control of arterial blood pressure

Question 1

what is systolic arterial blood pressure?

Answer 1

the pressure exerted by the blood on the walls of the aorta and systemic arteries when the heart contracts

Question 2

what is diastolic blood pressure?

Answer 2

the pressure exerted by the blood on the walls of the aorta and systemic arteries when the heart relaxes

Question 3

define hypertension

Answer 3

clinical blood pressure of 140/90 mmHg or higher and day time average of 135/85 or higher

Question 4

what is pulse pressure?

Answer 4

the difference between systolic and diastolic blood pressure

Question 5

at what point is diastolic pressure recorded?

Answer 5

the 5th korotkoff sound - the point at which sound disappears

Question 6

define mean arterial blood pressure - MAP

Answer 6

the average arterial blood pressure during a single cardiac cycle

Question 7

what MAP is needed to perfuse the coronary arteries , brain and kidneys?

Answer 7

at least 60 mmHg

Question 8

define systemic vascular resistance

Answer 8

the sum of resistance of all vasculature in the systemic circulation

Question 9

what does the baroreceptor reflex do?

Answer 9

short-term regulation of mean arterial blood pressure

Question 10

how does postural hypotension come about?

Answer 10

results from failure of baroreceptor repsonses to gravitational shifts in blood, when moving from horizontal to vertical position

Question 11

list some risk factors for postural hypotension

Answer 11

• age related
• medications
• certain diseases
• reduced intravascular volume
• prolonged bed rest

Question 12

list some symptoms of postural hypotension

Answer 12

• lightheaded-ness
• dizziness
• blurred vision
• faintness
• falls

Question 13

what are 2 main factors that affect extracellular fluid volume?

Answer 13

1. water excess or deficit

2. Na+ excess or deficit

Question 14

how do hormones regulate the extracellular fluid volume

Answer 14

-thye act as efffectors to regulate by regulating the water and salt balance in our bodies

Question 15

what hormones regulate extracellular fluid volume?

Answer 15

• the Renin-Angiotensi-Aldosterone system = (RAAS)
• Natriuretic Peptides =(NPs)
• Antidiuretic Hormone (Arginine Vasopressin) = (ADH)

Question 16

what is the role of the Renin-Angiotensi-Aldosterone system and how is it formed?

Answer 16

• regulates plasma volume and SVR
• renin released from kidneys -> stimulates formation of angiotensin I
• angiotensin I converted to angiotensin II by ACE (angiotensin converting enzyme
• angiotensin II stimulates release of ALdosterone from adrenal cortex = vasoconstriction
• aldosterone acts on kidneys to increase sodium and water renention = increases plasma volume

Question 17

what is the role of natriuetic peptides and how are they formed?

Answer 17

• synthesised by heart
• released in repsonse to cardiac distension
  cause excretion of salt and water in kidneys = reducing blood volume and pressure
  -decrease renin release - decrease blood pressure
• vasodilators - decrease SVR and BP
  -NPs provide a counter-regulatory system for the Renin-Angiotensin-Aldosterone System (RAAS)
  -2 types = antrial natriuretic peptide(ANP) and brian-type natriuretic peptide (BNP)
• ANP rleased in repsonse to atrial distension

Question 18

what is the role of anti-diuretic hormones and how are they formed?

Answer 18

• synthesised by the hypothalamus, stored in the posterior pituitary
• secretion stimulated by reduced extracellular fluid volume or increased extracellular fluid osmolality
• release is stimulated by increased plasma osmolality
• acts in kidney tubules to increase the water re -absorption of water