Lecture 2 - Histology 1 (Baekey) Flashcards Preview

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

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

1. mucosa
2. submucosa
3. core

2

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

stratified squamous epithelium (keratinized in herbivores not carnivores)

3

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

fibroelastic connective tissue and skeletal muscle

4

what does the primary palate form from?

caudal growth of the medial palatal process

5

what does the secondary palate form from?

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

6

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

brachycephalic dogs, Abyssinian cats

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

7

what layers do you see within the hard palate

1. mucosa - keratinized stratified squamous epithelium
2. lamina propria - extensive vascular beds for heat exchange

8

what is the function of the soft palate?

divides oropharynx and nasopharynx

9

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

dorsal surface: nasopharynx w/ respiratory epithelium
ventral (oral) surface: keratinized stratified squamous epithelium

10

what are the layers of the soft palate?

1. lamina propria
2. core: fibrous connective tissue and skeletal muscle

11

what cell types do you find in the tongue?

stratified squamous epithelium covering a core of skeletal muscle

12

what are the 5 different tyeps of papillae?

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

13

what characteristics about filiform papillae are significant?

its keratinized (especially in cats) and in rows

14

what characteristics about conical papillae are significant?

keratinized; located on dorsal surface of root

15

what characteristics about fungiform papillae are significant?

gustatory (taste buds), scattered

16

what characteristics about foliate papillae are significant?

taste buds, serous glands at base

17

what characteristics about vallate (circumvallate) papillae are significant?

ringed by furrow; taste buds; serous glands at base

18

what cell types do you find in taste buds?

gustatory cells
sustentacular cells
basal cells
nerve fibers

19

location of tastes

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

20

taste is mediated by what cranial nerves?

7, 9, and 10

21

describe the development of teeth

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

what is dental papilla derived from?
and what does it form?

dental papilla is derived from neural crest

forms from tooth dentin and pulp

23

define eruption

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

describe the development of permanent teeth

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

what is an example of ectopic teeth?

ear teeth in horses

26

what are the 3 cell types seen in teeth

1. ameloblasts
2. odontoblasts
3. cementoblasts

27

describe ameloblasts

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

28

describe odontoblasts

neural crest origin
- deposit predentin at the dentinoenamel junction
- predentin is mineralized, forming dentin
- odontoblastic processes extend as odontoblasts retreat

29

describe cementoblasts

forms cementum which binds dentin to alveolar bone via peridontal ligaments

30

what are the two types of teeth?

1. brachydont
2. hypsodont

31

what are the four parts of a brachydont tooth?

1. crown
2. neck
3. root
4. pulp cavity

32

what is significant about the crown of a brachydont?

enamel covers dentin
ameloblasts disintegrate at eruption

33

what is significant about the neck of a brachydont?

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

34

what is significant about the root of a brachydont?

cementum covers dentin
anchored to bone by fibrous bundles called periodontal ligaments

35

what is significant about the pulp cavity of a branchydont?

contains loose connective tissue, blood vessels, nerves

36

what animals have a hypsdont teeth

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

37

what are significant characteristics of a hypsdont teeth?

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

what are the major salivary glands?

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

39

what is significant about adenomeres in salivary glands?

they are predominately serous

40

what is significant about myoepithelial cells in salivary glands?

they contract to express secretions

41

what cell types do you find within ducts of salivary glands

low cuboidal epithelum to stratified squamous epithelium

42

what is significant about striated ducts in salivary glands?

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

43

what tunics lie within the esophagus?

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

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

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

45

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

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

46

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

between the circular and longitudinal muscle layers

47

where are submucosal and myenteric plexuses found?

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

48

what is the function of myenteric plexus?

gut motility

49

function of submucosal plexus

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

50

interstitial cells of Cajal

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

how is healing in the esophagus?

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

52

what are the tunics of the glandular stomach

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

53

name the 4 regions of the glandular stomach

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

where is the pyloric spincter located?

in tunica muscularis at gastroduodenal junction

55

mucosal lining cells

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

what are the 4 epithelial cells of gastric glands

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

what is repair and replacement of the stomach like?

repair is excellent

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

58

name the parts of the compound forestomach

1. rumen
2. reticulum
3. omasum
4. abomasum

59

significance of reticulum

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

60

significance of rumen

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

61

significance of omasum

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

62

significance of abomasum

same as glandular stomach
- major chamber used at birth

63

what are some adaptations to increase absorptive and secretory surface

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

64

what are the regions of the small intestine (3)

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

65

what are the 3 tunics located in the small intestine?

1. mucosa
2. submucosa
3. muscularis

66

what are the layers within the mucosa of the small intestine

1. lamina epithelium
2. lamina propria
3. lamina mucularis

67

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

- crypts of Lieberkuhn (mucosal glands)
- capillary network and lymph lacteals in villi
- stratum compactum in carnivore

68

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

extends into villi and serves to pump lacteals and capillaries

69

what is contained within the submucosa of the small intestine

- submucosal glands in the duodenum secrete an alkaline fluid that neutralizes stomach acids
- submucosal nerve plexuses innervate the villi

70

what is located within the muscularis of the small intestine

inner circular and outer longitudinal layers
- myenteric nerve plexus

71

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

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

what is another name for submucosal nerve plexuses?

Meissner's nerve plexus

73

what is another name for myenteric nerve plexuses?

Auerback's nerve plexus

74

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

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

75

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

terminal digestion of carbs and proteins and absorption

- they are columnar with apical microvilli densely packed into a brush border

76

what is the function of goblet cells

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

what do enteroendocrine cells secrete?

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

78

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

migrate thru epithelium; more numerous caudally

79

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

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

80

function of paneth cells

secrete enzymes; regulate microbial environment through secreted products

81

function of basal stem cells

retain mitotic activity and replace other cells

82

what is repair and replacement of the small intestine like?

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

83

what are the functions of the large intestine

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

84

histological features of large intestine

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

4 regions of the large intestine

1. cecum
2. colon
3. rectum
4. anus

86

features of cecum

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

87

features of colon

contain taeniae coli (pigs and horses)
- have longitudinal bands of smooth muscle
- have crypts of Lieberkuhn

88

features of rectum

thicker tunica muscularis than colon
- tunica adventitia present

89

features of anus

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

repair and replacement of large intestine

replacement similar to small intestine
- repair is less successful because of foreign material, bacteria and inadequate blood supply, leakage is common

91

what are the functions of hepatocytes

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

hepatic lobule

plates of parenchyma delimited by interlobular connective tissue
- sinusoids
- has central vein in center

93

sinusoids

- sandwiched between plates
- fenestrated
- hae no basal lamina
- endothelium is surrounded by hepatocyte microvilli

94

biliary system of flow is:

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

95

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

hepatic duct --> cystic duct --> gall bladder

96

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

hepatic duct --> bile duct --> duodenum

97

what makes of the portal triad in interlobular connective tissue?

1. interlobular bile duct
2. hepatic artery
3. hepatic portal vein

98

what makes up hepatic vasculature

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

99

what is the space of Disse?

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

100

what are von kupffer cells

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

101

what does the central vein do?

drain sinsuoids

102

which animals lack a gall bladder?

horse and rat

103

what are the tunics within the gall bladder

mucosa - simple columnar epithelium, folds when empty
muscularis - smooth muscle

104

cell types in exocrine pancreas

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

cell type of the avian esophagus and crop

made up of keratinized stratified squamous epithelium

106

what is the function of the crop

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

107

layers of the proventreniculus (glandular stomach)

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

108

layers of the ventriculus (gizzard)

mucosa - koilin, cornified secretory product
muscularis - smooth muscle and dense white fibrous connective tissue

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