Kidneys
One of the major functions of the kidneys is filtration. The kidneys filter and remove excess water, salts, wastes and restore nutrients into the body. The portal into the kidney is known as renal sinus, which is located within the cleft portion of the kidney known as the renal hilum. The blood supply for the kidneys is the renal vein and artery that lie anterior to the renal pelvis. The perinephric fat is a fat that encapsulates the kidneys to protect them from injury. Internally, the major structural unit of the kidney is the nephron. The nephrons regulate the filtration and removal of the materials listed above. There are two types of nephrons, the cortical nephrons and the juxtamedullary nephrons. These two types are named based on there location. Cortical nephrons are located in the superficial renal cortex and the juxtamedullary nephrons are located in the renal medulla. Each nephron contains the internal filtering component, the renal corpuscle, which filters out the large solutes from the blood. The renal tubule is responsible for reabsorption of the water. The renal corpuscle is contains the glomerulus and the Bowman’s capsule, and is the starting point of the nephron. The glomerulus is an intricate part of the kidney filtration system because it is a tuft of capillaries that receives the blood supply needing to be filtered. The glomerulus also provides the pressure to push water and solutes out and into a space where they enter the Bowman’s capsule. Podocytes, located in the visceral inner layer of the Bowman’s capsule, receives the fluids that have been filtered by the glomerulus, and this fluid is further processed to form urine. After passing through the renal tubule, the filtrate flows into the collecting duct system. The following are components of the renal tubule: Proximal convoluted tubule, Loop of Henle (Descending and Ascending), Thin ascending limb of loop of Henle, Thick ascending limb of loop of Henle, Distal convoluted tubule. The collecting duct is generally impermeable to water unless ADH (antidiuretic hormone) is present and as much as three-fourths of the water in the fluid can be reabsorbed as it leaves the collecting ducts. Urine leaves the medullary collecting ducts in the following order: renal papillae, renal calyces, renal pelvis, and then arrives into the urinary bladder.
FSGS
Focal Segmented Glomerulosclerosis is an uncommon nephrotic disease occurring in adolescents. It is a complete failure of the kidneys. It occurs when scarring occurs on some of the glomeruli in the kidney. The appearance of the glomeruli is more of crystallization. This causes kidney failure within the patient, and the patient must receive dialysis or a kidney transplant to avoid death. The causes of FSGS can be genetic, HIV, and the use of heroin to name a few. There is still much to learn about this disease, as there is no cure for it. Some individuals can receive a kidney transplant and be free of it, however, some individuals, like my brother, have recurrent FSGS, where even after a kidney transplant the disease returns. We are hoping the continued studies that a cure can be found for recurrent FSGS. My brother is awaiting a kidney transplant, and they do have certain medications that can inhibit the return of the disease, but there is always a possibility of it returning.
FSGS Kidney
Normal Kidney
Suprarenal glands
The suprarenal glands are located on the superior portion of the kidney and connected to the diaphragm through connective tissue. Like the kidneys, each gland of the suprarenal glands contain a hilum where the veins and lymphatic’s exit. Each gland contains two major parts: the suprarenal medulla and suprarenal cortex. The function of the cortex is to secrete corticosteroids and androgens. The adrenal glands act as a warning system to the kidneys by releasing these hormones in response to body stress. The hormones released will cause the kidney to retain sodium and water in response to whatever the body is experiencing. The medulla is portion of the adrenal gland is important for our flight or fight response. The cells in the medulla known as chromaffin cells) secrete a substance known as catecholamine’s (which is mostly epinephrine) into the bloodstream from the presynaptic neuron signals. This secretion activates our adrenaline and noradrenaline.
Cushing’s Syndrome
Cushing’s Syndrome is a disease in the adrenal glands where too much of the corticosteroids are produced. When over production of corticotrophin occurs, the adrenal gland is stimulated to continue to produce corticosteroids. This production of corticotrophin occurs in the pituitary gland. This is just one possible cause of Cushing’s syndrome. Another cause could be excessive cortisol levels in the blood due to a tumor in the pituitary gland, adrenal gland, or elsewhere in the body. If the patient has a pituitary adenoma causing the Cushing’s, then one option is transphenoidal adenomectomy, where the surgeon goes into the pituitary gland. Other treatment options such as radiotherapy are used as well. Common symptoms of Cushing’s Syndrome are weight gain in the back, face, and collar bone, easy bruising, and loss of muscles to name a few.
Urinary Bladder
The urinary bladder is an organ that collects urine after it has been filtered from the kidneys. The urinary bladder resides on the pelvic floor and the urinary bladder is composed of transitional epithelium. Urine enters the bladder via ureters and exits via the urethra. For urine to exit the bladder, there is an involuntary and voluntary controlled sphincter to regulate exiting. The detrusor muscle is a layer of smooth muscle located in the wall of the urinary bladder. As the bladder fills with urine, the rugae begin to stretch and the wall begins to thin. The detrusor muscle senses this and through parasympathetic signaling alerts the need to urinate. The adult bladder usually holds 300-350 mL of urine but can hold up to 500-700 mL, however, this large amount can cause injury to the bladder. At 25% fullness, the bladder alerts the need to void. If the bladder ever reached 100% fullness, the voluntary sphincter in the bladder would deactivate, and voiding would automatically begin.
If injuries occur to the anterior abdominal wall, rupturing can occur to the bladder. An injury example would be the fracture of the pelvis, which would take away the support to the urinary bladder that the pelvic floor provides. When a rupture occurs, the urine can escape either extraperitoneally or intraperitoneally. The determination of this is whether the tear occurs superior part of the bladder or the posterior part of the bladder.
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