Midterm Flashcards
what is blood pressure
force exerted by circulating blood on the walls of blood vessels
systolic blood pressure
blood pressure when the heart (ventricles) is contracting in a BP reading
diastolic blood pressure
the time when the heart is in a period of relaxation and dialation
stroke volume
amount of blood ejected into the aorta with each heartbeat
heart rate
of heart beats per minute
peripheral resistance
the resistance factors in the circulatory systems that affects the ease of blood flow
- tone of BVs
- viscosity of blood
- increase in peripheral resistance = increase in cardiac output and vice versa
normal BP
120/80
hypotension
90 or less/60 or less
pre hypertension
130-139/85-89
stage 1 hypertension (mild)
140-159/90-99
stage 2 hypertension (moderate)
160-179/100-109
stage 3 hypertension (severe)
180-209/110-119
stage 4 hypertension (very severe)
210+/120+
pulse pressure
the difference between the systolic and diastolic pressures. Palpated as a rhythmical throbbing over an artery, normally assessed at the wrist or neck
when taking BP, which artery is the stethoscope on
brachial artery
false high BP reading causes
- Narrow cuff size
- Wrapping cuff loosely or unevenly
- Recording BP immediately after a meal, cigarette, exercise or if bladder is full
- Deflating cuff too slowly
- “White coat” syndrome- fear of doctors
false low reading
- Having a person’s arm above their heart
- Diminished hearing of health professional
false high or low reading
- defective equipment
- Performing the technique too quickly or without attention to detail
baroreceptors and location
- Receptors within BV walls that sense pressure changes.
- Locations: Carotid sinus - in the neck at the point where the carotid of the aorta, large veins, pulmonary BV and the heart
chemoreceptors and location
- Monitor the concentration of O2, CO₂ and H in the blood Located in the carotid sinus and the heart
- Influence breathing rate
- May change vascular tone through communication with the vasomotor centers of the brain
how does the autonomic nervous system affect BF
- Short term influences on BP- HR and peripheral resistance
- Parasympathetic stimulates the vagus nerve decreasing HR Sympathetic stimulation increases BP
how does the central nervous system affect blood flow
Prevents ischemia of brain tissue in extreme cases of insufficient causing massive vasoconstriction to raise BP
Renin-Angiotensin-Aldosterone mechanism
- Utilize salt retention or excretion to influence BP
- Renin, a kidney enzyme, released with sympathetic NS firing causes vasoconstriction, salt and water retention, invreasing BP
how do hormones affect blood flow
Influence vasoconstriction
- ex. Renal prostaglandins & vasopressin