Unit 4 Study Guide

Afferent Arteriole

A small artery that carries blood to the glomerulus in the kidney.

Aldosterone

A hormone that helps regulate sodium and potassium balance by increasing sodium reabsorption in the kidneys.

Amylase

An enzyme that breaks down starches into sugars.

Appendix

A small, tube-like structure attached to the large intestine, often considered part of the digestive system.

Autoregulation

The process by which the kidneys maintain a constant glomerular filtration rate despite changes in blood pressure.

Bicarbonate Ions

Negatively charged ions that help regulate pH and are involved in buffering acid in the blood.

Bile Salts

Compounds derived from cholesterol that aid in the emulsification and digestion of fats.

Bladder

A muscular sac that stores urine before it is excreted from the body.

Bowman's Capsule

The cup-shaped structure in the kidney that surrounds the glomerulus and collects filtrate.

Chief Cells

Cells in the stomach that secrete pepsinogen, the precursor for the enzyme pepsin.

Chyme

The semi-fluid mass of partly digested food that is expelled from the stomach into the duodenum.

Collecting Duct

The final segment of the nephron, where the reabsorption of water and sodium takes place.

Colon

The large intestine, responsible for absorbing water and electrolytes, and forming feces.

Countercurrent exchange

A mechanism that enhances the efficiency of exchange processes, like in the Loop of Henle of the nephron.

Defecation Reflex

The physiological process for expelling feces from the body.

Distal Convoluted Tubule

The segment of the nephron following the loop of Henle, involved in further reabsorption and secretion.

Duodenum

The first part of the small intestine where most chemical digestion occurs.

Efferent Arteriole

A small artery that carries blood away from the glomerulus in the kidney.

Enterocyte

Specialized epithelial cells in the intestine responsible for absorbing nutrients.

Epiglottis

A flap of tissue that covers the trachea during swallowing to prevent food from entering the airway.

Esophagus

The muscular tube that connects the throat to the stomach.

Excretion

The process of removing waste products from the body.

Exocrine Gland

Gland that secretes substances through ducts to the surface or into cavities.

Filtrate

The liquid that passes through the glomerulus into Bowman's capsule, containing water and solutes.

Filtration

The process by which blood is filtered in the kidneys to form urine.

Gall Bladder

An organ that stores bile before it is released into the duodenum.

Gastric Glands

Glands in the stomach that produce gastric juice containing hydrochloric acid and enzymes.

Glomerular Filtration Rate

The rate at which blood is filtered in the glomeruli of the kidneys.

Glomerulus

A network of capillaries in the kidney where blood filtration occurs.

Ileum

The final section of the small intestine, where absorption continues and connects to the large intestine.

Jejunum

The middle segment of the small intestine, primarily responsible for nutrient absorption.

Kidney

An organ that filters waste from the blood to form urine.

Lacteal

A small lymphatic vessel in the intestine that absorbs fats.

Lipase

An enzyme that breaks down fats into fatty acids and glycerol.

Liver

An organ that processes nutrients, produces bile, and detoxifies the blood.

Loop of Henle

A section of the nephron that concentrates urine and conserves water.

Lymphatic System

The network of vessels that transport lymph, a fluid containing infection-fighting white blood cells.

Mouth

The entry point for food where digestion begins.

Mucus

A slippery secretion that moistens and protects the lining of the digestive tract.

Nephron

The functional unit of the kidney responsible for filtering blood and forming urine.

Pancreas

An organ that produces digestive enzymes and hormones like insulin.

Parietal Cells

Cells in the stomach that secrete hydrochloric acid.

Pepsin(ogen)

An enzyme that breaks down proteins and is secreted as an inactive precursor (pepsinogen) by the stomach.

Peritubular Capillaries

Capillaries surrounding the nephron that facilitate reabsorption and secretion.

Pharynx

The part of the digestive tract that connects the mouth to the esophagus.

Podocytes

Specialized cells in the glomerulus that help filter blood.

Portal Systems

Circulatory systems that direct blood from one capillary bed to another through veins.

Protease

An enzyme that breaks down proteins into peptides or amino acids.

Proximal Convoluted Tubule

The first segment of the nephron after Bowman's capsule, where most reabsorption occurs.

Reabsorption

The process of absorbing substances back into the bloodstream from the renal tubules.

Rectum

The final section of the large intestine that stores feces before excretion.

Renal Artery

The artery that carries blood to the kidneys.

Renal Corpuscle

The part of the nephron that includes the glomerulus and Bowman's capsule.

Renal Cortex

The outer region of the kidney that contains the renal corpuscles.

Renal Medulla

The inner region of the kidney that contains the loop of Henle and collecting ducts.

Renal Pelvis

The area of the kidney where urine collects before moving to the ureter.

Renal Vein

The vein that carries filtered blood away from the kidney.

Rugae

Folds in the stomach lining that allow for expansion.

Saliva

The fluid secreted by salivary glands that begins the digestion of food.

Salivary Glands

Glands that produce saliva, which contains enzymes for digestion.

Secretion

The process through which substances are released from cells into the lumen or external environment.

Small Intestine

The part of the digestive system where most digestion and absorption take place.

Sphincters

Muscular valves that control the flow of substances through the digestive tract.

Stomach

An organ that chemically and mechanically digests food.

Ureter

The duct that carries urine from the kidneys to the bladder.

Urethra

The tube that carries urine from the bladder to the outside of the body.

Urinary Tract Infection

An infection that affects any part of the urinary system.

Urine

The waste product formed by the kidneys through filtration and reabsorption.

Vasa Recta

Capillary networks that run parallel to the loops of Henle and are involved in concentration of urine.

Vasopressin

Also known as antidiuretic hormone (ADH), it regulates water balance in the body.

Villi

Small finger-like projections in the small intestine that increase surface area for absorption.

Active mechanisms of reabsorption in the nephron

primary/secondary active transport

passive mechanisms of reabsorption in the nephron

diffusion, facilitated diffusion, and osmosis

analyses of urine sample

• yellow color is due to urobilin pigment, H2O reabsorption determines urobilin content

• if blood is observed in the urine, it is most likely the result of a UTI

  • bacteria attach to urinary tract lining, release toxins and enzymes that damage epithelial cells and expose/damage blood vessels

Autoregulation of glomerular filtration rate (GFR)

GFR is autoregulated by arteriole vasoconstriction

chemical digestions within the GI tract

• begins with saliva in the mouth

• next HCl in the stomach

mechanical digestion within the GI tract

• begins with teeth in the mouth

enzymes involved in digestion

flow of blood around the nephron

• ~20% of blood volume enters nephron with each passes through glomerulus

• 100% of blood plasma is filtered each day