The renal capsule is a thin yet tough layer of fibrous connective tissue that surrounds each of the two kidneys. The primary components of this tissue are the proteins elastin and collagen. The role of this covering is to support the mass of the kidneys as well as provide protection for the delicate tissues of the kidneys.
The kidneys are a pair of organs responsible for filtering waste materials from the body. If kidney damage occurs, the patient's health or even life can become threatened. Therefore, the protection provided by the renal capsule is of vital importance. While this membrane is made of tough fibers, it is a rather thin covering. This tissue is covered with a layer of fatty tissue known as perinephric adipose tissue.
The fatty tissue covering the renal capsule helps to cushion the kidney and provide shock resistance during movement. This is of significant importance because the kidneys do have a limited amount of space in which to move around within the body. Without proper shock absorption, the simplest of daily activities could cause damage or bruising of these vital organs.
The renal capsule contains smooth muscle fibers as well as elastic fibers. Smooth muscle fibers allow muscles to contract automatically, without any thought processes necessary, thus allowing the kidneys to function completely on their own. Elastic fibers allow the kidney tissues to stretch as necessary and then return to a normal state. Interestingly, both of these types of fibers have been found to increase in number as the patient ages.
The interlobar arteries are responsible for providing the blood supply to the renal capsule. These are small blood vessels that branch out from the primary renal arteries. The interlobar arteries travel through the outer portion of the kidneys known as the renal cortex and terminate once they reach the renal capsule.
If this important covering is damaged, whether by a traumatic event or as part of a naturally occurring disease, there is a risk of developing decreased kidney function. If this occurs, it is important to visit a kidney specialist regularly in order to monitor kidney function percentages. If the amount of function decreases significantly, the patient may begin to experience kidney failure, also referred to as renal failure. There are currently only two reliable methods of treatment available for renal failure, with one being a kidney transplant. The other option is dialysis, a medical procedure in which the patient is connected to a machine that removes the blood from the body, cleans out the waste materials, and then returns the clean blood back to the body.