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A Level Biology > Mass Transport In Animals > Flashcards

Mass Transport In Animals Flashcards

1
Q

Why do large multi cellular organisms need transport systems to carry substances between exchange substances

A

Most cells to far away from exchange surfaces or each bother for Diffusion alone to maintain composition of tissue fluid within suitable metabolic range

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2
Q

What is the function of the circulatory system

A

Transports raw materials from specialised exchange organs to body cells

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3
Q

Describe the 2 circuits the closed double circulatory system is made of

A

1 takes blood from heart to the lungs

Other loop takes blood around the rest of the body

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4
Q

What is pulmonary circulation

A

Deoxygenated blood in the right side of the heart is pumped to lungs

Oxygenated blood is returned to the left side of the heart

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5
Q

What is systematic circulation

A

Oxygenated blood in the left side of the heart is pumped to tissues and organs in the body

Deoxygenated blood returns to the right side of the heart

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6
Q

Why is pulmonary and systematic circulation important for mammals

A

Prevents the mixing of oxygenated and deoxygenated blood
Blood pumped to the body is fully saturated with oxygen

Efficient delivery of oxygen anf glucose for respiration
Blood pumped at higher pressure

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7
Q

What do coronary arteries do

A

Deliver oxygenated blood to the cardiac muscle

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8
Q

What blood vessels enter and leave the heart

A

Aorta, vena cava and pulmonary artery

Pulmonary vein

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9
Q

What is the function of the blood vessels that enter and leave the heart ?
(Aorta, vena cava and pulmonary artery, pulmonary vein

A

Aorta - takes oxygenated blood from the heart to the body (respiring tissues)

Vena cava - takes deoxygenated blood from respiring tissues to the heart

Pulmonary artery - takes deoxygenated from the heart to the lungs

Pulmonary vein- takes oxygenated blood from the lungs to the heart

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10
Q

What are blood vessels that enter and leave the kidney

A

Renal arteries and veins

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11
Q

What is the function of the renal veins and arteries

A

Renal vein - takes deoxygenated blood to the vena cava from the kidney
Renal arteries- takes oxygenated to the kidneys

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12
Q

What does the cardiac muscle contain a lot of ?

A

Large numbers of mitochondria and myoglobin

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13
Q

Describe the gross structure of the heart

A

The aorta is right at the top and is mostly to the right of the picture - attached to left ventricle

Pulmonary artery is the one in the middle that loops in aorta and comes of to the right - attached to right ventricle

Pulmonary vein is on the right side of the picture below pulmonary artery

The vena cava comes out on the left side of picture next to aorta
Right atrium - top left side
Right ventricle - bottom left side 
Left atrium - top right side 
Left ventricle - bottom right side
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14
Q

Describe where the valves are in the heart

A

The atrioventricular vale is the valve between the right ventricle and right atrium and same for the left side of heart

Semilunar valves are in the pulmonary artery and aorta

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15
Q

Describe how blood flows into heart

A

Right atrium -> AV valve -> right ventricle -> semilunar valve into pulmonary artery and away from the heart

Blood taken to lungs where it is oxygenated and is returned to the heart through the pulmonary vein

Enters in left atrium and passes through AV valve into left ventricle
Blood passes into semi lunar valve into aorta which takes blood into aorta and the whole body

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16
Q

What do the av and semi lunar valves do

A

Atrioventricular- prevent back flow of blood from ventricles to atria when ventricles contract

Semi lunar valves - prevent back flow of blood from arteries to ventricles and back into heart when ventricles contract
Link ventricle to pulmonary artery and aorta

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17
Q

Why does the left side of the heart have thicker muscular wall

A

Generates higher blood pressure

For oxygenated blood to travel greater distance all around the body

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18
Q

Why does the right side of the heart have a thinner wall ?

A

Generates lower pressure

For deoxygenated blood to travel a small distance to the lungs where high blood pressure would damage the alveoli

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19
Q

What is the function of a vein

A

Take blood back to heart under low pressure

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20
Q

Describe the structure of a vein

A

Large lumen (wider than arteries)
Very little elastic or muscle tissue
Thin walls - carry blood away from tissues as pressure of blood is low (wont burst)

Valves - prevent back flow of blood

Contraction of skeletal muscles surrounding veins, squeezes
Maintaining blood flow

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21
Q

What is the function of the arteries

A

To carry oxygenated blood from the heart to the rest of the body

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22
Q

Describe the structure of the arteries

A

Thick smooth muscle layer-
Can contract pushing blood along
Can control blood flow

Thick elastic tissue layer
Stretches as ventricle contracts under high pressure and recoils when ventricle relaxes at low pressure
Smooth pressure surges and maintained high pressure

Thick wall
Withstand high pressure and prevents artery bursting

Smooth endothelium
Narrow lumen - increases and maintain high blood pressure

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23
Q

Arteries divide into smaller vessels called

A

Arterioles

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24
Q

What is the function of arterioles

A

Control blood flow from arteries to capillaries

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25
Describe how arterioles control blood flow
They have thicker muscle layer than arteries This muscle can contract and restrict blood flow to capillaries by narrowing lumen Or Dilate to increase blood flow to capillaries by enlarging lumen
26
What is the function of capillaries
Exchange substances between blood and body tissues
27
What are 4 adaptations of capillaries for efficient exchanging of substances
``` Thin walls (one cell thick of endothelial cells) Short diffusion pathway -> rapid diffusion ``` Large number of branched capillaries -> increases surface area to vol ratio Narrow lumen -> rbc squeezed flat against capillary -> reduces diffusion distance Capillaries are found near cells -> short diffusion pathway Pores in walls -> substances can escape
28
Why do capillaries have gaps between lining (pores) of endothelial cells ?
They acts as sieve controlling which molecules can leave the capillaries Allows white blood cells to escape
29
What is tissue fluid
The fluid that surrounds cells . It proved a constant environment in which cells live
30
What is tissue fluid made of
Water, oxygen. Glucose , amino acids -> respiring cells | Small molecules that can leave blood plasma
31
Why doesn’t tissue fluid contain red blood cells or big proteins
They’re too large to be pushed out through capillary wall
32
What do cells do with tissue fluid
They take in oxygen and nutrients whilst releasing metabolic waste
33
Describe the formation of tissue fluid at the arterioles end of capillaries
At the arterial end due to the contraction of the left ventricle there is higher hydrostatic pressure inside the capillaries rather than tissue fluid. Hydrostatic pressure > osmotic pressure This pressure forces fluid and water out of capillaries into spaces around the cells by ultra filtration However large proteins remain because they’re to large to leave capillary This lowers the water potential
34
Describe the return of tissue fluid to the circulatory system towards venue end of capillaries
As fluid leaves capillary the hydrostatic pressure is lower in the capillary than blood Osmotic pressure>hydrostatic pressure Due to increasing conc of proteins that are too large to leave capillaries Water potential of capillary lowered Water re enters capillary from the tissue fluid by osmosis down water potential gradient.
35
Water potential at venue end of capillary is more negative than arterioles end why ?
Water has left capillaries But proteins in blood are too large to leave Increasing conc of blood proteins means more negative water potential
36
What happens to excess tissue fluid
It is drained into lymphatic system
37
What is swelling ?
Excess tissue fluid
38
What happens to excess tissue fluid after it drains into lymphatic system
Forms lymph which is colourless or pale yellow fluid that is like tissue fluid but has more lipids
39
Describe the lymphatic system
Network of tubes that act as a drain and has a dead end
40
Why does lymphatic system have dead end
So pressure on them can only produce movement in one direction
41
What does the lymphatic system do with the excess fluid
Transports it and returns it back into circulatory system by draining contents into blood stream via 2 ducts that join veins close to the heart
42
How is contents of lymphatic ssytem moved ?
Hydrostatic pressure of tissue fluid | Contraction of body muscles that squeeze lymph vessels
43
Why can a low protein diet lead to accumulation of tissue fluid
Low conc of protein Osmotic imbalance Water potential in capillary not lowered so water potential gradient is reduced More tissue fluid formed at arterioles end No water absorbed into blood capillary by osmosis
44
Why can high blood pressure lead to accumulation of tissue fluid
Blood vessels open wider High bp = high hydrostatic pressure Increases outward pressure from arterial end More fluid forced out More tissue fluid formed Less return of fluid Lymphatic system not able to drain away all excess fluid
45
What does the heart consist of 2 —— ——-
muscular pumps
46
Name and explain an adaption of the ventricles
Thicker walls than Atria Have to push blood out of heart but atria only have to push blood into ventricles
47
What does opening and closing the valves depend on ?
The relative pressure of the heart
48
When are valves forced open
When there is higher pressure behind the valve
49
When are the valves forced shut
When there is higher pressure in front of the valve
50
What are the 3 stages in the cardiac cycle
1. Atrial systole 2. Ventricular systole 3. Diastole
51
Describe atrial systole
``` Atria contracts Decreasing the volume inside atria Pressure inside atria is higher than pressure inside ventricles Atrioventricular valves are forced open Blood is forced into the ventricles ```
52
Describe ventricular systole
``` Atria relax Ventricles contract Volume inside ventricles decreases Increasing pressure inside ventricles AV valves shut Semi lunar valves open Because Pressure inside ventricles is higher than pressure inside atria Blood is pushed out the heart through arteries ```
53
Describe diastole
Atria and ventricles relax Increasing volume and decreasing pressure in both chambers Due to decreasing pressure, pressure is higher in Pulmonary artery and aorta than pressure inside ventricles Semi lunar valves shut Blood from vein fills atria This increases pressure in atria slightly than ventricles Pressure inside atria is higher than reassure inside ventricles So AV valves open Blood flows passively to ventricles from atria
54
Look at graph | At what point is blood flowing in the aorta and why
At point A This is ventricular systole Pressure inside ventricle is higher than pressure inside atria Shuts AV valve and opens semi lunar valve Blood forced in aorta
55
Look at graph why is ventricular volume decreasing on second part of the graph ?
In ventricular systole the ventricles are contracting and pressure is increasing Therefore volume inside the ventricles is decreasing
56
Look at graph at point c, why are the semi lunar valves shut
- Ventricles are relaxing - Pressure is higher in pulmonary than aorta - Forces semilunar valves shut
57
State equation for cardiac output
Cardiac output = stroke volume X heart rate
58
What do cardiac output, stroke volume and heart mean in equation
Cardiac output- amount of blood pumped out of the heart per minute Stroke volume - volume of blood pumped out. By the heart per minute Heart rate - number of beats per minute
59
How do you find the heart rate from cardiac cycle
``` One beat = 1 cardiac cycle Find the length of 1 cardiac cycle Human average is 0.83 secs Then find the heart rate in beats per minute 60 secs / length of 1 cardiac cycle ```
60
When to know certain valves are closed from cardiac cycle data
Semi lunar open - pressure in ventricle higher than aorta / pulmonary artery Semi lunar closed - pressure in aorta or pulmonary artery is higher than in ventricle Av open When pressure in atrium is higher than in ventricles Av closed When pressure in ventricle exceeds than atrium
61
How can atheroma result in heart attack
Narrowing of coronary arteries Restricts blood flow to heart muscle Heart anaerobically respires , less atp, not enough energy to contract Lactate produced which damages heart tissue
62
What are the risk factors for heart disease
``` Age High salt diet Saturated salt Stressful lifestyle Smoking cigarettes High blood pressure - causes damage to endothelium of artery ```
63
What to mention in data interpretation questions ?
Describe overall trend Positive, negative correlation Describe most obvious trend Manipulate data to support statement Find change between two points or percentage change
64
How should you mention conflicting evidence
``` Small sample size Take in account other risk factors Used similar groups Way in which information is collected Different environmental or lifestyle differences Correlation does not imply causation ```
65
On ecg the big jump represents what
Ventricular systole
66
On ecg the medium jump (curve) in the line represents what
Diastole
67
Name two substances which are at higher conc in the blood at the arterioles end of capillary than venule
Glucose and oxygen
68
Explain how fluid may be returned to the blood
Lymph vessels return fluid to the blood Reabsorption by osmosis Proteins are retained in blood capillary
69
Why does tissue fluid accumulate in the ankles
Gravity | Fewer lymph vessels in this area
70
Why do veins having large lumen help blood flow and being thin at low blood pressure
Can be compressed - thin | Less resistance to flow
71
What is function of eleastic fibres and smooth muscle in arteries
Allow walls to stretch and recoil Smooth muscle - regulates the diameter of lumen and Vascularconstriction

A Level Biology (16 decks)

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