Anatomy and Physiology: Renal, Fluid Balance, Digestive, and Metabolic Systems

Vocabulary practice flashcards covering renal autoregulation, fluid and electrolyte balance, gastric secretions, digestive enzymes, and mitochondrial electron transport chain energetics.

Urea

A nitrogenous waste product filtered from the blood by the kidneys that results from the breakdown of proteins and amino acids.

Uric Acid

A nitrogenous waste product excreted by the kidneys that is produced by nucleic acid catabolism.

Creatinine

A waste product derived from creatine phosphate catabolism; its excretion is measured as an indicator of glomerular filtration rate (GFR) and kidney failure.

Vascular Pole

The region of the renal corpuscle where blood enters through the larger afferent arteriole and exits through the efferent arteriole.

Urinary Pole

The region of the renal corpuscle where glomerular filtrate collects within the capsular space and flows outward into the proximal convoluted tubule.

Myogenic Mechanism

A component of renal autoregulation wherein smooth muscle in the tunica media of the afferent arteriole contracts in response to stretching from a pressure bulge to stabilize glomerular capillary pressure and GFR.

Macula Densa

Sensory cells situated at the end of the loop of Henle that monitor urine flow and send a paracrine signal to juxtaglomerular (JG) cells to contract when GFR is elevated.

Inulin

An exogenous test molecule utilized clinically to assess kidney failure.

Type 1 Diabetes

A genetic disorder characterized by the inability of pancreatic beta cells to produce the hormone insulin.

Type 2 Diabetes

A metabolic disorder in which pancreatic beta cells synthesize insulin, but target tissues exhibit insulin resistance due to unresponsiveness at insulin receptors.

Gestational Diabetes

A condition in pregnancy where novel gestational hormones interfere with maternal insulin receptors, excessively elevating maternal blood glucose levels.

Diabetes Insipidus

A condition caused by the hyposecretion of antidiuretic hormone (ADH), which prevents adequate water reabsorption in the renal collecting ducts.

Trigone

The smooth triangular anatomical region of the urinary bladder formed between the two ureteral openings and the internal urethral orifice.

Osmolarity

A physical measurement of solute concentration within a solution, defining the amount of solute particles per unit volume.

Sensible Water Loss

Measurable, conscious fluid loss from the body occurring through urine, feces, and sweat.

Insensible Water Loss

Unnoticed fluid output that exits the body via expired respiratory breath and cutaneous transpiration across the skin.

Preformed Water

Body water acquired directly through the ingestion of liquids and food.

Metabolic Water

Water generated intracellularly as a byproduct of ATP synthesis.

Esophageal Hiatus

An anatomical opening through the diaphragm that permits the passage of food via the esophagus into the stomach.

Mucous Cells

Gastric gland cells that produce an alkaline mucus layer to protect epithelial cells from stomach acid and retard epithelial cell death.

Chief Cells

Gastric gland cells that secrete gastric lipase and the inactive zymogen pepsinogen, which is cleaved into active pepsin to digest proteins.

Parietal Cells

Gastric gland cells responsible for secreting the hunger hormone ghrelin, intrinsic factor for vitamin $B_{12}$ absorption, and hydrochloric acid ($HCl$).

Secretin

A duodenal enteroendocrine hormone stimulated by chyme that signals the pancreas to secrete neutralizing bicarbonate ions ($HCO_3^-$) into the duodenum.

Cholecystokinin (CCK)

A gastrointestinal hormone that signals the pancreas to release replacement digestive enzymes, including zymogens, pancreatic amylase, pancreatic lipase, and nucleases.

Enterokinase

An intestinal brush border enzyme that cleaves inactive trypsinogen into active trypsin, thereby triggering the activation of chymotrypsinogen and procarboxypeptidase.

Chloride Shift

The active transport exchange mechanism in parietal cells where intracellular bicarbonate ($HCO_3^-$) is exported to the bloodstream in exchange for chloride ($Cl^-$).

Bile

A digestive secretion synthesized by the liver and stored in the gallbladder that coats small lipid droplets to prevent coalescence and facilitate intestinal reabsorption.

Gastric Inhibitory Peptide (GIP)

A hormone produced in the small intestine that prompts pancreatic beta cells to release insulin.

Cytochrome Oxidase Complex

The terminal protein complex in the electron transport chain that pumps $H^+$ and retains electrons until they are accepted by molecular oxygen.

ATP Synthase

A turbine-like mitochondrial enzyme that harnesses the diffusion of $H^+$ back into the matrix to drive the phosphorylation of ADP into ATP.

Beta Oxidation

A catabolic pathway that cleaves fatty acid chains into smaller fragments for cellular energy metabolism.

Deamination

The biochemical removal of an amino group from an amino acid molecule to prepare its carbon skeleton for ATP synthesis.