Digestive system Flashcards
1
Q
What is mouth cavity proper bound by laterally?
A
Dental arcades
2
Q
What is the cavity called lateral to teeth?
A
Vestibule
3
Q
What is the pharynx?
A
Muscular cross over point between alimentary and respiratory tracts
4
Q
Describe pH of stomach
A
Low pH
5
Q
Describe pH of small intestines
A
Low pH
6
Q
Describe pH of large intestine
A
Higher pH
7
Q
What are the 4x layers [and their constituent layers] of the GIT wall? (parietal –> serosal)
A
- Mucosa [epithelium, lamina propria, muscularis mucosa]
- Submucosa [Loose CT, nerves, vessels, lymphatics, mucus secreting glands]
- Muscularis externa [inner circular smooth muscle, outer longitudinal smooth muscle]
- Outer CT/ Serosa [loose CT covered by visceral peritoneum]
8
Q
What are intrinsic accessory glands
A
Those in GIT walls that secrete mucus/ enzymes into lumen
9
Q
What are extrinsic accessory glands
A
Those that are outside GIT and deliver products via ducts
10
Q
Examples of extrinsic accessory glands
A
Salivary/ pancreas/ liver
11
Q
What does the cranial abdomen region include?
A
Xiphoid process of sternum, Left and right hypochondrial (cartilage of ribs)
12
Q
What are the three regions of the abdomen bound by transverse planes?
A
Cranial - Middle - Caudal
Cranial is biggest as it extends far cranial between ribs of each side
Caudal is smallest, as it ends caudally at pelvic inlet
13
Q
What does the middle abdomen region include?
A
Umbilicus; left and right flank as defined by paralumbar fossar
14
Q
What does the caudal abdomen region include?
A
Pubic brim; left & right inguinal canals (this creates femoral triangle)
15
Q
What is the abdomen’s cranial boundary?
A
Diaphragm
16
Q
What is the abdomen’s dorsal boundary? (3)
A
Lumbar vertebrae; sublumbar muscles; arms of diaphragm
17
Q
What is the abdomen’s lateral boundaries?
A
Diaphragm, 3x muscles of body wall [internal/ external abdominal oblique, transverse abdominal mm), left and right ilium
18
Q
What is the abdomen’s ventral boundary?
A
Left and right rectus abdomens mm
19
Q
What is the abdomen’s caudal boundary?
A
Pelvic inlet
20
Q
Where is the peritoneum tethered?
A
Dorsal part of body wall
21
Q
What is the name of the peritoneum that lines body cavity
A
Parietal
22
Q
What is name of peritoneum that lines organs
A
Visceral
23
Q
What are the connecting peritoneums of the stomach
A
Greater and lesser omentum (double layers, v thin)
24
Q
Describe the greater omentum
A
Covers most of ventral abdominal cavity, sits between body wall and intestines for protection
25
What are the two sagittal planes of the abdomen?
Left and right hypochondriac regions and median xiphoid region
26
Where is the abdomen??
From diaphragm to pelvis, muscle and bone bound cavity, lined internally by the transversalis fascia, which is c`overed in most places by peritoneum
27
What is the SI responsible for absorption of?
Fat, protein, digested carbohydrates
28
What is the LI responsible for?
Water adsorption +/- fermentation
29
Describe the peritoneum
- Simple squamous mesothelium on CT layer
- Semi-permeable to water and small molecules
- Secretes peritoneal fluid, WBC
30
What are 3 types of peritoneum?
1. Parietal
2. Viscleral
3. Connecting
31
What is parietal peritoneum?
Attached to wall abdominal cavity
32
What is visceral peritoneum?
Lining internal organs
33
What is connecting peritoneum?
Achor
34
Describe the mesentery
anchors intestines to dorsal body wall. Great mesentery attaches the SI to the roof at the 1st & 2nd lumbar vertebrae
35
Describe the mesocolon
Attaches the LI to dorsal body wall & continues as mesorectum
36
Describe greater omentum
Originates from stomach and covers most of ventral body wall
37
Connective peritoneum is also known as (3) ?
Ligaments, omenta, mesenteries
38
Describe the lesser omentum?
Connects lesser curvature of stomach to liver
39
Function ameloblasts?
Make enamel
40
Function odontoblasts?
Make dentine
41
Function cementoblasts?
Make cementum
42
What are the 5x main structures of the tooth?
```
Enamel (covering)
Dentine (laid down with age)
Cementum (supports/ covers brachydont)
Pulp cavity (NV/BV/CT)
Alveolus/Peridontal ligament (embed in alveolus socket)
Gingiva (sulcus)
```
43
What is dental formula dog?
3 1 4 2/ 3 1 4 3 x 2 = 42
44
What is dental formula of cat?
3 1 3 1/ 3 1 2 1 x 2= 30
45
What is dental formula horse
3 1(0) 3(4) 3/ 3 1(0) 3 (4) 3 x 2 = 36-44
46
How to age horse teeth?
Infundibulum
Mark
Star
47
Does infundibulum get more or less black with age?
Less (cup not as full of cementum as ages)
48
Is star on lingual or labial surface?
Labial
49
until what age do horses teeth grow?
17yrs
50
What is the P1 horse tooth?
Wolf tooth
51
Does the equine P1 have a deciduous precursor
No (wolf tooth)
52
What are 11 ways to age teeth?
- Eruption time of deciduous vs. permanent teeth
- changes in incisors
- Occlusal morphology
- Teeth in wear
- Tooth shape with wear
- Stain
- Dental cup/mark
- Curvature of dental arch of lower incisors
- Angle of incisors
- Hooks
- Galvayne's groove
53
Which parts of GIT have muscular mucosal in lamina propria?
Everywhere but oral mucosa
54
Where is muscular tunic skeletal muscle vs. smooth muscle in GIT?
Skeletal --> tongue/ palate/ cheeks
| Smooth --> elsewhere
55
What are lips and cheeks innervated by?
CN VII
56
What're the 3 main muscles of the tongue?
Styloglossus, Hyoglossus, Genioglossus, lingual intrinsic muscles
57
What is the action of the temporalis muscle?
Pulls mandible up
58
Is Temporalis larger in carni or herbs?
Carnivore
59
Where is temporalis muscle?
Covers frontal/ parietal/ temporal/ occipital bones
60
Where is masseter muscle?
Maxillary region & zygomatic arch
61
what is function of masseter?
Raises mandible, moves mandible laterally
62
What is the function of the pterygoids?
Close jaw, move jaw medially
63
What is the function of the digastrics?
Opening movement of chewing
64
Where is diagastricus
from occipital bone to mandible, caudal to temperomandibular joint
65
Describe temperomandibular joint
Articulares b/w zygomatic process temporal bone and condyloid process of mandible
66
How does temperomandibular joint differ between herbivores and carnivores?
Intra articular disc in herbivores flattened allowing grinding and complex movement
Bony processes surrounding joint in carnivores makes a hinge
67
Where is oropharynx
Ventral to soft palate, essentially tongue area
68
Where is nasopharynx
Dorsal to hard & soft palate, from internal nostrils to free boundary soft palate
69
Where is laryngopharynx
Dorsal to larynx
70
What is the function of the dilator muscles in rostral pharynx
widen for bolus
71
What is the function of the constrictor muscles in dorsal midline of pharynx
move bolus
72
What is the function of the shortener muscles in rostral-caudal pharynx
Shorten pharynx
73
What are the roentgen signs?
```
Size
Shape
Margins
Location
Opacity
```
74
Describe flora transition during bacterial plaque invasion
G+ to G- for gingivitis/ periodontitis/ stomatitis
75
Define gingivitis
Reversible inflammation of the gingiva associated with plaque. Oedema of the gingival margin can produce pseudo pockets
76
Define periodontitis
Irreversible loss of CT attachement with true pocket formation. Preceded by gingivitis and bacterial plaque is culprit. Hallmark is attachment loss.
77
Define Random burst theory
PD progresses as brief episodes of acute inflammation with longer periods of quiescence
78
Define stomatitis
Lesions throughout oral mucosa that is not GV/ PD
79
Define plaque
Pellicle protein forming on tooth that prevent deposition of salivary calcium phosphate good medium for bacteria attachment
80
Define calculus
Mineralised plaque
81
Describe sequence of events leading to pellicle and plaque deposition
Saliva baths tooth attachment of glycoproteins/ mucopolysaccharides, Bacterial colonisation by mainly G+ into gingival sulcus & inflammation, Maturation of plaque to G-
82
What are secondary factors leading to PD pocket formation?
Crowding, malocclusions, deciduous teeth retention, mouth breathing, plaque rententive diet, concurrent Dx
83
Describe best control of PD
Combination mechanical and chemical control
84
Describe how the epithelium protects against PD
Oral mucosa forms tight gingival sulcus
85
Describe how inflammatory response contributes to PD
If flow of inflammatory cells disrupts the oral epithelium, ulceration occurs and bacteria flood CT. Complement produces further tissue destruction and leads to possible bone resorption.
86
Describe how saliva protects against PD
Antibacterial proteins, histatins (angtifungal/ antiyeast), secretory igG by local B cells
87
What is xerostomia
Reduced salivary volume
88
Describe crevicular fluid
IgG, IgA, IgM, Macrophages, T, B cells most humoral components of blood
89
Describe how tooth anatomy protects from PD
Conical shape, hard smooth enamel, 2ary dentine laid down to protect pulp
90
What is tooth resorption?
Progressive resorption of dentine beginning at cemento-enamel junction
91
Where is tooth resorption most common
Mesial premolars at buccal side
92
What secretions to parotid gland produce?
Serous
93
Where does parotid gland open?
Adjacent to upper P4
94
Where does mandibular gland open?
Sublingual caruncle
95
What secretions does mandibular gland produce?
Muco-serous
96
Where does sublingual gland open?
Sublingual caruncle
97
What secretions does sunlingual gland produce?
Muco-serous
98
Where does buccal gland open
Buccal cavity
99
What secretions do buccal gland produce?
Serous
100
Where does zygomatic gland open?
Opposite last molar
101
What secretions to zygomatic gland produce?
Serous
102
What are the only species with zygomatic glands?
Dog/ cat
103
Describe the gland structure
Acinus --> intercalated duct --> striated duct --> interlobular duct --> primary duct
104
Describe histology of serous acini
Pyramidal cells w/ round basal nuclei, basophilic perinuclear cytoplasm, secretory granules in apical cytoplasm
105
Describe histology of mucus acini
Cells swollen with mucus secretions, flattened basal nucleus
106
Describe histology of intercalated duct
Low cuboidal epithelium
107
Describe histology of striated duct
Columnar epithelium with basal striations due to mitochondrial alignment
108
Describe histology of interlobular duct
Simple columnar/ stratified columnar epithelium
109
Which muscle rapidly contracts during swallowing
Mylohyoideus
110
Describe motility patterns of larynx during swallowing
Soft palate raised, glottis closed, hyoid apparatus drawn rostrally, pharynx shortened
111
Describe the path of the cervical oesophagus
Begins dorsal to cricoid cartilage (larynx) and to LHS trachea, by time reaches thorax is dorsal to trachea and medial to jugular groove
112
Describe path of thoracic oesophagus
Enters thoracic inlet, is within the mediastinum membrane in the thorax, passes dorsal to base of heart and trachea bifurcation, leaves via oesophageal hiatus of diaphgragm
113
Describe path of abdominal oesophagus
Passes over dorsal border of liver (indent) to join dorsal stomach at cardia
114
Describe epithelium of oesophagus
Stratified squamous +/- keratinised)
115
Describe lamina propria of oesophagus
Collagen, elastic fibres, leucocytes, ducts of submucosal glands
116
Which part of oesophagus is muscularis mucosae found?
Caudal end
117
Describe species variation in terms of different types of muscularis mucosa in the oesophagus
Dogs/ ruminants have skeletal muscle, Other species have cranial skeletal muscle and smooth in caudal 1/3rd
118
Describe submucosa of oesophagus
Loose CT, collagen, glands, BV
119
Describe muscularis externa of oesophagus
Form cranial & caudal oesophageal sphincters
120
Describe where is adventitia or serosa in oesophagus
Adventitia in cervical portion where CT merges with surrounding structures, seroca in thorax and abdomen where CT covered by epithelial layer
121
List 4 consecutive stomachs of ruminants
Reticulum rumen abomasum omasum
122
Where is the reticulum?
LHS cranial to rumen
123
Where is omasum?
RHS of rumen/ reticulum
124
Where is abomasum?
Elongated on abdominal floor
125
Where is rumen?
LHS most of abdomo cavity
126
External pressure where will elicit pain response in case of reticulitis?
Xiphoid process
127
Which ribs help define boundary of reticulum?
6th-8th ribs (lateral boundaries)
Most forward part of diaphragm
Lies dorsal to xiphoid process
128
Does reticulum occupy more space in ox or sheep?
Sheep
129
What does the visceral surface of the reticulum touch?
The atrium of the rumen
130
How many "openings" does the reticulum have??
3 (Cardia/ reticular groove/ reticular folds)
131
Describe the reticulum's 3 "openings"
Cardia= where oesophagus opens into reticulum (& rumen!)
Ruminoreticular orifice= the wide opening b/w the rumen and reticulum which communicate over the U-shaped fold
Reticulo-omasal orifice= Extends from the cardia to the reticule-omasal orifice
132
Where does the cardia open into in ruminants?
Both the rumen and the reticulum
133
Describe the primary reticular folds of the reticulum plz
Primary fold ridges form honeycomb-like pattern
Shorter 2ary folds within cells
Low papillae on both 1ary and 2ary folds
134
Describe the layers of reticular wall
1. Mucosa
2. submucosa
3. Muscularis externa
4. Serosa
135
What is the function of the reticulum?
-Seive for coarse material --> passes back to rumen & fine material to omasum
136
Describe the space that the rumen occupies?
Left half abdominal cavity from 8th rib to pelvic inlet. Abdominal roof to floor and across midline in left body. (80% total stomach capacity)
137
Where does the greater omentum originate from?
Right longitudinal groove of rumen
138
Describe the ruminal mucosal surface
Long, numerous papillae on ventral and dorsal caudal blind sacs
Fewer & less prominent in ventral sac
Short/ absent on dorsal sac (gas here instead)
Note: VFAs stimulate development of papillae
139
Which GIT compartments of ruminants feature muscle layers in the papillae?
```
1ary papillae of the reticulum (discontinuous from muscular externa)
Omasum papillae (continuous from muscular external layer)
None in rumen papillae!
```
140
What are 5 salient features & functions of the rumen?
1. Mix ingesta
2. Absorb VFAs
3. Papillae inc SA for absorption & assist mixing
4. Papillae act as heating rods to speed up fermentation
5. Rumination & eructation
141
Describe the location of the omasum
Right of the midline from 7th to 11th rib. Next to the rumen & reticulum
142
What is the right side of the omasum covered by/ connected to?
The lesser omentum
143
What are the two openings to/ from the omasum?
Reticulo-omasal orifice
| Omaso-abomasal orifice
144
Describe the omasal laminae
Many parallel folds of four different sizes. Core of the laminae contains elements of the lamina muscularis mucosae and tunica muscularis
145
What is the function of the omasum?
Absorbs FAs, water, salts
Two-stage pump for transfer of ingest from the reticulum to the abomasum
Sieve for particle separation
146
What is an alternative term for the abomasum
True stomach
147
Describe the position and gross anatomic features of the abomasum
Elongated & lies on abdominal floor, between ventral sac of rumen and reticulum.
Large cranial pole and fundus & narrow caudal pole at pyloric region
148
Name the two openings to the abomasum
omaso-abomasal orifice
| pylorus
149
Describe the mucosa of the abomasum
Dark coloured mucosa present in spiral folds at fundus & body, dec approaching flexure.
Torus is the lighter coloured mucosa of the pylorus has a few low rugae.
Mucosa has a thick muscular mucosa --> submucosa --> muscular externa --> serosa only present at origin of the momentum
150
What is the function of the abomasum
Glands produce digestive enzymes and Hil for digestion and mucus for protection.
151
What is the function of the gastric groove?
A conduit for conveying milk from the oesophagus into the abomasum (bypassing the rumen).
Formed by the two muscular folds of the reticular groove meeting (folding into a tube) and passing ventrally on on the medial wall of the atrium + reticulum (bypassing rumen & reticulum) and Omasal groove from reticule-omasal orifice to omaso-abomasal orifice to bypass omasum!!
152
Which artery supplies blood to the compound stomach of the ruminant?
Branches of the celiac artery
153
Which veins empty the ruminant GIT
Satellite veins draining to portal vein
154
Which nerves supply the compound stomach of the rumen?
Branches from the dorsal and ventral trunks of the vagus nerve
155
The reticulum smaller or larger in small ruminants?
Larger (7-8% total stomach capacity)
