Flashcards in Dig System Deck (33)
List the organs, in order, that make up the alimentary canal and list the other organs of the digestive system.
1. oral cavity
2. fauces (gullet)
6. small intestine
7. large intestine
Other Digestive Organs:
3. salivary glands
*major glands = salivary glands, liver, pancreas
State the two major functions of the digestive system and subdivide the concept of nutrient intake into its separate processes.
1. Nutrient Intake
- Prehension: process of getting food materials into oral cavity
- Mastication: physical degradation of ingesta within the oral cavity (grinding and mashing of solid food materials with the teeth)
- Deglutition: physical process of swallowing
- Emulsification: initial breakdown of lipids where they are dispersed as tiny droplets within the ingesta
- Hydrolysis: chemical "de-polymerization" of proteins, carbs, lipids which releases their basic organic building blocks
- Absorption: physical passage of nutrients through mucosal lining of intestinal wall and into its cardiovascular capillaries (most nutrients) and lymphatic capillaries (fat micelles)
2. Solid Waste Elimination
- dehydration of non-absorbed ingesta to form feces which are removed by defecation
Name and state the composition of the four major layers of the walls of the tubular digestive organs and similarly identify the layers of the mucosa.
Epithelium in Mucosa- simple columnar or stratified squamous epithelium (depending on where you're at in body)
Epithelium in Serous Membrane - mesothelium (simple squamous)
Connective Tissue Proper:
C.T. Proper in Mucosa - lamina propria
Smooth Muscle Tissue:
In Mucosa - muscularis mucosae
1. Mucosa: innermost layer and surrounds the lumen
- epithelium: lines the lumen
*stratified squamous epithelium up till stomach (protective lining)
*from stomach down it's simple columnar epithelium (secretory/absorptive roles)
- lamina propria: layer of c.t. proper that surrounds and supports epithelium
*highly vascularized and serves a pathway for nerve fibers in mucosa
*contains lymphatic nodules
- muscularis mucosae: smooth muscle tissue that surrounds lamina propria
*causes mucosa in stomach and small intestine to have numerous folds which increase surface area
2. Submucosa: surrounds muscularis layer, highly vascularized
3. Tunica Muscularis: surrounds submucosa
*thick layer of smooth muscle tissue that is responsible for peristaltic and other movements of esophagus, stomach, and intestine
*longitudinal and circular layers are responsible for peristaltic motion
4. Serous Membrane: outermost layer of alimentary canal covered by c.t. proper and mesothelium (visceral peritoneum)
5. Tunica Adventitia: where organs aren't covered by serous membrane and mesothelium isn't present
(It's just the c.t. proper by itself)
Identify the boundaries of the oral cavity and its two major subdivisions.
- the upper and lower lips form the boundaries of the mouth
1. Oral Cavity Proper - bounded by teeth
2. Oral Vestibule - between lips or cheeks and the teeth
Define fauces and discuss its landmarks.
Fauces - tubular passageway that connects oral cavity to pharynx
. superior wall = soft palate
. palatine uvula
. palatopharyngeal arches (posterior)
. palatoglossal arches (anterior)
. palatine tonsils
Sketch the superior (dorsal) surface of the body and apex of the tongue and label its major landmarks.
Root - posterior, attached to hyoid bone
Body - main, dorsal is where papillae are, has terminal groove (separates dorsum of tongue from root), and median groove (blind foramen to apex)
Apex - tip of tongue
Blind foramen - indentation in posterior half
Lingual Frenulum - fold of oral mucosa that attaches inferior aspect of tongue to floor of oral cavity
Sublingual Fold - ridges on side of frenulum
Sublingual caruncle - little bump at front of sublingual fold
Differentiate the six types of lingual papillae.
1. Filiform Papillae: most numerous, form light colored hair-like projections over dorsum of tongue
2. Conical Papillae: larger, located on posterior aspect of tongue
3. Fungiform Papillae: mushroom shaped and interspersed among filiform p. (2nd most numerous, form pink dots on tongues surface)
4. Lentiform papillae - less elevated but just like fungiform's
5. Vallate papillae - resembles large fungiforms, located near posterior aspect of oral cavity
6. Foliate papillae - edges of tongue near palatoglossal arches
*only fungiform and vallate have taste buds
State the permanent and deciduous human dental formulae.
Permanent: 2 [ I 2/2 C 1/1 P 2/2 M 3/3 ] = 32
Deciduous: 2 [ I 2/2 C 1/1 P 2/2 ] = 20
Sketch a tooth in a sagittal section and label its crown, neck, root, pulp cavity, enamel, dentin, cementum, periodontium, and dental alveoulus.
Crown - visible portion
Neck - junction of the crown and root
Root - embedded portion
Pulp Cavity - hollow space filled with soft tissue termed dental pulp
*Enamel - covers crown, hardest substance in body, calcium salts
*Dentin - second most dense, deep to enamel and cementum
*Cementum - covers root of tooth, bone- like c.t. that periodontium attaches to
(* three mineralized substances forming a tooth)
Periodontium - c.t. proper that anchors each tooth in its socket
Dental Alveoulus - space that holds tooth
Name and differentiate the several surfaces of a given tooth.
1. Masticatory (occlusal) surface - faces opp. dental arch
2. Lingual Surface - surface of tooth adjacent to the tongue
* on superior teeth, lingual surface is sometimes called palatal surface
3. Vestibular Surface - oriented towards oral vestibule
4. Labial Surface - on incisors and canines
5. Buccal Surface - on premolars and molars
6. Approximate Surface - "dental floss" surface
. mesial - toward middle
. distal - toward back of mouth
Properly designate any tooth using anatomic nomenclature and the numerical (1-32) system.
State the ages by which a) the first deciduous teeth erupt, b) a full set of deciduous teeth is present, c) the first permanent teeth erupt, and d) all permanent teeth except the third molars have erupted.
*infants are edentulous (without teeth)
a) 6 mo.
b) 2 yrs.
c) 6 yrs.
d) 13 yrs.
*later erupt at 17 yrs. but some fail to erupt at all
State the official name for each of the following: front teeth, eye teeth, cuspids, bicuspids, wisdom teeth.
Front teeth - incisor teeth
Eye teeth - canine teeth
Cuspids - canine teeth
Bicuspids - premolar teeth
Wisdom teeth - molar teeth (last one on each side of arch)
Define pharynx and differentiate it's three parts.
Pharynx - connects fauces to esophagus and nasal cavity to the layrnx
1. Nasal part of the pharynx (nasopharynx)
2. Oral part of the pharynx (oropharynx)
3. Laryngeal part of the pharynx (laryngopharynx)
*there are 7 openings into/out of the pharynx
*separates ingesta from inspired air (puts them down the right tubes)
Name the three parts of the esophagus and indicate the composition of the tunica muscularis in the top, middle, and bottom thirds.
* esophagus is tubular organ that connects pharynx to stomach; moves bolus down via peristaltic movements in tunica muscularis
1. Cervical Part
2. Thoracic Part
3. Abdominal Part (once it goes through diaphragm)
Upper part = skeletal m.t.
Central part = mix of both skeletal and smooth m.t.
Lower part = smooth m.t.
Diagram and label the stomach.
Cardiac Part - where esophagus attaches (near heart)
Fundus - bulges to the left, directly contacts diaphragm
Body - large central portion
Pyloric part - funnel shaped terminal portion
Lesser/Greater curvatures of stomach
Gastric Folds - allow stretch in mucosa of stomach
Differentiate pylorus, pyloric ostium, pyloric sphincter muscle, pyloric canal, and pyloric part of the stomach.
* these 5 are collectively where the stomach meets the small intestine
1. Pylorus -junction of stomach w/ duodenum
2. Pyloric ostium (opening) - leads to pyloric canal
3. Pyloric sphincter m. - controls the entry of stomach contents into duodenum
4. Pyloric canal - canal leading from stomach to duodenum
5. Pyloric part of the stomach - funnel-shaped terminal portion
Name the three major cell types in the lining epithelium of the stomach and state the function of each.
1. Parietal Cells - secrete hydrochloric acid
2. Principal (chief) Cells - secrete pepsinogen
3. Mucus Producing Cells - secrete mucus to prevent the stomach from autodigestion
* HCl + Pepsinogen = Pepsin
- proteolytic enzyme which begins breakdown of proteins
List in order, the three main parts of the small intestine and schematically draw and label the landmarks of the duodenum.
*joins stomach to large intestine
1. Duodenum (12 in)
- descending duodenum receives accessory pancreatic ducts and hepatopancreatic ampulla
Parts: superior, descending, horizontal, ascending
Flexures: superior duodenal, inferior duodenal, duodenojejunal
Duodenal Papilla: Major (receives hepatopancreatic ampulla) and Minor (receives accessory pancreatic duct)
*only part that has submucosal glands
* shortest villi
* main role = hydrolysis
2. Jejunum (8 ft)
* medium length villi
* main role is hydrolysis and absorption
3. Ileum (12ft)
*joins large intestine via ileal papilla
*main role is absorption
* greatest number of lymphatic nodules
List the structural modifications found in the small intestine that increase the absorptive capacity.
*small intestine's main role is hydrolysis and absorption of most nutrients
Circular folds- allow stretching and increases surface area available for absorption
Intestinal Villi - projections of intestinal mucosa that increase the surface area to maximize absorption
Microvilli - comprise the lining epithelium (simple columnar epithelial cells), biggest impact on the surface area
Diagram and label the large intestine including its four major components and their various landmarks.
- has finger like projection = vermiform appendix (if infected = appendicitis)
- 3 parts: ascending, transverse, descending
- 3 curved parts: right colic flexure, left colic flexure, and sigmoid colon
Rectum (6 in)
- part of large intestine
- will have taenia coli on its outside
- distention causes sensation relating to the need to defecate
Anal Canal (1 in)
- terminal passageway, opens at anus, expels feces
- internal anal sphincter m. in tunica muscularis
Differentiate the functional roles of the stomach, small intestine, and large intestine.
Stomach: stores ingesta and mixes it with acid and pepsin to begin digestion of proteins
Small Intestine: receives chyme from stomach, mixes it with pancreatic juice, bile, and intestinal secretions and is major organ of hydrolysis and absorption
Large Intestine: absorbs water and electrolytes to dehydrate unabsorbed chyme to form feces
State the approximate lengths of various parts of the alimentary canal.
Small Intestine: 21 ft (2.5 cm in diameter)
Large Intestine: 5-6 ft (5 cm in diameter)
Duodenum: 12 in
Jejunum: 8 ft
Ileum: 12 ft
Name the three major pairs of salivary glands, state where each pair is located, and indicate where the ducts from each open into the oral cavity.
1. Parotid Glands
- Location: below and anterior to ears
- Open: papilla of the parotid duct opposite of second superior molar tooth
2. Sublingual Glands
- Location: below the tongue on each side of the midline
- Open: ipsilateral sublingual caruncle as well as a number of small ducts posterior to it
3. Submandibular Glands
-Location: medial to left and right bodies of mandible
- Open: left and right sublingual caruncles with sublingual glands
* salivary glands produce weak amylase that breaks down starches into glucose
* parotid gland can be moved to eye to prevent dry eye (will water your eye if hungry)
Name the lobes of the liver and state where the gallbladder is located relative to them.
1. Right lobe - largest lobe
2. Left lobe - second largest
3. Caudate lobe - small, above and behind hepatic porta (where hepatic portal vein, proper hepatic artery, and common hepatic duct are located in hilar area)
4. Quadrate lobe - (four sided) front and bottom
*gallbladder is located between right lobe and quadrate lobe
Diagram and label a hepatic lobule and discuss the flow of blood and bile through it.
1. Hepatocytes (liver cells) are arranged around central veins to form functional units called hepatic lobules
2. Hepatic Triads are located at several loci around the periphery of each lobule (a triad consists of a branch of the proper hepatic artery, hepatic portal vein, and the biliary ductule
3. Blood flows from the proper hepatic artery and the hepatic portal vein through sinusoidal capillaries (spaces between hepatocytes)
4. These are the second capillaries in the hepatic portal system and allow hepatocytes to absorb metabolite and toxins
5. Blood from proper hepatic artery and hepatic portal vein flow CENTRALLY to central vein
Diagram and label a hepatic lobule and discuss the flow of blood and bile through it.
6. central veins coalesce to form venous channels which empty into 3-4 hepatic veins
7. these leave the liver and drain into inferior vena cava
8. hepatocytes produce bile as an exocrine product (aids in emulsification, digestion, and absorption of lipids)
9. bile is secreted into biliary channels termed bile canaliculi
10. bile canaliculi carries bile peripherally to dump into biliary ductules within hepatic triads
11. these ductules empty into larger biliary channels which form R/L hepatic ducts
12. these then form the common hepatic duct which receives cystic duct and then continues to form bile duct
13. bile duct is joined by pancreatic duct to form the hepatopancreatic ampulla (opens at major duodenal papilla in small intestine)
Diagram and label the biliary duct system.
1. the gallbladder is a storage reservoir for bile secreted by the liver
2. the gallbladder consists of a fundus, body, and neck (connects to the cystic duct)
3. swells as it fills with bile and contracts via smooth m.t. in tunica muscularis to force bile back though cystic duct into bile duct and then into descending duodenum
4. the sphincter m. of the hepatopancreatic ampulla determines if bile is stored in gallbladder or continued into descending duodenum
- if relaxed bile continues into descending duodenum
- if contracted bile is forced into cystic duct and stored into gallbladder
List the three gross parts of the pancreas, name its two ducts, and indicate where each one terminates.
1. Head of the pancreas - widest part, near descending duodenum
2. Body of the pancreas - along horizontal part of duodenum (continues toward spleen)
3. Tail of the pancreas - left extremity
*Pancreatic Duct - this joints the bile duct to form the hepatopancreatic ampulla and empties into descending duodenum at MAJOR DUODENAL PAPILLA
*Accessory Pancreatic Duct - branches from the pancreatic duct and enters duodenum at MINOR DUODENAL PAPILLA