Session 1 Lecture - Introduction to the CV System Flashcards
Which ventricle is filled with oxygenated blood?
Left ventricle
What are capillaries composed of?
Single layer of endothelium (simple squamous cells) and basal lamina
What are the factors that affect diffusion?
1) Area available for exchange (larger area = quicker exchange)
2) Diffusion resistance (nature of molecule)
3) Concentration gradient
Which tissues will have more capillary density?
Those that are more metabolically active
What is the rate of blood flow known as?
Perfusion rate
Give three examples of tissues that require constant high blood flow
1) Brain
2) Heart muscle (myocardium)
3) Kidneys
Give two examples of tissues where blood flow varies
1) Skeletal muscle
2) Gut
What is the cardiac output?
Amount of blood flow per minute
In a 70kg adult this is 5L of blood per minute
Name and describe the three layers of the pericardium
1) Fibrous layer (thick and not very elastic)
2) Parietal layer (outer serous layer attached to the the fibrous layer)
3) Visceral layer or epicardium (inner serous layer attached to the heart)
What is the name for excess fluid in the pericardium?
Cardiac tamponade
How does cardiac tamponade occur?
From a rupture of the heart (blood entering the pericardium) or cancer
The fibrous layer does not allow room for expansion so build up fluid causes compression on the heart
What is the name for fluid removal after cardiac tamponade?
Pericardiocentesis
What is the transverse pericardial sinus?
Space between the ascending aorta and pulmonary trunk (leading to pulmonary arteries)
It is the space that surgeons often use to put a clamp during heart lung bypass
Name the three branches of the arch of aorta
1) Brachiocephalic trunk
2) Left common carotid artery
3) Left subclavian artery
Which arteries branch off the aortic sinus? (part of coronary circulation)
Right and left coronary arteries
Which arteries branch off from the left coronary artery?
1) Left anterior descending coronary artery (LAD) also known as anterior interventricular coronary artery
2) Circumflex coronary artery
Which arteries branch off of the right coronary artery?
1) Posterior descending coronary artery
2) Acute marginal coronary artery
What is the name of the main venous drainage of the coronary circulation?
The coronary sinus (drains into right atrium to be pumped out to be oxygenated)
Which veins in the coronary circulation appear anterior?
1) Anterior cardiac veins
2) Great cardiac vein
3) Small cardiac vein
Which veins in the coronary circulation appear posterior?
1) Left marginal vein
2) Left posterior ventricular vein
3) Middle cardiac vein
Which is the only veins in coronary circulation that feeds directly into the right atrium rather than coronary sinus?
1) Anterior cardiac veins
Why are patients likely to have a myocardial infarction if coronary artery blocked?
They are end arteries with few anastomoses (connections)
What is the fluid from unclotted blood called?
Plasma
What is the fluid from clotted blood called?
Serum
Serum = plasma - clotting factors
What is peripheral resistance?
The total resistance posed to the ejecting heart
Why might you get sludging of blood in the peripheries?
Increase in plasma viscosity = increase in whole blood viscosity
Most common cause is multiple myeloma (cancer of plasma cells)
What is polycythaemia?
Increase in red blood cells
What is leukaemia?
Increase in white blood cells
What is thrombocythaemia?
Increase in platelets
How can you measure inflammation?
Measure the levels of C-reactive protein (CRP) in the bloodstream
Give three examples of acute phase plasma proteins and why they might increase in number
1) Fibrinogen
2) Complement factors
3) C-reactive proteins
They increase in response to inflammation
What are the two different types of blood flow?
1) Turbulent flow
2) Laminar flow
In laminar blood flow where does blood move quickest?
In the middle of the blood vessel (creating a parabolic profile)
Describe turbulent blood flow and 5 possible times when it might occur
It is blood flowing in all directions in the vessel and continually mixing
It may occur when:
1) The rate of blood flow is too great
2) When it passes by an obstruction in the vessel
3) When the blood has to make a sharp turn
4) When blood passes over a rough surface
5) Increased resistance to blood flow
What is the relationship between flow and velocity?
When velocity increases flow decreases
Does the aortic arch contain elastin?
Yes it does
How are pressure and velocity related?
Pressure is inversely related to velocity
What is the name for the up and down strokes of the systole and diastole curve?
1) Up = anacrotic limb
2) Down = dicrotic limb
When do the coronary arteries fill?
During diastole (not systole)
What are the names of the four valves in the heart and where do they appear?
1) Tricuspid valve (three leaflets) - between the right atrium and right ventricle
2) Pulmonary valve - between the right ventricle and pulmonary trunk
3) Mitral or bicuspid valve (two leaflets) - between the left atrium and left ventricle
4) Aortic valve - between the left ventricle and ascending aorta
What is the dicrotic notch?
The point when the aortic valve shuts
How do you measure pulse pressure?
Systolic pressure - diastolic pressure
How can you estimate mean arterial pressure?
Diastolic pressure + 1/3 of the pulse pressure
When is retrograde flow in the arterial system highest?
When peripheral resistance is high (the blood bounces back)
The strength or volume of the pulse is determined by 2 things..
1) The force the left ventricle ejects the blood
2) The pulse pressure
What is a thready pulse?
A reduced pulse volume which can occur from left ventricular failure or hypovolaemia
What is a bounding pulse?
A strong pulse pressure which can occur from bradycardia (slow heat rate) as this widens the pulse pressure
What is the pulse that we feel?
A shockwave that arrives slightly before the blood itself
Does a low peripheral resistance increase or decrease diastolic pressure?
Decrease diastolic pressure
e.g. from vasodilation of arterioles
Does a low peripheral resistance increase or decrease pulse pressure?
Low peripheral resistance = low diastolic pressure = increased pulse pressure
Remember pulse pressure = systolic - diastolic
What percentage of the arm must a blood pressure cuff cover?
80%
What are phase 1 and phase 5 sounds when taking blood pressure?
Phase 1 = when you first start to hear sound when deflating (systolic pressure)
Phase 5 = when you no longer hear a sound when deflating (diastolic pressure)
