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Circulation Flashcards

1
Q

Features of a mass transport system

A

A system of vessels that carry substances (usually tubes)
A way of making sure substances are moved in the right direction
Moves materials fast enough to supply the needs of the organism
A suitable transport medium

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2
Q

Single circulatory system

A

Only passes through the heart once
Occurs in fish

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3
Q

Parts of a double circulatory system

A

Systemic circulation - carries oxygenated blood from the heart to the cells of the body
Pulmonary circulation - carries deoxygenated blood from the heart to the lungs to be oxygenated, then back to the heart

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4
Q

What is the mass transport system in mammals called

A

The cardiovascular system

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5
Q

Functions of the cardiovascular system

A

Carrying hormones
Forming part of the defence system of the body
Distributing heat
Delivers materials and takes away waste

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6
Q

What are the components of the blood

A

Plasma
Erythrocytes
Leucocytes
Platelets

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7
Q

What does plasma transport

A

Digested food products for energy
Nutrient molecules
Excretory products
Chemical messages (hormones)
Heat to maintain a steady body temperature

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8
Q

Erythrocytes function

A

Contain haemoglobin (carries oxygen) - formed in the bone marrow
Transport oxygen from lungs to all cells

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9
Q

Erythrocytes adaptations

A

Disc shape for large surface area to volume ratio for oxygen to diffuse rapidly
No nucleus so more space for haemoglobin allowing more oxygen

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10
Q

Leucocytes main function

A

To defend the body against infection

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11
Q

What are the types of leucocytes

A

Granulocytes - neutrophils, eosinophils, basophils
Agranulocytes - monocytes, lymphocytes

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12
Q

Granulocytes

A

Have granules in the cytoplasm of cells that take up stain that are obvious under microscopes
Have lobed nuclei
Non specific immune system

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13
Q

Agranulocytes

A

Do not have granules
Have unlobed nuclei

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14
Q

Platelets function

A

Tiny fragments of large cells called megakaryocytes involved in the clotting of blood

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15
Q

Haemoglobin structure

A

A large globular protein made up of four peptide chains, each with an iron containing prosthetic group - can pick up four molecules of oxygen to form oxyhaemoglobin

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16
Q

Binding of oxygen to haemoglobin

A

Forms oxyhaemoglobin by binding to an iron containing prosthetic group
The first oxygen molecule that binds to the haemoglobin alters the arrangement of the molecule making it easier for the following molecules to bind

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17
Q

The bohr effect

A

If there is a high partial pressure of carbon dioxide in the air, haemoglobin has a lower affinity to oxygen

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18
Q

Types of respiratory pigments

A

Haemoglobin
Foetal haemoglobin
Myoglobin

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19
Q

Foetal haemoglobin

A

Found in a developing foetus - depends on its mother to supply oxygen
Oxygenated blood from the mother runs through the placenta close to the deoxygenated foetal blood
Foetal haemoglobin has a higher affinity for oxygen than the mother, so can remove oxygen from the maternal blood
There is also a counter current exchange system

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20
Q

Myoglobin

A

Found in muscle tissues of vertebrates
Has a much higher affinity for oxygen then haemoglobin so becomes easily saturated with oxygen
Does not give up oxygen easily so acts as an oxygen store
Myoglobin releases oxygen when carbon dioxide levels are high and oxygen levels are low

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21
Q

Process of carbon dioxide leaving the cell

A

It passes from tissue into red blood cells by diffusion - combines with water to form carbonic acid (catalysed by carbonic anhydrase)
Carbonic acid dissociates to give hydrogen ions and hydrogencarbonate ions
Hydrogencarbonate ions leave the red blood cell by diffusion letting chloride move in (chloride shift)
Haemoglobin acts as a buffer accepting the hydrogen ions to form haemoglobinic acid (avoids changing blood pH)

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22
Q

2 main substances involved in blood clotting

A

Serotonin
Thromboplastin

23
Q

Serotonin function

A

Causes smooth muscle of the blood vessel to contract
This narrows the blood vessel, cutting of blood flow to the damaged area

24
Q

Thromboplastin function

A

An enzyme that sets in process a cascade if events that leads to the formation of a clot

25
The blood clotting cascade
Thromboplastin catalyses the conversion of prothrombin (large soluble protein) into the enzyme thrombin - happens on a large scale and needs calcium ions Thrombin converts fibrinogen (soluble plasma protein) to fibrin (insoluble substance) - this forms a mesh to cover wounds Platelets and blood cells get caught in this mesh forming a blood clot Proteins in the structure of the platelets contract making the clot tighter and forms a clot
26
Artery structure
External layer of tough tissue Small lumen Thick layer of elastic and smooth muscle Smooth lining
27
What are arterioles
The smallest branches of the artery (smallest lumen as furthest away from the heart)
28
Capillary structure
Thin walls (one cell thick) No elastic fibres, smooth muscle or collagen so they can fit between individual cells
29
Vein structure
Relatively large lumen Tough outer layer consisting of collagen fibres Relatively thin layer of smooth muscle with few elastic fibres Smooth inner surface Valves
30
Adaptations of veins to get blood back to the heart
Semilunar valves (one way) - if blood starts to flow backwards the valves close Many veins are situated between large muscle blocks - when exercising, the muscles squeeze the veins helping blood return to the heart
31
What brings deoxygenated blood to the heart
Vena cava (vein)
32
What carries deoxygenated blood to the lungs
Pulmonary artery
33
What brings oxygenated blood to the heart
Pulmonary vein
34
What carries oxygenated blood away from the heart
Aorta (artery) Carotid arteries (to neck and head)
35
Process of blood entering and leaving the heart
Deoxygenated blood from the body enters the right atrium through the vena cava When atrium is full it contracts, opening the tricuspid valve (an atrioventricular valve) and forcing blood into the ventricle The ventricle then contracts forcing blood into the pulmonary arteries (to lungs), and the tricuspid valve closes to prevent backflow Blood returns from lungs in pulmonary veins and is pumped into the left atrium Atrium contracts forcing blood into the ventricle, bicuspid valve closes Blood leaves after ventricle contracts through aorta (at high pressure in order to get around the body)
36
Systole
Contraction of the heart (atrial systole + ventricular systole)
37
Diastole
When the heart relaxes between systole and fills with blood
38
Control of the heart beat process
Sinoatrial node (SAN) is the hearts pacemaker It sets up a wave of excitation that causes the atria to start contracting (initiating the heartbeat) Annulus fibrosus (a region of non conducting tissues) prevents the excitation from directly reaching the ventricles The wave of excitation stimulates the atrioventricular node (AVN) Has a slight delay then passes wave of excitation to bundle of His (conducting fibres in septum) Bundle of His splits into two branches and carries excitation to purkyne tissue The purkyne tissues spread around the ventricles causing them to contract
39
What does an electrocardiogram (ECG) measure
The changes in electrical excitation of the heart (electrical activity)
40
What is an ECG used to investigate
The rhythms of the heart
41
What is atherosclerosis
A condition in which yellow fatty deposits or plaque (atheroma) build up on the lining of the arteries, causing them to be narrowed, blocking blood flow
42
What can atherosclerosis cause
Damage to the blood vessel lining (endothelium) and therefore could cause a aneurysm Reduced lumen size causes raised blood pressure
43
What is an aneurysm
When blood builds up behind the blockage, causing the artery to bulge and therefore weakening it meaning it could split open
44
Problems with high blood pressure
Can cause damage to small blood vessels in kidney or eye causing kidney failure or blindness
45
What types of issues can atherosclerosis cause
Angina Myocardial infarction (heart attack) Aneurysm Stroke
46
Non modifiable risk factors for atherosclerosis
Genetics Age Sex
47
Modifiable risk factors for atherosclerosis
Weight Diet Smoking Exercise Stress
48
What is tissue fluid
The fluid that surrounds all the cells in the body
49
What factors are involved in the formation of tissue fluid
Water potential - plasma proteins exert an osmotic effect Hydrostatic pressure - the residual pressure from the heartbeat that is still present as the blood enters the arterial end of the capillary beds
50
Formation of tissue fluid
When hydrostatic pressure is greater than oncotic pressure, fluid leaves the capillary and tissue fluid forms When hydrostatic pressure is lower than oncotic pressure, water moves into the capillary and tissue fluid is lost
51
What is oncotic pressure
The tendency for water to move into the capillaries by osmosis
52
What is lymph
The fluid that travels in the lymphatic system
53
How is lymph formed
When remaining tissue fluid drains into blind ended tubes called lymph capillaries

Biology (26 decks)

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