Lecture 7: Digestive Physiology #1 Flashcards
What does the alimentary canal entail?
It is the tube from the mouth to the rectum that includes the mouth, pharynx, esophagus, stomach, small intestine & large intestine
What is the alimentary canal’s function?
It digests and absorbs food while the accessory organs assist in the process.
What are accessory organs?
Teeth, tongue, gallbladder, salivary glands, live, and pancreas
What are the six functions of the digestive tract?
Ingestion, Propulsion (swallowing & peristalsis), mechanical digestion (chewing, churning, segmentation), chemical digestion, absorption, and defecation
What is mechanical digestion?
It is the physical breakdown of feed stuffs by chewing, churning, and segmentation. It utilizes the teeth, stomach and intestines
What is chemical digestion?
Changes macromolecules to monomers, changes thing on a molecular level. (polysaccharides to monosaccharides, proteins to amino acids, fats to glycerol & fatty acids)
Name three digestive processes
Motility, secretion, and membrane transport
Explain motility in digestion
Muscle contractions that break up food and mix it with enzymes and keep it moving
Explain secretion in digestion
Digestive enzymes and hormones
Explain membrane transport in digestion
Absorption of nutrients
Name different methods of control in the gastrointestinal tract
Nervous control, hormones, and paracrine secretions
What is the enteric nervous system?
Enteric nervous system is the gut brain
What are intrinsic controls?
Short reflexes mediated by local nerve plexuses (gut brain)
What is extrinsic control?
Long reflexes involving CNS centers
What is the peritoneum?
The serous membrane of the abdominal cavity. There are two parts: the visceral and parietal
What is the peritoneal cavity?
The space in the abdomen that houses the gastrointestinal tract. It lubricates the digestive cavity and allows organs to slide against each other.
What is the mesentery?
The fold of peritoneum that wraps around the intestines
Explain functions of the oral cavity
Ingestion, mechanical digestion, propulsion, salivary amylase (chemical breakdown of starch), pharynx & esophagus pass food to stomach
Explain features & functions of the tongue
Functions: acquisition of food/water, repositioning and mixing food, formation of bolus, and initiation of swallowing, speech, and taste.
Features: papillae and taste buds on dorsal surface and lingual glands that secrete saliva, tonsils in root
What is saliva made of?
It is a hypotonic solution that is 97-99.5% water and solutes (electroylytes, mucus, lysozome, immunoglobin A, and salivary amylase)
What are the layers of the gastrointestinal tract (from innermost to outermost)?
Mucusa, Submucosa, Muscularis externa, and Serosa
Describe the mucosa
