Blood Pressure Flashcards
What is the definition of blood pressure?
The pressure of blood against the walls of the
main arteries
What is systolic blood pressure?
The peak blood pressure in the artery
following ventricular systole (contraction)
What is diastolic blood pressure?
The level to which the arterial blood
pressure falls during ventricular diastole (relaxation)
What is hypertension?
High BP - above 140/90mmHg
What is hypotension?
Low BP - systolic reading of less than 90mmHg
What does mmHg mean?
Millimetre of mercury
What is the name of the device used to measure BP?
Sphygmomanometer (said: sfigg-mom-an-om-eter)
What is the procedure for taking a BP reading? (16 steps)
- Ensure correct cuff size
- Obtain IC
- Encourage woman to empty bladder
- Ensure woman is relaxed with both feet on the floor
- Wash hands
- Identify position of brachial artery via palpation
- Apply BP cuff 2-3cm above brachial artery site
- Ensure valve is closed, inflate and palpate
radial pulse – rarely seen but is correct
procedure. - Deflate cuff quickly
- Put stethoscope on and place diaphragm over brachial artery
- Inflate cuff 30mmHg higher than expected systolic BP, deflate slowly until ‘thudding’ is heard
- When thudding starts, record as systolic reading
- When thudding ends, record as diastolic reading
- Deflate cuff and remove
- Record findings
- Clean equipment
Steps 8&9 often skipped in practice
What can high BP indicate?
Distressed emotional state, pre-eclampsia, recent exercise, pain, sudden change in posture, pre-existing medical conditions
3 things BP is influenced by?
- Cardiac output (amount of blood pumped in 1 min)
- Total blood volume
- Peripheral vascular resistance (PVR) (resistence to flow of blood, factors such as lumen diameter and blood viscosity can affect this)
What is the tunica interna?
A smooth, single layer of cells called the
epithelium in direct contact with the blood. The cells are easily
damaged by hypertension or toxins such as cigarette smoke.
What is the tunica media?
The middle layer comprising smooth muscle and
elastin. This area is under the influence of the sympathetic
nervous system and can initiate vasoconstriction or vasodilation.
What is the tunica externa?
The outer layer comprising connective tissue
fibres that protect the blood vessels and secure them to any
surrounding tissues.
Arteries supply the body with oxygenated blood, but there are 2 exceptions to this. What are they?
Pulmonary arteries from the heart - these carry deoxygenated blood to the lungs
Umbilical artery - carries deoxygenated blood from the fetus to the placenta
Which are the largest veins?
The superior and inferior venae cavae.