renal

Examples of renal in the following topics:

• Nephron: The Functional Unit of the Kidney

  • Eighty-five percent of nephrons are cortical nephrons, deep in the renal cortex; the remaining 15 percent are juxtamedullary nephrons, which lie in the renal cortex close to the renal medulla.
  • A nephron consists of three parts: a renal corpuscle, a renal tubule, and the associated capillary network, which originates from the cortical radiate arteries.
  • The renal tubule is a long, convoluted structure that emerges from the glomerulus.
  • The third part of the renal tubule is called the distal convoluted tubule (DCT); this part is also restricted to the renal cortex.
  • Urine leaves the medullary collecting ducts through the renal papillae, emptying into the renal calyces, the renal pelvis, and finally into the bladder via the ureter.

• Kidney Structure

  • The outermost layer, the renal fascia, is a tough connective tissue layer.
  • The third and innermost layer is the renal capsule.
  • Renal blood supply starts with the branching of the aorta into the renal arteries (which are each named based on the region of the kidney they pass through) and ends with the exiting of the renal veins to join the inferior vena cava.
  • Each segmental artery splits further into several interlobar arteries that enter the renal columns, which supply the renal lobes.
  • Externally, the kidney is surrounded by the renal fascia, the perirenal fat capsule, and the renal capsule.

• Kidney Function and Physiology

  • Second, the renal tubules collect the filtrate.
  • In the loop of Henle, the filtrate continues to exchange solutes and water with the renal medulla and the peritubular capillary network.
  • Tubular reabsorption occurs in the PCT part of the renal tubule.
  • Additionally, the loop of Henle invades the renal medulla, which is naturally high in salt concentration.
  • It tends to absorb water from the renal tubule and concentrate the filtrate.

• Other Hormonal Controls for Osmoregulation

  • This, in turn, stimulates the renal tubules to reabsorb more sodium.
  • Almost all of the sodium in the blood is reclaimed by the renal tubules under the influence of aldosterone.
  • By contrast, absence of aldosterone means that no sodium is reabsorbed in the renal tubules; all of it is excreted in the urine.
  • ANP also prevents sodium reabsorption by the renal tubules, decreasing water reabsorption (thus acting as a diuretic) and lowering blood pressure.

• Characteristics of Mammals

  • Mammals lack a renal portal system: a system of veins that moves blood from the hind or lower limbs and region of the tail to the kidneys.
  • Renal portal systems are present in all other vertebrates except jawless fishes.

• Arteries, Veins, and Capillaries

  • These major arteries include the carotid artery, which takes blood to the brain; the brachial arteries, which take blood to the arms; and the thoracic artery, which takes blood to the thorax and then into the hepatic, renal, and gastric arteries for the liver, kidneys, and stomach, respectively.

• Male Reproductive Anatomy

  • The penis is an organ that drains urine from the renal bladder and functions as a copulatory organ during intercourse.

• Diffusion

  • This occurs in the kidney where blood pressure forces large amounts of water and accompanying dissolved substances, or solutes, out of the blood and into the renal tubules.

• Facilitated transport

  • An example of this occurs in the kidney, where both forms of channels are found in different parts of the renal tubules.