Lecture 2 - Histology 1 (Baekey) Flashcards Preview

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Flashcards in Lecture 2 - Histology 1 (Baekey) Deck (108)
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1
Q

what are the 3 different layers of lips within the oral cavity?

A
  1. mucosa
  2. submucosa
  3. core
2
Q

what cell type is found within the mucosa of the lips?

A

stratified squamous epithelium (keratinized in herbivores not carnivores)

3
Q

what type of tissue do you find within the core layer of the lips?

A

fibroelastic connective tissue and skeletal muscle

4
Q

what does the primary palate form from?

A

caudal growth of the medial palatal process

5
Q

what does the secondary palate form from?

A

lateral palatal processes that elevate and grow medially and use in the center with the primary palate and nasal septum

6
Q

in what species do you most commonly see a cleft palate? what is it caused by?

A

brachycephalic dogs, Abyssinian cats

can be caused by ingestion of lupine (wildflowers) by pregnant sheep or cattle

7
Q

what layers do you see within the hard palate

A
  1. mucosa - keratinized stratified squamous epithelium

2. lamina propria - extensive vascular beds for heat exchange

8
Q

what is the function of the soft palate?

A

divides oropharynx and nasopharynx

9
Q

what is on the dorsal and ventral surface of the soft palate?

A

dorsal surface: nasopharynx w/ respiratory epithelium

ventral (oral) surface: keratinized stratified squamous epithelium

10
Q

what are the layers of the soft palate?

A
  1. lamina propria

2. core: fibrous connective tissue and skeletal muscle

11
Q

what cell types do you find in the tongue?

A

stratified squamous epithelium covering a core of skeletal muscle

12
Q

what are the 5 different tyeps of papillae?

A
  1. filiform
  2. conical
  3. fungiform
  4. foliate
  5. vallate (circumvallate)
13
Q

what characteristics about filiform papillae are significant?

A

its keratinized (especially in cats) and in rows

14
Q

what characteristics about conical papillae are significant?

A

keratinized; located on dorsal surface of root

15
Q

what characteristics about fungiform papillae are significant?

A

gustatory (taste buds), scattered

16
Q

what characteristics about foliate papillae are significant?

A

taste buds, serous glands at base

17
Q

what characteristics about vallate (circumvallate) papillae are significant?

A

ringed by furrow; taste buds; serous glands at base

18
Q

what cell types do you find in taste buds?

A

gustatory cells
sustentacular cells
basal cells
nerve fibers

19
Q

location of tastes

A

sweet = tip of tongue
salt = tip
sour (acid) = sides
bitter = region of circumvallate papillae

20
Q

taste is mediated by what cranial nerves?

A

7, 9, and 10

21
Q

describe the development of teeth

A
  1. invagination of oral ectoderm forms dental lamina
  2. dental buds form at base of dental lamina
  3. dental buds differentiate into inverted cups called enamel organs, which produce deciduous teeth
22
Q

what is dental papilla derived from?

and what does it form?

A

dental papilla is derived from neural crest

forms from tooth dentin and pulp

23
Q

define eruption

A

occurs in each deciduous tooth as downward growth of root exerts pressure against alveolar bone, and the crown is forced upward to break through enamel organ and gingiva

24
Q

describe the development of permanent teeth

A

a second bud forms off of the dental lamina. the growing permanent tooth puts pressure on the root of the deciduous tooth, causing the root to be resorbed and the deciduous tooth to fall out

25
Q

what is an example of ectopic teeth?

A

ear teeth in horses

26
Q

what are the 3 cell types seen in teeth

A
  1. ameloblasts
  2. odontoblasts
  3. cementoblasts
27
Q

describe ameloblasts

A

apical processes (Tome’s processes) secrete slightly mineralized rods; mineralization initiates in rods, forming enamel (the hardest substance in the body)

28
Q

describe odontoblasts

A

neural crest origin

  • deposit predentin at the dentinoenamel junction
  • predentin is mineralized, forming dentin
  • odontoblastic processes extend as odontoblasts retreat
29
Q

describe cementoblasts

A

forms cementum which binds dentin to alveolar bone via peridontal ligaments

30
Q

what are the two types of teeth?

A
  1. brachydont

2. hypsodont

31
Q

what are the four parts of a brachydont tooth?

A
  1. crown
  2. neck
  3. root
  4. pulp cavity
32
Q

what is significant about the crown of a brachydont?

A

enamel covers dentin

ameloblasts disintegrate at eruption

33
Q

what is significant about the neck of a brachydont?

A

attachment to gum epithelium is weak, providing entry point for infection

34
Q

what is significant about the root of a brachydont?

A

cementum covers dentin

anchored to bone by fibrous bundles called periodontal ligaments

35
Q

what is significant about the pulp cavity of a branchydont?

A

contains loose connective tissue, blood vessels, nerves

36
Q

what animals have a hypsdont teeth

A

all horse teeth, ruminant cheek teeth, rodent incisors, pig canines

37
Q

what are significant characteristics of a hypsdont teeth?

A

constantly erupting and growing

enamel organ breaks open before tooth erupts, cementum is then deposited on enamel and ameloblasts continue to make enamel

infundibulum provides additional enamel surface for chewing

38
Q

what are the major salivary glands?

A

parotid, mandibular, sublingual, molar (cat), zygomatic (carnivores)

39
Q

what is significant about adenomeres in salivary glands?

A

they are predominately serous

40
Q

what is significant about myoepithelial cells in salivary glands?

A

they contract to express secretions

41
Q

what cell types do you find within ducts of salivary glands

A

low cuboidal epithelum to stratified squamous epithelium

42
Q

what is significant about striated ducts in salivary glands?

A

columnar epithelium

striations are due to mitochondria and infoldings of basal membrane; these influence ionic and water content of saliva

43
Q

what tunics lie within the esophagus?

A
  1. mucosa - has 3 laminar sublayers
  2. submucosa - has mixed glands and a submucosal nerve plexus
  3. muscularis - inner circular, outer longitudinal and has a myenteric nerve plexus
44
Q

what are the 3 layers within the mucosa of the esophagus?

A
  1. lamina epithelialis - stratified squamous
  2. lamina propria - contains many lymph nodes
  3. lamina muscularis - increases in thickness caudally, exhibits longitudinal folds
45
Q

what is the cell type of the muscularis tunic of the esophagus in various species?

A

dogs, ruminants = striated
pigs, horses, cats, humans - striated cranially, smooth caudally
birds - all smooth

46
Q

where is the myenteric nerve plexus located within the muscularis tunic within the esophagus?

A

between the circular and longitudinal muscle layers

47
Q

where are submucosal and myenteric plexuses found?

A

throughout the gut tube and constitute the enteric nervous system, derived from neural crest

48
Q

what is the function of myenteric plexus?

A

gut motility

49
Q

function of submucosal plexus

A

sensing the environment within the lumen, regulating gastrointestinal blood and lymph flow and controlling epithelial cell function

50
Q

interstitial cells of Cajal

A

myoid cells of mesenchymal origin that are also found in these plexuses. they provide a pacemaker function to the peristaltic action of the enteric nervous system

51
Q

how is healing in the esophagus?

A

poor; due to leakage, poor tissue strength and connective tissue support and segemented/marginal blood supply

52
Q

what are the tunics of the glandular stomach

A

mucosa: gastric folds, gastric pits
epithelium
lamina propria: carnivores have stratum compactum and submucosal and myenteric nerve plexuses

53
Q

name the 4 regions of the glandular stomach

A
  1. esophageal = stratified squamous epithelium
  2. cardiac = simple columnar, branched, coiled glands
  3. fundic = simple columnar, longer tubular glands w/o branching
  4. pyloric = similar to cardiac but with deeper gastric pits
54
Q

where is the pyloric spincter located?

A

in tunica muscularis at gastroduodenal junction

55
Q

mucosal lining cells

A

simple columnar surface epithelium expands and contracts depending upon degree of distension caused by fodo itnatek. these cells secrete a neutral mucus that lubricates and protects the stomach lining. the apical portion of these cells exhibits short microvilli.

56
Q

what are the 4 epithelial cells of gastric glands

A
  1. parietal cells - secretes HCl
  2. mucous neck cells - located between the parietal cells; secrete acid mucous
  3. chief (zymogen) cells - secrete gastric enzymes (pepsin)
  4. enteroendocrine cells - secrete monoamine and peptide hormones into lamina propria and blood. upon stomach distension G cells secrete gastrin, which stimulates HCl release by parietal cells.
57
Q

what is repair and replacement of the stomach like?

A

repair is excellent

gastric lining cells are replaced every 2 - 3 days
glandular cells are replaced every 5 - 7 days

58
Q

name the parts of the compound forestomach

A
  1. rumen
  2. reticulum
  3. omasum
  4. abomasum
59
Q

significance of reticulum

A

function: fermentation
- concial papillae (no smooth muscle)
core of tunica muscularis

60
Q

significance of rumen

A

function: mechanical breakdown
has core of isolated smooth muscle made of laminal muscularis mucosa
- has secondary and tertiary papillae

61
Q

significance of omasum

A

function: mechanical breakdown
- primary folds contain lamina muscularis
- secondary papillae present

62
Q

significance of abomasum

A

same as glandular stomach

- major chamber used at birth

63
Q

what are some adaptations to increase absorptive and secretory surface

A
  1. increased length
  2. circular mucosal folds
  3. glands
  4. villi
  5. microvilli
64
Q

what are the regions of the small intestine (3)

A
  1. duodenum: main site of submucosal glands
  2. jejunum
  3. ileum: peyer’s patches are large lymph nodule aggregations
65
Q

what are the 3 tunics located in the small intestine?

A
  1. mucosa
  2. submucosa
  3. muscularis
66
Q

what are the layers within the mucosa of the small intestine

A
  1. lamina epithelium
  2. lamina propria
  3. lamina mucularis
67
Q

what is located within the lamina propria located within the mucosa of the small intestine

A
  • crypts of Lieberkuhn (mucosal glands)
  • capillary network and lymph lacteals in villi
  • stratum compactum in carnivore
68
Q

what is significant about the lamina muscularis located within the mucosa of the small intestine

A

extends into villi and serves to pump lacteals and capillaries

69
Q

what is contained within the submucosa of the small intestine

A
  • submucosal glands in the duodenum secrete an alkaline fluid that neutralizes stomach acids
  • submucosal nerve plexuses innervate the villi
70
Q

what is located within the muscularis of the small intestine

A

inner circular and outer longitudinal layers

- myenteric nerve plexus

71
Q

what type of cells are found in both nerve plexuses (submucosal and myeneteric nerve plexus)

A

interstitial cells of Cajal - they are modified myoid cells of mesenchymal origin that interact with nerve terminals and serve as pacemakers for the contractile activity of the gut muscles

72
Q

what is another name for submucosal nerve plexuses?

A

Meissner’s nerve plexus

73
Q

what is another name for myenteric nerve plexuses?

A

Auerback’s nerve plexus

74
Q

what cell types do you find wtihin the surface mucosa of the small intestine?

A
  1. lining cells (enterocytes)
  2. goblet cells
  3. enteroendocrine cells
  4. lymphocytes
75
Q

what is the function of lining cells aka enterocytes? what do they look like?

A

terminal digestion of carbs and proteins and absorption

  • they are columnar with apical microvilli densely packed into a brush border
76
Q

what is the function of goblet cells

A

in surface mucosa they = secrete protective mucus
in intenstinal crypts of Lieberkuhn they - produce a glycoprotein mucus that lubricates and protects the surface of the epithelium

77
Q

what do enteroendocrine cells secrete?

A

locally-acting hormones such as serotonin, glucagon, secretin, cholecystokinin

78
Q

what do lymphocytes do within the surface mucosa of the small intestine?

A

migrate thru epithelium; more numerous caudally

79
Q

what cell types do you find within the intestinal crpts of Lieberkuhn (straight tubular glands) within the small intestine

A
  1. lining cells
  2. goblet cells
  3. enteroendocrine cells
  4. paneth cells
  5. basal stem cells
80
Q

function of paneth cells

A

secrete enzymes; regulate microbial environment through secreted products

81
Q

function of basal stem cells

A

retain mitotic activity and replace other cells

82
Q

what is repair and replacement of the small intestine like?

A

good; stem cells in crypts replace other cells approx every 3 days

83
Q

what are the functions of the large intestine

A
  1. microbial activity; including fermentation in nonruminant herbivores
  2. absorption of water, vitamins and electrolytes
  3. secretion of lubricating mucus
84
Q

histological features of large intestine

A
  1. larger lumen than small intestine
  2. villi not prominent
  3. longitudinal folds instead of plicae circulares
  4. diffuse and nodular lymphatic tissue
  5. submucosal and myenteric nerve plexus
85
Q

4 regions of the large intestine

A
  1. cecum
  2. colon
  3. rectum
  4. anus
86
Q

features of cecum

A

have longitudinal folds called taeniae ceci (in pigs and horses)

87
Q

features of colon

A

contain taeniae coli (pigs and horses)

  • have longitudinal bands of smooth muscle
  • have crypts of Lieberkuhn
88
Q

features of rectum

A

thicker tunica muscularis than colon

- tunica adventitia present

89
Q

features of anus

A

columnar epithelium of rectum gives way to stratified squamous eptihelium of anus

  • glands are prominent on anal side of recto-anal junction.
  • at ano-cutaneous junction epithelium becomes keratinized in some species
90
Q

repair and replacement of large intestine

A

replacement similar to small intestine

- repair is less successful because of foreign material, bacteria and inadequate blood supply, leakage is common

91
Q

what are the functions of hepatocytes

A
  1. synthesize sugars, plasma proteins, clotting factors, lipids, urea, etc.
  2. secrete bile salts, bile acids
  3. excrete bile pigments
  4. store lipids, vitamines, glycogen
  5. transofrm toxins, drugs, hormones
  6. metabolize lipids, proteins, carbs
  7. hematopoesis occurs during fetal development
92
Q

hepatic lobule

A

plates of parenchyma delimited by interlobular connective tissue

  • sinusoids
  • has central vein in center
93
Q

sinusoids

A
  • sandwiched between plates
  • fenestrated
  • hae no basal lamina
  • endothelium is surrounded by hepatocyte microvilli
94
Q

biliary system of flow is:

A
  1. bile canaliculi
  2. biliary ductules
  3. interlobular bile duct
  4. intrahepatic duct
  5. hepatic duct
95
Q

what is the flow from the hepatic duct to the gall bladder?

A

hepatic duct –> cystic duct –> gall bladder

96
Q

what is the flow from the hepatic duct tot he duodenum?

A

hepatic duct –> bile duct –> duodenum

97
Q

what makes of the portal triad in interlobular connective tissue?

A
  1. interlobular bile duct
  2. hepatic artery
  3. hepatic portal vein
98
Q

what makes up hepatic vasculature

A
  1. hepatic artery
  2. hepatic portal vein
  3. von kupffer cells
  4. central vein
99
Q

what is the space of Disse?

A

it separates hepatocytes from endothelial cells and drains to portal lymphatic vessels

100
Q

what are von kupffer cells

A

they line sinusoids within the liver along the endothelial cells. they are macrophage-like and phagocytose erythrocytes

101
Q

what does the central vein do?

A

drain sinsuoids

102
Q

which animals lack a gall bladder?

A

horse and rat

103
Q

what are the tunics within the gall bladder

A

mucosa - simple columnar epithelium, folds when empty

muscularis - smooth muscle

104
Q

cell types in exocrine pancreas

A
  1. serous acinar cells - secrete zyogmen granules containing enzymes
  2. centroacinar cells - line acinus
  3. cuboidal epithelium lines intralobular and interlobular secretory ducts
  4. larger ducts may contain goblet cells or mucous glands
105
Q

cell type of the avian esophagus and crop

A

made up of keratinized stratified squamous epithelium

106
Q

what is the function of the crop

A

an esophageal diverticulum that serves as a storage organ. the lamina epithelialis produces crop milk which moistens food and is diagnostically useful

107
Q

layers of the proventreniculus (glandular stomach)

A

mucosa - grooves (sulci); mucosal (rugosal) glands open into bases of the sulci
submucosa - glands open into excretory duct leading to papilla

108
Q

layers of the ventriculus (gizzard)

A

mucosa - koilin, cornified secretory product

muscularis - smooth muscle and dense white fibrous connective tissue

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