Through a Urinary lens, and other systems : explain how Jane's body is physiologically responding to the blood loss in order to restore to homeostasis and how that will affect urine production.

Question

 Jane was riding her horse on a warm sunny day (101 degrees Fahrenheit) when suddenly her horse stopped and reared up in the air. Jane was not prepared for this and fell hard backwards into the ground. As she hit the ground Jane's leg was gashed open by a large, sharp boulder that she fell next to. Jane began to bleed severely. Jane's body spends the next couple hours physiologically compensating for her blood loss. From what we have learned so far this quarter, we know that her blood loss causes blood volume, blood pressure, and cardiac output to plummet.

Answer 1

In response to the blood loss caused by Jane's injury, her body will activate several physiological mechanisms to restore homeostasis. One of the first responses will be to initiate vasoconstriction in the blood vessels to help maintain blood pressure and divert blood flow away from less essential organs and tissues. The activation of the renin-angiotensin-aldosterone system (RAAS) will also occur, which leads to the release of aldosterone from the adrenal glands. Aldosterone promotes the reabsorption of sodium and water in the kidneys, which helps to restore blood volume and blood pressure.

As a result of these compensatory mechanisms, Jane's urine production will likely decrease due to the decreased blood flow to the kidneys. This decrease in urine production is the body's way of conserving water and maintaining blood volume. The urine that is produced will be more concentrated due to the increased reabsorption of water and electrolytes in the kidneys.

In addition to these responses, the body will also release erythropoietin (EPO) from the kidneys to stimulate the production of red blood cells in the bone marrow. This increase in red blood cell production will help to replace the lost blood and restore oxygen-carrying capacity to the body.

Overall, Jane's body will undergo several physiological responses to restore homeostasis after the blood loss caused by her injury. The decrease in urine production and the increased concentration of urine are just some of the many changes that occur in the body during this process.

Answer 2

Hey Raven,

I'd start with making the question as simple as possible. These types of questions like to embellish the description to make things overwhelming for us when we're taking tests. Lets say, "Jane has a wound and is losing blood volume, how does the kidney try to compensate and how does that effect urine output?" So we can start with the most basic response: There will be a decrease in urine output to preserve volume. Next, to support that response, we need to know why this happens. Given that you've learned about blood loss and its effect on blood volume, blood pressure, and cardiac output, I would consider how these things affect the kidney and how that could lead to decreased urine output. The RAAS system sounds like it could fit!

Decreased blood volume leading to decreased cardiac output and concurrent decreased blood pressure means decreased perfusion to the Kidney (more specifically the glomerulus). The juxtaglomerular cells will detect decreased perfusion and begin to release renin. Renin will then convert angiotensinogen (produced by liver) to angiotensin I, which is then converted into angiotensin II by ACE (produced by lungs). Then the angiotensin II will go to the adrenal gland and stimulate secretion of Aldosterone. The aldosterone comes back to the Kidney to stimulate resorption of salt and water into the body. Because you're resorbing water into the blood in effort to compensate for the blood loss, you will produce less urine.

Feel free to reach out with any questions!

Best, Anthony