9 Flashcards
what are the risks of low BP
hypotension, inability to exercise, fatigue
what are the risks of high BP
aneurysms causing a hemorrgahic stroke
which arteries are particurlary at risk in physical stress of hypertension
atheromatous arteries bc theyre less compliant. so high bp can cause atheroma to rupture then become a thrombus or embolus and block arteries
what are the two systems that regulate BP and hoe fast do they act
neuronal system (fast acting) hormonal system (slow acting)
what’s the name of the hormonal system that regulates BP
renin angiotensin aldosterone hormonal system
RAA RAA RASPUTIN
what type of feedback is the neuronal control of BP
where’s the sensor?
negative feedback
sensor is found in carotid sinus in the internal carotid arterty
other sensor is in aortic sinus above aortic valve
what’s one key feature of artery walls in the sinus
they have more elastic fibres and so are more stretchy. they distend during each systole
what nerve endings are found in the carotid sinus and what are they sensitive to
sinus nerve endings which are sensitive to the stretch in the sinus wall.
what two nerves may the sinus nerve join after it gets excited
glossopharyngeal (9) or vagus cranial nerve. (10)
or both!!!!!!
what does carotid body sense
sensor for blood chemistry! like 02 blood levels
what cranial nerve does the glossopharyngeal nerve originate from
9 cranial
what type of cranial nerve is the glossopharyngeal nerve
mixed nerve.
PRIMARILY sensory (from carotid sinus, tongue, pharynx, larynx
motor (secretomotor. parasympathetic to parotid gland and stylopharyngues)
what type of cranial nerve is the vagus nerve
mixed nerve.
sensory (from lungs, heart, oesophagus)
motor (lungs heart oesophagus=
where do afferent nerve (vagus and glossopharyngeal) synapse
on nucleus of the solitary tract (NTS) of medulla oblongata
where is the nucleus of the solitary tract in relation
rostrocaudally within lower medulla
what’s the integrating centre for visceral afferents from mouth, throat and neck
the nucleus of the solitary tract
what does the nucleus of the solitary tract project to
vasomotor centre.
where is the vasomotor centre located
rostral ventrolateral of the medulla
what is the function of the vasomotor centre
to go, ok does the info from the sinus match the normal blood BP
how does the vasomotor centre correct an inadequate BP
through SNS and PNS
SNS via reticulospinal tract
PNS via nucleus ambiguous
what receptors sense the changes to carotid sinus wall
baroreceptor
where are baroreceptors located
in carotid sinus
what is the response of baroreceptors
AP firing
which of high or low BP corresponds to high baroreceptor input and what’s the result
high BP
activation of parasympathetic
which of high or low BP corresponds to low baroreceptor input and what’s the result
low BP
activation of sympathetic and INHIBITION of parasympathetic
what is the equation for mean arterial output
MAP= CO x total peripheral resistance
where do reticulospinal tract axons synapse
on sympathetic pre-ganglionic neurons in the intermediate part (IML) of the lumbar and thoracic ventral horn.
where do lateral reticulospinal tract axons arise from
From the reticular formation of the medulla of the brainstem.
what hormone do postganglionic neurones release to act on arteriole smooth muscle
noradrenaline on alpha1 adrenergic receptors
when the baron¡receptor input is too high what happens
vasomotor centre is inhibited so sympathetic system is shut off
parasympathetic is activated via nucleus ambiguous which stimulates vagus nerve which acts on SA node to slow HR and CO.
which of SNS and PNS affects resistance to reduce BP
sympathetic results in vasoconstriction
para only reduces HR
what’s the baroreceptor reflex
the observation that electrical stimulation of baroreceptors reduces BP.
what’s a carotid massage
medical maneuver that can be used to reduce BP or slow down a dangerously rapid heartbeat or to diagnose certain heart rhythm disturbances. Massaging the sinus in this way increases the rate of firing in the sinus nerve and increases vagal output. To perform a carotid massage, you’ll need to massage the area at the base of the patient’s neck, where the carotid artery enters the head. An incorrectly performed CSM can cause serious health repercussions, especially in elderly patients and should only be used by experienced health professionals (see URL below)
what’s essential or type 1 hyper T
where there is no clear pathology associated with the condition.
what’s one theory underlying hyperT
feedback signal has decreased because the receptors in the carotid sinus have come less sensitive to stretch
why would the baroreceptors in carotid sinus be less sensitive
bc the walls of the sinus are less elastic than normal so it will require greater pressure to stretch them the normal amount.
why do smokers tend to be hypertensive
Cigarette smoking produces free radicals in the blood that damage the arterial endothelium and elastic lamina, resulting in arterial stiffness, inflammation, and alterations to release of relaxing and anti-thrombotic factors.
If this damage extends to the carotid sinus, this could explain why smokers tend to be hypertensive.
maybe be permanent
what conditions are associated with hyperT and why
diabetes I or II bc damages endothelium
type A ppl pron e to chronic stress
lifestyle change to fix BP
exercise
