NUIP 2080: Lecture Exam 4 (Digestive and Endocrine system)

accessory organs

ailementary canal

what are the 2 main subdivisions of the digestive system?

ailmentary canal

• aka GI tract

• tube extending from the mouth to the anus

• contains the oral cavity, pharynx, esophagus, stomach, SI and LI

• opens to the outside at both ends

ingestion

secretion

motility

digestion

absorption

defacation

what are the 6 digestive processes?

mouth

• function: ingestion, mastication, chemical digestion

• boundaries: cheeks, palate, tongue, lips

roof of mouth

within the mouth

contans hard palate, the soft palate, and the uvula

hard palate

• anterior 2/3 of mouth

• composed of bone

• separates oral cavity from nasal cavity

soft palate

• posterior 1/3 of mouth

• composed of muscle

• separates the oral cavity from the nasopharynx

uvula

midline muscular flap that hangs down from the soft palate

tongue

• skeletal muscle covered with a mucous membrane

• contains papillae and lingual frenulum

• essential for taste, swallowing, and speech

papillae

• mucous membrane projections covering the dorsum of the tongue

• different types dependent on shape and location

lingual frenulum

fold of mucous membrane which connects part of the tongue to the bottom of the oral cavity

ankyloglossia

“tongue tied”

lingual frenulum is too short, which interferes with the movement of the tongue and can cause speech difficulties

tx: clipping of the lingual frenulum

teeth

• embedded in a body ridge in the jaw called the “alveolar ridge.”

• upper jaw = maxilla, lower jaw = mandible

gingivae (gums)

epithelial and CT covering the alveolar ridge

root

crown

neck

what are the 3 main parts of a tooth?

root of tooth

• part of a tooth embedded in the alveolar ridge

• contains the cementum and periodontal ligament

cementum

bone-like substance that covers the dentin of the root

periodontal ligament

fibrous membrane which anchors the cementum to the alveolus

crown

• part of the tooth projecting into the oral cavity

• contains the enamel

enamel

hard, white crystalline substance that covers the dentin of the crown

neck

slightly constricted area between the crown and root of the tooth

dentin

hard, yellow calcified CT (similar to bone) that makes up the bulk of the tooth

pulp cavity

• central cavity within the dentin

• contains pulp which consists of specialized CT containing blood vessels and nerves

root canal

extension of the pulp cavity into the root

apical foramen

opening at the end of each root canal through which blood vessels and nerves can enter/exit

dental cavity (carie)

point of enamel destruction due to acids and enzyme produces by oral bacteria

incisors
canines
premolars
molars

what are the 4 main types of teeth?

incisors

• front teeth

• chisel shaped

• used for cutting

canines

• single cone (“fang-like”)

• used to tear food

premolars

• broad crowns

• 8 total (4 on top, 4 on bottom)

• used to crush food

salivary glands

• produce saliva which facilitates the fragmentation and swallowing of food

• 3 pairs of major salivary glands and numerous minor salivary glands

continuously; local

minor salivary glands secrete ___ and are under ___ control

(answer as __;__)

parotid

submandibular

sublingual

what are the 3 major salivary glands?

parotid salivary gland

• largest of the major salivary glands

• below + anterior to ear

• duct empties opposite 2nd upper molar

• worry for them with mumps

major salivary glands

secrete most of the saliva

secrete in response to parasympathetic stimulation

submandibular salivary gland

major salivary gland that is medial to the angle of mandible

sublingual salivary gland

major salivary gland that is on the floor of the mouth

pharynx

• muscular passageway (constrictors)

• food passes through the mouth → oropharynx → laryngopharynx → esophagus

peritoneum

• double-layered serous membrane

• contains a parietal and visceral layer, along with the mesentery

parietal peritoneum

lines the walls of the abdominal cavity

visceral peritoneum

covers some of the abdominal organs

continuous with the parietal peritoneum

peritoneal cavity

space between the visceral and parietal layers or the peritoneum

mesentery

• A two-layered fold of parietal peritoneum that suspends some of the organs in the abdominal cavity

• parts of the mesentery take their names from the part of the colon to which they attach

peritonitis

acute inflammation of the peritoneum

causes: wounds in the abdominal wall, perforations or rupture of microbe–containing abdominal organs, rubbing together of inflamed peritoneal surfaces

mucosa

submucosa

muscularis

serorsa

what are the 4 layers of the GI tract wall, from deep to superficial?

tunica mucosa

• mucous membrane

• divided into epithelial lining, lamina propria, and muscularis mucosa

epithelial lining of the tunica mucosa

• borders of the GI tract lumen

• esophagus + anus = stratified squamous

• remainder = simple columnar

• renews rapidly (every 5-7 days)

Lamina propria of tunica mucosa

loose CT to which the epithelial cells are attached within the GI tract layers

muscularis mucosa

thin layer of smooth muscle fibers within the GI tract layers

tunica submucosa

thick layer of CT that supports the mucosa with its larger blood vessels, lymphatics, nerves and glands

tunica muscularis

• double layer of muscle tissue

• contains an inner circular layer and an outer longitudinal layer

skeletal (voluntary)
smooth (involuntary)

upper esophagus + external anal sphincter = ___ (__) muscle

rest of GI tract= ___ (__) muscle

sphincters

thickened areas of the inner circularly arranged layer, which by contracting controls the movement of “food” from one region of the GI tract to another

tunica serosa (adventitia)

outer layer of CT in the GI tract

Most of the esophagus - this layer merges with CT of the surrounding structures

rest of tract - CT is covered w/ the visceral peritoneum

enteric NS

ANS

what are the 2 neural innervations of the GI tract?

enteric nervous system innervation of GI tract

• submucosal plexus and myenteric plexus

• controls most of the tract activity (motility and secretion)

autonomic nervous system innervation of GI tract

overrides + regulates the enteric NS

sympathetic and parasympathetic pulses

inhibits GI activity

stimulates GI activity

what does the sympathetic nervous system do to the GI tract?

what does the parasympathetic (vagus) nervous system do to the GI tract?

esophagus

• muscular tube that joins the pharynx to the stomach

• most of it lies within the thorax posterior to the trachea

• enters the abdomen through an opening in the diaphragm → inch later → stomach

esophageal hiatus

opening in the diaphragm that allows the esophagus to pass from the chest to the abdomen.

to transport food via peristalsis

what is the sole function of the esophagus?

upper: skeletal muscle

lower: smooth muscle

how does the tunica muscularis differ in the upper and lower esophagus?

hiatus hernia

part of the stomach protrudes above the diaphragm through the esophageal hiatus

Gastroesophageal Reflux Disease

lower esophageal sphincter fails to close adequately after food has entered the stomach → contents + acid can reflux (back up) into the inferior portion of the esophagus → irritate the esophageal wall, resulting in a burning sensation

tx: histamine-2 (H2) blockers to block acid secretion + neutralizing acid (Tums)

pyrosis (heartburn)

burning sensation in the chest caused by stomach acid flowing back into the esophagus

stomach

• dilated part of GI tract located in L upper part of abdomen

• J shaped

• has 2 openings, 2 curvatures, 2 surfaces

cardiac orifice

pyloric orifice

what are the 2 openings of the stomach?

cardiac orifice

entrance of the esophagus

surrounded by the lower esophageal sphincter

achalasia

lower esophageal sphincter fails to relax normally as food approaches

pyloric orifice

• connects the stomach's pyloric canal to the duodenum

• contains the pyloric sphincter

pyloric sphincter

thickened muscle around the pyloric orifice

pylorospasm

• seen within infants

• smooth muscle fibers of the sphincter fail to relax normally → food does not pass easily → stomach becomes overly full→ infant vomits often to relieve the pressure.

• tx: drugs that relax the muscle fibers of the pyloric sphincter.

Pyloric stenosis

narrowing of the pyloric sphincter that must be corrected surgically

s/s: projectile vomiting—the spraying of liquid vomitus some distance from the infant.

lesser curvature on the R concave medial border

greater curvature on the L convex lateral border

what are the 2 curvatures of the stomach?

(answer as : [Name] on the [side] [convex/concave] [medial/lateral] border)

lesser omentum

peritoneal fold that attaches the lesser curvature to the liver

greater omentum

• peritoneal fold extending from the greater curvature and forming an apron that covers the anterior surface of the transverse colon + SI

• contains lympth nodes and deposits of fat

cardiac region

fundus

body

pyloric region

what are the 4 main parts of the stomach?

pyloric region

distal part divided into antrum and pyloric canal

mucosa

submucosa

what are the three layers of the stomach wall?

simple columnar epithelium

what is the mucosa of the stomach composed of?

longitudinal folds that flatten as the stomach fills

what does the mucosa + submucosa form in the stomach?

rugae of stomach

longitudinal folds that flatten as the stomach fills

mucosa neck cells

pariteal cells

chief cells

what are the 3 secretory (exocrine) cells of the stomach?

mucosa neck cells

cells within the stomach mucosa that secrete mucus

pariteal cells

cells in the stomach that secrete HCl

contributes to intrinsic factor production (for V B12 absorption)

chief cells

secretes pepsinogen and gastric lipase secretion

enteroendocrine cells

produce the hormone gastrin

oblique layer

• modification of the tunica muscularis

• additional layer of muscle

• allows for greater contraction strength for greater food mashing + mixing

small intestine

• longest + most convoluted part of the GI tract

• simple columnar epithelium lining

• main functions: nutrient digestion + absorption

duodenum

jejunum

illeum

what are the 3 regions of the small intestine?

duodenum

• first 25 cm of SI

• C-shaped; curves around head of pancreas (retroperitoneal)

duodenal papilla

• opening in the duodenum

• contains the hepatopancreatic ampulla

hepatopancreatic ampulla

• formed by joining the common bile duct and the pancreatic duct

• empties into the duodenum through this opening

ileocecal sphincter

thickened ileal wall muscle where ileum joins cecum of LI

plicae circulares

villi

digestive enzymes

what are the three modifications of the SI wall?

plicae circulares of SI

• permanent folds of the tunica mucosa and submucosa

• serve to increase the surface area of the mucosa

villi of SI

• finger-like projections of the mucosa into the lumen

• serve to increase the surface area of the mucosa

• each villus is covered with a single layer of endothelial cells

digestive enzymes of the SI

• associated with the membranes of the microvilli of the epithelial cells → absorption

• not secreted into the intestinal lumen = “contact digestion”

contact digestion

final breakdown of nutrients occurring directly on the surface of the small intestine's mucosa

Large intestine

• 1.5 m long

• largest diameter

• mucosa: simple columnar epithelium

  • absorptive cells for water

  • goblet cells secrete mucus that lubricates the passage of the colonic contents