Dr. Hitesh Motwani

Dept of Oral & Maxillofacial Surgery

Hypertension

Part-1

Generally, the term ‘blood pressure’ refers to arterial

blood pressure.

Arterial blood pressure is defined as the lateral pressure

exerted by the column of blood on wall of arteries.

BLOOD PRESSURE

1. Systolic (Normal systolic pressure: 120 mm Hg)

2. Diastolic (Normal diastolic pressure: 80 mm Hg)

3. Pulse pressure(Normal pulse pressure: 40 mm Hg (120 – 80 = 40)

4. Mean arterial(Mean arterial blood pressure = Diastolic pressure + 1/3 of pulse pressure

= 80 + 40/3

= 93.3 mm Hg)

BLOOD PRESSURE

VARIATIONS:

PHYSIOLOGICAL VARIATIOIN:

1. Age

2. Sex

3. Body Built

4. Diurnal Variation

5. After Meals

6. During Sleep

7. Emotional Condition

8. After Exercise

PATHOLOGICAL VARIATION:

1. Hypertension 2. Hypotension

FACTORS MAINTAINING

ARTERIAL BLOOD PRESSURE

Arterial blood pressure Factors

Arterial blood pressure is

directly proportional to

1. Cardiac output

2. Heart rate

3. Peripheral resistance

4. Blood volume

5. Venous return

6. Velocity of blood flow

7. Viscosity of blood

Arterial blood pressure is

inversely proportional to

1. Elasticity of blood vessel

2. Diameter of blood vessel

REGULATION OF ARTERIAL BLOOD

PRESSURE• Body has four regulatory mechanisms to maintain the blood

pressure within normal limits

NERVOUS MECHANISM FOR REGULATION OF

BLOOD PRESSURE – SHORT-TERM REGULATION

• Vasomotor System:

1. Vasomotor center

2. Vasoconstrictor fibers

3. Vasodilator fibers.

Vasoconstrictor area

Vasodilator area

Sensory area

a.k.a pressor area

a.k.a depressor area

Controls both the areas

Parasympathetic vasodilator fibers

Sympathetic vasodilator fibers

Antidromic vasodilator fibers

• Antidromic or Axon Reflex:

Mechanism Of Action Of Vasomotor Center In

REGULATION OF BLOOD PRESSURE

1. Baroreceptor Mechanism

2. Chemoreceptor Mechanism

3. Higher Centers

4. Respiratory CentersGlossopharyngeal nr.

Vagus nr.

Mechanism Of Action Of Vasomotor Center In

REGULATION OF BLOOD PRESSURE

Decrease

inactivation

Mechanism Of Action Of Vasomotor Center In

REGULATION OF BLOOD PRESSURE

Chemoreceptor Mechanisim

Mechanism Of Action Of Vasomotor Center In

REGULATION OF BLOOD PRESSUREHigher Centers

Mechanism Of Action Of Vasomotor Center In

REGULATION OF BLOOD PRESSURERespiratory Center

RENAL MECHANISM FOR REGULATION OF

BLOOD PRESSURE – LONG-TERM REGULATION

Blood

Pressure

excretion

excretion

decreases

RENAL MECHANISM FOR REGULATION OF

BLOOD PRESSURE – LONG-TERM REGULATION

HORMONAL MECHANISM FOR

REGULATION OF BLOOD PRESSURE

Hormones which increase arterial

blood pressure

Hormones which decrease arterial

blood pressure

1. Adrenaline

2. Noradrenaline

3. Thyroxine

4. Aldosterone

5. Vasopressin

6. Angiotensin

7. Serotonin

1. Vasoactive intestinal

polypeptide (VIP)

2. Bradykinin

3. Prostaglandin

4. Histamine

5. Acetylcholine

6. Atrial natriuretic peptide

7. Brain natriuretic peptide

8. C type natriuretic peptide

Inc. systolic

Dec. diastolicActs mainly through alpha recp.

General vasoconstrictor effectInc. in rate & force of contraction

Inc. in C.O

SBP inc. & DBP dec.

Dec. in DBP is due to release of

metabolites due to inc. metabolic

activity & dec. TPR

Causes retention of salt & water

Inc. ECF vol. & blood vol.Retn. Of water

Vasopressor actn.Constriction of systemic arterioles

Secreted in stomach

Vasodilatn.

During inflammation

vasodilator

Allergic condn, inflammation or

damage

Produced by atrial

musculature of

heart

LOCAL MECHANISM FOR REGULATION

OF BLOOD PRESSURE

Local vasodilators

Metabolic products Endothelins (ET)

1. Carbon dioxide

2. Lactate

3. Hydrogen

4. Adenosine

EDRF:

1. Nitric oxide

Local vasoconstrictors

(Endothelins)

EDCF:

1. ET1

2. ET2

3. ET3

APPLIED PHYSIOLOGY

Pathological variations of arterial blood pressure:

A. Hypotension.

B. Hypertension.

• Definition

Hypotension is the low blood pressure. When the

systolic pressure is less than 90 mm Hg, it is considered

as hypotension.

HYPERTENSION

Definition

• Hypertension is defined as the persistent high blood pressure.

CLASSIFICATION:

JNC-7

Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC)

CLASSIFICATION:

British Hypertension Society

Types of Hypertension• Hypertension is divided into two types:

1. Primary hypertension or essential hypertension.

i. Benign hypertension

ii. Malignant hypertension.

2. Secondary hypertension:i. Cardiovascular hypertension

ii. Endocrine hypertension

iii. Renal hypertension

iv. Neurogenic hypertension

v. Hypertension during pregnancy

PATHOPHYSIOLOGY OF

HYPERTENSION

ANTIHYPERTENSIVE DRUGS

CLASSIFICATION:

1. ACE Inhibitor

2. Angiotensin (AT1) Antagonist

3. Calcium Channel Blockers

4. Diuretics

5. B-Adrenergic Blockers

6. B+a Adrenergic Blockers

7. A- Adrenergic Blocker

8. Central Sympatholytics

9. Vasodilators

Vasodilators:

1. hydralazine

2. Sodium

Nitroprusside

THANK YOU