cvs - blood pressure Flashcards
What are the typical values for systematic blood pressure?
120/80 mmHg (Systolic/Diastolic)
What are the typical values for pulmonary blood pressure?
25/8 mmHg
What are the typical values for venous pressure?
6-8 mmHg
How do you calculate BP?
Blood Pressure (BP)=Cardiac Output × Peripheral Resistance
What factors affect BP?
*Cardiac Output
*Peripheral Resistance
What is autoregulation and its function?
*Mechanism: Changes in blood flow are detected by local receptors during microperfusion.
*Function: Ensures that tissues receive adequate blood flow based on their metabolic needs
What is neural regulation and its function?
Function: Provides short-term regulation of blood pressure.
*Mechanism: Responds to transient changes in arterial pressure via baroreflex mechanisms, involving sensors like baroreceptors that quickly adjust heart rate and vessel diameter.
What falls under hormonal regulation?
*Renin-Angiotensin-Aldosterone System (RAAS)
*Anti-Diuretic Hormone (ADH; Arginine Vasopressin)
*Atrial Natriuretic Peptide (ANP)
*Erythropoietin
*Adrenaline/Noradrenaline
What is the function and mechanism of RAAS?
- Function: Increases blood pressure by promoting sodium
and water retention, and vasoconstriction. - Mechanism: Activated by low blood pressure or low blood volume
What is the mechanism and function of ADH?
- Function: Promotes water reabsorption in the kidneys,
reducing urine output and increasing blood volume. - Mechanism: Released in response to high blood osmolarity or low blood volume
What is the mechanism and function of the ANP?
- Function: Reduces blood pressure by promoting sodium
excretion and vasodilation. - Mechanism: Released from the atria of the heart in
response to high blood volume
What is the mechanism and function of the erythropoietin?
- Function: Increases red blood cell production, which can
increase blood viscosity and volume. - Mechanism: Released by the kidneys in response to hypoxia
What is the mechanism and function of adrenaline?
- Function: Enhances the body’s “fight-or-flight” response,
increasing heart rate, the force of contraction, and vasoconstriction. - Mechanism: Released by the adrenal medulla in response
to stress or sympathetic nervous system activation
What are baroreceptors and where are they found?
Baroreceptors are specialised (stretch-sensitive mechanoreceptors) nerve endings
located primarily in the carotid sinus and aortic arch that detect changes in blood pressure and help regulate it through reflex mechanisms.
What do bareorecptors do?
Baroreceptors send afferent signals via the glossopharyngeal nerve (from the carotid sinus) and the vagus nerve (from the aortic arch) to the cardiovascular centres in the medulla oblongata of the brainstem.
What are the two cardiovascular centres?
*vasomotor centre
*cardiac centre
What does vasomotor centre do?
The Vasomotor Center controls sympathetic vasoconstrictor neurons
What does cardiac centre do?
The Cardiac Center modulates heart rate through sympathetic and
parasympathetic neurons.
What is the sympathetic nervous systems role in BP?
Function: Increases heart rate, contractility, and vasoconstriction,
leading to an increase in blood pressure
What is the sympathetic nervous system mechanism in BP?
Baroreceptors: Located in the carotid sinus and aortic arch,
baroreceptors detect changes in blood pressure and send
signals to the brainstem.
Response to Low BP: When blood pressure drops,
baroreceptors decrease their firing rate, leading to increased
sympathetic activity. This results in:
Increased heart rate (tachycardia)
Increased force of cardiac contractions
Vasoconstriction of blood vessels
What is the role of the parasympathetic nervous system in BP?
Function: Decreases heart rate and promotes vasodilation,
leading to a decrease in blood pressure
What is the parasympathetic nervous system mechanism in BP?
Baroreceptor: Detects increases in blood pressure and send
signals to the brainstem.
Response to High BP: When blood pressure rises,
baroreceptors increase their firing rate, leading to increased
parasympathetic activity. This results in:
Decreased heart rate (bradycardia)
Vasodilation of blood vessels