can they do? (2)

A
  • mechanical ventilation of tracheal system - here musckes in abodmen and thorax actively pumps air in by changing shape of body and thus pressure , forcing air in / out depending in where pressure is
  • collapsible enlarged trachea of air sads - act as air resevoir- vsn be done by movement of wings etc wish pump air in
39
Q

Where would many tracheoles be found in insect?

A

Leg and flight muscles , more water leaves when active

40
Q

Sequence of events for co2 releasing?

A
  • first difuses into tracheal liquid, then bsck into tracheoles to trachea and spriacels open as there is a build up of co2, but slso mechanical ventislltion cause pressure snd this leaves
41
Q

When do spiracels open?

A

When active

- build up co2

42
Q

What problems must aquatic animals over face and why dont they move water in and out

A
  • although they dint need to prevent water loss, there is much LESS DISSOLVED OXYGEN THAN IN AIR AND DIFFUSION IS MUCH SLOWER IN WATER
  • as a resukt fish evolved specialised lungs = GILLS! That help get enough oxygen
  • which only goes one direction, as it would take too much energy to move in and out,
43
Q

Structure of gills

A
  • Gills are supporter by a bony arch for structure
  • each gill has two rows of many filaments
  • each filament then has lamellaw acroos it where gas exchange takes place here
44
Q

How is gills structure features specialised for gas exchnage! (3) fick

A
  • many gill filaments provide large surfsce area meeded for diffusion, this increased by filaments too
  • lamellae have rich blood supply for good concentrwtion graduent ( haemgoblovin carry)
  • also distance between lamellae and water only 5 um so more diffusion
45
Q

What extra features to gills have to ensure maximum diffusion (2)

A

1) tips of adjacent filaments overlap with each other, and this provides resistance to flow of water over fillelmslowing down the movement of the water , giving MORE TIME FOR EXCHANGE TO TAKE PLACE
2) counter current system flow

46
Q

Explain counter current system and why its better thsn parallel

A
  • water moving in from mouth and towards gikls moves in OPPOSITE direction ti flow of blood, giving rise to a counter current flow
  • this gives the highest concentrated water will always flow next to the lowest possible concentrated blood for oxygen, so the concentration gradient is highest at all timeds mesning most diffusion
  • if a parallel system used, 50% oxygen taken, here 80% is twken , bonh fish better than cartilagous

This way oxugen continues to diffuse as it moves, whereas parallel diffuses then stops as it is equilibrium

47
Q

How do different type of fish ensure a continous current of water trsvels through them ti survive?

A

Cartiganous fish have ti keep moving to ram water in = called rsm ventilation

Bony fish more adapted uses buccal pumping which allows water to go in even if still

But all fish can actively do it by moving and point mouth upstream

48
Q

Explain buccal pumping

A

An active process

1) mouth opens, which lowers the floor of buccal cavity. The operculum is closed but cscity also expands
2) this increases buccal volume, lowering pressure and as high pressure outside water is suked in
3) next mouth closes raising the floor of buccal cavity , increasing pressure here moving water to gills. At same time opercular cavity move inwards . These increase pressure in opefular cavity and water forced there and over gille
4) thisnpressure opens operculum snd water leaves

Happens again

A Level Biology Me (41 decks)

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