PATHOPHYSIOLOGY OF HYPERTENSION

 

      Hello everyone . It's a great joy to meet u all . In todays topic we are going to discuss about PATHOPHYSIOLOGY OF HYPERTENSION .   I have given explanation for this content  in YouTube in Tamil and English . 

TAMIL :https://youtu.be/aS5d4EcwMzo

ENGLISH :https://youtu.be/0wWfK2nTaKg

CARDIAC OUTPUT:

§  The cardiac output is the amount of blood ejected from each ventricle in one minute.

§  The amount of blood ejected by each contraction of each ventricle is called the stroke volume.

 FORMULA TO CALCULATE CARDIAC OUTPUT :

CARDIAC OUTPUT = STROKE VOLUME  *   HEART RATE

 

 PERIPHERAL RESISTANCE :

§  It is also called as systemic vascular resistance.

§  It is the amount of resistance which is in the blood flow and it’s difficult for the blood to flow with resistance.

§  Total peripheral resistance is used in the calculations of blood pressure, blood flow, and cardiac functions.

§  The causes of increased peripheral resistance in blood vessels are Arteriolar Vasoconstriction

§  Increased sympathetic activity ( increased production of epinephrine & norepinephrine)

§  {Epinephrine: example in case of any emergency situation, chasing of an animal etc.

§  Norepinephrine: helps to maintain the blood pressure levels in case of emergency. }

§  Epinephrine is also called as adrenaline and Norepinephrine is also called as noradrenaline.

§  These hormones are released by the adrenal medulla

§   Epinephrine is released only during the stress.

§  Norepinephrine is released into the blood circulation continuously at low levels.

§  Both epinephrine and norepinephrine can affect the Heart, The sugar levels, and the blood vessels.

§  Norepinephrine can also make your blood vessels become narrower which increases the blood pressure.

BLOOD PRESSURE = CARDIAC OUTPUT * PERIPHERAL RESISTANCE 

PATHOPHYSIOLOGY OF HYPERTENSION : { RENIN ANGIOTENSIN MECHANISM :}

• When there is fat accumulation it leads to plaque formation in the blood vessels .This leads to the vasoconstriction of the blood vessels leads to decreased blood flow and decrease in the blood pressure.
• This causes the liver to produce a protein called ANGIOTENSINOGEN .
• The  excretion of the protein mainly happens in the kidneys .
• So the kidneys produces RENIN to break the angiotensinogen.
• so the ANGIOTENSINOGEN is converted into ANGIOTENSINOGEN I.
• With the help of ANGIOTENSINOGEN CONVERTING ENZYME [ACE] from the lungs ANGIOTENSINOGEN I  is converted into ANGIOTENSINOGEN II.
• This causes vasoconstriction in the blood vessels.
• this increases the peripheral resistance and leads to INCREASED BLOOD PRESSURE.

PATHOPHYSIOLOGY OF HYPERTENSION : 

• [ ALDOSTERONE MECHANISM :]

• When there is fat accumulation it leads to plaque formation in the blood vessels .This leads to the vasoconstriction of the blood vessels leads to decreased blood flow and decrease in the blood pressure.
• Which causes RENIN ANGIOTENSIN MECHANISM as we discussed earlier 
• This releases ALDOSTERONE from the adrenal cortex 
• Also releases VASOPRESSIN from pituitary gland which is an anti diuretic hormone .
• This causes the kidneys to retain SODIUM and excrete potassium .
• so the water is being attracted to the sodium and the BLOOD VOLUME INCREASES
• Which leads to INCREASED CARDIAC OUTPUT AND INCREASE IN BLOOD PRESSURE .