Exam 4-- Urinary and Digestive Systems

Organs of the Urinary System

Two Kidneys, Two Ureters, Urinary Bladder, and Urethra.

Kidney Functions

Filters blood and excretes toxic metabolic wastes, regulates blood volume, pressure, osmolarity, electrolytes, and acid-base balance.

Urea

A waste product that comes from protein catabolism.

Renal Corpuscle

The structure where blood plasma is filtered.

Glomerular Filtration

The process where water and solutes pass from blood in the glomerulus into the nephron capsular space.

Nephron Loop

A U-shaped portion of the renal tubule with a descending and ascending limb.

Juxtamedullary Nephron

A nephron type close to the medulla with very long loops extending to the apex of renal pyramids.

Tubular Reabsorption

The process of reclaiming water and solutes from tubular fluid and returning them to the blood.

Aldosterone

A steroid hormone that stimulates sodium reabsorption and potassium secretion.

ADH (Antidiuretic Hormone)

Stimulates kidney water retention and affects urination frequency.

Countercurrent Multiplier Mechanism

Mechanism by which the nephron loop continuously recaptures salt and returns it to the medulla.

Diuretics

Any chemical that increases urine volume.

Micturition

The act of urinating, controlled by the micturition reflex.

Urochrome

The yellow pigment giving urine its characteristic color, a byproduct of hemoglobin breakdown.

Polyuria

An excessive amount of urination, defined as more than 3 liters per day in adults.

Pancreatic Juice

An alkaline mixture of water, enzymes, and electrolytes secreted into the pancreatic duct.

Defecation

The release of feces from the rectum, which is stimulated by the stretching of the rectum.

Nephron Renal Corpuscle

Consists of the glomerulus and a two-layered glomerular capsule that encloses the glomerulus.

Vascular Pole

The side of the renal corpuscle where the afferent arteriole enters and the efferent arteriole exits.

Urinary Pole

The side of the renal corpuscle where the renal tubule begins.

Mesangial Cells

Cells that help maintain the structure of the glomerulus and can remove debris.

Renal Tubule

Duct leading away from the glomerular capsule and ending at the tip of the medullary pyramid.

Proximal Convoluted Tubule (PCT)

Arises from the glomerular capsule and is involved in the reabsorption of water and nutrients.

Renal Autoregulation

The ability of the nephrons to adjust their own blood flow and glomerular filtration rate (GFR) without external influence.

Nitrogenous Wastes

Any substance that is useless to the body or present in excess of the body's needs.

Metabolic Waste

Waste substance produced by the body.

Excretion

The process of separating wastes from body fluids and eliminating them.

Minor Calyx

A small cup-like structure that surrounds the renal papilla.

Major Calyx

Formed by the convergence of 2-3 minor calyces.

Renal Pelvis

Formed by the convergence of 2-3 major calyces.

Digestive System

The organ system that processes food, extracts nutrients, and eliminates waste.

Ingestion

The selective intake of food.

Digestion

The mechanical and chemical breakdown of food into a form usable by the body.

Absorption

The uptake of nutrient molecules into the epithelial cells of the digestive tract and then into the blood and lymph.

Compaction

The process of absorbing water and consolidating indigestible residue into feces.

Mechanical Digestion

The physical breakdown of food into smaller particles.

Chemical Digestion

A series of hydrolysis reactions that breaks down dietary macromolecules into monomers.

Digestive Tract

A 30-foot long muscular tube extending from the mouth to the anus.

Accessory Organs

Organs such as the teeth, tongue, salivary glands, liver, gallbladder, and pancreas that assist in digestion.

Mucosa

The innermost layer of the digestive tract, which secretes mucus and absorbs nutrients.

Muscularis Externa

The muscle layer responsible for peristalsis in the digestive tract.

Peristalsis

Wave-like involuntary contractions that move food through the digestive tract.

Gastric Juice

Fluid produced by the gastric glands, containing hydrochloric acid and digestive enzymes.

Salivary Amylase

An enzyme that begins the chemical digestion of starches in the mouth.

Intrinsic Factor

A glycoprotein secreted by the parietal cells of the stomach, essential for vitamin B12 absorption.

Gallbladder

Pouch that stores and concentrates bile produced by the liver.

Pancreas

A flattened, sponge-like gland that secretes enzymes and hormones for digestion.

Villi

Tiny, finger-like projections in the lining of the small intestine that increase surface area for absorption.

Haustral Contractions

Churning movements in the large intestine that mix residue and promote absorption of water and salts.

Defecation Reflex

The reflex that triggers the elimination of feces from the body.

Pepsinogen

Inactive form of pepsin secreted by chief cells in the stomach.

Chyme

Acidic, soupy mixture of semi-digested food that passes from the stomach to the small intestine.

Segmentation

Movement in the intestines that mixes food and promotes absorption.

Constipation

Occurs when fecal movement is slow, leading to excessive water reabsorption and hardened feces.

Diarrhea

Occurs when the large intestine absorbs too little water.

Submucosa

The layer of the digestive tract that contains blood vessels, nerves, and connective tissue.

Serosa

Outer layer of the digestive tract.

Extrinsic Muscles

Muscles that control the movement of the tongue.

Myenteric Plexus

A network of nerves between the muscular layers that controls peristalsis.

Intraperitoneal

When an organ is enclosed by mesentery on both sides.

Retroperitoneal

When an organ lies against the posterior body wall and is covered by peritoneum on its anterior side.

Oral Cavity

The entry point of the digestive system, involved in ingestion, taste, chewing, and initial digestion.

Lingual Papillae

Bumps and projections on the tongue that are the sites of most taste buds.

Palate

Separates the oral cavity from the nasal cavity.

Crown (of a tooth)

The portion of a tooth above the gum line.

Root Canal

Space in the root leading to the pulp cavity in the crown of a tooth.

Mastification

The process of breaking down food into smaller pieces for swallowing.

Saliva

Fluid that moistens the mouth, begins starch and fat digestion, cleans teeth, and inhibits bacterial growth.

Gastric Rugae

Permanent ridges or folds in the inner lining of the stomach.

Deglutition

Swallowing; a complex action involving muscles in the mouth, pharynx, and esophagus.

Esophageal Sphincter

A muscle that prevents the backflow of stomach contents into the esophagus.

Wisdom Tooth

The third molar, typically emerging between the ages of 17 to 25.