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Biology a level - ocr a > Chapter 8 - Transports Systems In Multicellular Animals > Flashcards

Chapter 8 - Transports Systems In Multicellular Animals Flashcards

1
Q

Why are specialised transport systems needed

A

High metabolic demands

  • diffusion over long distances is not enough to supply with needed quantities
  • make lots of waste products, require lots of oxygen + food

SA:V is low
- not enough surface to transport required quantities

Hormones need to be transported

Waste products removed l

Food digested in one organ needs to be transported to every single cell

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2
Q

What features do circulatory systems have in common

A
  • liquid transport medium that circulates around the system
  • have vessels that Carr the transport medium
  • pumping mechanism to move the liquid around
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3
Q

What is a

Mass transport system

A

When substances are transported in a mass of fluid with a mechanism for moving the fluid around the body

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4
Q

What are open circulatory systems

A

Blood isn’t enclosed in blood vessels all the time
It flows freely through the body cavity (haemocoel)
returns to heart through an open ended vessel

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5
Q

Example of open circulatory system in insect

A

Heart is segmented and contracts a wave, starting from the back pumping the blood into a single main artery

Artery opens up in haemocoel

Insect haemolymph transports food and nitrogenous waste

Haemolymph circulates but steep diffusion gradients can’t be maintained - can’t control the amount of haemolymph flowing to a particular tissue

Makes its way back to heart through open ended vessel

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6
Q

What is a closed circulatory system

A

The blood is enclosed inside blood vessels

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7
Q

Single circulatory systems definition

A

Single

- blood only passes through the heart once for each complete circuit of the body

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8
Q

Why single closed circulation is less efficient than double

A

Blood has to pass through 2 sets of capillaries , to exchange:

  • O2 + CO2
  • substances between blood and cells in organ systems

After passing through theses capillaries, blood pressure is very low, returns to heart slowly

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9
Q

Why is double closed circulatory efficient

A

Blood travels twice through the heart for each circuit of the body

Each circuit only passes through one capillary network

Which means
- High pressure and fast flow

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10
Q

Similarities between open and coded systems

A

Liquid transport medium
Vessels to transport the medium
Pumping mechanism to move fluid

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11
Q

Differences between open and closed systems

A

Open has few vessels
Closed has transport medium enclosed by vessels
Open isn’t enclosed

Closed can target specific tissues and cells

Open - transport medium pumped into body cavity (low pressure)
Closed - transport pumped by heart into artery (high pressure)

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12
Q

Arteries

A
  • Thick muscular walls
  • Have elastic tissue to stretch and recoil
  • Inner lining is folded - allows expansion
  • smooth muscle
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13
Q

Arteriole

A

-More smooth muscle than elastic

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14
Q

Capillaries (adaptations)

A
  • large surface area for diffusion of substances
  • single endothelial cell thick
  • cross sectional area greater than arterioles so rate of blood flow falls, more time for exchange of materials
  • substances pass out of fenestrations
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15
Q

Veins

A
  • Wide lumen
  • Collagen - but little elastic/smooth
  • Valves
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16
Q

Venules

A
  • Thin walls

- Smooth muscle

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17
Q

Adaptations that enable the body to overcome blood flow against gravity

A
  • one way valves
  • big veins run between active muscles so when muscles contract the blood is squeezed up the veins
  • breathing movements and pressure changes cause blood in veins of chest and abdomen to move towards the heart
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18
Q

What does blood consist of

A

Plasma
- dissolves glucose, amino acids, mineral ions, hormones, large plasma proteins: albumin (maintaining osmotic potential), fibrinogen (blood clotting), globulins

Red blood cells / white blood cells
- carry oxygen

Platelets
- clotting mechanism

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19
Q

Functions of blood

A

Transport of:

  • O2 + CO2
  • digested food
  • nitrogenous waste
  • hormones
  • cells and antibodies involved in immune response
  • platelets to damaged areas

Maintains a steady body temperature

Minimising pH changes

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20
Q

How are substances transports between the capillaries and tissue fluid

A
  • at start of capillary bed nearest to arterioles
  • the hydrostatic pressure forcing fluid out of the capillaries is greater then the oncotic pressure attracting water in by osmosis
  • so fluid is squeezed out of capillary into tissue fluid
  • capillaries towards venules
  • have a lower hydrostatic pressure than oncotic pressure because the pulse is lost
  • water moves back into the capillaries by osmosis
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21
Q

What causes oncotic pressure

A

Plasma proteins in blood give capillaries high solute potential

Water has a tendency to move into capillaries by osmosis

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22
Q

What is tissue fluid

A

Fluid surrounding cells in tissues

Exchanges Oxygen water nutrients

Same components as blood but without:

  • red blood cells
  • plasma proteins
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23
Q

What are lymph vessels

A

Lymph transports excess tissue fluid to the heart
Has less oxygen and nutrients than tissue fluid and plasma
Contains fatty acids absorbed from villi on small intestine

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24
Q

How does the cardiac cycle pump blood round the body

A

Atrial systole

  • ventricles are relaxed
  • atria contract - decreases volume - increases pressure
  • pushes blood into ventricle by atrioventricular valves

Ventricular systole

  • atria relax
  • ventricles contract - increase pressure - valves to close
  • opens semi lunar valves
  • blood forced into aorta/ pulmonary artery

Diastole

  • ventricles and atria relax
  • semi lunar valves close
  • atria fill with blood
  • atrioventricular valve opens
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25
Calculate cardiac output
Heart rate X Stroke volume
26
Cardiac muscle is myogenic Myogenic definition
Can contract and relax without signals from nerves
27
How does the heart beat
- sinoatrial node sends wave of electrical activity to atrial walls - left and right atria contract at the same time - non conducting collagen tissue prevents wave from ventricles - SAN transfers waves of electrical conductivity (WOEA) to atrioventricular node - slight delay before AVN passes wave to bundle of HIS - HIS conducts wave of electrical actively to purkyne tissue - cause ventricles to contract at same time
28
Double circulatory systems definition
Double | - blood only passes through the heart twice for each complete circuit of the body
29
Components utilised in blood vessels
elastic fibres smooth muscle collagen
30
How are elastic fibres utilised in vessels
Composed of elastin Can stretch and recoil Providing vessel walls with flexibility Helps withstand force of blood Evens the surges of blood - continuous flow
31
How are smooth muscle utilised in vessels
Contracts or relaxes Changes the size of lumen Controls the flow of blood to individual organs
32
How are collagen utilised in vessels
Provides structural support to maintain the shape and volume of the vessel
33
Smooth muscles role in vasoconstriction of arterioles
- smooth muscle contracts - constricts the vessel - prevents flowing into capillary bed
34
Smooth muscles role in vasodilation of arterioles
- smooth muscle relaxes - dilates - blood flows through capillary bed
35
How is the fluid in the lymph capillaries transported
Squeezing of body muscles Has valves - prevent backflow Lymph returns to blood
36
What do the lymph nodes on the lymph vessels do
Lymphocytes build up in nodes Produce antibodies Passed into blood Intercept bacteria and other debris from lymph - is digested by phagocytes
37
What is hydrostatic pressure
The pressure from heart beat forcing liquid out through fenestrations in capillaries
38
What is oncotic pressure
Result of water potential in capillary from the plasma proteins moving water into the capillary by osmosis
39
What is the heart made of
Cardiac muscle
40
What do the coronary arteries do
Supply cardiac muscle with the oxygenated blood in needs to keep contracting and relaxing
41
What is the heart surrounded by to prevent itself from over dispensing with blood
Inelastic pericardial membranes
42
How does blood move throughout the heart
- Heart is relaxed (diastole) and atria fill - Tricuspid valve opens (atrioventricular right) - Atrium and ventricle fills - Atrial systole - Ventricles contract - Tricuspid valve closes - Pumps blood into aorta/pulmonary artery - Semi lunar valve closes
43
What is diastole
Heart relaxes Atria and ventricles fill with blood Volume and pressure in heart builds
44
What is atrial systole
Atria contracts
45
What is ventricular systole
Ventricles contract Pressure increases Blood forced out
46
What do the tendinitis chords do in valves
Make sure valves are not turned inside out by pressures exerted when the ventricles contract
47
What is an electrocardiogram
Technique for measuring tiny changes in the electrical conductivity of the skin That result does the electrical activity of the heart Produces a trace which can be used to analyse the health of the heart
48
How to get an ECG reading
Electrodes stuck to clean skin | Electrodes pick up tiny changes and feed to machine
49
Tachycardia
Heartbeat is rapid Over 100bpm Shows the heart isn’t pumping blood efficiently
50
Bradycardia
Heart beat is slow | Below 60bpm
51
Ectopic heartbeat
Extra heartbeats that are out of normal rhythm Early contraction of the atria or ventricles depending on graph
52
Atrial fibrillation
Rapid impulses in the atria But do not contract properly Atria and ventricles loss rhythm Stop contracting
53
P wave caused by
Contraction (dépolarisation) of the atria
54
QRS peak caused by
Dépolarisation of ventricles
55
T wave caused by
Relaxation (repolarisation) of ventricles
56
Height of the wave means
More electrical charge | Stronger contraction
57
What is the role of haemoglobin
Binds to and transports oxygen at carbon dioxide from Lungs - cells Cells - lungs
58
What is the reversible binding of oxygen in haemoglobin
Haemoglobin + 4O2 oxyhaemoglobin HbO8 Is reversible When oxygen leaves oxyhaemoglobin disassociates
59
How does haemoglobin saturation depend on partial pressure of oxygen
Oxygen loads into haemoglobin = high partial pressure of oxygen Oxygen unloads = where = low partial pressure of oxygen
60
What does the | Partial pressure of oxygen mean
Measure of oxygen concentration in cells
61
What happen to o2 when affinity is low
Releases oxygen
62
Why is the graph s shaped
Steep - when first O2 molecule joins, shape changes, to make easier for other oxygens to join Plateaus - when haemoglobin is saturated - harder to pick up more oxygen
63
Why is fetal haemoglobin have a higher affinity
Fetus blood is better at absorbing oxygen than mothers blood Fetus gets blood from placenta when OXYGEN SATURATION has decreased For fétus to get enough oxygen to survive it needs to have a higher affinity Otherwise it’s haemoglobin would not be saturated enough
64
When does haemoglobin release oxygen more readily
At high partial pressures of CO2 Made by respiration This is where O2 is being used up
65
How is CO2 transported
CO2 diffuses into red blood cell Dissociates into H+ and HCO3- H+ make haemoglobin release O2 to carry H+ HCO3 diffuses out into plasma To make up for this loss Cl- diffuse into red blood cell = chloride shift Maintains the balance between plasma and blood At low pCO2, HCO3- + H+ rejoin to make CO2 Diffuses into alveoli breathed out
66
What is the Bohr shift
The shift in the oxygen dissociation curve | Caused by changes in carbon dioxide levels
67
What happens when carbon dioxide increases to | Dissociation curve
Shifts to the left To show oxygen is release more form the blood Because there’s a lower concentration of haemoglobin
68
What does the fetal adult dissociation curve look like
Fetal is shifted to the left To show more oxygen is loaded on to the haemoglobin Has a higher affinity that’s adult

Biology a level - ocr a (11 decks)

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