Chapter 7- Blood And Circulation Flashcards
1
Q
Circulatory system
A
- body’s main internal system
- links between the cell (has requirements) and the outside environment (supplies requirements)
2
Q
Important functions of blood
A
- transporting oxygen and nutrients to all cells of the body
- transporting carbon dioxide and other wastes away from the cell
- transporting hormones to cells
- maintaining the PH of body fluids
- distributing heat and maintaining body temp
- maintaining water content and ion concentration of body fluids
- protection against disease causing micro-organisms
- clotting when vessels are damaged
3
Q
What is blood made up of
A
- liquid part called plasma (makes up 55%)
- non-liquid part consisting of cells and cell fragments which are called the formed elements (makes up 45%)
.
4
Q
What is included in the formed elements
A
Erythrocytes
Leucocytes
Thrombocytes
5
Q
What is plasma
A
- makes up 55% of blood volume
- 91% of plasma is water
- 9% is made up of dissolved substances: glucose, amino acids, lipids, ions, gasses, hormones, plasma proteins, wastes
6
Q
What is blood
A
- made up of a liquid part called plasma and cell fragments called formed elements
7
Q
What is formed elements
A
- make up 45% of the blood
- includes erythrocytes, leucocytes, thrombocytes
8
Q
Leucocytes
A
- white blood cells
- larger but fewer in number than erythrocytes
- remove dead or injured cells and invading micro organisms, they live for a few minutes during infection and a years when an infection isnt present
there are different types of leucocytes: - granulocytes: which have a granular cytoplasm and a lobed nucleus
- Lymphocytes: a spherical nucleus and a agranular cytoplasm
9
Q
Erythrocytes
A
- red blood cells
- biconcave discs they are thinner in the middle than around the edge
- no nucleus which allows room for haemoglobin ( a substance which combines with oxygen)
- haemoglobin is red which gives blood its colour
- live for about 120 days
- produced in bone marrow
- destroyed in the liver
- they transport oxygen
10
Q
Thrombocytes
A
- small cell fragments with no nucleus
- one- third of the size of a erythrocyte
- formed in the red bone marrow
- last for 7 days
- important for blood clotting
11
Q
Transport of Oxygen
A
- oxygen isn’t very soluble in water, so only 3% of it is carried in the blood
- other is carried in combination with haemoglobin
- oxygen combines with haemoglobin when oxygen concentration in the blood are high (occurs in lungs in blood capillaries)
- oxyhemoglobin breaks down to haemoglobin when the oxygen concentration is low
- tissue fluid around cells has low oxygen concentration because cells are always using oxygen so as blood flows through capillaries of body cells the erythrocytes give up their oxygen which diffuses into the tissue fluid and then into the cell
- -
12
Q
Haemoglobin
A
- only found in red blood cells
- combines with oxygen to form oxyhaemoglobin
- presence of haemoglobin increases oxygen carrying capacity by 60-70 times
13
Q
Oxygenated blood
A
- blood with a high proportion of haemoglobin
- oxyhaemoglobin is bright red in colour so the blood in the arteries is bright red (except for arteries to the lungs)
14
Q
Deoxygenated blood
A
- located in the veins except for the veins from the lungs
- haemoglobin is dark red and purplish in colour so therefore deoxygenated blood is dark red
15
Q
Why are red blood cells suited to their function of oxygen transport
A
- contain haemoglobin which is able to combine with oxygen
- have mo nucleus so there is more room for haemoglobin molecules
- are shaped like bi concave discs which increase the surface area for oxygen exchange and the thick edges allow more room for haemoglobin molecules
16
Q
What are the ways in which carbon dioxide can be carried
A
- 8% carbon dioxide can dissolved in the plasma and carried in solution
- 22% combines with the globin part of haemoglobin to form carbaminohaemoglobin
- remaining 70% is carried in the plasma as bicarbonate ions
17
Q
Transport of carbon dioxide
A
- carbon dioxide diffuses from blood to plasma due to difference in carbon dioxide concentration
- some carbon dioxide dissolves in plasma, some combines with haemoglobin bur most reacts with water to form carbonic acid
- carbonic acid then dissociates into hydrogen and bicarbonate ions
18
Q
What happens to carbon dioxide in the alveoli
A
- alveoli are the air sacs of the lungs and are surrounded by a dense network of capillaries
- in the blood capillaries the carbon dioxide dissolved in the plasma diffuses out of blood and into the air due to concentration difference
- carbaminohaemoglobin breaks down and the carbon dioxide molecules released also diffuse into alveolus
- the hydrogen and bicarbonate ions re combine to form carbonic acid, which breaks down under enzyme action into water and carbon dioxide—– this carbon dioxide also diffuses into the alveolus
19
Q
How are nutrients and wastes transported
A
Dissolved in blood plasma
20
Q
Transport of nutrients
A
- nutrients are obtained from the food we eat
- inorganic nutrients are transported as ions (sodium, calcium and potassium ions)
- organic nutrients dissolved in blood plasma include (glucose, vitamins, amino acids, fatty acids and glycerol)
21
Q
Transport of wastes
A
- metabolic wastes are substances produced by cells that cannot be used and if left in the body it can have a harmful effect
- important organic wastes transported in solution in blood plasma are urea, creatinine and uric acid
22
Q
The heart
A
- is a pump that pushes the blood around the body
- located in middle of chest cavity between two lungs
- completely enclosing the heart is a membrane called the pericardium
- the pericardium allows the heart to move as it beats while holding it in place
- the wall of the heart is made up of a muscle called the cardiac muscle
23
Q
Blood vessels
A
- blood is pumped into heart through blood vessels which carry the blood to the cells of the body or the lungs and then bring it back to the heart again
- the same blood flows continually through the heart and is referred to as circulation
24
Q
What are the blood vessels that join to form the channels where the blood flows
A
Arteries: carry blood away from the heart
Capillaries: tiny vessels that carry blood between the cells
Veins: carry blood back to the heart
25
Capillaries
- microscopic vessels that form a network carrying blood to every cell in the body
- enables cells to get the requirements and get rid of waste
-
26
How is the structure of capillaries suited to its function
- one layer of cells for substances to easily pass through
27
The circulation
- after blood has gone through the lungs it loses most of its pressure so the blood has to return to the heart to be pumped again before going to the rest of the body
- thus the heart is a double pump
- the left side pumps blood to lungs and right side pumps blood to rest of body
28
Circulation of the blood
Deoxygenated blood flows through lung capillaries and oxygen diffuses from air into blood. The now Oxygenated blood goes through the pulmonary vein, through the left atrium and atrioventricular valve, down into the left ventricle and then back up through the semi lunar valve and out the aorta
Then as the oxygenated blood flows through the capillaries of the body, oxygen and nutrients diffuse out of the blood and to the body cells and carbon dioxide diffuses from the cells into the blood, and the blood becomes deoxygenated. Then the blood goes through the superior or inferior vena cava (depending on which half of the body the blood flowed through) through the right atrium and down the atrioventricular valves and down into the right ventricle, then the blood foes back up the semi luna valves and out the pulmonary trunk and then the process starts over again
29
Valves in the heart
- ensure blood only flows in one direction
| - there are two main set of valves: the atrioventricular valves and the semi lunar valves
30
Atrioventricular valves
- flaps of thin tissues with the edges held by tendons
- when ventricle contracts the blood catches behind the flaps and they billow out like a parachute which seals off the opening between the atria and the ventricles blood is then forced to leave the heart through the arteries
31
Semi lunar valves
- stops blood flowing back into the ventricles when the ventricles relax
- each valve has three cups
- when blood flows through the artery the cups are pressed flat against the artery wall, when the blood tries to flow back the cups fill up and seal the opening up
32
Blood flow
- the requirements of cells vary on depending what we are doing for example when we are exercising out body uses up more oxygen and nutrients and produces more carbon dioxide and wastes compared to when we are at rest
- to cater for the requirements the blood flow needs to be able to change
- blood flow can change in two ways: by changing the output of blood from the heart and changing the diameter of the blood vessels supplying the tissues
33
The cardiac cycle
- also known as the heartbeat
- its the sequence of events that occurs in one complete beat of the heart
- the pumping phase when the heart muscle contracts is called the systole
- the filling phase when the heart muscle relaxes is called diastole
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What happens during diastole
- for a short time both atria and ventricles are in diastole
| - the atria fill up with blood and the ventricles also receive blood as the valves between them are open
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What is atrial systole
- the contraction of the atria, then follows and forces the remaining the blood into the ventricles
36
Ventricular systole
- the atria is relaxed and refill while the ventricles relax
- forces blood into arteries
- although each side of the hear is a different pump they operate together and both atria contract simultaneously as do the ventricles
37
Cardiac output
- it is the amount of blood leaving one of the ventricles every minute
- rate of blood flow depends on how fast the heart is beating and how much blood the heart pumps with each beat
- the heart rate and stroke volume both factors that influence the stroke volume
- the heart rate is the number of times the heart beats per minute
- stroke volume is the volume of blood forced from a ventricle of the heart with each contraction
38
Blood flow in the arteries: vasoconstriction
- arteries are the blood vessels that carry blood away from the heart
- the walls of the artery contain smooth muscle snd elastic fibres
- when the ventricles contract and push blood back into the arteries, the walls in the arteries stretch to accommodate extra blood
- when the ventricles relax, the artery walls recoil, the recoil keeps the blood moving and maintains the pressure
- the muscle in the artery wall does not relax to pump the blood along
- although the muscle can contract to reduce the diameter of the artery and there fore reduce the blood flow
39
Blood flow in the arteries: vasodilation
- muscles relaxing to increase blood flow opposite of vasoconstriction
40
Atrioles
- when large arteries receive the blood from the ventricles the arteries divide into small arteries and those arteries divide into smaller arteries these are known as arterioles
- they supply blood to the capillaries and have smooth muscles in the walls
- contraction and relaxation is important for regulating blood flow through the capillaries
41
Blood flow in veins
- veins carry blood to the heart
- capillaries join into small veins, venules that then join up to make larger veins
- veins don't have muscle walls so they cant change their diameter that arteries do
- blood pressure in the veins is low because it loses most of the pressure flowing through the capillaries
- walls of veins are much thinner than arteries
- pressure in veins is constant so the walls doesn't gave to be elastic
- because of low blood pressure , veins have valves to prevent back flow of blood
- as you exercise more waste is produced and these wastes acts as vasodilators, this increases the blood flow
42
Blood clotting minor injury
- prevents entry of infecting micro-organisms and minimises blood loss from injury of blood vessels
- the muscles in the arteries that have been injured constrict straight away to reduce blood flow
- walls are usually smooth but when injury occurs it creates a rough surface for thrombocytes to stick
- sticking thrombocytes attract more so it creates a plug at the site of injury that helps reduce blood loss
- the plug releases substances that act as vasoconstrictors
43
Blood clotting serious injury
- formation of blood clot involves large number of clotting factors that are present in the blood plasma
- the reactions that result from the clotting factors forms threads of an insoluble protein called fibrin
- the fibrin forms a mesh trap that traps blood cells, thrombocytes and plasma
- the mesh with the trapped material is the clot
- the threads stick to the damaged blood vessel and hold the clot in position
44
Clot retraction
- a slow process that occurs after the formation of the clot
- the network of threads contract and become stronger and pull the edges of the damaged vessel together
- as this occurs a fluid called serum is squeezed out, the clot then dries and forms a scab which prevents the entry of infecting micro organism
45
The lymphatic system
- As blood enters capillaries the high pressure forces some of the fluid in the blood out the wall and into the tissues
- the lymphatic system collects some if that fluid that escapes from the blood capillary and returns it to the circulatory system
- it plays an important part in the bodies internal defence against disease causing micro organisms
46
What does the lymphatic system consist of
- a network of lymph capillaries joined to larger lymph vessels
- lymph nodes, which are located along some of the lymph vessels
47
Lymph vessels
- when fluid leaks out of an arterial end it can sometimes mostly be returned to the blood through the venous end
- the excess fluid is removed and returned to the blood by the lymphatic system (fluid returned this way is called lymph)
- the lymphatic system does not circulate its a one way system carrying fluid away from tissues
- lymph vessels originate as blind ended tubes in the spaces between the cells in most tissues
- lymph vessels are usually slightly larger than lymph capillaries and more permeable so disease causing organisms and proteins can easily pass into the lymph capillaries
- network of lymphs join up to form to lymphatic ducts that empty the lymph into large veins in the upper chest
48
Lymph nodes
- also called lymph glands
- occur at intervals along lymph vessels
- bean shaped
- surrounded by connective tissue that enters into the node forming a framework
-
49
Where are lymph nodes most numerous
Neck
Armpit
Groin
Around alimentary canal
50
Whats within the lymph node framework
- Masses of lymphoid tissue, which contain lymphocytes, macrophages and plasma cells
- spaces between the cells of the lymphoid tissue are criss-crossed by a network of fibres
- lymph enters through vessels on the convex side of the node, filters through spaces and passes out through vessels on the opposite side
- lymph passes through several nodes before entering the circulatory system
51
Role of the lymphatic system
- lymph entering the lymph nodes contain cell debris, foreign particles and micro organisms that have penetrated the bodies external defences
- some of these organisms may cause disease and therefore have to be destroyed
- bacteria are trapped in the meshwork of the fibres and the lymph flows through the spaces of the nodes and large phagocytic cells called macrophages destroy these particles
52
How do macrophages destroy the bacteria particles
- the macrophages ingest the particles by phagocytosis and projections from the macrophages surround the particle and take it into the cell where it is destroyed by enzymes and is killed within 10 to 30 mins
- when infection occurs the formation of lymphocytes increase and the lymph nodes become more swollen and sore
53
Blood groups and transfusions
- a blood transfusion can be given to someone who has lost a lot of blood or other conditions like anaemia
- it involves blood or a blood product from a donor being injected directly into a patients bloodstream
- early transfusions involved the transfer of animal blood
- an Australian doctor experimented with blood transfusions which lead to the discovery of the ABO blood group system
- years later another doctor discovered the Rh blood group system
- a number of other blood group systems have been discovered but the ABO and Rh are important in blood transfusions
54
What is an antigen
A substance that is capable of stimulating the formation of a specific protein called an antibody
55
What is an anitbody
Are produced in response to an antigen and are able to combine with the antigen that initiated that response
Protect our bodies against invaders
56
ABO blood groups
- on the surface of the red blood cells a person may have antigen A, antigen B, both antigens or neither
- in the blood a person can have either anti B, anti A, neither anti B or anti A or both anti A and anti B
- when giving a blood transfusion its important you don't give them a blood type that has an antibody than can attack and kill the antigen you have:
Blood group A: can have blood group AB
Blood group B: can have blood group AB
Blood group AB: can have all blood types
Blood group O: can only have blood group 0
57
Rh blood groups
- named after the rheesus monkey
- a person with Rh antigens is Rh positive
- a person with no Rh antigens is Rh negative
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Agglutinate
The mixing of blood types that are incompatible can cause the erythrocytes to clump together
59
Whole blood
- a type of transfusion
- blood taken from the donor but with a chemical to prevent clotting
- used in cases of severe blood loss
60
Red cell concentrates
- a type of transfusion
- mostly used
- produced by spinning blood at a high speed in a centrifuge
- heavier cells sink to the bottom leaving the lighter plasma at the top
- concentrate may or may not have leucocytes and platelets removed
- used on patients suffering heart disease or sever anaemia
61
Plasma
- type of transfusion
- the liquid part of the blood
- may be given to patients that require extra clotting factors to control sever bleeding or to patients with liver disease
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Platelet concentrate
- type of transfusion
| - given to patients with abnormal platelets or a reduced number of platelets
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Cyropresipitate
- type of transfusion
- obtained by freezing the plasma and thawing it slowly
- when thawed the cryoprecipitate remains solid
- contains substances necessary for blood clotting
- may be used to treat forms of haemophilia, but often used for sever bleeding
64
Imminoglobulin
- type of transfusion
- a group of proteins that act as antibodies
- extracted from blood and used in patients who are deficient in antibodies
- particular immunoglobulins from certain donors are used to treat patients with no immunity to a particular disease
- tetanus immunoglobulins may be used to treat tetanus
65
Autologous
- a type of transfusion
- when an own patients blood is used
- blood is collected prior to operation
- often used for elective surgery
- blood is collected about 4 weeks before the operation
- eliminate the risk of transmission of disease and possible side effects of transfusions
