things to know: Chapters 24 and 25 Flashcards

Comprehensive vocabulary flashcards covering the anatomy and physiology of the urinary system, including structures of the kidney, nephron function, and clinical terms related to urination and renal failure.

Kidneys

A component of the urinary system that function in the regulation of blood composition, including the excretion of wastes and the maintenance of normal fluid and electrolyte balance.

Ureters

Tubes that receive urine from the kidneys and conduct it to the bladder using gravity and peristalsis.

Urinary bladder

Receives and stores urine prior to its elimination from the body.

Urination (micturition)

The elimination of urine from the body.

Urethra

Conducts urine from the bladder to the exterior.

Filtrate

Filtered fluid.

Hilum

The medial indentation of the kidney.

Retroperitoneal

Behind and outside the peritoneal cavity; the position in which the kidneys lie.

Fibrous capsule

A layer of collagen fibers that covers the outer surface of the kidney.

Renal sinus

An internal cavity within the kidney.

Renal cortex

The superficial portion of the kidney in contact with the fibrous capsule.

Renal medulla

An area extending from the renal cortex to the renal sinus that contains renal pyramids.

Renal pyramid

A conical structure extending from the cortex of the kidney to a tip called the renal papilla.

Renal column

A band of granular tissue that separates adjacent pyramids.

Kidney lobe

Consists of a renal pyramid, the overlying area of renal cortex, and adjacent tissues of the renal columns.

Minor calyx

Collects urine from a single lobe.

Major calyx

Forms through the fusion of $4-5$ minor calyces.

Nephrons

Microscopic, functional units of the kidney.

Glomerulus

Ball shaped capillary beds.

ADH

Antidiuretic Hormone.

Renal pelvis

A large, funnel shaped structure that collects urine from the major calyces and is continuous with the ureter.

Cortical nephrons

Nephrons located almost entirely within the cortex.

Juxtamedullary nephrons

Nephrons that have a long nephron loop that extends deep into the renal medulla.

Renal corpuscle

A spherical structure consisting of the glomerular capsule (Bowman's capsule) and the glomerulus (capillary network).

Proximal convoluted tubule (PCT)

The initial segment of the renal tubule, proximal to the renal corpuscle.

Distal convoluted tubule

The last segment of the renal tubule, distal to the renal corpuscle.

Nephron loop (loop of Henle)

The middle segment of the renal tubule consisting of an ascending limb and a descending limb.

Collecting duct

Receives fluid from many nephrons and carries it to the papillary duct which drains into the minor calyx.

Blood flow to kidneys (pathway)

Abdominal Aorta -> Renal Arteries -> segmental arteries -> interlobar arteries -> arcuate arteries -> cortical radiate arteries -> afferent arterioles -> glomerulus -> efferent arterioles -> peritubular capillaries.

Blood flow returning from the kidneys (pathway)

cortical radiate veins -> arcuate veins -> interlobar veins -> renal veins -> inferior vena cava.

Peritubular capillaries

Capillaries that surround the entire renal tubule.

Vasa recta

Connects to the peritubular capillaries of the juxtamedullary nephrons.

Urea

Metabolic waste from the breakdown of amino acids.

Creatinine

Metabolic waste generated from the breakdown of creatine phosphate.

Uric acid

Metabolic waste generated from the breakdown of RNA.

Filtration

A process in which blood pressure forces water and solutes across the membranes of the glomerular capillaries and into the capsular space.

Reabsorption

The transport of water and solutes from the tubular fluid, across the tubular epithelium, and into the peritubular fluid (blood).

Secretion

The transport of solutes from the peritubular fluid, across the tubular epithelium, and into the tubular fluid.

Juxtaglomerular complex

Consists of specialized cells that secrete renin when glomerular blood pressure decreases.

Glomerular hydrostatic pressure (GHP)

The blood pressure in the glomerular capillaries which tends to push water and solute molecules out of the plasma and into the filtrate.

Glomerular filtration rate (GFR)

The amount of filtrate the kidneys produce each minute.

Autoregulation

A process triggered by decreased GFR that results in the dilation of afferent arterioles, constriction of efferent arterioles, and constriction of mesangial cells to increase glomerular blood pressure.

Central regulation

Activated if autoregulation is insufficient; involves the juxtaglomerular complex releasing renin and the activation of the renin-angiotensin-aldosterone system.

Obligatory water reabsorption

Occurs at the proximal convoluted tubule and descending limb of the Loop of Henle, resulting in the recovery of approximately $85\%$ of the volume of filtrate produced.

Facultative water reabsorption

A process along the DCT and collecting system that is precisely controlled and dependent upon anti-diuretic hormone.

Anti-diuretic hormone

Hormone produced by the hypothalamus and released by the posterior pituitary that causes the appearance of aquaporins, increasing the rate of osmotic water movement.

Aquaporins

Special water channels that dramatically increase the rate of osmotic water movement.

Average daily urine production

Approximately $1200\,mL$ produced by a normal, healthy person each day.

Normal urine pH range

$$4.5-8$$

Chronic renal failure

A condition where kidney function deteriorates gradually and associated problems accumulate over time.

Acute renal failure

Occurs when exposure to toxic drugs, renal ischemia, urinary obstruction, or trauma causes filtration to slow suddenly or stop.

Hemodialysis

The use of an artificial dialysis membrane and machine to regulate the composition of blood through passive diffusion.

Urinary tract

Consists of the ureters, urinary bladder, and urethra; responsible for transport, storage, and elimination of urine.

Rugae

Folds of the urinary bladder lining that disappear as the bladder fills.

Trigone

The triangular area bounded by the ureteral openings and the entrance to the urethra that acts as a funnel during bladder contraction.

Internal urethral sphincter

An involuntary sphincter located at the entrance to the urethra.

External urethral sphincter

A voluntary sphincter located at the entrance to the urethra.

Urgency

A strong desire to urinate.

Frequency

An increased need to urinate more often.

Polyuria

The production of excessive amounts of urine.

Oliguria

Low urine output, defined as a urine volume of $50-500\,mL/day$.

Anuria

Very low urine output, defined as $0-50\,mL/day$.

Incontinence

An inability to control urination voluntarily.