Digestive System Flashcards
(116 cards)
six functions of the digestive system
- ingestion
- secretion
- propulsion
- digestion
- absorption
- defecation
organs of the alimentary canal
- oral cavity (mouth)
- pharynx
- stomach
- small intestine
- large intestine
accessory organs and structures involved in the digestive process
- teeth
- tongue
- salivary glands
- liver
- gallbladder
- pancreas
peritoneal membrane (or peritoneum, the serous membrane of the abdominopelvic cavity)
consists of two layers
- parietal peritoneum (outer)
- visceral peritoneum (inner)
- peritoneal cavity (between the layers)
intraperitoneal vs. retroperitoneal regions
intraperitoneal are located entirely within the peritoneal cavity
retroperitoneal are located partly or completely outside the cavity
2 prominent mesenteries of the abdominopelvic cavity
greater omentum and lesser omentum
4 layers that make up the wall of the GI tract
mucosa, submucosa, muscularis externa, and either the serosa or adventitia.
role of the mucosa layer
coats the epithelium, protecting it and the underlying tissues from ingested food and chemicals secreted by digestive organs. Houses regenerative epithelial cells that have a high rate of mitosis, allowing the mucosa to replace epithelial cells as they are damaged or sloughed off in the alimentary canal
nerve plexus in the submucosa layer
submucosal plexus
nerve plexus in the muscularis layer
myenteric plexus
sphincter
special, circular muscles that open and close certain body parts. Most often, the action of a sphincter is to regulate the passage of some type of fluid, such as bile, urine or fecal matter
relationship of smooth muscle contraction and the types of motility
in oral cavity, the pharynx, the superior portion of the esophagus, and the last portion of the large intestine, motility is due to skeletal muscle. In the rest of the alimentary canal, motility is the work of smooth muscle. Motility takes several forms (swallowing, churning, peristalsis, and defecation)
interaction of the sympathetic, parasympathetic and enteric nervous systems and their effects on mobility and secretions
Nervous system regulation of motility is accomplished by the nerves of the ANS. The sympathetic and parasympathetic branches of the ANS generally have opposite effects on gastrointestinal motility—sympathetic activity inhibits digestive processes, and parasympathetic activity stimulates them
Short reflexes from the ENS (local)
long vs. short reflexes and their regulation over the digestive process
short reflexes- reflex pathways are confined to local neurons
long reflexes- must travel outside the local digestive neurons to the CNS to function
3 hormones that participate in regulating digestion
gastrin ( stomach ), secretin ( small intestine ), cholecytokinin (small intestine), gastric inhibitory peptide (small intestine), and motilin (small intestine)
function of hard and soft palate
hard- assists in mechanical digestion
soft- prevent food from entering the nasal cavity
function of the intrinsic and extrinsic muscles of the tongue
intrinsic- control the shape and size of the tongue, push the food against the hard palate during chewing, which assists in mechanical digestion, and also push the bolus posteriorly during swallowing
extrinsic- control the position of the tongue, move the tongue during chewing and help turn the food into a bolus
function of the papilla on the tongue
filiform- assists in mechanical digestion
fungiform, circumvallate, foliate- taste buds
3 major salivary glands
- parotid
- submandibular
- sublingual
components of saliva
water, enzymes, mucus, salivary amylase, lysozyme, secretory IgA, bicarbonate ions, other solutes
functions of saliva
moistening, lubricating, cleansing the oral mucosa. deters growth of bacteria in the oral cavity, mechanical digestion, chemical digestion
roles of the sympathetic and parasympathetic nervous system in regulating saliva production
Sympathetic nerves innervate the salivary glands and their ducts, triggering increased saliva production and facilitating saliva transport through ducts
sympathetic- stimulate mostly mucous cells
parasympathetic- stimulate mostly serous
mastication
the process of chewing during which food is physically broken into smaller pieces by the teeth, tongue and hard palate
structure of the teeth
crown (visible portion), root (embedded), enamel (outer layer of hard mineralized substances), pulp(soft inner gelatinous substance), dentin (inner layer of mineralized tissue in both the root and crown)