1
Q
what are the key features and functions of erythrocytes? (red blood cells)
A
- made in the bone marrow
- bi-concave shape, round and flattened with a central indentation to maximise the surface area for exposure to oxygen
- transport oxygen and carbon dioxide within the body
- do not have a nucleus which increases space to carry the maximum amount of haemoglobin
- haemoglobin combines with oxygen so erythrocytes are able to transport more oxygen
- small and flexible, allowing them to get into narrow blood vessels called capillaries
2
Q
what are the key features and functions of leukocytes? (white blood cells)
A
- immune cells that defend the body against infection
- detect abnormal material and destroy it
3
Q
what are the key features and functions of lymphocytes?
A
- 2 types
- B cells develop in the bone marrow
- B cells produce antibodies to destroy antigens such as bacteria, viruses and toxins
- T cells develop in the thymus gland and destroy the body’s own cells that have been taken over by viruses or have become cancerous
4
Q
what are the key features and functions of neutrophils?
A
- Small and fast
- One of the first cell types to travel to the site of infection
- Protect the body against bacterial infection
- Highly mobile and attracted to any area of infection by chemicals produced by damaged cells
5
Q
what are the key features and functions of monocytes?
A
- the largest of the white blood cells
- Originally formed in the bone marrow
- Released into the blood and tissues
- When certain germs enter the body, they quickly rush to the site for attack
6
Q
what are the key features and functions of platelets?
A
- Produced in the bone marrow
- Fragments of larger cells
- Disc shaped
- Help to form blood clots by clumping together to slow or stop bleeding and to help wounds heal
7
Q
what are the key features and function of the plasma?
A
- largest component of blood (55%)
- clear yellow-ish coloured liquid
- carries platelets, red blood cells, white blood cells and proteins
- provides a means of transport for glucose, lipids, amino acids, hormones, dissolved food molecules, carbon dioxide and oxygen
- carries proteins including fibrinogen which helps with blood clotting
- helps with temperature regulation of the body - blood removes heat from tissues such as muscles and circulates it around the body
8
Q
what are the 5 main function of blood?
A
- transport
- temperature regulation
- exchange of materials with body tissue
- preventing infection
- blood clotting
9
Q
temperature regulation
A
- the process of thermoregulation maintains optimum body temperature
- the blood plays a role in thermoregulation
- it distributes heat throughout the body, from the core to the surface and vice versa
10
Q
transport
A
- blood vessels are where delivery and waste removal takes place
- oxygen, nutrients and hormones are delivered around the body in the blood and carbon dioxide and other waste products are removed
11
Q
exchange of materials with body tissues
A
- capillaries allow exchange of substances with body tissues through their thin walls
- as blood travels at high pressure in the arteries towards the capillaries, pressure filtration occurs which results in plasma passing through the capillary wall into the tissue fluid which surrounds the cell
- tissue fluid provides cells with useful substances such as glucose and oxygen and waste products are passed out of the cells into the tissue fluid to be removed
- most of the tissue fluid is returned to the blood. any excess tissue fluid is absorbed by lymphatic vessels which return it to the circulatory system as lymph.
- plasma and tissue fluid are composed of similar substances except for plasma proteins which is only found in plasma. They are too large to be filtered through the capillary walls
12
Q
preventing infection
A
- white blood cells are immune system cells
- they are ready to attack invaders such as bacteria and viruses
- when fighting infection, the body produces more white blood cells
13
Q
blood clotting
A
- an important process that prevents excessive bleeding when a blood vessel is injured
- platelets and proteins in your plasma work together to stop the bleeding by forming a clot over the injury
14
Q
describe the pathway of blood
A
deoxygenated blood enters from the vena cava into the right atrium.
blood collects in the right atrium until it is full and then starts to squeeze through the tricuspid valves into the right ventricle.
blood is then pushed through the pulmonary valves into a vessel called the pulmonary artery to the lungs.
oxygenated blood from the lungs passes through the pulmonary vein and collects in the left atrium.
the blood then passes through the mitral valves into the left ventricle.
the blood is then forced into the aorta through the aortic valves.
15
Q
what are the 14 parts of the heart?
A
superior vena cava
pulmonary veins
right atrium
tricuspid valve
pulmonary valve
right ventricle
inferior vena cava
myocardium
aorta
pulmonary artery
left atrium
mitral valve
aortic valve
left ventricle
16
Q
what is the function of the superior vena cava?
A
a large vein that carries blood from the upper body to the heart
17
Q
what is the function of the pulmonary veins?
A
takes blood from the lungs into the left atrium of the heart
18
Q
what is the function of the right atrium?
A
deoxygenated blood enters the right atrium through both vena cava
19
Q
what is the function of the tricuspid valve?
A
separates the right atrium and the right ventricle
20
Q
what is the function of the pulmonary valve?
A
separates the pulmonary artery and the right ventricle
21
Q
what is the function of the right ventricle?
A
pumps deoxygenated blood to the lungs through the pulmonary artery
22
Q
what is the function of the inferior vena cava?
A
a large vein that carries blood from the lower body to the heart
23
Q
what is the function of the myocardium?
A
this is the muscular wall of the heart, it contracts to pump blood
24
Q
what is the function of the aorta?
A
a large artery that carries blood from the heart to the body
25
what is the function of the pulmonary artery?
carries blood from the right ventricle to the lungs for oxygenation
26
what is the function of the left atrium?
blood enters the left atrium from the pulmonary vein
27
what is the function of the mitral valve?
separates the left atrium and the left ventricle
28
what is the function of the aortic valve?
separates the left ventricle and aorta
29
what is the function of the left ventricle?
pumps oxygenated blood to the body through the aorta
30
what is the function of semilunar valves?
these valves close as the heart pumps blood into the pulmonary artery and the aorta.
they close to prevent the backflow of blood and the lub-dub sounds of the heart is these valves opening and closing.
31
why is the left ventricle wall thicker than the right ventricle wall?
the thicker wall allows the left ventricle to develop the pressure needed to force the blood through the arterial system all around the body.
the blood leaving the right ventricle moves through the pulmonary artery to the lungs, where high pressure would damage the delicate capillary network where gas exchange takes place.
32
why is the system referred to as a double circulatory system?
because blood passes through the heart twice per circuit.
the right ventricle sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart.
the left ventricle sends newly oxygenated blood around the body.
33
what is diastole?
the relaxed phase of the cardiac cycle where the chambers of the heart are refilling with blood.
when the heart muscle relaxes, the chambers fill with blood and a persons blood pressure decreases.
34
what is systole?
when the heart muscle contracts, it pushes blood out of the heart and into the large blood vessels of the circulatory system.
from here, the blood goes to all of the organs and tissues of the body.
during systole, a persons blood pressure increases.
35
describe blood flow through the heart
blood from the lungs, which is oxygenated, returns to the heart via the pulmonary vein and enters the left atrium.
blood passes through the mitral valve into the left ventricle.
blood is forced out of the aorta and carries the oxygenated blood to the rest of the body.
deoxygenated blood returns from the body to the right atrium via the superior and inferior vena cava.
the blood is squeezed through the tricuspid valve into the right ventricle.
blood is forced through the pulmonary artery, which carried the deoxygenated blood to the lungs.
36
what are the 3 stages of the cardiac cycle?
1) Atrial Systole - contraction of both atria
2) Ventricular Systole - contraction of both ventricles
3) Complete Cardiac Diastole - relaxation of the atria and ventricles
37
what is the location and role of the sinoatrial node? (SA)
- the SA node is situated in the upper wall of the right atrium of the heart
- it is known as the 'pacemaker' and is responsible for setting the rhythm of the heart
- it ensures both atria contract simultaneously
38
what is the location and role of the atrioventricular node? (AV)
- the AV node is situated at the bottom of the right atrium of the heart
- it is responsible for delaying the electrical impulses it receives from the SA node
- This delay allows time for blood to empty out of the atria into the ventricles
39
what is the location and role of Purkinje fibres?
- These are very fine specialised cardiac muscle fibres that rapidly transmit impulses from the atrioventricular node to the ventricles.
40
what is an ECG?
electrocardiogram
shows the spread of the electrical signal generated by the SA node as it travels through the atria, the AV node and the ventricles.
A normal ECG trace shows 5 waves named P, Q, R, S and T.
41
what does the ECG trace tell us about what is happening in the heart?
- the waves represent the electrical activity of the heart
- the different sections represent different activities within the heart
- The P wave at the beginning shows atrial contraction
- The QRS complex shows ventricular contraction (systole)
- The T wave shows ventricles relaxing (Diastole)
- If the waves are disordered or out of rhythm, the ECG trace indicates which part of the heartbeat is problematic.
42
what are arteries?
structure and function
- the biggest blood vessel
- carry oxygenated blood away from the heart
- blood flows quickly under high pressure
- blood flows in pulses
- the artery walls are thick, elastic and muscular
- do not have valves except for at the base of the large arteries leaving the heart
- the internal diameter is small
- an artery cross section is round
- the heart pumps blood out through the main artery called the aorta
- tough on the outside, smooth on the inside
- middle layer muscle is very strong
- inner layer is smooth so blood can flow easily
- when the heart beats, the artery expands as it fills with blood
- when the heart relaxes, the artery contracts, exerting a force that is strong enough to push the blood along
43
what are capillaries?
structure and function
- smallest blood vessel
- have walls made of a single layer of cells
- the arteries deliver oxygenated blood to the capillaries where the exchange of oxygen and carbon dioxide occurs
- the capillaries deliver waste-rich blood to the veins
44
what are veins?
structure and function
- carry deoxygenated blood to the heart
- blood flows slowly under low pressure
- blood flows smoothly with a squeezing action
- vein walls are thin with little muscle
- have valves to prevent backflow
- internal diameter is large
- cross-section is oval
- transport blood back to the lungs and heart
- 3 layers - tissue, muscle and epithelial cells
45
what does the lymphatic system consist of?
lymph
lymph vessels
lymph nodes
lymph organs - e.g the spleen and thymus
bone marrow
46
what is the role of the lymphatic system?
- it is a drainage and filtrations system
- it removes excess fluid from body tissues
- it absorbs fatty acids and transports fat into the blood stream to be absorbed in the small intestine
- it produces white blood cells, which in turn produce antibodies
47
what is the role of hydrostatic pressure?
hydrostatic pressure is the pressure from heart contractions that forces water and dissolved substances in blood plasma out through capillary walls into surrounding tissues, forming tissue fluid.
48
what is blood plasma?
- clear straw-colored liquid component of blood
- contains plasma proteins, which have role in blood clotting and supporting the immune system
- osmotic regulation (control of the water content of the body, avoiding too much water entering or leaving the cells)
49
what is tissue fluid?
- fluid between body cells
- also known as interstitial fluid
- carries nutrients and oxygen to tissue cells
- is formed from filtering of blood from capillaries due to hydrostatic pressure
- facilitates substance exchange between cells and the blood by helping to bring oxygen and nutrients to cells, and removing waste products from them as well.
50
what is lymph?
- filtered watery fluid drained by the lymphatic system
- formed from plasma
- contains white blood cells
- lymph is involved in the removal of wastes and infectious organisms from tissues
- passes through vessels of increasing size before returning to the blood
51
what are blood proteins?
- also known as plasma proteins
- the most abundant plasma proteins are albumins, which are the main contributors to the thickness or viscosity of plasma and to osmotic pressure. This pressure retains fluid within blood vessels - it is the opposite force to hydrostatic pressure. If plasma protein levels fall, the osmotic pressure also falls and fluid leaking from the bloodstream can accumulate in the tissues and cause a condition called oedoma. This is a build up of fluid in the body that causes the affected tissue to become swollen. Albumin is a carrier protein for steroids, fatty acids and thyroid hormones.
- the second most abundant group are the globulins, which include the immunoglobulins/antibodies. These are protective proteins essential for the body's immune response and are made by lymphocytes.
- a third type is fibrinogen, which has a role in blood clotting
52
What is the role of blood proteins in creating osmotic pressure?
they pull water back into the capilllaries
53
What is the role of blood proteins in blood clotting?
platelets and proteins work together to form a clot to stop bleeding
54
what is the role of blood proteins in the formation of tissue fluid?
tissue fluid is formed from 'leaked plasma'.
it does not contain plasma proteins and red blood cells
55
what is the relationship between blood proteins and osmosis with regards to the formation of tissue fluid?
the blood proteins pull water back into the capillaries by osmosis.
56
biological explanation of hypertension
high or raised blood pressure is a condition in which the blood vessels have persistently raised pressure
57
symptoms and effects of hypertension
- rarely has symptoms
- excessive pressure on the walls of arteries
- causes the artery walls to weaken
- can cause them to burst
- can lead to strokes and heart disease
- can also damage capillaries in the kidney and retina
58
causes of hypertension
age
family history
stress
high fat and salt diet
lack of exercise
smoking
alcohol
caffeine
being overweight/obese
other conditions such as kidney disease, diabetes or hormone problems
59
monitoring of hypertension
blood pressure readings taken regularly
60
treatments of hypertension
changes in diet - low fat and salt
regular exercise
reduced alcohol intake
stop smoking
getting enough sleep
reduce stress
medication - ACE inhibitors and Beta blockers
61
care needs of hypertension
reduce carbohydrates - reduces fat storage/blood sugar peaks that can damage arterial walls.
reduce salt intake - linked with high blood pressure and strokes.
avoid sudden strenuous exercise - puts pressure on blood vessels - leads to stroke
lose weight - reduces blood pressure
take up regular appropriate exercise - helps lose weight and lowers blood pressure
stop smoking - reduces pressure and prevents damage to arterial walls
reduce alcohol intake - lowers pressure, reduces weight
reduce caffeine
reduce/avoid stress
62
lifestyle impacts of hypertension
- poor memory
- risk of stroke
- chest pain
- heart attack
- blurred vision
63
biological explanation of coronary heart disease - angina
chest pain caused by reduced blood flow to the heart muscle. it's not usually life threatening, but its a warning sign that you could be at risk of a heart attack or stroke.
64
symptoms of coronary heart disease - angina
chest pain
breathlessness
nausea
dizziness
tightness in the chest
feeling weak
65
causes of coronary heart disease - angina
coronary arteries supplying blood to the heart muscle become narrowed by a build-up of fatty substances.
unhealthy diet
smoking
lack of exercise
obesity
age
high cholesterol levels
diabetes
66
monitoring of coronary heart disease
ECG to measure electrical activity of the heart and show any damage to the heart muscle or signs of CHD.
blood tests to check the levels of certain fats, cholesterol, sugar and proteins in the blood
67
treatment of coronary heart disease
medication:
- nitrates relax the coronary arteries and allow more blood to reach the heart, these can be used to treat or prevent angina
- cholesterol-lowering medicines, such as statins
- anti-platelet medicines such as aspirin, and anticoagulant medicines make the blood less likely to form clots and reduce the risk of a heart attack.
- ACE inhibitors lower blood pressure and are used if someone has had a heart attack.
surgical procedures:
- angioplasty passes a tiny deflated balloon into a narrow artery and then inflates it, pushing the artery open. Sometimes a stent or mesh tube is inserted.
- a coronary artery bypass graft is surgery to bypass the narrow coronary arteries to improve the flow of blood to the heart.
- can't be cured but treatment can help manage symptoms and reduce the chances of problems.
68
care needs for coronary heart disease
reduce carbohydrates - reduces fat storage/blood sugar peaks that can damage arterial walls.
reduce salt intake - linked with high blood pressure and strokes.
avoid sudden strenuous exercise - puts pressure on blood vessels - leads to stroke
lose weight - reduces blood pressure
take up regular appropriate exercise - helps lose weight and lowers blood pressure
stop smoking - reduces pressure and prevents damage to arterial walls
reduce alcohol intake - lowers pressure, reduces weight
reduce caffeine
reduce/avoid stress
69
lifestyle impacts of coronary heart disease
impact on being able to complete daily living tasks
emotional and social impacts
high risk of heart attack
70
evaluation of nitrates as treatment - CHD/Hypertension
medication that relaxes the coronary arteries and allows more blood to reach the heart.
can be used to treat or prevent angina.
+ lowers blood pressure, reduces stress on the heart, relieve angina symptoms
- common side effects such as dizziness, light-headedness, flushing or a warm feeling in the face.
71
evaluation of cholesterol lowering medicines - statins as treatment
CHD/Hypertension
medication that lowers the level of cholesterol in the blood.
+ reduce a persons chance of having a heart attack or stroke, needing surgery or requiring a stent.
- need to take them for the rest of their life, side effects such as feeling weak, digestive problems, muscle pain and mental fuzziness
72
evaluation of antiplatelet medicines - aspirin or clopidogrel as treatment
CHD/Hypertension
makes the blood less likely to clot
+ reduces the risk of heart attacks by preventing abnormal clotting in the arteries, help relieve symptoms such as chest pain, poor circulation and shortness of breath.
- more prone to nosebleeds, bruising or bleeding for longer than usual if you cut/injure yourself.
73
evaluation of ACE inhibitors as treatment
CHD/Hypertension
lower blood pressure
are used if someone has had a heart attack.
+ improve the blood flow to the heart by preventing the production of a substance that narrows blood vessels.
- side effects such as a dry cough, too much potassium in the blood, extreme tiredness, loss of taste, headaches
74
evaluation of angioplasty as a treatment
CHD/Hypertension
surgical procedure that passes a tiny deflated balloon into a narrow artery and then inflates it, pushing the artery open.
+ blood flow through the coronary arteries improves, symptoms get better.
- bleeding or bruising under the skin where catheter was inserted, damage to the artery where the sheath was inserted, allergic reaction to the contrast agent, all risks associated with surgery
75
evaluation of coronary artery bypass surgery as a treatment
CHD/Hypertension
surgery to bypass the narrow coronary arteries to improve the flow of blood to the heart.
+ significant improvement in symptoms such as breathlessness and chest pain, heart attack risk lowered.
- risk of complications such as irregular heartbeat, wound infections, temporary reduced kidney function, memory problems, difficulty concentrating, bleeding, blood clots.
76
evaluation of lifestyle changes as treatment
CHD/Hypertension
maintaining a healthy weight to reduce chances of developing high blood pressure.
regular exercise will ensure your circulatory system is more efficient.
dietary changes such as low fat/salt diet.
stop smoking/drinking.
+ slows the progression of CHD, alleviates symptoms, healthy weight reduces chance of hypertension, lower cholesterol levels, reduced risk of having a heart attack.
- hard to implement and commit to, lack of information on what to do, time can be an issue, healthy food is more expensive, easy access to cigarettes/alcohol/unhealthy food, lack of motivation to exercise - embarrassment
Unit 4 HSC
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