Week 1 Flashcards
What is the function of phenylephrine?
It is an alpha-1 receptor agonist
Dramatically contracts vessels, targets smooth muscle cells
Can be found in tablets to treat cold and flu
What is the function of an alpha-1 antagonist?
Inhibit vessel constriction
Which neurotransmitters affect the sympathetic nervous system?
Adrenaline and noradrenaline
What can be found in the external lamina?
Tunica adventitia - immune cells, nerves
Describe the tunica media
A vascular layer made of smooth muscle cells
Smooth muscle cells are separated from endothelial cells by internal plastic lamina. This contains lots of little holes which are the only communication between endothelial cells and smooth muscle cells and this can be affected by hypertension
Which class of hypertension treatment often ends in -pril?
ACE inhibitors
Desribe the different valves of the heart
Tricuspid valve: between right atrium and ventricle
Mitral valve: between left atrium and ventricle
Pulmonary valve (semi-lunar): between right ventricle and pulmonary artery
Aortic valve (semi-lunar): between left ventricle and aorta
Explain the stages if the cardiac cycle
Atrial systole
Atrial diastole
Ventricular systole
First phase - Ventricular contraction pushes AV valves shut but semi-lunars are not open
Second phase - ventricular pressure rises and exceeds pressure in arteries, SL valves open and blood is ejected
Ventricular diastole
Early - blood flows back against SL valves and forces then closed
Late - all chambers are relaxed, ventricles fill passively
What is stroke volume?
The volume of blood ejected on each stroke
What is inoptropy? What is meant by negative and positive inotropy?
Contractile capability of heart muscle
Negative inotropy: smaller stroke volume
Positive inotropy: larger stroke volume
What is the formula for cardiac output?
Stroke volume x heart rate/min
How is mean arterial pressure calculated?
MAP = cardiac output x peripheral vascular resistance
