Chapter 25 - Digestive System Flashcards
What two specific things does digestion do?
- Breakdown of ingested food
- Absorption of nutrients into blood
Process whereby food is changed into a form that can be absorbed
Digestion
- Production of ATP
- Anabolic and catabolic cellular activities
Metabolism
What does the alimentary canal contain?
Mouth Pharynx Esophagus Stomach Intestines Rectum Anus
What are the accessory organs of the digestive system?
Salivary glands
Liver
Gallbladder
Pancreas
Layers of the structure of the wall
Mucosa
Submucosa
Muscularis
Serosa
Inner most layer
Mucosa
Three layers of mucosa with meanings
Mucosal epithelium
Lamina propria - blood vessels, sensory nerves, lymph vessels, MALT
Muscularis mucosa - smooth muscle and elastic fibers
Two layers of the muscularis mucosa
Circular and longitudinal
What does the mucosa have that increases surface area?
Folds
What glands does the mucosa have?
Mucous and digestive enzymes
Functions of the mucosa
Protection
Absorption
Secretion
What is the submucosa?
Loose CT Glands BV Lymph vessels Nerves
Functions of the submucosa?
- Nourish surrounding tissues
- Carry away absorbed materials
What is the muscularis?
Layers of smooth muscles
Two layers of the muscularis with meanings
Inner = circular = decreases diameter when contracted Outer = longitudinal = shorten tube when contract
Another name for the serosa
Visceral peritoneum
The serosa does not exist superior to the _____. Instead there is _____
Diaphragm
Adventitia
What is the serosa made out of?
Epithelium and CT
Function of serosa
Protection
Secrete serous fluid
A series of membranes in the abdominal cavity
Peritoneum
Part of the peritoneum that adheres directly to the internal organs
Visceral
Part of the peritoneum that adheres to the abdominal wall
Parietal
Two facts about the visceral and parietal layers of the peritoneum
- Are continuous with one another
- Peritoneal cavity in between
What are mesentaries?
- Sheets of peritoneum connected to organs
- Access route for vessels and nerves
- Stabilize position
Perioteneum that connectes the stomach to the liver
Lesser omentum
Describe the omentum
- Starts at the stomach
- Descends inferior
- Then ascends to form a pouch or “apron” - filled with adipose
- Attaches to the colon
Peritoneum that attaches to the majority of the small intestine
Mesentary proper
Peritoneum that attaches to the large intestine
Mesocolon
What does the mesentery proper and mesocolon do together?
Both allow for nerves and lymphatics to connect to intestines
Explain peristalsis
- Propels bolus (food) down the tract
- Circular muscles contract first (prevents bolus form moving back)
- Longitudinal next (advances it down the tract)
Explain segmentation
- No net movement in any particular direction
- Goal is to fragment bolus
- Mostly circular muscle contractions
Functions of the mouth
Mastication and mixing Lubrication Speech Taste and evaluation Limited digestion
Palatine bone of roof of mouth
Hard palate
CT extension of the palate
Soft palate
Dangles at the end of the soft palate
Uvula