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Exchange Of Substances - Biology > Circulation & Blood Vessels > Flashcards

Circulation & Blood Vessels Flashcards

(61 cards)

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1
Q

Why do large organisms need a transport system

A

Because they have a small surface area to volume ratio, so diffusion is too slow

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2
Q

Give an example of a transport system

A

The circulatory system in humans

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3
Q

Why do organisms need a transport system

A

Increasing size means a decrease in the SA:VOL ratio, so we can’t rely on simple diffusion and need to develop a specialized transport system to carry raw materials from specialized exchange organs to cells

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4
Q

How many miles of blood vessels does the body contain

A

60,000 miles

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5
Q

What are the features of a mass transport system

A

A medium to carry materials (BLOOD)
A form of mass transport to move the transport medium around in bulk, over large distances
A closed system of tubular vessels containing the transport medium (VEINS, ARTERIES, CAPILLARIES)
A mechanism for moving the transport medium with the vessels (MUSCULAR CONTRACTION OF HEART)
A mechanism to maintain mass flow in one direction (VALVES)
A mechanism for controlling the flow of the transport medium (VASOCONSTRICTION AND VASODILATION)

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6
Q

In the circulatory system in humans, what is the suitable medium in the mass transport system

A

The blood

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7
Q

In the circulatory system in humans, what is the closed system of tubular vessels in the mass transport system

A

The blood vessels
Veins, arteries, capillaries

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8
Q

In the circulatory system in humans, what is the mechanism for moving the transport medium within the vessels in the mass transport system

A

The contraction of the heart

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9
Q

In the circulatory system in humans, what is the mechanism to maintain flow in one direction in the mass transport system

A

Backflow valves

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10
Q

In the circulatory system in humans, what is the mechanism of controlling the flow of the blood in the mass transport system

A

Vasoconstriction and vasodilation

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11
Q

Why does a transport system need to be controlled

A

To control the speed of transport by having the ability to increase or decrease the speed of transport

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12
Q

Why does a transport system need a pump

A

To pump the liquid around the system

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13
Q

What does pulmonary refer to

A

The lungs

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14
Q

What does hepatic refer to

A

The liver

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15
Q

What does renal refer to

A

The kidneys

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16
Q

What is a single circulatory system? What animals have it

A

The blood passes through the heart once for a complete circuit
Fish have it

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17
Q

What is a double circulatory system? What animals have it

A

Where the blood passes through the heart twice
Mammals have it

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18
Q

Which is more efficient, double or single circulation?

A

Double

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19
Q

What happens in a double circulatory system

A

Pulmonary and systematic circulation

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20
Q

What happens in pulmonary circulation

A

Blood gets oxygenated and CO2 is removed

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21
Q

What happens in systematic circulation

A

Oxygenated blood from the lungs is pumped rapidly at an increased pressure by the heart

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22
Q

What are all the types of blood vessel in order

A

Arteries
Arterioles
Capillaries
Venules
Veins

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23
Q

What do arteries and arterioles do

A

Arteries carry blood AWAY from the heart
Arterioles control the blood flow from arteries to capillaries

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24
Q

What do veins and venules do

A

Venules act as a transition point between capillaries and veins
Veins carry blood TOWARDS the heart

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25
What is the function of the tough outer layer in blood vessels? What is it made of
Resists pressure changes from within and outside Made from collagen
26
What is the function of the muscle layer in blood vessels
Contracts and relaxes Controls size of lumen and blood flow
27
What is the function of the elastic layer in blood vessels
Helps to maintain blood pressure by stretching and coiling
28
What is the function and adaptations of the thin inner lining layer in blood vessels? What is the lining called
Very smooth to reduce friction Thin to allow diffusion Called the endothelium
29
What layers do arteries have in order
OUTER Collagen fibres Smooth muscle Elastic fibres Endothelium Lumen INNER
30
What layers do veins have in order
OUTER Collagen fibres Smooth muscle Elastic fibres Endothelium Lumen INNER
31
What layers do capillaries have
OUTER Endothelium Lumen INNER
32
In which blood vessel are muscle and elastic layers thicker? Why
Thicker in arteries If the vessel wasn’t thick the high blood pressure would cause the blood vessel to burst and to maintain blood pressure
33
Why are a muscle and elastic layers thinner in veins and arteries
Because they have a lower blood pressure and no recoil action so are less likely to burst
34
What adaptation do only veins? What does this prevent and why would this happen
Veins have valves Valves stop blood flowing backwards Blood could flow backwards because it is under a lower pressure compared to arteries
35
If blood is under low pressure what causes the blood to move through the veins
Body muscles contract which means veins are compressed As veins are pushed on, blood is moved through it
36
Describe the structure of arterioles
Thicker muscle layer than arteries Thinner elastic layer than arteries
37
What does the thick muscle layer in arterioles do
Contracts causing vasoconstriction which narrows the lumen Regulates blood flow to capillaries
38
What does the thinner elastic layer in arterioles mean
Means that the pressure will be lower than in arteries
39
Describe the structure of arteries
Thick muscle layer Thick elastic layer Thick walls
40
Why do arterioles have a thick muscle layer
To control the flow of blood to the tissues
41
What does the thick elastic layer in arteries do
Stretches under high pressure (when the ventricle contracts) Recoils under low pressure (when the ventricle relaxes) It also smooths blood flow which reduces the amount of pressure changes
42
Describe the structure of veins
Thin muscle layer Thin elastic layer Thin walls Back flow valves
43
What does the thin muscle layer in veins mean cannot happen
The thinness means that veins cannot control blood flow to tissues
44
What does the thin elastic layer in veins mean cannot happen
It means that the pressure is too low to recoil
45
What do the thin walls in veins allow to happen
The thin walls mean valves have low pressure so can be flattened
46
Describe the structure and adaptations of capillaries
No elastic or muscle tissue One cell thick walls Spaces between endothelial cells on the end of the capillary Lots of capillaries which are highly branched Narrow internal diameter (small lumen)
47
Why are one cell thick walls in capillaries an adaptation
Gives a short diffusion distance so diffusion is quick
48
Why are spaces between endothelial cells in capillaries an adaptation
Allows white blood cells (specifically neutrophils) to escape and deal with infection within the tissuee
49
Why are lots of highly branched capillaries an adaptation
Gives a large surface area for diffusion so more can happen at once
50
Why is narrow lumen in capillaries an adaptation
It means capillaries are small enough to permeate tissues so no cell is ever far from a capillary This means diffusion distance is short as networks called capillary bed are created
51
How is a capillary bed made? What do they do and how
Red blood cells are squeezed flat against the side of a capillary creating a network called capillary bed Capillary beds reduce diffusion distance by being closer to the cells they supply oxygen to
52
What is blood plasma
A straw coloured liquid which is mainly clear with substances dissolved into it
53
What is tissue fluid? Where is it found
Tissue fluid has a similar composition to blood plasma, but has fewer components Tissue fluid bathes in almost all the cells of the body
54
55
What is an oedema? How are they formed
An oedema is a build up of fluid which accumulates around tissues This happens if blood pressure is high (hypertension), so pressure at the arteriole end is too high so more fluid is pushed out of the capillary and accumulates around tissues
56
What happens at the arterial end of a capillary? Is the pressure high or low
Water/fluid is pushed out, pressure is high (hydrostatic) Small, soluble substances (eg glucose and oxygen) are moved out and large proteins remain in the protein - this is called ultrafiltration
57
What do the proteins left in the blood at the arterial end of the capillary create
They create a water potential between the capillary and the tissue fluid
58
What happens at the venous end of a capillary? Is the pressure high or low
CO2 and waste products are pushed in, hydrostatic pressure is lower so less water is pushed out Remaining tissue fluid enters the lymph vessels and drains back into the veins closer to the heart
59
What happens to the water potential gradient between the capillary and the tissue fluid at the venous end
The water potential gradient between the tissue fluid and capillary remains the same as the arteriole end so water beings to flow back into the capillary from the tissue fluid by osmosis
60
What does the lymph system do
Carries tissue fluid back into circulation Drains tissue fluid into veins close to the heart
61
How is the contents of the lymph system moved
By the hydrostatic pressure of the tissue fluid that has left the capillaries By the contraction of body muscles which squeezes lymph vessels The lymph system also has valves to stop back flow similar to veins

Exchange Of Substances - Biology (10 decks)

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