Digestive Tract and Kidney Function Flashcards

Digestive System Overview

• The digestive system starts at the mouth and ends at the anus.

Peritoneum

• A thin, shiny serous membrane lining the abdominopelvic cavity.
• It folds back to cover most organs within the cavity.
• Parietal peritoneum: Layer in contact with the body wall.
• Visceral peritoneum: Layer covering the organs, allowing them to slide over each other.

Mucosal Epithelium

• From the mouth through the esophagus and in the anus, the mucosal epithelium consists of stratified squamous cells.

Digestive Processes

• Ingestion: The mouth/oral cavity receives food.
• Mastication: Teeth break food into smaller portions.
• Saliva: Produced by the salivary glands.
• Deglutition: Food moving towards the throat to be swallowed.
• Peristalsis: A wave of circular muscle contraction that propels food through the digestive tract.

Organs of the Digestive System

• Tongue: A muscular organ that projects into the mouth, aids in chewing and swallowing, and is a primary organ of speech.
• Pharynx: Commonly referred to as the throat.
• Esophagus: Food is lubricated with mucus here, and peristalsis moves it into the stomach.
• Stomach: Receives food from the esophagus.

Sphincters

• Lower esophageal sphincter: Controls the passage of food from the esophagus to the stomach.
• Pyloric sphincter: Controls how rapidly food moves into the small intestine.

Digestion in the Stomach

• Hydrochloric acid denatures proteins and prepares them for digestion.
• Ingested food, gastric juice, and mucus mix to form chyme.

Small Intestine

• Roughly 20 feet long.
• Duodenum: The first segment, about 10 inches long.
• Jejunum: The second segment, approximately 2/5 of the small intestine's length.
• Ileum: The final segment, which terminates into the cecum of the large colon.

Large Intestine

• Roughly 5 feet long.
• Ileocecal valve: Permits food passage from the ileum of the small intestine into the cecum.
• Defecation: The process of eliminating feces from the body.

Accessory Organs

• Liver: The largest accessory organ.
  • Manufactures bile.
  • Plays a crucial role in controlling blood glucose.
  • Synthesizes urea, a waste product of protein metabolism, which is released into the blood and transported to the kidneys for elimination.
  • Vital in removing harmful substances like alcohol and certain drugs through detoxification.
• Gallbladder: Stores and releases bile.
• Pancreas: Produces enzymes that digest fats, proteins, carbohydrates, and nucleic acids.
  • Releases large amounts of sodium bicarbonate, an alkaline fluid that neutralizes the acidic chyme in the small intestine, protecting the digestive tract lining.

Digestion Locations

• Carbohydrate digestion: Occurs in the mouth and small intestine.
• Protein digestion: Occurs in the stomach and small intestine.
• Fat digestion: Occurs in the small intestine.

Kidney Function

• Glomular filtration: Movement of materials out of the blood within the nephron.
• Decreased levels of aldosterone will result in low blood pressure

Urinary System Structures

• Ureter: Connects the kidney to the bladder.
• Renal artery: Brings oxygenated blood to the kidneys.
• Renal vein: Takes oxygen-depleted blood away from the kidney.
• Urethra: Allows urine to be passed from the bladder to the outside of the body.
• Nephron: The functional unit of the kidney.

Physiological Regulation

• Activation of the Renin-Angiotensin-Aldosterone system results in increased blood pressure.
• Vomiting can cause an alkaline shift in pH.
• Buffer systems, respiration, and kidney function help the body maintain pH homeostasis.
• The majority of fluid reabsorption occurs in the proximal convoluted tubules.
• Aldosterone affects water reabsorption at the distal convoluted tubules.
• ADH affects fluid reabsorption at the collecting duct.