Digestive System (Final Exam) Flashcards Preview

RUSVM Microanatomy Orange 2016 > Digestive System (Final Exam) > Flashcards

Flashcards in Digestive System (Final Exam) Deck (43)
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1
Q

What is the lining epithelium of the GI tract?

A

Stratified squamous epithelium from lips to nonglandular stomach.
Simple columnar in glandular stomach and intestine.

2
Q

What is the oral cavity? What is it composed of? What do ruminants have that is special here?

A

Lips, cheeks, palate, pharynx, tongue.
Lamina propria of CT (submucosa missing)
Has labiae and buccal salivary glands and tonsils.
Dental pad in ruminants (keratinized)

3
Q

Describe the tongue.

A

Covered by mucosa (lamina propria = loose CT, gland); Submucosa is missing!
Dorsal/upper side is keratinized and surface is irregular due to present of papillae (mechanical and gustatory)
Some papillae have taste buds
Skeletal muscle arranged in 3 DIRECTION - move tongue in all directions

4
Q

What are the cells that form the hard structures of the tooth?

A

Ameloblasts –> Enamel (covers external surface)
Odontoblasts –> Dentin (beneath enamel)
Cementoblasts –> Cementum

5
Q

What are the soft tissues of the tooth?

A

Tooth pulp - loose CT and nerves (root mesenchyme is derived from neural crest cells)
Periodontal Ligament - from fibroblasts

6
Q

Describe tooth development.

A

Odontoblasts cover surface of mesenchymal papilla and produce predentin and dentin
Ameloblasts are tall columnar cells that will produce enamel

7
Q

What is the general organization of digestive organs?

A

Mucosa - inner epithelium, middle lamina propria (loose CT of mucous membrane with cells of immune system), this outer muscularis mucosae (smooth muscle of mucosa)
Submucosa (+/-) - not in tongue
Muscularis - inner circular, outer longitudinal
Tunia Serosa (mesothelial lining) or Adventitia (no mesothelium) - peritoneum, pleural lining

8
Q

Describe the Tunica Submucosa

A

Loose CT, loose than lamina propria mucosae
Facilitates motility of mucosa
May contain glands, vessels, nerve plexus (submucous plexus of Meissner) and lymphatic nodules

9
Q

Describe the Tunica Muscularis

A

Smooth or skeletal muscle
Usually 2 layers: inner circular, outer longitudinal
Control lumen size, motility of tube
Contains myenteric plexus (Auberbach), vessels, nerves, nerve cell bodies in ganglia or on plexus

10
Q

Describe Tunica Serosa/Adventita

A

T. Serosa = mesothelium, loose CT +/- adipose tissue
T. Adventitia - loose/dense CT only, no mesothelium
Most external tunic.
If associated with pleural, pericardial or peritoneal cavities is composed of mesothelium and underlying CT

11
Q

Where does Tunica Adventitia occur in the GI tract?

A

portion of esophagus, rectum
Also vagina, bronchi, trachea
Where passing through mediastinum, body wall or the neck.

12
Q

Describe the esophagus.

A

Mucous glands in submucosa.
May have lamina muscularis mucosae
Heals poorly
Tunica muscularis may be skeletal or combo of skeletal/smooth
Tunica adventita is outermost in cervical and thoracic regions.

13
Q

What are gastric pits?

A

Invaginations of lining epithelium

14
Q

What type of glands is the cardiac region composed of? The fundic region?

A

Cardiac Region - mostly of mucous glands

Fundic Region - proper gastric glands (parietal and chief cells)

15
Q

What are the 3 types of gastric glands?

A
  1. Mucous Glands
  2. Proper gastric glands
  3. Pyloric Glands
16
Q

Describe the cardiac gland region of the stomach.

A

Near the esophageal stomach junction composed mainly of mucous glands and a few parietal cells

17
Q

Describe the fundic region of the stomach

A

Composed of parietal (secrete hydrochloric acid, acidophilic, secrete intrinsic factor for vitamin B12 absorption) and chief cells/peptic cells (produce pepsinogen, basophilic, secrete chymosin (rennin in ruminants) in infants - curdles milk)

18
Q

Describe the pyloric region of the stomach.

A

Has mucous glands and G cells that produce GASTRIN

19
Q

Describe the small intestine.

A

Lined by simple columnar epithelium
Goblet cells increase aborally
Has plicae, microvilli, villi (increase SA)
VILLI only in Small Intestine
At base of villi = CRYPTS of LIEBERKUHN
Lacteals at center of villi
Duodenum has Brunners Glands (duodenal glands) in submucosa

20
Q

What are lacteals?

A

Blind-ended lymphatic vessels in intestinal villi.
Chyle found in lacteals is filtered through intestinal lymph nodes before ultimately re-entering the blood at the jugular veins.
Fat rich fluid - ends up in thoracic duct

21
Q

What are Peyer’s Patches?

A

Aggregations of lymphoid nodules present in lamina propria and submucosa of small intestine
Seen in distal jejunum, ileum

22
Q

What are Paneth Cells?

A

Located near crypt base in some species (primates, horses, rodents)
Considered to have both secretory and phagocytic functions - produce cryptdin and lysins (toxic to bacteria)
Act in paracine manner by opening anion channel in enterocytes causing chloride secretion from crypt erythrocytes
Eosinophilic, round, granules

23
Q

What are enteroendocrine cells?

A

AKA enterochromaffin, argentaffin
Localized in crypts
Produce seratonin, etc, in response to chemical and mechanical stimuli

24
Q

Describe the large intestine

A

No villi, absorbs H2O, secretes mucus
Still has intestinal crypts but relatively long
Bands (Taenia coli - smooth muscle, elastic fibers)
Increase in # of goblet cells

25
Q

What are the 3 different glandular regions of the anus?

A
  1. Anal Glands - empty into lumen of anus
  2. Anal Sac Glands - empty into anal sacs (outside = skeletal muscle, inside = smooth muscle (Look like liver cells in glands)
  3. Circumanal Glands - nonpatent ducts, no function knwon
26
Q

Describe anal sacs.

A

Paired anal sacs are located lateral and below the anus in carnviores.
Anal sacs are lined by keratinized stratiied squamous epithelium.
Located between the inner smooth muscle of the internal anal sphincter and the outer skeletal muscle of the external anal sphincter.
Glands of anal sac are: Apocrine, Tubular Sweat Glands in dog; Apocrine, Tubular and both Sebaceous and apocrine sweat glands in the Cat

27
Q

Describe circumanal/perianal glands.

A

Present in subcutis around the anus in dog (also in skin near the prepuce, tail, flank and groin)
Composed of: modified sebaceous glands in upper portion and non-sebaceous glands in lower portion
Non-sebaceous glands resemble hepatocytes (hepatoid glands)

28
Q

What does saliva contain?

A

water, salts, enzymes, igA, lysozyme, lactoferrin

Function: digestion, moisture, lubrication, evaporative cooling, local immunity

29
Q

What are salivary glands divided into? Describe.

A

Major Salivary Glands - parotid, sublingual, submandibular

Minor Salivary Glands (are intramural) - lingual, palate, labial, buccal, zygomatic (carnivores), molar (cats)

30
Q

What type of secretion do salivary glands give off?

A
Serous, Mucous, Mixed
Parotid Gland - serous 
Mandibular Gland - mixed
Sublingual Gland - mixed 
Zygomatic Gland - serous
31
Q

What are the secretory units of salivary glands called?

A

Adenomeres

32
Q

What is each lobe of the liver covered y?

A

Covered by mesothelium lcoated over a CT layer known as teh Capsule of Glisson

33
Q

What are hepatocytes?

A

Parenchymal cells arranged in plates with adjacent sinusoids.
Plates are organized into hepatic lobules.

34
Q

What are the 2 poles of a hepatocyte:

A

Bile Pole

Vascular Pole

35
Q

What is the space of disse?

A

Site of exchange between blood and hepatocyte

36
Q

What is the function of hepatocytes?

A

Storage of metabolites (energy)

Lipids and carbohydrates are stored in the liver in the form of triglycerides and glycogen

37
Q

What are macrophages called in the liver? Where are they located?

A

Kupffer cells.

Located adjacent to sinusoids.

38
Q

What are portal triads/portal tracts/portobiliary space?

A

Branch of hepatic artery, branch of portal vein and bile ductules are seen at edges

39
Q

What is the hepatic acinus? Describe blood flow.

A

Refers to the vascular flow pattern between lobules of the liver.
Flow begins at triad, flows towards central veins via sinusoidal capillaries.
Hepatocytes nearest central vein receive blood lowest in O2 (first to be damaged if vascular compromise exists)

40
Q

What are the zones of the hepatic acinus?

A
Zone 1 (perilobular) - high in O2, high in nutrients, high pathogen exposure
Zone 2 - moderate
Zone 3 (centrilobular) - low
41
Q

What is the Gallbladder?

A

Accepts bile from cystic duct for storage. Abundance mucosae folds when gallbladder is empty.
Simple columnar eptihelium, with microvilli, tight junctions, mitochondria, secretory vesicles
Epithelial cells are capable of modifying bile
No lamina muscularis mucosae
Tunica serosa surrounds almost whole organ

42
Q

What kind of secretory units does the exocrine pancrease have?

A

Tubuloacinar - drain into intercalated ducts lined by cuboidal cells.

43
Q

How does the pancreas differ from a serous salivary parotid gland?

A

Has no striated ducts
Duct system in pancreas is less developed
Has endocrine pancreatic islets of Langehans