Cardiovascular and blood Flashcards
Components and physiology
1
Q
What is the cardiac output formula?
A
Cardiac output (L/min) = Stroke volume (L) x Heart rate (bpm)
2
Q
What are the four main components of blood?
A
RBCs, WBCs, Plasma, Platelets
3
Q
What is the main function of erythrocytes?
A
Carrying oxygen around the body
4
Q
What does haematocrit mean? And what is the average value in humans?
A
The % of RBCs in the blood. 45%
5
Q
How long do erythrocytes usually live for?
A
120 days
6
Q
Where are blood cells formed in the adult body?
A
Bone marrow
7
Q
In utero, where are blood cells formed?
A
Yolk sac, liver and spleen, bone marrow
8
Q
In children, where are blood cells derived from?
A
All bones
9
Q
What cell type do all blood cells derive from?
A
Haemopoietic stem cells
10
Q
What hormone is required to stimulate the form of red blood cells?
A
Erythropoietin (EPO)
11
Q
What key hormone stimulates the development of granulocyte?
A
Granulocyte-macrophage colony- stimulating factore (GM-CSF)
12
Q
What hormone is required for the production of platelets?
A
Thrombopoietin (TPO)
13
Q
What catalyses the conversion of fibrinogen to fibrin?
A
Thrombin
14
Q
What does the enzyme thrombin do?
A
Catalyses the conversion of fibrinogen to fibrin. Also activates multiple procoagulant factors
15
Q
In the erythrocyte, what does oxygen bind to?
A
Haem group
16
Q
What metal is present in haemoglobin?
A
Iron
17
Q
Where are RBCs removed from the blood?
A
Spleen, liver, bone marrow and any blood loss
18
Q
What are the two kinds RBCs production failures that cause anemia?
A
Hypoplastic anaemia (not enough formed) Dyshaemopoietic anaemia (ineffective production)
19
Q
What is happening to RBCs with haemolytic anaemia?
A
Too many RBCs are being broken down
20
Q
What is the most common cause of anaemia?
A
Iron deficiency
21
Q
Name the 5 main types of white blood cells and there approximate life span.
A
Neutrophils (6-8 hours) Monocytes (20-40 hours) Basophils (days) Eosinophils (days) Lymphocytes (weeks to years)
22
Q
What is the most numerous kind of WBC?
A
Neutrophils
23
Q
What do neutrophils release?
A
Cytokines and chemotaxins
24
Q
How do you recognise a neutrophil on a histological slide?
A
Lobed nucleus (~3-5 lobes)
25
What do monocytes differentiate into?
Macrophages and dendritic cells
26
What is the function of dendritic cells?
Antigen presenting cells
27
What is the function of macrophages?
Many functions. Detection, phagocytosis, APC and release cytokines to activate other cells. Found stationary in tissue and mobile in blood.
28
What differentiates into dendritic cells and macrophages?
Monocytes
29
What do basophils differentiate into in tissues? And what is it's function?
Mast cells. Important in inflammatory and allergic responses. Found in connective tissue. Release histamine. Filled with basophil granules.
30
What cells produce and store histamine?
Mast cells
31
What do mast cells differentiate from?
Basophils
32
Describe the histological appearance of a eosinophil cell.
Pink granules, large nucleus. 'Eosin stain loving cell- hence very pink'
33
Describe the histological appearance of a basophil cell.
Purple granules throughout the cell
34
What WBC is known as the 'clever' or most complex cell?
Lymphocytes
35
What is the function of the B-lymphocyte?
Antibody production. Key role in adaptive immunity.
36
Where do B-lymphocytes mature?
Bone marrow
37
Where do T-lymphocytes mature?
Thymus
38
What do T helper cells (CD4+) do in an immune response?
Suppress or regulate the immune response by releasing cytokines.
39
What do cytoxic T cells (CD8+) do in an immune response?
Attack and destroy foreign/damaged/infected cells (by lysis)
40
In general, what's the immunological role of T lymphocytes?
Cell mediated immunity. Finding and killing targeted cells.
41
What are the four types of phagocytes?
Neutrophils
Monocytes
Basophils
Eosinophils
42
What do B-lymphocytes differentiate into?
Plasma cells (which secrete antibodies)
43
What vessels are part of microcirculation in the body?
Arterioles
Capillaries
Venules
44
Albumin is a globular protein found in the plasma of blood. Where is it formed and what is it's role?
Liver. Maintains oncotic pressure
45
What activates platelets?
Tissue factor- found everywhere but endothelial cells (so coagulation occurs everywhere but the blood stream)
46
What is formed during primary haemostasis?
Platelet plug
47
What are the 3 steps involved in platelet plug formation?
Platelet adhesion- platelets stick to exposed collagen (via Von Willebrand factor on surface)
Platelet activation- once adhered, platelets activate other platelets
Platelet plug formation- fibrinogen binds the platelets together
48
What cells produce immunoglobulins (antibodies)?
B lymphocytes
49
What is the main aim of the coagulation cascade?
To convert fibrinogen into fibrin to form a blood clot
50
What is the aim of the fibrinolytic system?
To breakdown a fibrin clot with plasmin enzyme as part of the healing process
51
What are the steps involved in haemostasis?
1. Vasoconstriction
2. Primary haemostasis/ platelet plug formation
3. Secondary haemostasis/ blood clot formation
52
What causes fluid to move out of capillaries at tissues?
A higher hydrostatic pressure in the capillaries
53
Approximately how much tissue fluid is reabsorbed into the capillaries at the venous end?
~ 95%
54
What process is occurring when tissue fluid is moving back into the capillaries?
Osmosis- due to the very low water potential in the blood
55
What molecules cause sympathetic stimulation of the heart? What mechanism occurs?
Adrenaline and noradrenaline. They cause increased Na permeability of the so the threshold potential is reached quicker
56
What molecules cause parasympathetic stimulation of the heart? How does this occur?
Acetylcholine. Decreased Na permeability so longer time to reach membrane potential
57
What difference is there between a normal cell action potential and a cardiac potential?
Cardiac action potential has a longer refractory period to prevent fatigue
58
What is the average blood pressure in the pulmonary system?
Systolic- 20
| Diastolic- 8
59
What is the average normal blood pressure in the systemic system?
120/80
60
What three factors allow venous return against gravity?
Valves
Respiratory pump
Muscle action pump
61
What is the function of lymph vessels?
To drain excess fluid from the muscles
62
What vein does lymph drain into?
Subclavian
63
What kinds of vessel has valves?
Veins and lymph vessels
64
What is the Frank Starling mechanism?
Also known as the 'length force mechanism' or 'Starlings law'. As preload/end diastolic volume increases, the total stroke volume and cardiac output increases. This is because there's an increased venous return so increased volume in the ventricles which stretches the myocardial cross fibres- causes an increased force of contraction.
65
At rest, what % potential is the heart working at?
~60%
66
What is afterload?
The pressure the heart has to work against to eject blood during systole.
67
How would an increased afterload affect stoke volume?
A decrease in stroke volume (and an increase in end systolic volume)
68
How would a decreased afterload affect stroke volume?
Increase stroke volume (to overcome the increased resistance)
69
What 4 factors affect the cardiac contraction?
These factors affect the PACE of cardiac contraction
Preload- as preload increases, SV increases
Afterload- the pressure the heart must work against
Contractility- force that heart beats with
'Eart rate- changing HR changes CO due to the formula CO=HRxSV
70
Where are the peripheral chemo and baroreceptors found?
The aortic arch and carotid sinus
71
Where are the central baroreceptors found? (rather than peripheral)
Atria, ventricles and pulmonary artery
72
Where are the central chemoreceptors found? (rather than preipheral)
Medulla
73
What nerves supply the two seperate peripheral baroreceptors?
Aortic arch supplied by vagus nerve
| Carotid sinus supplied by sinus nerve (a branch of the glossopharyngeal/CNIX nerve)
74
What is the name of the hormone system that regulates blood pressure?
Renin-angiotensin-aldosterone system
75
What does the renin-angiotensin-aldosterone system control?
Blood pressure
76
In reference to cardiovascular function, what is intrinsic and extrinsic regulation?
Intrinsic is also known as homeostatic. Cells, tissues, organs and organ systems adjust automatically in response to change.
Extrinsic regulation- controlled by nervous or endocrine systems in response to activity e.g. exercise
77
The intrinsic ability of the heart to adapt to changing volumes of venous return is also known as what?
Starlings law of the heart
78
What are the two divisions of the autonomic nervous system that can affect cardiac output?
Sympathetic and parasympathetic
79
Name 4 organs that are continuously conditioning the blood.
Lungs- gaseous exchange
Kidneys- blood vol and electrolyte composition
Skin- temperature
Liver- removal of toxins
