Urinary and Digestive Systems Review

Vocabulary flashcards covering the organs, functions, enzymes, and metabolic wastes of the urinary and digestive systems based on the lecture transcript.

Organs of the Urinary System

The group of organs consisting of two kidneys, two ureters, one urinary bladder, and one urethra.

Urea

The main nitrogenous metabolic waste product formed from the breakdown of proteins and amino acids.

Uric Acid

A metabolic waste product resulting from the cellular breakdown of nucleic acids, specifically DNA and RNA.

Creatinine

A metabolic waste product produced from energy metabolism and tissue turnover in skeletal muscle.

Blood Urea Nitrogen (BUN)

A measure of nitrogenous waste in the blood originating from proteins that are reduced to amino acids.

Cortical Nephrons

Nephrons with shorter loops that make up $85\%$ of all nephrons and constitute the majority of nephrons in humans.

Juxtamedullary Nephrons

Nephrons with longer loops that make up $15\%$ of nephrons and are characteristically found in camels.

Glomerular Filtration Membrane

A selective barrier that allows water, glucose, amino acids, urea, and ions through, but excludes blood cells, platelets, and large plasma proteins like albumin.

Angiotensin Converting Enzyme (ACE)

An enzyme located on endothelial cells in the lungs that converts angiotensin I into angiotensin II, a potent hormone that constricts blood vessels and increases blood pressure.

Aldosterone

A hormone that acts directly on the distal convoluted tubule (DCT) of the nephron.

Antidiuretic Hormone (ADH)

A hormone that promotes water retention, resulting in decreased urine output.

Detrusor Muscle

The smooth muscle located within the wall of the urinary bladder.

Hilum of the Kidney

The medial concave border of the kidney through which the renal artery enters and exits.

Pathway of Urine Through the Kidney

The anatomical route of urine: renal pyramids (collecting ducts) $\rightarrow$ minor calyx $\rightarrow$ major calyx $\rightarrow$ renal pelvis $\rightarrow$ ureter $\rightarrow$ urinary bladder $\rightarrow$ urethra.

Glomerulus

A capillary structure entered by afferent arterioles and exited by efferent arterioles that functions to separate liquid waste and extra water from the blood.

Salivary Amylase

An enzyme in the mouth operating at pH $4.0$ to $5.4$ that begins the chemical digestion of starches into maltose and smaller carbohydrates.

Lingual Lipase

An enzyme secreted in small amounts by the tongue that plays a minor role in initiating fat digestion.

Pepsin

A gastric enzyme functioning at pH $1.5$ to $2.0$ that breaks down proteins into smaller peptides.

Pancreatic Lipase

The enzyme secreted by the pancreas into the duodenum that digests the majority of dietary fats, breaking lipids down into fatty acids and glycerol.

Brush Border Enzymes

Enzymes located on the microvilli of the small intestine lining—including maltase, sucrase, lactase, and peptidases—that complete carbohydrate and protein digestion.

Zymogens

Inactive enzyme precursors secreted to prevent auto-digestion of the cells and tissues that synthesize and store them.

Pepsinogen

A zymogen secreted by stomach cells that is converted into active pepsin by stomach acid.

Trypsinogen

A zymogen secreted by the pancreas that is activated into trypsin once it reaches the small intestine.

Hydrochloric Acid ($HCl$)

A component of gastric juice that helps digest proteins, activates pepsinogen into pepsin, and protects the body by destroying ingested microorganisms.

Bile

A digestive fluid produced by the liver, stored in the gallbladder, and released into the duodenum.

Lacteals

Specialized lymphatic structures in the small intestine responsible for absorbing dietary fats and lipids.

Ileum

The longest and largest segment of the small intestine.

Lower Esophageal Sphincter

A muscular valve between the esophagus and the stomach that regulates food entry and prevents acid reflux.

Pyloric Sphincter

A muscular ring that controls the passage of chyme from the stomach into the small intestine.

Sequence of Protein Digestion

The sequential enzymatic processing of proteins: intact proteins $\rightarrow$ pepsin $\rightarrow$ trypsin or chymotrypsin $\rightarrow$ peptidases $\rightarrow$ individual amino acids.