BPK 105 Study Guide - Final Guide: Hypotension, Blood Vessel, Body Fluid
27 Apr 2018
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Module 12 - Study Guide
Study Guide
- The kidney maintains a consistent fluid environment for cells in terms of volume and ion
concentration. This homeostatic regulation is evident in each portion of the nephron.
When studying the kidney, keep in mind the overall role of homeostatic regulation of
body fluid and try to understand the contribution of each portion of the nephron with
respect to this role.
Arteries and Veins
- This section discusses the vascular (blood vessel) system of the functional unit of the
kidneys, the nephron.
- The glomerular capillaries are the first vascular region of the nephron. This area is
designed to facilitate the filtration of blood. Water, ions, glucose, and waste products
move out of the capillary into the Bowman’s capsule. This is the fluid that then
moves through the tubule system of the nephron.
- The fluid filtered into Bowmans capsule is destined to be eliminated from the body as
urine. It is the role of the remaining portions of the nephron to selectively bring the
important components back into the body. These important components are
reabsorbed into the region of blood flow known as the vasa recta.
- As we can see, blood flow is important in providing the filtered fluid for the nephron. It is
also important to facilitate the reabsorption of a vast majority (99%) of this fluid (water,
ions, glucose) back into the body, saving it from elimination in the urine.
Regulation of Urine Concentration and Volume
- In the overview we discussed the advantages of filtering all the body’s blood about 35
times per day.
- One of these advantages was that we are able to regulate the concentration and the
volume of blood.
- If we are dehydrated (low blood volume and blood pressure) we need to reabsorb as
much water from the kidneys tubules as possible; this will reduce the volume of water we
lose in the urine. The low blood pressure stimulates the release of antidiuretic
hormone from the hypothalamus. This results in more water being reabsorbed in the
collecting ducts, lower urine volume, and less fluid loss.
- Low blood pressure will also stimulate the renin-angiotensin-aldosterone system and the
release of Atrial Natiuretic Hormone. These will stimulate a greater sodium and water
reabsorption in the distal tubule, returning blood pressure and volume back toward
normal.
Document Summary
The kidney maintains a consistent fluid environment for cells in terms of volume and ion concentration. This homeostatic regulation is evident in each portion of the nephron. When studying the kidney, keep in mind the overall role of homeostatic regulation of body fluid and try to understand the contribution of each portion of the nephron with respect to this role. This section discusses the vascular (blood vessel) system of the functional unit of the kidneys, the nephron. The glomerular capillaries are the first vascular region of the nephron. This area is designed to facilitate the filtration of blood. Water, ions, glucose, and waste products move out of the capillary into the bowman"s capsule . This is the fluid that then moves through the tubule system of the nephron. The fluid filtered into bowmans capsule is destined to be eliminated from the body as urine.
