Cardiorespiratory Flashcards
What is the cardiac output formula?
Cardiac output (L/min) = Stroke volume (L) x Heart rate (bpm)
What are the four main components of blood?
RBCs, WBCs, Plasma, Platelets
What is the main function of erythrocytes?
Carrying oxygen around the body
What does haematocrit mean? And what is the average value in humans?
The % of RBCs in the blood. 45%
How long to erythrocytes usually live for?
120 days
Where are blood cells formed in the adult body?
Bone marrow
In utero, where are blood cells formed?
Yolk sac, liver and spleen, bone marrow
In children, where are blood cells derived from?
All bones
What cell type do all blood cells derive from?
Haemopoietic stem cells
What hormone is required to stimulate the form of red blood cells?
Erythropoietin (EPO)
What key hormone stimulates the development of granulocyte?
Granulocyte-macrophage colony- stimulating factore (GM-CSF)
What hormone is required for the production of platelets?
Thrombonin
What hormone is required for the production of platelets?
Thrombopoietin (TPO)
In the erythrocyte, what does oxygen bind to?
Haem group
What metal is present in haemoglobin?
Iron
How are RBCs removed from the blood?
Spleen, liver, bone marrow (and any blood loss)
What are the two kinds RBCs production failures that cause anemia?
Hypoplastic anaemia (not enough formed) Dyshaemopoietic anaemia (ineffective production)
What is occuring to RBCs with haemolytic anaemia?
Too many red blood cells are being broken down.
What is the most common cause of anaemia?
Iron deficiency
Name the 5 main types of white blood cells and there approximate life span.
Neutrophils (6-10 hours) Monocytes (20-40 hours) Basophils (days) Eosinophils (days) Lymphocytes (weeks to years)
What is the most numerous kind of WBC?
Neutrophils
What do neutrophils release?
Chemotaxins and cytokines
How do you recognise a neutrophil on a histological slide?
Lobed nucleus (~3-5 lobes)
What do monocytes differentiate into?
Macrophages and dendritic cells
What do basophils differentiate into in the tissues?
Mast cells
What cells produce and store histamine?
Basophils/ mast cells
Describe the histological appearance of a eosinophil cell.
Pink granules, large nucleus. ‘Eosin stain loving cell- hence very pink’
Describe the histological appearance of a basophil cell.
Purple granules throughout the cell
What WBC is known as the ‘clever’ or most complex cell?
Lymphocytes
What is the function of the B-lymphocyte?
Make antibodies when stimulated by foreign antigens
Where do B-lymphocytes mature?
Bone marrow
Where do T lymphocytes mature?
Thymus
What do T helper cells (CD4+) do in an immune response?
Suppress or regulate the immune response. They can release cytokines.
What do cytoxic T cells (CD8+) do in an immune response?
Target damaged/infected cells for cell death (by lysis)
In general, what’s the immunological role of T lymphocytes?
Aids B cells. Generate cellular or cell-mediated immunity
What’s the general immunological role of B lymphocytes?
Makes antibodies to presented protection
What are the four types of phagocytes?
Neutrophils, Monocytes, Basophils, Eosinophils,
Which is microcirculation?
The transport of blood around the smallest blood vessels i.e. arterioles, capillaries and venules
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
What activates platelets?
Tissue factor- found everywhere but endothelial cells (so coagulation occurs everywhere but the blood stream)
What is formed during primary haemostasis?
Platelet plug
Briefly describe how a platelet plug is formed.
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
What cells produce immunoglobulins (antibodies)?
B lymphocytes
What is the main aim of the coagulation cascade?
To convert fibrinogen into fibrin to form a blood clot
What is the aim of the fibrinolytic system?
To break a fibrin clot with plasmin enzyme as part of the healing process
What are the steps involved in primary haemostasis?
Vasoconstriction
What causes fluid to move out of capillaries at tissues?
A high hydrostatic pressure
Approximately how much tissue fluid is reabsorbed into the capillaries at the venous end?
~ 95%
What process is occurring when tissue fluid is moving back into the capillaries?
Osmosis- due to the very low water potential in the blood
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
What molecules cause parasympathetic stimulation of the heart? What mechanism occurs?
Acetylcholine. Decreased Na permeability so longer time to reach membrane potential
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
What is the average blood pressure in the pulmonary system?
Systolic- 20
Diastolic- 8
What is the average normal blood pressure in the systemic system?
120/80
What three factors allow venous return against gravity?
Valves
Respiratory pump
Muscle action pump
What is the function of lymph vessels?
To drain excess fluid from muscles
What vein does lymph drain into?
Subclavian veins
What kinds of vessel has valves?
Veins, lymph vessels
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.
At rest, what % potential is the heart working at?
~60%
What is afterload?
The pressure the heart has to work against to eject blood during systole.
How would an increased afterload affect stoke volume?
Decreased stoke volume
How would a decreased afterload affect stroke volume?
Increase stroke volume (to overcome the increased resistance)
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
What is the difference between contractility and Starlings law?
In starlings law, myosin cross bridges are altered by sympathetic innervation
With contractility, myosin cross bridges are altered by sympathetic innervation
Where are the peripheral chemo and baroreceptors found?
The aortic arch and carotid sinus
Where are the central baroreceptors found? (rather than peripheral)
Atria, ventricles and pulmonary artery
Where are the central chemoreceptors found? (rather than preipheral)
Medulla
What nerves supply the peripheral baroreceptors?
Aortic arch supplied by vagus nerve
Carotid sinus supplied by sinus nerve (a branch of the glossopharyngeal/CNIX nerve)
What is the name of the hormone system that regulates blood pressure?
Renin-angiotensin-aldosterone system
What does the renin-angiotensin-aldosterone system control?
Blood pressure
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
The intrinsic ability of the heart to adapt to changing volumes of venous return is also known as what?
Starling’s law of the heart
What are the two divisions of the autonomic nervous system that can affect cardiac output?
Sympathetic and parasympathetic
Name 3 organs that are continuously conditioning the blood.
Lungs- gaseous exchange
Kidneys- blood vol and electrolyte composition
Skin- temperature
What occurs during secondary haemostasis?
Formation of fibrin from fibrinogen by activated coagulating factors particularly thrombin. Fibrin stabalises a platelet plug.
