Term | Definition |
Calcitrol | Vitamin D |
Hilum | The part of an organ where structures such as blood vessels enter or leave |
Retroperitoneal | External or posterior to the peritoneum |
Nephron | Functional unit of the kidney |
Glomerulus | A capillary network within the renal corpuscle in a kidney |
Glomerular Capsule (Bowman's Capsule) | Two layers of tissue that surround the glomerulus |
Renal tubule | composed of a single layer, long, winding, tube |
Proximal Convoluted Tubule | The first region of the renal tubule |
Nephron Loop | Loop of Henle- Each nephron loop has two limbs |
Distal convoluted tubule | Originates at the renal cortex and extends to a collecting tubule |
Filtration Membrane | A porous, thin, and negatively charged structure that is formed by the glomerulus and visceral layer of Bowman's capsule |
Peritubular Capillaries | The anatomic structures and physiologic conditions that influence tubular reabsorption and tubular secretion |
Vasa Recta | Straight capillaries that lie parallel to the loop of henle |
Filtrate | The materials that pass through a filter |
Filtration | The filtering of something through a filter to remove waste and other substances |
Reabsorption | Being absorbed more than once |
Pedicels | Renal hilum--or a foot process of a podocyte |
Renal Threshold | Concentration of a substance dissolved in the blood above which the kidneys begin to remove it into the urine |
Aldosterone | Hormone produced by the adrenal gland; plays a major role in regulation of plasma sodium, extracellular potassium, and arterial blood pressure |
Antidiuretic Hormone (ADH) | Hormone released by the posterior pituitary gland; increases water reabsorption in the kidney and decreases urine production |
Atrial Natriuretic Peptide | A powerful vasodilator and a protein hormone released by heart muscle cells |
Aquaporins | Protein channels in the plasma membrane allowing the passage of water |
Obligatory Water Absorption | Water follows reabsorbed solutes due to osmotic gradients created between the filtrate and intracellular fluid |
Facultative Water Reabsorption | Permeability is controlled by ADH |
Urea | A nitrogenous waste product produced by amino acid metabolism and eliminated in urine |
Creatinine | Nitrogenous waste product resulting from the breakdown of creatine and excreted in urine |
Ureters | Tubes that connect the kidney to the bladder |
Urinary bladder | The sac that holds urine for excretion |
Detrusor Muscle | Muscle that acts to expel urine from the bladder |
Urethra | Tube that extends from the bladder and conducts urine to th exterior of the body |
Micturition | Urination |