Blood Pressure Flashcards
(25 cards)
What is the vasculature?
Network of blood vessels connecting heart with all other organs and tissues in body
What do arteries and aterioles do?
Bring oxygen rich blood and nutrients from heart to organs and tissues
What do veins and venules do?
Carry deoxygenated blood back to the heart
What takes place in the capillaries?
The exchange of gases and transfer of nutrient between blood and tissue
What forms the cardiovascular system?
The heart and vasculature
Arteries
Transport high-pressure blood from heart to smaller arteries and aterioles
Aterioles
Connect arteries and capillaries
Veins
Act as reservoir of blood and transport low pressure blood from venules to heart
Venules
Connect capillaries and veins
Capillaries
Allow gas exchange, nutrient transfer and waste removal between blood and tissue fluid
Structure of blood vessels - tunica interna
Smooth single layer of cells called the epithelium in direct contact with the blood. Cells easily damages by hypertension or toxins eg cigarette smoke
Structure of blood vessels - tunica media
Middle layer comprising of smooth muscle and elastin, under influence of sympathetic nervous system and can initiate vasoconstriction and vasodilation
Structure of blood vessels - Tunica externa
Outer layer comprising connective tissue fibres that protect the blood vessels and secure them to surrounding tissues
Arterial system
Arteries supply body with with oxygenated blood
2 exceptions:
Pulmonary arteries from heart carry deoxygenated blood to lungs
Umbilical artery carries deoxygenated blood from fetus to placenta
Aorta = largest artery, leaving left ventricle and extends down left side
Venous system
Veins thin elastic vessels act as reservoir of blood, large lumen and valves to ensure one way blood flow
Superior and inferior venae cavae = largest veins
BP is influenced by…
Total volume of blood in body
Cardiac output - amount of blood pumped in 1 min
PVR peripheral vascular resistance to flow of blood in arterial system, influenced by vessel length, lumen diameter, blood viscosity
BP can be affected by change in cardiac output or PVR
What is blood pressure?
Pressure of blood against the walls of main arteries
Systolic blood pressure
Peak blood pressure in the artery following ventricular systole (contraction)
Diastolic blood pressure
Level to which BP falls during ventricular diastole (relaxation)
Hypertension
If consistently over 140/90mmHg
Hypotension
Systolic reading of less than 90
Factors causing variation in BP
Emotional state Temperature Respiration Bladder distension Pain Exercise Race/ethnicity Tabacco use Diurnal variation Alcohol use White coat hypertension Sudden change in posture Underlying medical conditions
Blood pressure, pregnancy and birth
Haemodynamic changes: increase blood volume, cardiac output, and blood viscosity
Hormonal changes: progesterone acts on smooth muscle
Impaired venous return - gravid uterus
Procedure
I.C + discuss
Apply cuff over brachial artery
Sphygmomanometer at level with woman’s heart
Suitable position legs uncrosses
Expose arm and palpate brachial artery, position cuff 2-3cm above antecubital fossa
Palpate brachial artery with fingertips and pump rapidly with other until pulse disappears, continue to inflate 30 mmhg above this
Slowly deflate taking note when pulse reappeared - approx systolic
Place stethoscope, inflate to 20-30 above approx reading
Slowly deflate 2mmhg per second listening for Korotkoff 1 sound
Continue to deflate until korotkoff 5 sound
Remove cuff and assist woman into comfortable position
Clean stethoscope
Document and discuss, refer if nec
