Lesson 21: Topic 17 - Mean Arterial Pressure Flashcards
(42 cards)
what determines mean arterial pressure?
MAP = CO(cardiac output) x TPR(total peripheral resistance)
how do we regulate MAP?
by altering cardiac output and tpr
why is mean arterial pressure important?
- # 1 homeostatically regulated variable in your body
- provides ‘driving force’ to move blood through the circulation
- contributes to the heart’s ‘workload’
what is hypotension?
having low blood pressure
what is the diagnosis of hypotension?
systolic BP/ diastolic BP = 90/60 mm Hg
what are the symptoms of hypotension?
- dizziness
- fainting
- blurred vision
- fatigue
why do we get dizziness and faint when we have low blood pressure?
because we have an insufficient blood supply going to our brain
why do we get blurred vision when we have low blood pressure?
insufficient oxygen delivery to our eyes
why do we have fatigue when we have hypotension?
insufficient blood delivery to our brain and also to our skeletal muscles and heart
what are causes of hypotension?
- dehydration (we have less water, we have less blood volume
- pregnancy
- heart failure
- anemia
how does pregnancy lead to hypotension?
because we are taking blood flow away from our systemic circulation and into the fetus
what are risk factors of hypotension?
- age
- medications
- certain diseases (Parkinson’s and diabetes)
why is parkinsons a risk factor for hypotension?
because Parkinsons affects the autonomic nervous system so it can impair the ability to regulate blood pressure
what is hypertension?
high blood pressure
why is hypertension called the ‘silent killer’?
because many people do not have symptoms right away and its not until it gets severe that the symptoms get bad
there are three stages of hypertension, what are they and what BP is classified with it?
- stage 1: SBP/DBP = 130-139/80-89mm Hg
- stage 2: >=140/>=90
- hypertensive crisis: >180/>120
what are the severe symptoms related to hypertension?
- stroke
- heart attack
- kidney failure
- blindness
- dementia
- sexual dysfunction
what is athelerosclerosis?
plaque build up in the brain and/or heart
how is sexual dysfunction a symptom of hypertension?
it is going to be damaging the blood vessels and the endothelial layer of the organs and the endothelial layer is responsible for producing nitric oxide which helps to vasodilate
what are the potential causes of hypertension?
- atherosclerosis
- kidney disease
- sleep apnea
- thyroid issues
what are the risk factors for hypertension?
- age
- obesity
- genetics
- inactivity
- smoking
- high sodium intake
- stress
- alcohol consumption
what is another name for arteries?
conduit vessels
what is the function of an artery?
conduit arteries must take blood from the heart and distribute it to the various organs/tissues as efficiently as possible
(ie. do not want to impede the blood flow)
how is it possible for arteries to take blood from the heart and distribute it to the various organs/tissues?
- minimize resistance to flow:
- they are large
- low contractility [smooth muscle – active process]
- high distensibility (compliance) [elasticity –passive process) - artery walls must be ‘strong’ to withstand high systolic blood pressure