XV Glossary

Acidosis: Low pH. (Chapter 15.2, Chapter 15.3)

Adipose capsule: A shock-absorbing layer of adipose tissue. (Chapter 15.3)

Afferent arterioles: Small blood vessels that carry blood into the glomeruli (filtering units) of the kidney’s nephrons. (Chapter 15.3)

Aldosterone: The main mineralocorticoid hormone that helps balance sodium and potassium levels and controls blood pressure and volume. (Chapter 15.3)

Alkalosis: Elevated pH. (Chapter 15.2, Chapter 15.3)

Antidiuretic hormone (ADH): A hormone released by the posterior pituitary that helps the body retain water when blood osmolality is high, such as during dehydration. (Chapter 15.3)

Bladder cancer: The most common cancer of the urinary system, causing symptoms like blood in urine, frequent urination, painful urination, and nighttime urination. (Chapter 15.4)

Buffer: A substance that resists changes in pH when small amounts of acid or base are added, helping maintain stable body chemistry. (Chapter 15.3)

Calcitriol: The active form of vitamin D that increases calcium absorption from the intestines and helps regulate calcium and phosphate levels in the blood. (Chapter 15.2)

Calcium pyrophosphate arthritis (pseudogout): An inflammatory joint disease similar to gout but caused by calcium phosphate crystal buildup rather than uric acid. (Chapter 15.4)

Chronic kidney disease (CKD): A progressive condition where damaged kidneys cannot effectively filter blood, causing harmful substances to build up in the body. (Chapter 15.4)

Dehydration: A condition that occurs when fluid intake is less than fluid output, leading to insufficient body water levels. (Chapter 15.3)

Diabetes insipidus (DI): A condition causing excessive production of dilute urine and extreme thirst due to insufficient ADH hormone or kidney unresponsiveness to ADH. (Chapter 15.4)

Dialysis: An artificial process that cleans the blood when the kidneys can no longer filter waste and excess fluid from the body. (Chapter 15.4)

Distal convoluted tubule (DCT): The final coiled section of the kidney tubule that connects the nephron loop to the collecting duct and fine-tunes urine composition. (Chapter 15.3)

Edema: Swelling caused by excess fluid trapped in the body’s tissues, often occurring in the hands, feet, ankles, or legs. (Chapter 15.2)

Efferent arterioles: Small blood vessels that carry blood away from the glomeruli to capillaries surrounding the nephrons. (Chapter 15.3)

End-stage renal disease: The final stage of chronic kidney disease when the kidneys stop functioning and dialysis or transplant is needed for survival. (Chapter 15.4)

Erythropoietin: A hormone produced primarily by the kidneys that stimulates the production of red blood cells in the bone marrow. (Chapter 15.2)

Estimated glomerular filtration rate (eGFR): A blood test that calculates how well the kidneys are filtering waste based on creatinine levels, age, and sex to diagnose kidney disease. (Chapter 15.3)

External urethral sphincter: A voluntary skeletal muscle below the internal sphincter that provides conscious control over urination. (Chapter 15.3)

Glomerular capsule: Surrounds the glomerulus and captures the filtrate being pushed out of the glomerular capillaries; also known as Bowman’s capsule. (Chapter 15.3)

Glomerular filtration rate (GFR): The volume of filtrate produced by both kidneys per minute, normally about 125 mL/min in males and 105 mL/min in females. (Chapter 15.3)

Glomerulonephritis: Inflammation of the glomeruli (kidney’s filtering units) that damages their ability to filter waste and excess water from the blood. (Chapter 15.4)

Glomerulus: A ball of capillaries at the beginning of each nephron that begins the filtration of blood. (Chapter 15.3)

Gout: A form of arthritis caused when uric acid crystals (a waste product from nucleic acid breakdown) are deposited in a body joint. (Chapter 15.4)

Insensible water loss: Water loss from the body that a person is unaware of, such as through breathing, sweating, and skin evaporation. (Chapter 15.3)

Internal urethral sphincter: An involuntary smooth muscle that automatically controls the release of urine from the bladder. (Chapter 15.3)

Juxtaglomerular apparatus (JGA): A specialized structure in the kidney where blood vessels and tubules meet that produces renin to help regulate blood pressure. (Chapter 15.3)

Ketones: Substances produced when the body burns fat for energy instead of glucose, detected in urine during conditions like diabetes or fasting. (Chapter 15.3)

Kidney stones: Crystal clusters formed from substances in urine that cause severe pain when passing through the urinary tract. (Chapter 15.4)

Micturition: The medical term for urination or emptying the bladder, which begins when bladder volume reaches about 150 mL. (Chapter 15.3)

Nephrologist: A physician who specializes in diagnosing and treating kidney diseases and conditions. (Chapter 15.4)

Nephrology: The study of the anatomy and physiology of the kidneys and kidney diseases. (Chapter 15.1)

Nephron loop (loop of Henle): A U-shaped portion of the kidney tubule with descending and ascending parts that reabsorbs sodium and water from filtered urine. (Chapter 15.3)

Nephrons: Functional units of the kidney that filter blood and convert the filtrate into urine. (Chapter 15.3)

Peritubular capillaries: Tiny blood vessels that surround nephrons in the kidney’s outer region (cortex) for exchange of substances. (Chapter 15.3)

Polycystic kidney disease (PKD): A genetic disorder causing fluid-filled cysts to grow in the kidneys, potentially enlarging them and damaging tissue leading to kidney failure. (Chapter 15.4)

Proximal convoluted tubule (PCT): The first, coiled section of the kidney’s renal tubule where initial filtration and reabsorption of substances from urine occurs. (Chapter 15.3)

Pyelonephritis: A severe kidney infection caused by bacteria that spread from the bladder up through the ureters, causing inflammation in the kidneys. (Chapter 15.4)

Renal artery: A blood vessel that branches off from the abdominal aorta and supplies oxygen-rich blood to the kidneys. (Chapter 15.3)

Renal capsule: A tough, fibrous outer covering of the kidney that protects it from trauma and infection. (Chapter 15.3)

Renal columns: Extensions of cortical tissue that separate renal pyramids in the medulla, divide the kidney into lobes, and support blood vessels entering and exiting the cortex. (Chapter 15.3)

Renal corpuscle: A structure composed of two parts: the glomerulus and the glomerular capsule. (Chapter 15.3)

Renal cortex: The outer region of the kidney. (Chapter 15.3)

Renal fascia: A layer of connective tissue that anchors the kidneys to surrounding structures and helps maintain their position in the abdominal cavity. (Chapter 15.3)

Renal hilum: The slight indentation on the medial side of each kidney where blood vessels, nerves, lymphatic vessels, and the ureters connect. (Chapter 15.3)

Renal pyramids: Six to eight cone-shaped tissues in the medulla of each kidney. (Chapter 15.3)

Sensible water loss: Water loss from the body that a person is aware of and can measure, mainly through urine production. (Chapter 15.3)

Specific gravity: A measure of the concentration of dissolved substances in urine compared to pure water, indicating how concentrated the urine is. (Chapter 15.3)

Transitional epithelium: A type of epithelium that can stretch and change shape. (Chapter 15.3)

Tubular reabsorption: The process by which the nephron returns water and solutes from the filtrate back into the blood. (Chapter 15.3)

Tubular secretion: The process by which substances are moved from the blood into the filtrate in the kidney tubules to be eliminated in urine. (Chapter 15.3)

Urethra: The tube that carries urine from the bladder to the outside of the body, with structural differences between males and females. (Chapter 15.3)

Urinalysis: A diagnostic laboratory test that examines urine composition to detect infections, diseases, or other health abnormalities. (Chapter 15.3)

Urinary incontinence: Involuntary loss or leakage of urine that can range from minor to significantly impacting quality of life. (Chapter 15.4)

Urinary tract infection (UTI): A common bacterial infection of the urinary tract that can affect the bladder (cystitis) or kidneys (pyelonephritis). (Chapter 15.4)

Urolithiasis: The presence of stones anywhere in the urinary tract, including kidneys, ureters, bladder, or urethra. (Chapter 15.4)

Urology: The study of male and female urinary systems, as well as the male reproductive system. (Chapter 15.1)

Vasa recta: Straight blood vessels that surround the nephron loops in the kidney’s inner region (medulla). (Chapter 15.3)