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bio > 3.1 - Exchange surfaces and breathing > Flashcards

3.1 - Exchange surfaces and breathing Flashcards

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Biology 101 flashcards
1
Q

larger organisms SA:V…

A

smaller

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2
Q

why do larger organisms need specialised exchange substances?

A
  • diffusion through the relatively small surface is not efficient enough to supply the large volume
  • diffusion pathway too long
  • rate too slow
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3
Q

why can expiration be passive

A
  • DOESNT INVOLVE MUSCLE CONTRACTION
  • NO ENERGY REQUIRED
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4
Q

passage of air

A
  • nose
  • trachea
  • bronchus
  • bronchioles
  • alveoli
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5
Q

cartilage in trachea

A

c - shaped ring

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6
Q

bronchi are … compared to trachea

A

narrower

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7
Q

bronchi cartilage

A

irregular

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8
Q

inner lining of trachea and bronchi

A
  • ciliated epithelium
  • goblet cells
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9
Q

inside surface of cartilage has

A

smooth muscle + elastice fibres (and blood vessels)

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10
Q

cartilage job

A
  • supports trachea and bronchi
  • prevents tubes from collapsing when pressure drops during inspiration
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11
Q

ciliated epithelium job

A
  • in bronchi, bronchioles and trachea
  • moves mucus up tubes , towards the throat to be coughed out, to prevent reaching lungs and infection
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12
Q

goblet cells

A
  • cells in trachea, bronchus, bronchioles
  • secrete mucus to trap dust and pathogens
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13
Q

during inspiration

A
  • EXTERNAL intercostal muscles contract, INTERNAL relax
  • ribcage moves up and out
  • diaphragm contracts, flattens, and moves down
  • vol in THORAX increases, pressure decreases
  • Pressure gradient created between lungs and atmospheric, so air drawn in
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14
Q

during expiration

A
  • EXTERNAL intercostal muscles realx, INTERNAL contract IF FORCEDD EXPIRATION
  • ribcage lowers and in
  • diaphragm relaxes and rises upwards
  • volume in thorax decreases, pressure increases
  • air forced OUT of lungs
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15
Q

features of efficient gas exchange surface

A
  • large surface area (eg root hair cells)
  • thin / short diffusion pathway (alveoli)
  • steep concentration gradient (blood supply)
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16
Q

trachea

A
  • wide tube with c shaped cartilage to SUPPORT and keep air passage open during pressure changes
  • lines by ciliated epithelium cells which move mucus (secreted by goblet cells) to the throat to be SWALLOWED , preventing lung infections
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17
Q

alveoli are lined with

A

epithelium cells

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18
Q

why do single celled organisms not need systems

A
  • substances can enter efficiently as distance to travel is short
  • ## RATE FAST
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19
Q

rib cage purpose

A

protects lungs

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20
Q

where does gas exchange ACTUALLY occur

A

alveoli

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21
Q

why do fish need a specialised exchange surface?

A
  • small SA:V
  • impermeable membrane, gases cant diffuse through skin
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22
Q

ventilation in fish

A
  • fish opens mouth by lowering floor of BUCCAL CAVITY. volume increases, pressure decreases, water flows in across pressure gradient
  • operculum valve is shut,+BUCCAL CAVITY RAISED: opercular cavity expands. volume increases, pressure decreases
    -buccal cavity raised. vol decreases, pressure increases
  • water forced from buccal cavity OVER the gills into the opercular cavity due to pressure gradient
  • BC and OC constrict- vol decreases, pressure increases, forces opercular valves shut, water rushes out of valves across pressure gradient
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23
Q

operculum

A
  • acts as a valve and pump for water (lets it in and out)
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24
Q

no. of pairs of gills in body fish

A

4

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25
Q

gills in body fish

A
  • 4 pairs
  • each supported by an arch, which have projections called gill filaments
  • on the gill filaments are the lamellae
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26
Q

blood and water flow across lamellae

A

COUNTER CURRENT (opposite direction)

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27
Q

why cant fish survive long out of water?

A
  • gill filaments held apart by water flow
  • stick together without water
28
Q

do insects have a transport system

A

NO

29
Q

result of no transport system in insects

A

oxygen needs to directly be transported to respiring tissues

30
Q

insect v mammals respiratory system (2)

A
  • insects have a direct connection to environment
  • mammals are more complex
31
Q

spiracles

A
  • opening to the tracheal system on the surface of an insect’s body
  • where the gases flow in and out
  • open (when active to bring in O2) and close (when resting to minimise H2O loss) to regulate flow of air
32
Q

insects exoskeleton

A
  • protects them from environment
  • prevents water loss
  • TOO THICK TO ALLOW DIFFUSION FOR GAS EXCHANGE
33
Q

mechanical ventilation in insects

A

pumping the abdomen

34
Q

need for exchanging substances

A
  • remove waste so they dont build up and become toxic
  • supply of oxygen and nutrients to survive
35
Q

features of an efficient exchange surface

A
  1. Increased SA:V (projections/folded membranes)
  2. Short diffusion distance (eg alveoli one cell thick)
  3. Steep concnetration gradient (good blood supply/ventilation)
36
Q

factors affecting the need for a specialised exhcnage system

A
  1. metabolic activity
  2. sa:v
  3. single/multicelled
37
Q

ventilation defintion (human)

A

refreshing of air in the lungs, so theres a higher O2 conc and lower CO2 conc than in the blood

38
Q

where does gas exchange actually take place in humans

A

alveoli

39
Q

passage of oxygen (alveoli)

A

diffuses from alveoli to blood in capillaries

40
Q

pasage of CO2 (alveoli)

A

diffuses from blood in capillaries to alveoli, to lungs to be exhaled

41
Q

alveoli: large SA

A
  • very small
  • but there are loads of them
42
Q

surfactant

A

lines the internal surface of the alveoli to prevent the cohesion between water, so stops them from collapsing. maintains large SA

43
Q

alveoli: short diffusion pathway

A
  • wall is one cell thick, so is that of capillary: TOTAL PATHWAY ONLY 2 CELLS THICK
  • both made of squamous epithelial cell (flattened)
  • capillaries very close to alveoli
  • capillaries v narrow, RBCs squeeze through. closer to alveoli and reduces rate of flow
44
Q

alveoli: concentration gradient

A
  • surrounded by network of capillaries
  • capillaries transport O2 away from the lungs to body cells to be respired. therefore conc O2 in lungs always higher than blood so it will diffuse
  • blood transports co2 from tissues to lungs. conc co2 always higher in blood than lungs so co2 diffuses to alveoli to be exhaled
45
Q

when do internal ICM contract

A

forced expiration eg exercise, sneezing, coughing. gets air out more forcedully

46
Q

alveolus wall

A
  • squamous epithelial cell
  • contains elastic fibres that STRETCH during inspiration (increaseSA)v
  • and recoil to help push air out during expiration
47
Q

why is cartilage c shaped not full in trachea

A

allows flexibility and space for food to pass down oesophagus

48
Q

walls of bronchioles

A

big ones have cartilage
- smooth muscle and elastic fibres

49
Q

glandular tissue

A
  • in loose tissue
  • prdocues mucus
50
Q

smooth muscle and elastic fibres together airways

A
  • smooth muscle contracts to contstrict airway, narrowing the lumen
  • important if there are harmful substances in the air. (involuntary eg allergic reaction)
  • smooth muscle cannot reverse this solo, elastic fibres stretch and recoil to redilate the airway
51
Q

site of gas exchange in fish

A
  • gills
52
Q

how are the gills good exchange surfaces

A
  • MANY LAMELLA = large SA
  • secondary lamellae on main lamellae = large SA
  • SHORT DISTANCE between blood and water: lamellae and filmanets contain a capillary network
  • CG: countercurrent flow
53
Q

countercurrent flow reason?

A
  • water has a loewr conc of o2 compared to air
  • fish need to maintain a steep cg across all lamellae
54
Q

how does ccf work

A
  • water flows over gill lamella in the OPPOSITE Direction to the flow of blood in the capllaries
  • never reach o2 equilibrium, steep diffusion cg maintained across all lamellae. max o2 moves from water into blood
55
Q

insect tracheal system

A
  • air enters through spiracles
  • travels along tracheae. lined with CHITIN for support, and impermeable so prevents gas exchange
  • branches off into tracheoles (elongated cells without chitin so have permeable walls) which contain tracheal fluid
  • O2 moves down CG from air to cells
  • CO2 moves against CG from cells to spiracles
56
Q

insect very active what happens?

A
  • tracheal fluid limits how much O2 can be diffused - when very active, insufficient O2, so muscle cells aerobically respire -> lactic acid, lowering water potential. tracheal fluid moves out of tracheols down concentration gradient
    ***- more SA of tracheole wall exposed to air
  • more o2 absorbed*
57
Q

4 MARKS SMOOTH MUSCLE

A
  • contracts, reduces diameter of lumen of bronchi and bronchioles
  • harder to inhale and exhale as more resistance to air flow
  • more air remains in the lungs
  • so increased breathing rate
58
Q

purpose of squamous

A

provide a short diffusion distance, as are flat

59
Q

6 MARKS ALVEOLI ADAPTATION

A
  1. wall is one cell thick = short diffusion pathway
  2. squamous walls = short diffusion pathway
  3. ELASTIC= can recoil and expel air
  4. large number = increased surface area
  5. small size = large SA:V
  6. Surfactant prevents collapse to maintain surface area
60
Q

3 ways airway diameter can be reduced

A
  1. smooth muscle contracts
  2. inflamation
  3. extra mucus secreted
61
Q

how does nasal cavity increase efficinecy of gas exhcange (2)

A
  1. large SA and good blood supply. warms air
  2. mucus secreting cells trap dust and microbes
62
Q

how does trachea increase efficinecy of gas exhcange (2)

A
  1. c chaped rings of cartilage prevent collapse, allowing gases in and out
  2. ciliated epithelial cells and goblect cells secrete mucus, trap dust and microbes and WAFT TOWARDS stomach
63
Q

how do bronchi/bronchioles increase efficinecy of gas exhcange (2)

A
  • smooth muscle. allows air to move in and out to maintain high concentration gradient
64
Q

why might something need a less developed exchange system? (3)

A
  1. smaller, larger SA:V
  2. shorter diffusion pathway
  3. less metabolically active, lower need for O2
  4. no hard exoskeleton so oxygen can dfifuse throug outer membrane
65
Q

insects thoraic and abdominal movement

A

-moving wings alters volume of thorax. vol decreases, pressure increases, air pushed out and vice versa
- some (eg locusts) : abdomen expands, spiracles at the front open and air enters. abdomen reduces in volume, spiraceles at the rear end open and air leaves

bio (24 decks)

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