blood pressure RAAS Flashcards
Nervous Regulation of Blood Pressure - Baroreceptors
Our body has special sensors called baroreceptors located in the walls of certain blood vessels, like the carotid arteries and aorta. These baroreceptors detect changes in blood pressure.
Nervous Regulation of Blood Pressure - Medulla Oblongata
The baroreceptors send signals to a part of our brain called the medulla oblongata, which acts as a control centre for blood pressure regulation.
Nervous Regulation of Blood Pressure - Autonomic Nervous System
the medulla oblongata sends nerve impulses through the autonomic nervous system. The autonomic nervous system controls involuntary processes in our body, such as heart rate, digestion, and blood vessel diameter.
Nervous Regulation of Blood Pressure -Adrenaline and Noradrenaline
Nervous Regulation of Blood Pressure -Sympathetic Nervous System
When blood pressure is too low, the medulla oblongata stimulates the sympathetic nervous system. This leads to the release of adrenaline (also known as epinephrine) and noradrenaline (also known as norepinephrine).
Nervous Regulation of Blood Pressure - Parasympathetic Nervous System
When blood pressure is too high, the parasympathetic nervous system is activated. This slows the heart rate and widens blood vessels, leading to decreased blood pressure.
Hormonal Regulation of Blood Pressure - Renin-Angiotensin-Aldosterone System (RAAS)
As mentioned in the previous explanation, the RAAS plays a significant role in regulating blood pressure through hormonal mechanisms.
Hormonal Regulation of Blood Pressure - Renin
When blood pressure decreases or the sodium level is low, the kidneys release a hormone called renin into the bloodstream.
Hormonal Regulation of Blood Pressure - Angiotensin II
Renin acts on angiotensinogen (a protein in the blood) to convert it into angiotensin I, which is then converted into angiotensin II by an enzyme called ACE (angiotensin-converting enzyme). Angiotensin II is a powerful hormone that narrows blood vessels, causing an increase in blood pressure.
Hormonal Regulation of Blood Pressure - Aldosterone
Angiotensin II also stimulates the release of aldosterone from the adrenal glands. Aldosterone acts on the kidneys, promoting sodium and water reabsorption into the bloodstream, which raises blood pressure.
Negative Feedback Mechanisms
Both the nervous and hormonal regulation of blood pressure involves negative feedback mechanisms. These mechanisms work to bring the blood pressure back to its normal range once it eviates
Nervous System Feedback
When the baroreceptors detect a change in blood pressure, they send signals to the medulla oblongata. The medulla then activates the appropriate response through the autonomic nervous system. Once the blood pressure returns to normal, the baroreceptors stop sending signals, and the reaction is halted, maintaining blood pressure within a healthy range.
