Urinary System Flashcards

Flashcards on the Urinary System

Urinary System

Also known as the renal system, it helps maintain the body's homeostasis by removing and restoring solutes and water from the blood.

Kidneys, ureters, urinary bladder, and urethra

Major Components of the Urinary System

Functions of the Urinary System

Excretion, maintaining blood volume and concentration, pH regulation, blood pressure regulation (via renin), erythrocyte concentration (via erythropoietin), and Vitamin D production (via calciferol)

Kidneys

Paired organs, reddish in color, kidney bean-shaped, about the size of a closed fist, located above the waist between the parietal peritoneum and the posterior abdominal wall.

Renal Sinus

The entrance to a cavity in the kidney, consisting of connective tissues and fat.

Renal Capsule

Innermost layer of the kidney, smooth, transparent, fibrous connective tissue membrane that connects with the outermost covering of the ureter and hilum, functioning as a barrier against infection and trauma.

Hilum

A notch near the center of the concave border of the kidney where the ureter leaves the kidney and where blood vessels, nerves, and lymph vessels enter and exit.

Adipose Capsule

Second layer of tissue in the kidney, a mass of fatty tissue that protects the kidney from blows and holds it in place in the abdominal cavity.

Renal Fascia

Outermost layer of tissue in the kidney, consists of a thin layer of fibrous connective tissue that anchors the kidneys to surrounding structures and the abdominal wall.

Renal Cortex

Space between the medulla and the outer capsule in the kidney; produces erythropoietin.

Renal Medulla

The innermost region of the kidney, arranged into pyramid-like structures, consisting of the bulk of the nephron structure.

Renal Pelvis

Connects the kidney with the circulatory and nervous systems.

Renal Pyramid

Striated, triangular structures that constitute the medulla; 8 to 18 per kidney.

Renal Papillae

The apex of the renal pyramid, projecting into the cavity of a calyx, through which collecting ducts discharge urine.

Renal Columns

Medullary extensions of the renal cortex in between the renal pyramids, allowing the cortex to be better anchored.

Minor Calyx

Funnel-shaped structure that surrounds the tip of each renal pyramid, collecting urine from the ducts of the pyramids; there can be 8 to 18 per kidney.

Major Calyx

A cavity formed by the convergence of several minor calyces, draining urine from the minor calyces into the renal pelvis.

Nephron

Functional unit of the kidney responsible for filtration of blood, maintenance of renal blood pressure, formation of urine, counter-current mechanism, acid-base balance, regulation, reabsorption and secretion of materials, and excretion of wastes.

Cortical Nephrons

85% of nephrons, shorter and located mostly in the cortex; produce standard urine; Loop of Henle does not extend past the cortex.

Juxtamedullary Nephrons

15% of nephrons, capable of producing concentrated urine due to longer Loops of Henle that extend past the cortex and into the medulla.

Afferent Arteriole

Transports arterial blood to the glomerulus for filtration.

Efferent Arteriole

Transports filtered blood from the glomerulus through the peritubular capillaries and vasa recta to the kidney venous system.

Glomerulus

The site of blood filtration, operating as a nonspecific filter, and producing filtrate.

Bowman's Glomerular Capsule

A sac that encloses the glomerulus, transferring filtrate to the Proximal Convoluted Tubule (PCT).

Proximal Convoluted Tubule (PCT)

A thick, constantly active segment of the nephron that reabsorbs most of the useful substances of the filtrate and is the primary site for secretion (or elimination) of drugs, waste and hydrogen ions.

Loop of Henle

U-shaped tube consisting of a descending and ascending limb; concentrates salt in the interstitium.

Descending Limb (of Loop of Henle)

Part of the counter-current multiplier, fully permeable to water and completely impermeable to solutes, allowing water to be absorbed and passing 'salty' filtrate to the next segment.

Ascending Limb (of Loop of Henle)

Part of the counter-current, impermeable to water and actively transports (reabsorbs) salt (NaCl) to the interstitial fluid of the pyramids in the medulla.

Distal Convoluted Tubule (DCT)

Variably active portion of the nephron, receiving dilute fluid from the ascending limb of the Loop of Henle.

Collecting Duct

Variably active portion of the nephron; the last segment to save water for the body, receiving fluid from the DCT.

Peritubular Capillaries

Transport reabsorbed materials from the PCT and DCT into the kidney veins and eventually back into the general circulation, helping complete the conservation process.

Ureters

Transport urine from the renal pelvis to the urinary bladder.

How Urine is carried through the Ureters

Through peristaltic contractions, as well as gravity and hydrostatic pressure

Urinary Bladder

A hollow muscular organ located in the pelvic cavity posterior to the pubic symphysis, consisting of the same tissue layers as the ureters.

Micturition

The way of expelling urine from the bladder; also known as urination or voiding.

Urethra

Small thin-walled tube leading from the floor of the urinary bladder to the outside of the body, transporting urine by peristalsis.

Kidney Stones

Also known as renal calculi, are composed of the precipitates of uric acid, magnesium or calcium phosphate, or calcium oxalate. They can form in the renal pelvis or in the collecting ducts.

Cystitis

Inflammation of the urinary bladder, usually caused by a bacterial infection.

Gout

A condition caused by high concentrations of uric acid in the plasma, with crystals of uric acid deposited in joints, causing inflammation and pain.

Glomerulonephritis

Inflammation of the kidneys, where the filtration membrane within the renal capsule is infected with bacteria.

Renal Failure

Results from conditions that interfere with kidney function, leading to accumulation of urea and other metabolites in the blood and can be treated by hemodialysis.