Ch.7: Digestive System Flashcards
How long is the digestive system?
30 feet, but appears shorter (about 1/3 of its length) in a living person due to muscle tone (partial contraction so length is less)
What are the accessory organs of the digestive system?
Salivary glands – contain amylase (digests carbohydrates).
Pancreas – produces enzymes for digestion.
Liver – produces bile (no enzymes).
What is the role of bile and lipase in fat digestion?
Bile breaks down fat into smaller droplets (emulsification).
Lipase digests these droplets into fatty acids and glycerol.
How long is the esophagus, and what happens if the lower sphincter malfunctions?
10 inches long
If lower sphincter is open → acid reflux
If lower sphincter is closed → achalasia (food can’t enter the stomach)
What does the stomach produce?
Pepsin (digests proteins) and hydrochloric acid (HCl) (creates acidic environment for digestion).
How long is the duodenum, and what enters it?
12 inches long
Receives bile from the liver and pancreatic juice from the pancreas.
What are the sections of the small intestine, and what happens there?
Jejunum – 7-8 feet, main site of nutrient absorption.
Ileum – 20 feet, continues absorption of nutrients.
Function: Hydrolysis of food and absorption of digested nutrients Vitamin absorption: Vitamin B12 & Vitamin K
What are the sections of the large intestine, and what happens there?
Colon (3-4 feet) – absorbs water from digested material.
Ileocecal valve – controls flow from ileum to cecum.
Cecum – start of the large intestine.
Vermiform appendix – small structure attached to the cecum.
Where do digestive processes occur?
Extracellularly (outside the cell) in the lumen of the stomach and intestine.
What is deglutition?
Swallowing.
What is motility, and what helps it?
Movement of food through the digestive tract.
Motilin and VIP (vasoactive intestinal peptide) help regulate motility.
Peristalsis: smooth muscle contraction & relaxation moves food forward.
Gravity plays NO role in digestion.
What are some key digestive secretions and their functions?
Bile (from liver) – helps break down fats.
Hydrochloric acid (HCl) (from parietal cells in the stomach) – needed to convert pepsinogen → pepsin.
Pepsin – enzyme that breaks down proteins (proteolysis).
What are the types of absorption in digestion?
Passive transport (no energy needed):
Osmosis
Facilitated diffusion (e.g., GLUT helps glucose enter blood).
Active transport (requires ATP):
Na⁺/K⁺ pump
SGLT (sodium-glucose transporter) moves glucose into intestinal cells (apical side).
GLUT moves glucose out (basolateral side).
What are the two layers of the serous membrane in the digestive system?
Parietal peritoneum – lines the body wall.
Visceral peritoneum – covers organs.
Between them: Peritoneal cavity (contains peritoneal fluid).
What are intraperitoneal organs?
Organs inside the peritoneal cavity:
Liver
Stomach
Parts of the small intestine
What are retroperitoneal organs?
Organs behind the peritoneal cavity:
Esophagus
Duodenum
Body of pancreas
Ascending & descending colon
Kidneys
What are the two sets of human teeth?
Milk teeth / Deciduous teeth – Fall out in childhood.
Permanent teeth – Last through adulthood.
What is the dental formula for milk (deciduous) teeth n permanent teeth?
I 2/2, C 1/1, Pm 0/0, M 2/2 (Per quadrant).
What are the quadrants of the dental arches?
4 quadrents
Maxillary arch (upper jaw):
starting from Right quadrant: Teeth numbered 1-16
Mandibular arch (lower jaw):
starting form Right quadrant: Teeth numbered 1-16
Which tonsils are paired and unpaired?
Unpaired: Pharyngeal tonsil
Paired: Palatine & Lingual tonsils
What type of epithelium is found in the esophagus and colon?
Esophagus: Non-keratinized stratified squamous epithelium
Colon: Simple columnar epithelium
What do the submucosal and myenteric nerve plexuses control?
Submucosal nerve plexus: Controls secretion.
Myenteric nerve plexus: Controls peristalsis.
What are the functions of key digestive hormones? Ghrekin, Gastrin, VIP, Motilin, secretin, cck , gip
Ghrelin – Stimulates hunger.
Gastrin – Stimulates HCl secretion from parietal cells.
Vasoactive Intestinal Peptide (VIP) – Relaxes smooth muscles & increases secretion.
Motilin – Regulates gut motility.
Secretin – Stimulates bicarbonate secretion.
Cholecystokinin (CCK) – Stimulates bile release from gallbladder.
Gastric Inhibitory Peptide (GIP) – Reduces gastric emptying.
Which sphincters are made of skeletal muscle?
Upper esophageal sphincter
External anal sphincter
What controls gastric emptying?
Pyloric sphincter – Slows emptying, especially after fatty meals.
What controls bile release into the duodenum?
Sphincter of Oddi, controlled by CCK.
What do parietal cells and chief cells secrete?
Parietal cells → HCl (acid)
Chief cells → Pepsinogen (converted to pepsin by HCl)
What structure increases surface area in the small intestine?
Villi (contain brush border enzymes).
What are diverticula in the colon?
Pouches that can form in the colon wall.
