Arteries, Veins And Total Peripheral Resistance Flashcards
(19 cards)
In which blood vessels is vascular smooth muscle present?
All except capillaries which cannot dilate or constrict
What is the function of vascular smooth muscle in blood vessels?
To contract or relax in order to determine the radius of a blood vessel
What occurs to the vascular smooth muscle of blood vessels in chronic hypertension?
They undergo hypertrophy
Which type of blood vessel are often particularly elastic and why is this useful?
The large arteries
This allows them to act as a pressure reservoir
What process can reduce the elasticity of a blood vessel?
Calcification
What happens to blood pressure as blood travels from the left ventricle to right ventricle in systemic circulation?
Pressure decreases
What happens to blood pressure as blood travels from the right ventricle to left ventricle in pulmonary circulation?
Pressure decreases
What is the approximate value of normal blood pressure?
120/80
What factors can effect average blood pressure?
Age
Environment
Obesity
What is the formula which relates mean arterial pressure to diastolic blood pressure and pulse pressure?
MAP = diastolic bp + 1/3 pulse pressure
What is pulse pressure?
The difference between systolic and diastolic blood pressure?
What formula relates mean arterial pressure to total peripheral resistance and cardiac output?
MAP = CO x TPR
The pressure rises and falls in arteries during the cardiac cycle. T/F?
True
Approximately, What proportion of blood is contained in the veins?
70%
What is hydrostatic pressure in the capillaries?
The pressure that blood exerts of the capillary wall
What is colloid pressure in the capillaries?
The intrinsic osmotic pressure of the blood due to plasma proteins
Describe the changes in hydrostatic and colloid pressure as blood travels from arteriole to capillary to venule.
Hydrostatic pressure decreases between arterial and venous ends of the capillary due to a drop in blood pressure. The colloid pressure remains constant because plasma proteins are too big to leave the capillary. This results in a net movement of fluid out of the capillaries
Why is it important that pulmonary hydrostatic pressure is much lower than systemic pressure?
So that there is a net fluid transfer at both ends of the capillary network to prevent pulmonary oedema
What is the function of alpha receptor anatgonists in relation to managing a patients blood pressure?
They decrease vasoconstrictor tone therefore decreasing total peripheral resistance without causing any direct change to heart rate or cardiac output so that blood pressure decreases as according to MAP = CO x TPR
