Hypertension 1

Question 1

What is Systolic BP?

Answer 1

• Pressure of the blood against the artery walls when the heart contracts
• 120mmHg

Question 2

What is Diastolic BP?

Answer 2

• Pressure against the artery walls when the heart relaxes between beats
• 80mmHg

Question 3

Define Prehypertension

Answer 3

• Systolic between 121-139mmHg

OR

• Diastolic between 81-89mmHg

Question 4

Define Hypertension

Answer 4

• Systolic 140 or above

OR

• Diastolic 90 or above

Question 5

Function of Arteries

Answer 5

Deliver molecules to tissues

Question 6

Function of Veins

Answer 6

Take molecules from tissues

Question 7

What is the importance of proper systolic and diastolic BP?

Answer 7

• Blood needs to be pumped out of the heart as well as taken into the heart
• Proper values of both systolic and diastolic pressure are crucial for proper function of the vascular system

Question 8

What is the function of Baroreceptors and where are they located?

Answer 8

• Detects changes in BP
• Location:
  
  • internal carotids
  • aortic arches

Question 9

What is the function of Chemoreceptors and where are they located?

Answer 9

• Detects changes in pH (H+, O2, CO2)
• Location
  
  • internal carotids
  • aortic arches

Question 10

What does a low pH indicate?

Answer 10

Inefficient blood flow and oxygenation

Question 11

What are major factors affecting BP?

Answer 11

• Peripheral resistance
• Cardiac output

Question 12

The amount of blood pumped is dependent on?

Answer 12

1. Heart rate
2. Heart contractility
3. Heart muscle health (metabolism)

Question 13

Define Cardiac Output

Answer 13

• The volume of blood pumped by the heart per minute (mL of blood/min)
• The more blood pumped into the system, the higher the BP is
• CO = HR x SV

Question 14

Define Peripheral Resistance

Answer 14

• Hydrostatic ‘back pressure’ working against heart attempt to pump the blood into the CV system

Question 15

What are the important hydrostatic parameters affecting BP?

Answer 15

• Proper blood flow would depend on hydrostatic parameters
  
  1. Force by which blood is pushed through the system
  2. Volume of blood in the system
  3. Diameter of conducting vessels
     
     • achieved by sympathetic nervous system

Question 16

What are the treatment aims of hypertension?

Answer 16

• Decrease arterial BP by decreasing:
  
  • cardiac function-related (CO)
  • blood volume (Peripheral resistance)
• Drugs affecting diameter of arteries (vasodilators) aren’t used in treatment of high BP but for other CV conditions e.g. angina
  
  • could impact BP therapy

Question 17

Discuss Primary (Essential) Hypertension

Answer 17

• Raised blood pressure with ‘no clear single identifiable cause’
• Factors are involved with blood pressure control including:
  
  • adrenergic nervous system
  • the RAAS
  • renal function changes
  • hormonal factors (e.g. vasopressin, adrenal hormones)
  • vascular endothelium
  • haemodynamic changes (e.g. changes in CO and peripheral vascular resistance)

Question 18

Discuss Secondary Hypertension

Answer 18

• Refers to elevated blood pressure that can be attributed to a specific cause
• Causes:
  
  • pregnancy
  • pheochromocytoma
  • aorta constriction
  • hyperthyroidism
  • Cushing’s syndrome
  • Primary hyperaldosteronism
  • Renoparenchymal diseases of the kidney
  • Renovascular disease
• Certain prescription, non-prescription and natural health products can also precipitate or worsen hypertension
  
  • treat primary cause

Question 19

Discuss Resistant Hypertension

Answer 19

• Blood pressure that remains above treatment goal despite concurrent use of three antihypertensive agents of different classes, one of which should be a diuretic
• If patient has blood pressure controlled with 4 or more medications = resistant hypertension

Question 20

What is the treatment aim of antihypertensive medications?

Answer 20

• To reduce the risk of CVD, target organ damage and mortality associated
• May be achieved by lowering SBP to <140mmHg and lower DBP to <90mmHg
• Majority of patients require a combination of lifestyle modifications and medications to achieve target blood pressures

Question 21

How do you calculate BMI and what is a healthy BMI range?

Answer 21

BMI = weight (kg)/height (m)²

• Healthy range: 18.5-22.9
• Obese: 27.5 and above

Question 22

What are non-modifiable risk factors?

Answer 22

• Increasing age (>55y)
• male gender
• family history of premature CVD (men <55 years or women <65 years) in a primary/first-degree relative

Question 23

What are modifiable risk factors?

Answer 23

• Sedentary lifestyle
• Poor dietary habits
• Smoking
• Dyslipidaemia
• Stress
• Abdominal obesity (BMI >25; waist circumference >102 cm in men or >88cm in women)
• Impaired glucose tolerance or diabetes mellitus

Question 24

Target organ damage

Answer 24

• Cerebrovascular disease
• Coronary artery disease
• Chronic renal disease
• Peripheral artery disease

Question 25

What are lifestyle modifications in hypertension treatment?

Answer 25

* Weight reduction * Physical activity * Healthy diet * Salt intake * Alcohol intake * Smoking * Emotional Stress

Question 26

What is the MOA of aldosterone? What happens if aldosterone receptors are blocked?

Answer 26

* Upregulates expression of epithelial sodium channels (ENaC) in the collecting duct, increasing Na+ absorption as well as Na+/K+ pump level * Overall effect: increase in BP * If aldosterone receptors are blocked, blood pressure decreases

Question 27

What happens when reuptake of Na+ from urine?

Answer 27

Reuptake of Na+ from urine brings water with it into the blood and raises BP

Question 28

Define Preload

Answer 28

Volume of blood in ventricles at end of diastole

Question 29

Define Afterload

Answer 29

Resistance in left ventricle must overcome to circulate blood

Question 30

Functions of Angiotensin II?

Answer 30

* Retention of Na+ by kidney (via aldosterone) * H2O retention by kidney (via Na+ uptake and vasopressin) * Salt appetite * Increased drinking (via Subfornical organ) * Increased BP

Question 31

What is the long-term regulation of Renin-Angiotensin-Aldosterone System (RAAS)?

Answer 31

1. Fall in blood pressure 2. Release of Renin 3. Angiotensinogen 4. Angiotensin I 5. Angiotensin II * Two pathways 1. Aldosterone \> sodium retention \> BP increase 2. Vasocontriction \> BP increase

Question 32

What are juxtaglomerular cells?

Answer 32

* Specialised smooth muscle cells which act as mechanoreceptors which stretch in response to increase in BP of the afferent arteriole * also synthesise and secrete the enzyme renin which serves to activate the inactive precursor, angiotensinogen (made by the liver), into angiotensin I

Question 33

Two major functions of ATII

Answer 33

* Vasoconstriction * Aldosterone Release