Digestive System I Flashcards
gastrointestinal tract
- aka alimentary canal
- includes mouth, pharynx, esophagus, stomach, small intestine, and the large intestine
accessory digestive organs
-includes the salivary glands, liver, gallbladder, and the pancreas
soft palate
- muscular arch: skeletal muscle
- covered w mucous membrane
uvula
- cone-shaped projection of soft palate
- prevents food and liquid from entering the nasopharynx
frenulum
- fold of tissue under tongue
- restricts movement
tongue intrinsic muscles
- interwoven skeletal muscle
- basically the body of the tongue
tongue extrinsic muscles
- attached the base of the tongue
- originate on hyoid and other structures
- ex: hyoglossus muscle
dorsal surface of tongue
- papillae
- lingual tonsils
tongue papillae
- small raised areas
- taste buds
- structures sensitive to touch
tongue lingual tonsils
-lymphoid tissue on posterior portion of tongue
crown of teeth
-exposed portion
neck of teeth
-gums attach here
root of teeth
-anchors tooth fairy in jaw
periodontal membrane of teeth**
-special type of CT which lines tooth socket
gingiva of teeth
-mucous membrane
alveolus of teeth
-socket (cavity) in base
enamel of teeth
-mostly CaPO4
dentin of teeth
-bone-like material
pulp of teeth
- nerves
- blood vessels
root canal of teeth
-canal in which pulp is found
salivary glands function
-responsible for production and secretion of saliva
types of salivary glands
- parotid glands
- submandibular glands
- sublingual glands
- buccal glands
parotid glands
- located inferior and anterior to ear
- drains into oral cavity near 2nd upper molar
- biggest gland
submandibular glands
- located just inside the mandible
- empties into the floor of the mouth
- exocrine glands
sublingual glands
- located under mucosa in floor of mouth
- empties into floor of mouth
- exocrine glands
buccal glands
- small glands located on mucosal membrane of the mouth
- think of buccinator
composition saliva
- water (99%)
- enzymes
- mucous
- salts
water in saliva function
-dissolves food and chemicals so they can be digested (and tasted)
enzymes in saliva
- lysosome
- amylase
- lipase
enzymes in saliva: lysozyme function
- destroys bacteria
- cleans teeth
enzymes in saliva: amylase function
-begins digestion of starches only a tiny bit**
enzymes in saliva: lipase function
-begins digestion of fats
mucus in saliva function
-lubrication
salts in saliva function
-maintains proper pH for digestive enzymes
what controls salivation?
-under control of the parasympathetic division of the ANS
pharynx structure**
- lines with stratified squamous epithelium
- mucous membrane (lubrication)
- skeletal muscle
is the initial step in swallowing a voluntary or involuntary process?
- voluntary
- involves elevation of root of tongue (helps pass bolus/food posteriorly into oropharynx)
mucosa: epithelium
- stratified squamous at beg. and end of tract(mouth, pharynx, esophagus, and canal)
- simple columnar in middle (stomach, small, large intestine)
- glands: lots of glands
mucosa: submucosa
- contains many blood vessels(nourishes mucosa & absorb nutrients)
- elastic and collagenous fibers(allow GI tract to expand)
- nerve plexuses innervate glands
lacteals function
- has lymphatic vessels
- absorbs fats
muscularis externa
-made of smooth muscle
serosa (adventitia)
-over covering composed of fibrous CT
where is skeletal muscle located?
- oral cavity
- pharynx
- part of esophagus
- anal canal
blood supply: celiac trunk
- supplies upper GI system
- gastric artery to stomach and esophagus
- splenic artery to spleen
- hepatic arteries to liver
blood supply: superior mesenteric
- duodenum and most of small intestine
- ascending and transverse colon
blood supply: inferior mesenteric
- transverse and sigmoid colon
- rectum
plexuses in the walls of digestive tract
- meissner’s plexus
- myenteric plexus
meissner’s plexus location and function
- located in submucosa
- aids in gland secretion
- innervates smooth muscle layer that squeezes mucosa
myenteric’s plexus location and function
- located in muscularis layer
- major nerve supply to smooth muscle of GI tract
esophagus location
- posterior to trachea
- begins at larynx
- passes through hiatus in the diaphragm to join stomach
esophagus structure
- mucosa
- submucosa
- muscularis externa
- gastroesophageal sphincter
esophagus: mucosa layer
-stratified squamous
esophagus: submucosa layer
-blood vessels and nerves
esophagus: muscularis externa layer
- upper 1/3
- middle 1/3
- lower 1/3
esophagus muscularis externa layer: upper 1/3
-skeletal muscle
esophagus: muscularis externa layer: middle 1/3
-combination of skeletal and smooth muscle
esophagus: muscularis externa layer: lower 1/3
-smooth muscle only (must be innervated by ANS)
esophagus: gastroesophageal sphincter
- aka cardiac sphincter
- composed of smooth muscle
- helps prevent stomach contents from being regurgitated into the esophagus
what nervous systems are the gut regulated by?
- parasympathetic nervous system
- sympathetic nervous system
- enteric nervous system
parasympathetic nervous system regulation
- responsible for normal digestive processes while body is at homeostasis
- fibers come from vagus or phrenic nerves
- could directly or indirectly activate the smooth muscle in walls of tract and glands in tract & secondary digestive organs
sympathetic nervous system regulation
- comes from thoracic region of spinal cord and sympathetic chain ganglia
- inhibit motility and secretion during flight or fight response to reroute sources to musculoskeletal system
enteric system regulation
- intrinsic system of the gut
- no direct connection w/ CNS and can operate independently
- controls glands and muscles of digestive tract
- receives input from ANS
lip function
- obicularis iris muscle
- composed of CT, skin, numerous sensory receptors, & blood vessels
cheek function
- stratified squamous epithelium
- formed by muscles of facial expression
hard palate
-formed by palatine and maxilla bones
