CVS+ Flashcards
Define pulse pressure.
The difference between the systolic and diastolic blood pressure. It is measured in millimetres of mercury.
Define blood pressure.
The pressure of blood on the walls of blood vessels in the circulatory system
What is endothelin?
An amino acid peptide that is produced by vascular endothelium.
When reading blood pressure, which number is systole and which number is diastole?
Top number is systole - the highest level your blood pressure will reach when your heat beats
Bottom number is diastole - the lowest level your blood pressure will reach when your heart relaxes between beats
What is Pouseille’s Law?
Flow = radius to the power of 4
States that the flow of a fluid (Q) is related to the viscosity of the fluid (V), the pressure gradient across the tubing (P) and the length of the tube (L).
What is Ohm’s Law?
Flow = pressure gradient/resistance
What 3 factors relate to viscosity and which is the most important?
- Haematocrit (most important)
- Blood flow
- Vessel diameter
What is auto-regulation and where is it optimum?
The ability of an organ to regulate its own blood supply
Renal, cerebral and coronary systems = excellent
Splanchnic, skeletal and muscular systems = moderate
Cutaneous = poor
Which valves are classed as atrioventricular?
The mitral valve and the tricuspid valve.
What are some of the features of the atrioventricular valves?
The mitral has two cusps, the tricuspid has three.
They are between the upper chambers of the heart (atria) and the lower chambers of the heart (ventricles)
They are intrinsic parts of their ventricles
The free edge of each cusp is attached to the chordae tendineae, which are attached to the papillary muscle. The papillary muscle contracts during systole to keep the chordae tendineae taught.
Which valves are classified as the semilunar valves?
The aortic and pulmonary valve
What are some of the features of the semilunar valves?
They are intrinsic parts of their arteries (which leave the heart)
Both have three cusps
The free edge of the cusps has a thickening, which helps to shape the valve when it is closed
What are the chordae tendineae?
A group of tough, tendinous strands in the heart. Commonly referred to as the “heart strings” since they resemble small pieces of string.
Attach on one end to the edges of the tricuspid and mitral valves of the heart and on the other end to the papillary muscles
They play a vital role in holding the atrioventricular valves in place while the heart is pumping blood
At what spinal level is the arch of the aorta?
T4
What is the surface marking for the apex beat?
The 5th intercostal space in the mid-clavicular line on the left. It is in the mitral valve area.
Define apex beat.
The furthest most point inferiorly and laterally from the sternum where the cardiac impulse is still palpable.
What produces the 1st heart sound and what is the character of the sound?
The closure of the mitral valve and the sound is ‘lub’
What produces the 2nd heart sound and what is the character of the sound?
The closure of the aortic valve and the sound is ‘dub’
What is the 3rd heart sound and who may you be able to hear it in?
Normal in under 25s as heart is more elastic and you are able to hear the blood for passive filling of the ventricle
Is there a 4th heart sound? If so, when it is heard?
Usually no! If there is it is entirely PATHOLOGICAL and is caused by the atria contracting forcefully in an effort to overcome an abnormally stiff or hypertrophic ventricle. Heard just before the first heart sound (S1).
When does the aorta fill with blood?
During systole
When do the coronary arteries fill with blood?
During diastole
What is the term for when the heart is on the opposite side?
Dextrocardia. It is a congenital abnormality (it is present from birth)
How many layers make up the heart wall? What are they?
- Epicardium — protective layer mostly made of connective tissue
- Myocardium — the muscles of the heart
- Endocardium — lines the inside of the heart and protects the valves and chambers