Renal Anatomy, Physiology, and Body Fluid Analysis Master Review

Comprehensive vocabulary flashcards covering the anatomy and physiology of the kidneys, urinalysis procedures, renal diseases, metabolic disorders, and body fluid analysis including CSF, amniotic, serous, synovial, seminal, and gastric fluids.

Nephron

The functional unit of the kidney, with approximately $1.3 \times 10^6$ in each kidney.

Renal Hilum

The characteristic indentation at the concave side of the kidney from which the ureter, blood vessels, and nerves emerge.

Renal Fascia

The superficial layer of the kidney composed of dense irregular connective tissue that anchors each kidney to surrounding organs.

Renal Parenchyma

The functional portion of the kidney comprised of the renal cortex and renal medulla only.

Juxtamedullary Nephrons

Nephrons located closer to the medulla that have longer loops of Henle and primarily function to concentrate urine.

Mesangial Cells

Contractile components of the renal corpuscle capable of removing entrapped macromolecules via phagocytosis and pinocytosis.

Podocytes

Visceral epithelial cells of the capillaries that interdigitate to form filtration slits lined with a slit diaphragm to filter albumin.

Macula Densa

Specialized cells in the distal convoluted tubule that detect and respond to changes in glomerular pressure.

Proximal Convoluted Tubule (PCT)

The tubule where $80 \%$ of the ultrafiltrate is reabsorbed, lined with simple cuboidal epithelium featuring microvilli.

Vasa Recta

A series of long U-shaped vessels adjacent to the loop of Henle in juxtamedullary nephrons where major exchanges of water and salts take place.

Glomerular Filtration Rate (GFR)

The rate at which the glomerulus filters blood, normally between $90$ to $120\,mL/min$.

Renal Threshold

The concentration of a solute in plasma at which the maximal tubular reabsorptive capacity ($T_m$) has been exceeded.

Renal Clearance

The volume of plasma in milliliters from which a substance is completely removed/cleared in the kidneys per unit time.

Creatinine

An endogenous substance of choice for clearance tests because it is produced at a constant rate and is not reabsorbed by renal tubules.

$$1.73\,m^2$$

The external body surface area of an average individual used to normalize creatinine clearance values.

Cystatin C

A potential marker for long-term monitoring of renal function that is produced at a constant rate, filtered by the GFB, and completely reabsorbed.

Osmolality

The concentration of a solution expressed as the total number of solute particles per kilogram of solvent.

Free Water Clearance

The volume of blood plasma that is cleared of solute-free water per unit of time; computed as $CH_2O = \text{Volume of Urine} - \text{Osmolar Clearance}$.

P-Aminohippurate (PAH) Clearance

The reference method for determining Renal Blood Flow because it is an exogenous weak organic acid completely secreted upon its first pass.

Urochrome

The pigment principally responsible for the normal yellow color of urine, which darkens when exposed to light.

Nocturia

A condition where an individual excretes more than $500\,mL$ of urine at night, associated with chronic progressive renal failure.

Isosthenuria

The inability of the kidneys to alter the specific gravity of the ultrafiltrate, resulting in urine with a consistent specific gravity of $1.010$.

Protein Error of Indicators

The chemical principle where indicator dyes release $H^+$ as a result of the presence of proteins (anions) at a constant pH of $3.0$.

Bence Jones Protein

An abnormal protein that coagulates between $40^{\circ}C$ and $60^{\circ}C$ and dissolves at $100^{\circ}C$, found in cases of multiple myeloma.

Galactosemia

An inherited disorder characterized by an inability to metabolize galactose to glucose, which can cause cataracts and irreversible brain damage.

Ketonuria

The increased excretion of ketones in urine (approximately $20\,mg/day$) due to increased fat metabolism.

Hematuria

The increased presence of intact red blood cells in urine, which results in a cloudy red appearance.

Hemosiderin

An insoluble storage form of iron that appears as yellow-brown granules in urine sediment $2$–$3$ days after a hemolytic episode.

Ictotest

The confirmatory tablet test for bilirubin based on an azocoupling reaction with a sensitivity of $0.05$–$0.1\,mg/dL$.

Greiss Reaction

The diazotization reaction used in nitrite reagent pads where nitrites react with an aromatic amine to form a diazo compound.

Sternheimer-Malbin Stain

A supravital stain consisting of crystal violet and safranin used to identify cells and casts in urine sediment.

Glitter Cells

Swollen neutrophils in hypotonic urine that demonstrate Brownian movement of refractile cytoplasmic granules.

Oval Fat Bodies

RTE cells or macrophages containing lipids that exhibit a Maltese cross formation under polarized microscopy.

Hyaline Casts

The most common casts observed in urine sediment, composed of a homogeneous uromodulin protein matrix with a low refractive index.

Waxy Casts

Fragmented, highly refractive casts with jagged ends indicating prolonged stasis and chronic renal failure.

Struvite Stones

Renal calculi composed of magnesium ammonium phosphate, often associated with UTI caused by urea-splitting organisms.

Staghorn Stones

Large branching stones in the renal pelvis that extend into two or more calyces.

Phenylketonuria (PKU)

A disease characterized by a mousy or musty urine odor due to the excretion of phenylacetic acid.

Alkaptonuria

An autosomal recessive disease involving a lack of homogentisic acid oxidase, causing urine to turn black upon standing.

Lesch-Nyhan Disease

A purine overflow disease characterized by orange sand (uric acid crystals) in the diapers of affected infants.

Xanthochromia

Yellow, pink, or orange discoloration of CSF supernatant indicating intracranial hemorrhage or bilirubin.

L/S Ratio

The lecithin-sphingomyelin ratio; a value of $2.0$ or greater indicates fetal lung maturity.

Chylous Effusion

An effusion caused by lymphatic obstruction, featuring a triglyceride concentration greater than $110\,mg/dL$ and the presence of chylomicrons.

Arthrocentesis

The procedure used by a physician to aseptically collect synovial fluid.

Rice Bodies

White, free-floating particles in synovial fluid that resemble polished rice, seen in tuberculosis or rheumatoid arthritis.

Sertoli Cells

Cells in the seminiferous tubules that regulate spermatozoa production by supplying nutrients and hormones.

Liquefaction

The process by which semi-solid semen becomes thinner and watery, which should normally occur within $30$ to $60$ minutes after ejaculation.

Spinnbarkeit

A test evaluating the viscoelasticity of ovulatory cervical mucus, which may form a thread up to $9\,cm$ and over at ovulation.

Human Chorionic Gonadotropin (hCG)

A glycoprotein hormone produced by the placental trophoblast that serves as the basis for most pregnancy tests.

Steatorrhea

The excretion of excess fecal fat ($>6\,g/day$), associated with pancreatic insufficiency or malabsorption syndromes.

Melena

The excretion of dark or black, pitchy stools resulting from the presence of large amounts of blood ($50$ to $100\,mL/day$).

Pilocarpine Iontophoresis

The action of inducing sweat in a local area using the drug pilocarpine and an electric current to test for cystic fibrosis.