Digestion Flashcards
Mesentery and Functions
Sheet of fused serious membranes that hold organs in place,
Store fat
Provides path for blood vessels
Ingestion
The initial intake of food ( eating)
Propulsion
Movement of food through alimentary canal ( swallowing, and peristalsis)
Segmentation
Mixing of food with digestive juices for more efficient absorption
Form of mechanical breakdown
Digestion
Enzymes are secreted and breakdown food molecules
Catabolic
Absorption
Digested end products get absorbed by active or passive digestion into blood or lymph
Mucosa and Functions
Inner lining of GI tract
Protect from infection/ disease
Secrete mucus
Absorb digestive end products
3 parts of mucosa
Epithelium - simple columnar most of the time
Lamina Propria - nourishes epithelium
Muscularis mucosae - provides movement of mucosa to aid digestion and absorption
Submucosa
Supplies blood vessels. Lymph and nerves returns stomach to original shape after a temporary large meal
Muscularis Externa
Smooth muscle superficial to submucosa composed of longitudinal and circular layer. Forms sphincters and responsible for peristalsis and segmentation
Serosa
Visceral peritoneum reduces friction and lubricates
Enteric Nervous System
Nerve supply to GI tract Controls blood flow, motility and has more neurons in spinal cord. Can function independently of CNS.
Myenteric Nerve Plexus
Between longitudinal and circular muscles of muscularis Externa
3 salivary glands
Submandibular
Parotid
Sublingual
What is saliva composed of
Electrolytes
Water
Salivary amylase and lingual lipase
Proteins
Urea and uric acid
Omentum
Fatty blankets that cover intestines adhere to inflammation — calls immune cells.
Folliate Papillae
Folds on side of tongue that allow for perception
Vallarta papillae
V shaped full of taste buds.
Pharynx
Connects esophagus and nasal cavity to larynx.
Deep longitudinal layer and superficial circular layer that forces food down
Esophagus
Top 3rd skeletal
Lowest third smooth
Middle mix of both
Joints stomach at cardiac sphincter
What happens when chyme moves back into esophagus
Acidic chyme can lead to heartburn
Presby esophagus and Mega esophagus
When sphincter and esophagus don’t coordinate leading to stomach content into esophagus or buildup if sphincter doesn’t open.
Swallowing Process
Buccal Phase - voluntary, tongue presses up forcing food down oral pharynx
Pharyngeal- Esophageal Phase - involuntary tongue blocks mouth epiglottis covers trachea
Intrinsic Muscles
Confined in tongue and NOT attached to bone
Extrinsic Muscles
Attached to bone and extend to tongue ( changes tongue position)
Cholecystokinin (CCK)
Functions
Source
Stimulus
Target Organ
Functions : inhibit gastric secretion, stim pancreatic juice, relax sphincter, expel bile
Duodenal Mucosa
Fatty Chyme
Stomach, Pancreas/ Liver , Sphincter, Gall bladder
GIP ( gastric inhibitory peptide)
Functions
Source
Stimulus
Target Organs
Inhibit HCl production and STIMS INSULIN RELEASE
Duodenal Glands
Fatty Chyme
Stomach, Pancreas
Gastrin
Function
Source
Stimulus
Target Organs
MORE HCl production, STIMS gastric emptying, Stims contraction and mass movement
G cells in stomach
Food in stomach or ACh
Parietal cells, Small Intestine, Large Intestine
Histamine
Functions
Source
Stimulus
Target Area
Increases HCl production
Enteric endocrine glands in stomach
Food in tum tum
Stomach
Intrinsic Factor
Glycoprotein for intestinal absorption of vitamin B12 – for mature erythrocytes
