🎯 Regulation of Blood Pressure – How Your Body Controls It
Your body must keep your blood pressure in a safe range. If it gets too low, your brain and organs won’t get enough blood. If it gets too high, it can damage blood vessels and the heart.
Let’s see how the body controls blood pressure, both short-term and long-term.
👂 Role of Baroreceptors – Short-Term Regulation
Baroreceptors are special pressure sensors in your body.
They are found in:
- Carotid arteries (supply brain and head)
- Aortic arch (curved part of the aorta)
How do they work?
- If blood pressure drops, these receptors detect the drop.
- They send signals to the brain.
- The brain responds by:
- Increasing the rate and strength of heartbeats
- Narrowing (constricting) arterioles (called vasoconstriction)
🟢 These actions help raise blood pressure back to normal.
💡 Example: When you stand up quickly and feel dizzy for a second — your blood pressure drops briefly. Baroreceptors immediately act to bring it back to normal.
🧪 Role of Hormones – Long-Term Regulation
In the long term, hormones help control blood volume, which directly affects blood pressure.
Let’s understand two major hormones involved:
🧴 1. ADH (Antidiuretic Hormone)
This hormone is made in the brain and released by the posterior pituitary gland.
When is it released?
- When blood pressure or blood volume drops (for example, due to sweating, dehydration, or bleeding)
What does ADH do?
- It increases thirst, making you drink more water
- It makes the kidneys reabsorb water (so less is lost in urine)
- It causes vasoconstriction (narrows blood vessels)
🟢 All these actions increase blood volume and blood pressure.
💡 Example: On a hot day, when you sweat a lot, ADH helps you retain water and maintain blood pressure.
🧂 2. ANH (Atrial Natriuretic Hormone)
This hormone is released from the walls of the right atrium of the heart.
When is it released?
- When the right atrium is stretched by too much blood volume
What does ANH do?
- It makes kidneys excrete more salt and water in the urine.
- This action reduces blood volume and lowers blood pressure.
💡 Example: If you drink too much water, ANH helps remove the extra fluid to prevent high blood pressure.