Question about high blood pressure after eating

[Astra]

So, after you eat, the food gets sent down to your stomach. From there into the duodenum. Carbs and amino acids, small fatty acids can pass the intestinal wall and are carried into circulation via the blood vessels.
Fatty acids that are large are carried into the lymph system.

So with all of the extra solute in the blood, the blood becomes hyper tonic compared to the tissue cells. This causes them to lose water and increases the blood volume. The increased volume increases blood pressure correct?

Also, this is the same reason we feel thirsty after eating something correct? The cells are getting dehydrated.

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[betterfuture]

Well from what I think, after you eat, the digestive system is primarily at work here. So basically, there is a call for more blood flow to the digestive organs so they can perform the work in order to break down the food. This means the heart has to pump even harder. There might be other factors involved but I can only think of this as the major reason.

 

[hopefulERdoc251]

Partially. I also think the salt content of our food contributes to it, but similar in concept that there's more solute ect.

 

[betterfuture]

Partially. I also think the salt content of our food contributes to it, but similar in concept that there's more solute ect.

Yeah, salt brings along with it more water which increases blood volume, thus affecting blood pressure.

 

[GatorsKW14]

Pretty much. Salt accumulation in the body increases extracellular osmolality which stimulates the brain thirst centers so you drink more water and also stimulates the pituitary to release antidiuretic hormone to cause reabsorption of water from the kidney tubules. Your urine output decreases so more water is retained in your body, increasing your extracellular fluid volume (including blood volume). Increased blood volume will increase your cardiac output and therefore your blood pressure. If you have normal kidney function, your kidneys will compensate for this increased blood volume and blood pressure by increasing sodium and water excretion, so pretty large increases in salt intake do not affect your blood pressure very much at all. If you have some sort of kidney disease, these mechanisms are not as effective and you will see much more significant increases in blood pressure with higher sodium intake.

 

[Astra]

Pretty much. Salt accumulation in the body increases extracellular osmolality which stimulates the brain thirst centers so you drink more water and also stimulates the pituitary to release antidiuretic hormone to cause reabsorption of water from the kidney tubules. Your urine output decreases so more water is retained in your body, increasing your extracellular fluid volume (including blood volume). Increased blood volume will increase your cardiac output and therefore your blood pressure. If you have normal kidney function, your kidneys will compensate for this increased blood volume and blood pressure by increasing sodium and water excretion, so pretty large increases in salt intake do not affect your blood pressure very much at all. If you have some sort of kidney disease, these mechanisms are not as effective and you will see much more significant increases in blood pressure with higher sodium intake.

It does not necessarily have to be salt in the food does it? It can be any water soluble molecule ( such as glucose) can also increase blood pressure right?

 

[GatorsKW14]

It does not necessarily have to be salt in the food does it? It can be any water soluble molecule ( such as glucose) can also increase blood pressure right?

High glucose will increase osmotic pressure drawing out water from the cells causing cellular dehydration like you said, but high glucose can also cause less glucose to be reabsorbed in the kidneys (occurs when the glucose level is high enough that the kidney is unable to keep up with glucose reabsorption). More glucose is therefore in the kidney tubules to be excreted as urine, and this glucose also increases the osmotic pressure in the tubules, causing increased water excretion as well. So high glucose draws out fluid from the cells as well as from the kidneys, causing both intracellular and extracellular dehydration. You are going to be peeing so much that your blood volume is actually not going to increase (and will eventually decrease), and therefore would not increase your blood pressure by this mechanism. This is why you see polyuria in uncontrolled diabetes. If your glucose levels do not increase that much following a meal, there won't be very high osmotic pressure to draw out so much fluid from the cells to begin with.

Sodium accumulates in the body relatively easily, so salt is known to be the major determinant of extracellular volume. There is new research indicating that sugar DOES increase blood pressure (and actually more significantly than salt) but this is by different mechanisms involving insulin and leptin, and even my newest edition medical physiology book does not discuss this. I highly doubt that the MCAT is requiring you to know information that isn't even taught in medical school physiology books yet.