1. filiform papillae 2. fungiform papillae 3. foliate papillae 4. circumvallate papillae

Digestive System Flashcards by Ashley DeAtley

the digestive system extends from ____ to ___

mouth to anus

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4 layers of the digestive tract

mucosa (next to lumen)
submucosa
muscularis externa
serosa or adventitia

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in the mucosal layer, consists of loose connective tissue and includes blood and lymph vessels and sometimes glands

lamina propria

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smooth muscle region called ___ ____ lies below the lamina propria in the mucosa

muscularis mucosae

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the movements caused by the ___ ____ act to increase contact of the mucosal epithelium with food in the digestive tract.

muscularis mucosae

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_____ is the only section of the intestine that has glands in the submucosa

duodenum

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parts of the mucosa

(lumen)
epithelial lining 
lamina propria 
muscularis mucosae 
(submucosa)

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this layer is often rich in macrophages

acts as a barrier to bacterial invasion
act to help prevent the spread of infectious organisms into the body via the digestive tract

lamina propria

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layer of dense or loose CT

has lymph and blood vessels, lies below the muscularis mucosae
contains a never plexus called Meissner’s plexus
may also contain glands and lymph nodes

submucosa

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the submucosa of the digestive tract has a nerve plexus called

Meissner’s plexus (parasympathetic)

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lies outside the submucosa, has two parts in the digestive tract and three in the stomach
- responsible for the gross movements of the digestive tract

muscularis externa

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2 layers of the muscularis externs

and 3rd in stomach

circular smooth muscle (closest to lumen)
longitudinal smooth muscle ( furthest from lumen
(3rd: stomach: oblique muscle layer, closest to lumen in stomach)

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thin layer of loose CT
outermost layer of intestine
- layer is rich in blood and lymph vessels and adipose cells
-covered in simple squamous epithelium which is continuous with the lining of the peritoneal cavity- mesothelium

serosa or adventitia

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the transition b/t the Stratified keratinized squamous epithelium of the skin and the stratified nonkeratinized squamous epithelium of much of the oral cavity occurs at the

lips

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below the stratified squamous epithelium of the oral cavity is a layer of loose CT called the ____ _____ that contains blood and lymph vessels, small glands, nerves and aggregations of lymphocytes

lamina propria

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together the stratified squamous epithelium and the lamina propria form the _____ _____, there is NO ___ ____

oral muscosae

NO muscularis mucosae

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the roof of the mouth consists of ____ and ___ plates

hard and soft palates

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the ___ ____ of the mouth has an intramembranous bone backing which is covered by a keratinized mucous epithelium

hard palate

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the ___- ___ of the mouth has a core of skeletal muscle and is covered by a non keratinized mucous epithelium

soft palate

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the ____ consists of a mass of striated muscle covered by a mucous epithelium - NonKSS in most places

tongue

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4 types of papillae

filiform papillae
fungiform papillae
foliate papillae
circumvallate papillae

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where are papillae found on the tongue

dorsal surface (top)

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this type of papillae has a elongated conical shape, most numerous and found on the entire dorsal surface. Long, pointy

filiform papillae

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this type of papillae are mushroom shaped, fewer in number that filiform, found over entire surface

fungiform papillae

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this type of papillae are arranged as closet packed folds along the posterior lateral margins of the tongue and are only common in young children - numerous taste buds in the epithelium covering the papillae

foliate papillae

these are extremely large circular papillae which has a flatted surface that extends above the other papillae. only ~12 on the entire tongue - MANY rase buds found on these - a deep groove encircles the body of the papilla

circumvallate papillae

at the base of the groove of a circumvallate papillae, there are ___ ___ glands that act to wash the surface of the papillae and clean material from taste buds.

serous (von Ebner's) glands

oval (football) shaped muticellular structures found in the oral cavity, on the side of papillae

taste buds

3 cell types of a rase bud

1. gustatory (taste) cells 2. sustentacular (support) cells 3. basal cells: stem cells for replacement of gustatory cells (only live 7-10 days)

in adults there are ___ permanent teeth

in childhood, there are ___ deciduous teeth

the tooth lies in a bony socket, the ____, that is covered by an oral mucosa celled the ____ (__) that consists of a Keratinized SSE and a lamina propria of Loose CT

``` the alveolus (bony socket) oral mucosa: gingiva (gums) ```

two major parts of the tooth

1. crown | 2. root

the portion of the tooth that protrudes above the gum line

crown

the portion of a tooth that extends into the alveolus

the root

3 layers of a tooth

inside: pulp dentin outside: enamel

these secrete organic matrix that mineralizes and forms the dentin

ondontoblasts

layers of a tooth to the bony socket

``` inside: pulp dentin cementum periodontal ligament alveolar bone outside: gingiva surround bone ```

ondontoblasts extend thin processes (____ ____) along which the organic matrix of the dentin is secreted

Tome's fibers

dentin is covered by a further layer of mineralized organic matrix - hardest substance in the body formed by ameloblasts before tooth "erupts" from socket

enamel

between the cementum and the bone of the socket lies the ____ ____- consists of fibroblasts and associated collagen fibers with glycosaminoglycans in between - forms cushion between tooth and bone - attaches tooth to bone

periodontal ligaments

when a dentist probes around your teeth he is checking the depth of the ___ ___ -

gingival sulcus

if your gingival sulcus is too deep, it indicates the breakdown between enamel and junctional epithelium, which is ____ ____

periodontal disease

prior to the ___ week of gestation in human embryos, the developing jaws are solid masses of tissue with little differentiation

5th

tooth development begins during the ___ to ___ weeks of gestation

5-6th week

the first indication of tooth development is the appearance of a thickened plate of epithelium labialgingival lamina (_______ _____) b/t the tongue and the upper and lower jaw

vestibular lamina

C shaped band of tissue in the gums of the upper and lower jaw is called the ___ __ or___ __

dental ledge of dental lamina

in regions where a tooth will form, a further ingrowth of the dental lamina form the ___ __

tooth bud

in 10 distinct regions of each jaw, the cells of the dental ledge proliferate rapidly by mitosis forming a cup shaped structure called the ___ ____ that is surround by jaw mesenchyme

enamel organ

the mesenchyme that fills the enamel organ cup will become the dental papilla which eventually forms the ____ and the ___ of the tooth

dentin and the pulp

the enamel organ and dental papilla are surrounded by a sheath of connective tissue called the __ __

dental sac

this stage of tooth development is first, and then differentiates into the bell stage

cap stage

formed from the cap stage of tooth development

bell stage

the inner enamel organ epithelium will eventually differentiate into cells called ____ that will form the enamel of the tooth

ameloblasts

neural crest cells in the dental papilla will form an epithelial layer directly adjacent to the ameloblasts that will differentiate into cells called ____ which will for the tooth dentin

ondontoblasts

the lips of the cup that forms the enamel organ are called the ____ ____

cervical loop

the cervical loop will partially generate as the root of the tooth develops and will become ___ ___ ___ ___

hertwig's epithleial root sheath

in species that continuously grow teeth like rabbits and mice, the ___ ___ is retained through adulthood

cervical loop

the central region go the root is called the

radicular pulp cavity

once the tooth is fully formed it is ready to undergo ___, this process occurs after birth and involves active movement of the tooth such that it penetrates the gum tissues and extends above them.

eruption

muscular tube that transports food from mouth to stomach

esophagus

the lining of the esophagus is

nonkeratinized stratified squamous epithelium

layers of the esophagus

1. mucosa(epithelium, lamina propria, muscularis mucosae) 2. submucosa 3. muscularis externa ( inner circular muscle, outer longitudinal muscle) 4. serosa or adventitia

three major regions of the stomach

1. cardia: cardiac stomach (connects with esophagus) 2. body (corpus) and funds (upper hump) 3. pyloric region( connects to duodenum)

the inner surface of the stomach is thrown into folds called ____ that include both mucosa and submucosa

rugae

a narrow circular region where esophagus connects to the stomach - produces mucous - simple unbranched tubular glands in lamina

cardiac stomach

4 cell types present in cardiac stomach

1. mucous secreting cells 2. lysozyme secreting cells 3. enteroendocrine cells 4. a few parietal cells

has branched tubular gastric glands, each gastric gland is separated into 3 regions (isthmus, neck, base) main part of stomach

body(corpus) and fundus

3 regions of a gastric gland

isthmus neck body

5 cell types present in gastric glands of the body and funds of the stomach

1. isthmus mucous cells 2. neck mucous cells 3. parietal (oxyntic) cells 4. chief (zymogenic) cells 5. enteroendocrine cells

which type of cell is present in all 3 regions of a gastric gland

parietal cells

cells present in the isthmus of a gastric gland

parietal cells | isthmus mucous cells

cells present in the neck of a gastric gland

neck mucous cells stem cells parietal cells

cells present in the base of a gastric gland

peptic cells parietal cells neck mucous cells nueroendocrine cells

present in isthmus - similar to mucous secreting epithelial cells of gastric pit region - secrete neutral mucus that protects surface from acid

isthmus mucous cells

may be present in clusters in the neck of gastric glands - secrete acid glycoprotein mucus irregular in shape with basal nucleus

neck mucous cells

these produce hydrochloric acid - present in entire gland but fewer at the base of gastric gland - rounded of pyramidal cells with spherical nucleus and acidophilic cytoplasm - secrete intrinsic factor - NO SECRETORY GRANULES

parietal (oxyntic) cells

what 2 things does a parietal cell secrete

1. hydrochloric acid | 2. intrinsic factor

essential for adsorption of vitamin B12 further down the digestive tract - secreted by parietal cells in the stomach (body and fundus)

intrinsic factor

mainly in the base of gastric gland in the body of the stomach - protein synthesizing and secreting cells structure - granules in cytoplasm - when pepsinogen is released, it activates these cells - forms the proteolytic enzyme pepsin and also secretes some lipase

chief (zygomatic) cells

chief cells in the body of the stomach become activated when ____ is released into the acidic environment of the stomach.

pepsinogen

what do the chief cells of the body of the stomach secrete/produce

1. pepsin | 2. some lipase

cells in the body of the stomach found at the base of gastric glands - hormone function - can release serotonin

enteroendorcrine glands

hormone % hydroxytryptamine (5-HT) is also called - secreted from enteroendorcrine glads - stimulates smooth muscle activity of the stomach

serotonin

the area of the stomach has deep gastric pits - these glands secrete lysozyme and gastrin - area closest to duodenum

pyloric stomach region | pylorus

hormone that stimulates the secretion of HCL by parietal cells that are mostly bin body and funds of stomach

gastrin

gastrin stimulates the secretion of ____ by parietal cells in the stomach body

hydrochloric acid (HCL)

the muscular layer of the stomach has 3 layers instead of 2

external muscle sublayer is longitudinal middle muscle sublayer is circular inner muscle sublayer is oblique

this organ will continue the process of digestion and will also act to absorb nutrients, essentially completing the digestive process that was started higher in the tract (mouth and saliva, stomach and acid/pepsin)

small intestine

long narrow tube about 21 ft in length

small intestine

how long is the small intestine

21 ft (4-7 meters)

3 segments of the small intestine

1. duodenum (closest to stomach) 2. jejunum 3. ileum

shortest part of the small intestine | 10 inches long (25-30 centimeters)

duodenum - 10 inches long

part of the small intestine that is 8ft long (250 cm)

jejunum

part of the small intestine that is 11 ft (350cm) long

ileum

what is the length of the entire small intestine

630 cm | 6.3 meters

what is the circumference of the small intestine

0.1 m

surface area of the small intestine

6.78 sq ft

the folds of the wall of the small intestine that include both the mucosa and the submucosa are called

``` plicae circularis ( or valves of Kerckring) singular: plica circularis ```

the mucosa of the small intestine is divided up into 3 characteristic sublayers

1. epithelial lining of lumen 2. lamina propria (loose CT) 3. muscularis mucosae (smooth muscle)

the epithelial lining of the small intestine is completely renewed every

2-5 days

there are around ____ microvilli convering every square millimeter of the surface of the small intestine

200 million

actual inner surface area of the small intestine

about 200 sq meters 2153 sq feet

cells present in to crypts of Lieberkuhn - interspersed b/t columnar enterocytes - less abundant in the duodenum and increase in number toward the ileum - they produce mucus- lubrication for the intestinal tract

goblet cells

these cells are found in the basal regions of the crypts of Lieberhuhn - synthesize a zymogen that is a precursor of lysozyme

Paneths cells

a neurohormone that will stimulate the contraction of smooth muscle causing an increase in motility of the intestine

serotonin

serotonin is secreted by

argentaffin cells

these cells take up amine precursors and decarboxylate them to amines for use in the synthesis of polypeptide hormones - have endocrine function - secrete gastrin, secretin, and somatostatin

APUD cells | Amine Precursor Uptake and Decarboxylation

APUD cells Amine Precursor Uptake and Decarboxylation cells secrete _____,_____,_____ that affect activities of the stomach and small intestine

gastrin secretin somatostatin

stomach-G cell

gastrin

small intestine-S cell

secretin

duodenum and pyloric stomach-D Cell

somatostatin

A-stomach cells

glucagon

I - small intestine

cholecystokinin

at the beginning of the duodenum, coiled tubular glands located in the submucosa open into the base of the intestinal crypts that lie between adjacent villi

Brunner's glands

Brunner's glands secrete ____ ___ that protects the duodenal epithelium from stomach acids

alkaline mucus

these structures are the intestinal glands - these extend into the lamina propria b/t adjacent villi - the epithelium lining these glands is continuous with the epithelium of the villi

crypts of liberkuhn

section of the small intestine - lacks brunner's glands - lacks lymph nodes in the lamina propria - lacteals (lymph vessel in the lamina propria) are well developed to maximize fat absorption

jejunum

section of the small intestine - presence of dense aggregations of diffuse lymphatic tissue and lymphoid nodules in the lamina propria and submucosa that are called peyer's patches

ileum

dense aggregations of diffuse lymphatic tissue and lymphoid nodules in the lamina propria and submucosa called - in ileum of SI

Peyer's patches

specialized for - water adsorption, electrolyte absorption, some vitamin absorption - condensation and formation of the fecal mass - mucus production for lubrication and gives body to feces

Large intestine

how long is the large intestine

1.5 meters

the epithelium lining the large intestine is a ____ ____ ____ of enterocyte absorptive cells with microvilli at apical ends and goblet cells

simple columnar epithelium

the entire walls of which compose the large intestine are made of

crypts of lieberkuhn

3 outer longitudinal bands of smooth muscle called the ____ ___-, in the muscularis externs of the colon

taenia coli

the serial layer of the colon is characterized by protuberances of adipose tissue called ___ ____

appendices epiploicae

there are a number of organ associated with the digestive tract that assist in the digestion of food in several ways (4)

1. salivary glands 2. pancreas 3. liver 4. gall bladder

secrete fluid and mucus to wet and lubricate ingested food | secrete various proteineceous enzymes (amylase, lipase, maltase) that initiate the process of digestion

salivary glands

what do salivary glands secret

``` fluid mucus amylase lipase maltase ```

7 types of salivary glands

1. labial 2. palatine 3. parotid 4. buccal 5. submaxillary 6. sublingual 7. anterior lingual

a mixed endocrine and exocrine organ involved in digestion

pancreas

precursors of enzymes like lipase and the proteolytic digestive enzymes trypsin, and chymotrypsin are synthesized and secreted by ___ ___ of the pancreas (exocrine function)

acinar cells

what is the exocrine function of the pancreas

zymogen secretion | enzymes (trypsin)

what is the endocrine function of the pancreas

hormone secretion

insulin, glucagon, and somatostatin are secreted by cells of the ___ ___ _____ in the pancreas

islets of langerhans

exocrine portion of pancreas is a ____, compound, acinar gland

racemose

small sacs that attach to a central (intercalated) duct of a racemose gland - compound

acinus cell

having the form of a raceme

racemos

a type of inflorescence composed of a group of structures connected to a central axis. usually related to flowers

raceme

T/F: the pancreas has a connective tissue capsule

true

ducts that the pancreatic acini connect to are called ______ ___ (ducts to which acini of a gland directly connect)

intercalated ducts

the intercalated ducts connect to ___ ___ located within the pancreatic lobes

intralobular ducts (not much CT)

the intralobular connect to larger ____ ____ in the septa between lobes

interlobular ducts (lots of CT)

interlobular ducts connect to the main pancreatic ducts, the major duct of ____ and the accessory duct of ______

major duct of Wirsung | accessory duct of Santorini

all secretions eventually reach the main pancreatic ducts that empty into the ___ ___ duct via the duct of Wirsung in humans

common bile duct

pancreatic exocrine secretion is controlled by the hormones ____ and _____

secretin and cholecystokinin

endocrine portion of pancreas - amongst the acini of the pancreas are globular cellular aggregations containing a number of different types of secretory cells and fenestrated capillaries, these aggregations are called

islet of langerhans

these contain the cells that secrete glucagon insulin and somatostatin

islets of langerhans

alpha cells of the islets of langerhans in the pancreas secrete

glucagon | 20% of the cells

what % of the islet of langerhans in the pancreas are alpha cells that secrete glucagon

20%

beta cells of the islets of langerhans in the pancreas secrete

insulin | 70% of cells

what % of the islet of langerhans in the pancreas are beta cells that secrete insulin

70%

delta cells of the islets of langerhans in the pancreas secrete

somatostatin | 5%

what % of the islet of langerhans in the pancreas are delta cells that secrete somatostatin

increases blood glucose

glucagon

lowers blood glucose

insulin

inhibits release of growth hormone

somatostatin

glucagon has what effect

increases blood glucose

insulin has what effect

lowers blood glucose

somatostatin has what effect

inhibits release of growth hormone

if enzymes are activated inside pancreatic ducts, it will cause ______, will start to digest pancreas

pancreatitis : inflammation of the pancreas