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Biology > Module 3 - Exchange and Transport > Flashcards

Module 3 - Exchange and Transport Flashcards

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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
Structure of veins/venules
Wide lumen for good blood flow Thin wall, can be squished by muscles to increase venous return Valves prevent back flow
26
Adaptations of capillaries
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
How does exchange occur between capillaries and all cells
By mass flow Fluid moves out of blood in capillaries carrying the nutrients Fluid moves back in the blood capillaries carrying the waste
28
How is tissue fluid formed and returned to circulatory system
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
Why does high blood pressure cause tissue fluid accumulation
Increased hydrostatic pressure, more tissue fluid forced out
30
Why does diet low in protein cause accumulation of tissue fluid
The water potential in capillary is not as low as normal, not as much fluid can move back in vias osmosis
31
Structure of haemoglobin
``` 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
What is affinity
The level of attraction haemoglobin has to 02
33
Role of haemoglobin in 02 transport
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
Relationship between 02 partial pressure and affinity/saturation of haemoglobin
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
Relationship between co2 pp and affinity/saturation of haemoglobin (BOHR SHIFT)
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
How does foetus receive o2
o2 dissociates from mothers haem to foetul haem, foetul haem has higerh affinity
37
Benefit of foetul haem having high affinity
ODC will be to the left, o2 dissociates from mothers haem to foetul haem at low pp02 in the placenta
38
Why do adults not keep with foetul haemoglobin
High affinity will mean less o2 will be unloaded at the respiring tissues
39
Affinity of organism in low o2 environment
Has a high affinity, curve to left, can readily associate o2 at low o2 partial pressures
40
Affinity of active organism
Has a low affinity, curve to right, so more o2 can be unloaded to meet cells demands for more respiration
41
Affinity of small organisms
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
Job of roots
Absorb water and minerals | water by osmosis, minerals by active transport
43
Function of xylem
Transport water and minerals up the plant to leaves
44
Xylem structure
Long hollow tube Narrow lumen Wall made of lignin so strong, water proof and adhesive wall contains pores
45
How does water move up xylem
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
Why does tree diameter decrease during day
``` 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
Leaf structure
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
Adaptation of palisade cells
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
Chloroplast structure
``` Organelle for photosynthesis Has double membrane Contains thylakoid discs Thylakoids contain chlorophyll Thylakoids stacks called granum Thylakoids surrounded by stroma ```
50
Gas exchange in leaves
``` 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
What is transpiration
Loss of water vapour via stomata
52
How does transpiration occur
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
Factors that increase rate of transpiration
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
What is a potometer
Measures rate of transpiration
55
Principle of potometer
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
Measuring rate of transpiration
Rate of transpiration = volume of transpiration/time | Volume of transpiration = distance bubble moved x csa of tube (πr2)
57
How to set up potometer
Healthy leaf and shoot Cut shoot underwater and connect to potometer (prevents air bubbles from blocking xylem) Ensure potometer is tight
58
What does potometer actually measure
Rate of water uptake as a result of water loss
59
What is a xerophyte
Plant adapted to reduce water loss
60
Xerophyte adaptations
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
Function of phloem
Transport organic material
62
Phloem structure
Sieve tube with companion cells
63
Translocation
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

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