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Biology > Module 3 - Exchange and Transport > Flashcards

Module 3 - Exchange and Transport Flashcards

1
Q

Why do fish and insects have specialised gas exchange system?

A

Multicellular, small SA:volume ratio, large diffusion distance
Can’t perform gas exchange via surface so they have gills and tracheal system

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2
Q

Structure of gills

A

Many gill filaments and lamellae = large SA
Gill lamellae have thin wall and are permeable
Countercurrent flow - water and blood pass over opposite directions, blood always passes water with high 02 concentration, maintains favourable conc gradient all across gradient

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3
Q

Structure of tracheal system

A

Spiracles, have valves to prevent water loss

Spiracles connect to trachea connect to tracheoles connect directly to respiring cells/ muscle fibres

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4
Q

How does gas exchange occur in tracheal system?

A 
Rest = down concentration gradient, simple diffusion of 02 and c02, tracheal fluid containing 02 seeps in
Active = ventilation, mass flow of 02 and c02, tracheal fluid containing 02 is sucked in
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5
Q

Function of lungs?

A

Site of gas exchange in mammals

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6
Q

What are lungs made up of?

A

Trachea, bronchi, bronchioles, alveoli

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7
Q

Structure of trachea/bronchi?

A

Strong c-shaped cartilage, c-shape gives flexibility
Goblet cells - make mucus, traps pathogens
Epithelial cells - have cilia, pushes mucus out of the lungs
They are the lining

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8
Q

Structure of bronchioles

A

Wall made of smooth muscle
Smooth muscle contracts, lumen smaller, bronchioles constrict, occurs near dangerous gases, reduces intake
Lining made of goblet cells and ciliated epithilial cells

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9
Q

Adaptation of alveoli

A

Many folded tiny alveoli so large SA
Thin wall so short diffusion distance
Elastic tissue so stretches increasing SA when breathing in, recoils when breathing out
Ventilation maintains concentration gradient

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10
Q

Adaptation of capillaries

A

Many tiny capillaries so large SA
One cell thick thin wall so large diffusion distance
Narrow lumen low diffusion distance
Circulation maintains concentration gradient

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11
Q

How 02 moves from alveoli to capillaries

A

Simple diffusion

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12
Q

How c02 moves from capillaries to alveoli

A

Simple diffusion

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13
Q

Process of breathing/ventilation

A

Inhalation - external intercostals contract, rib cage moves up and out, diaphragm contracts , increase thoracic cavity/ volume DECREASING pressure

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14
Q

Pulmonary ventilation

A

PV = tidal volume x breathing rate

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15
Q

Blood vessels of heart

A

Vena Cava supplies R atrium with deox blood from body
Pulmonary vein supplies L atrium with oxy blood from heart
R ventricle supplies pulmonary artery with deox blood
L ventricle supplies aorta with oxy blood

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16
Q

Job of valves

A 
Ensure one way flow
Atria - ventricles - arteries
2 valves - AV valves, semi-lunar valves
AV valves - between atria and ventricles
SL valve - between ventricles and arteries
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17
Q

When are AV open ore closed

A 
Open = pressure in atria bigger than ventricles
Closed = pressure in ventricles greater than atria
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18
Q

When are SL open or closed

A 
Open = pressure in ventricles bigger than arteries
Closed = pressure in arteries bigger than ventricles
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19
Q

Process of cardiac cycle

A

All relaxed, AV valve open SL valve closed
SA node causes atria to contract with an impulse
Sent too AV node allowing ventricles to fill with blood
Impulse travels through bundle of his and into ventricle walls through purkinje fibres causing contraction of ventricles, av valves close, sl valves open
ventricles relax, sl close, av open

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20
Q

Formula for cardiac output

A

CO = stroke volume x heart rate

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21
Q

CHD and myocardial infarction

A

High pressure damages lining of coronary artery
cholesterol build up beneath lining
breaks through lining forming atheromatous plaque
blood clot forms
blocks coronary artery
less blood flow

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22
Q

Risk factors of CHD

A

Age, gender, ethnicity

saturated fats, salts, smoking, obesity

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23
Q

Atheroma and aneurysm

A

Atheroma weakens wall of artery, blood builds up in the wall, the wall swells then bursts = aneurysm

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24
Q

Structure of arteries/arterioles

A

Narrow lumen
Thick wall
Elastic tissue - withstand pressure, recoils to maintain pressure and smooth out
Smooth muscle for vasodilation/constriction
Collagen prevents tearing

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25
Q

Structure of veins/venules

A

Wide lumen for good blood flow
Thin wall, can be squished by muscles to increase venous return
Valves prevent back flow

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26
Q

Adaptations of capillaries

A

Many small capillaries, large sa
Thin wall, short diffusion distance
Pores between cells, allows fluid to move in and out
Narrow lumen, increase diffusion time but decrease diffusion distance

27
Q

How does exchange occur between capillaries and all cells

A

By mass flow
Fluid moves out of blood in capillaries carrying the nutrients
Fluid moves back in the blood capillaries carrying the waste

28
Q

How is tissue fluid formed and returned to circulatory system

A

At arterial end there is a build up of hydrostatic pressure
Pushes fluid out of capillaries via pores
Fluid carries nutrients
Fluid surrounds the cells
At venous end fluid moves back in by osmosis
Capillary has low water potential due to protein presence, too large to move out
Any excess tissue fluid is picked up by lymph system and returned to vena cava

29
Q

Why does high blood pressure cause tissue fluid accumulation

A

Increased hydrostatic pressure, more tissue fluid forced out

30
Q

Why does diet low in protein cause accumulation of tissue fluid

A

The water potential in capillary is not as low as normal, not as much fluid can move back in vias osmosis

31
Q

Structure of haemoglobin

A 
Globular protein - soluble and specific
Quaternary
Each chain has a haem group
Each haem has Fe2+
Each Fe2+ carries and 02
Each haemoglobin carries 4 lots of 02
32
Q

What is affinity

A

The level of attraction haemoglobin has to 02

33
Q

Role of haemoglobin in 02 transport

A

Haem has high affinity in lungs, high pp of 02 and low pp of c02 in lungs and becomes saturated
Haem is transported in rbc in the blood
Haem has low affinity in respiring tissues, low pp of 02 and high pp of c02 in respiring tissues so 02 is unloaded, haem becomes unsaturated

34
Q

Relationship between 02 partial pressure and affinity/saturation of haemoglobin

A

Positive correlation
As 02 partial pressure increases, affinity/saturation of haemoglobin increases
The correlation is not linear but is curved, 02 dissociation curve/ODC
Middle portion of ODC has a steep gradient, when respiring tissues change from resting to active and pp02 falls, so large drop in affinity, more 02 delivered to respiring tissues

35
Q

Relationship between co2 pp and affinity/saturation of haemoglobin (BOHR SHIFT)

A

Negative correlation
As co2 pp increases, affinity/ saturation of haem decreases
The co2 lowers the pH of the blood, changes the shape of haem so 02 is released, lowers affinity, shifts ODC to the RIGHT, called the bohr shift
Benefit = more o2 delivered to respiring cells

36
Q

How does foetus receive o2

A

o2 dissociates from mothers haem to foetul haem, foetul haem has higerh affinity

37
Q

Benefit of foetul haem having high affinity

A

ODC will be to the left, o2 dissociates from mothers haem to foetul haem at low pp02 in the placenta

38
Q

Why do adults not keep with foetul haemoglobin

A

High affinity will mean less o2 will be unloaded at the respiring tissues

39
Q

Affinity of organism in low o2 environment

A

Has a high affinity, curve to left, can readily associate o2 at low o2 partial pressures

40
Q

Affinity of active organism

A

Has a low affinity, curve to right, so more o2 can be unloaded to meet cells demands for more respiration

41
Q

Affinity of small organisms

A

Large sa:volume ratio, lose lots of heat, needs to respire for heat, low affinity, curve to right, unloads enough o2 for cells demands of more respiration

42
Q

Job of roots

A

Absorb water and minerals

water by osmosis, minerals by active transport

43
Q

Function of xylem

A

Transport water and minerals up the plant to leaves

44
Q

Xylem structure

A

Long hollow tube
Narrow lumen
Wall made of lignin so strong, water proof and adhesive
wall contains pores

45
Q

How does water move up xylem

A

Transpiration/ loss of water at leaves
Osmosis of water from top of xylem into leaf (transpirational pull)
Applies TENSION to water in xylem
Water particles stick together pulling each other up COHESION
-Cohesion-tension theory
Supported by:
-capillary action - water automatically moves up lumen
-adhesion - water particles stick to lignin
-root pressure - water absorbed at roots pushes water up by hydrostatic pressure

46
Q

Why does tree diameter decrease during day

A 
More light and temp
Higher rate of transpiration
Higher transpirational pull
Water pulled via cohesion-tension
Water adheres to lignin, pulls xylem walls inwards
47
Q

Leaf structure

A

Upper layer called UPPER EPIDERMIS
Waxy cuticle on upper epidermis, acts as barrier reducing water loss
Beneath UPPER EPIDERMIS there are PALISADE CELLS
PALISADE CELLS allow photosynthesis
Beneath PALISADE CELLS are SPONGY MESOPHYLL CELLS
MESOPYLL CELLS are loosely packed allowing gas exchange
Lower layer called LOWER EPIDERMIS

48
Q

Adaptation of palisade cells

A

Located near top of leaf, close to light
Large SA for light
Thin cell wall so short diffusion pathway
Contains many chloroplasts
Large vacuole, pushes chloroplasts closer to edge and therefore light

49
Q

Chloroplast structure

A 
Organelle for photosynthesis
Has double membrane
Contains thylakoid discs
Thylakoids contain chlorophyll
Thylakoids stacks called granum
Thylakoids surrounded by stroma
50
Q

Gas exchange in leaves

A 
Lower epidermis has guard cells
When turgid guard cells open forming a stomata
Gas exchange occurs through stroma
Day - C02 IN 02 OUT
Night - 02 IN C02 OUT
51
Q

What is transpiration

A

Loss of water vapour via stomata

52
Q

How does transpiration occur

A

Moist lining of spongy mesophyll evaporates forming vapour
Builds up in air spaces
If conc of water vapour is high enough and stomata is open, diffuses out

53
Q

Factors that increase rate of transpiration

A

Light - more light, more stomata open, higher SA for diffusion
Temp - more evaporation, higher vapour conc and kinetic energy
Wind - more wind, maitains conc gradient
Humidity -less humidity, less vapour outside, conc gradient

54
Q

What is a potometer

A

Measures rate of transpiration

55
Q

Principle of potometer

A

As transpiration occurs, plant pulls up more water from potometer by cohesion-tension, causes bubble to move towards plant
More water lost by transpiration, more water taken up, further the bubble moves

56
Q

Measuring rate of transpiration

A

Rate of transpiration = volume of transpiration/time

Volume of transpiration = distance bubble moved x csa of tube (πr2)

57
Q

How to set up potometer

A

Healthy leaf and shoot
Cut shoot underwater and connect to potometer (prevents air bubbles from blocking xylem)
Ensure potometer is tight

58
Q

What does potometer actually measure

A

Rate of water uptake as a result of water loss

59
Q

What is a xerophyte

A

Plant adapted to reduce water loss

60
Q

Xerophyte adaptations

A

Needle like leaves - reduce SA
Thick waxy cuticle - impermeable barrier, waterproof
Dense spongy mesophyll, less air spaces for vapour build up
Sunken stomata, hairy leaves, rolled up leaves, traps moist layer of air, reduce conc gradient

61
Q

Function of phloem

A

Transport organic material

62
Q

Phloem structure

A

Sieve tube with companion cells

63
Q

Translocation

A

Mass flow of water carries sucrose
H+ actively transported out of companion cell into cell wall
Sucrose diffuses (facilitated) from source to companion cell
Co-transport of sucrose (against conc) and H+ (with conc)
Lowers wp in phloem, osmosis from xylem, increases hydrostat pressure
Forces sucrose to sink down pressure gradient
Sucrose into sink via active transport, lowers wp of sink
Osmosis of water into sink, some returns to xylem
Lowers pressure

Biology (14 decks)

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