Digestion Flashcards
1
Q
Define the four boundaries of the oral cavity (rostral, caudal, lateral and corners)
A
Rostral: lips
Caudal: pharynx & palatoglossal arches
Lateral: vestibule
Corners: commissure of the mouth
2
Q
What is the vertical slit in the upper lip of dogs and cats called
A
The philtrum
3
Q
What bones make up the hard palate
A
The incisive, maxillary and palatine bones
4
Q
What are the incisive papilla/ducts
A
They connect the oral and nasal cavities
5
Q
What is another name for the vomeronasal organ
A
The Jacobson’s organ
6
Q
What is the function of the rugae
A
To aid food to move caudally
7
Q
Define the soft palate
A
A muscular ‘self’ dividing pharynx into nasal and/or oral compartments
8
Q
What makes the horse an obligate nasal breather
A
The soft palate is very long
9
Q
Describe fungiform papillae of the tongue
A
Dotted around, like toad stools/mushrooms
10
Q
Describe the vallate papillae of the tongue
A
Caudal ‘bulls-eyes’ dome with a moat
11
Q
Describe the filiform papillae of the tongue
A
All over the tongue surface, very small
12
Q
Parotid salivary gland: opening
A
Vestibule, near upper 4th premolar
13
Q
Mandibular salivary gland: opening
A
Sublingual caruncle
14
Q
Sublingual salivary gland: opening
A
Sublingual caruncle & frenulum
15
Q
What is the upper lip of the pig called
A
The rostrum
16
Q
What is the upper lip of the ox called
A
Nasolabial plate
17
Q
What is the main muscle of the cheeks
A
The buccinator
18
Q
What takes the place of the upper incisors in ruminants
A
The dental pad
19
Q
What causes the roughness of the cat’s tongue
A
Conical, filiform papillae
20
Q
What causes the median groove in the dog’s tongue
A
The lyssa
21
Q
What nerves innervate the rostral two thirds of the oral cavity
A
The lingual branch of the mandibular nerve
22
Q
What nerve is responsible for taste
A
The facial nerve
23
Q
What nerve innervates the muscles of the tongue
A
The hypoglossal nerve
24
Q
What are the two parts of the sublingual gland
A
The monostomatic part and the diffuse polystomatic part
25
Name 3 important physiological functions of saliva
1. Lubricates bolus
2. Contains lysozymes & buffers
3. Has enzymes for carb digestion
26
Define diphyodont
Two sets of teeth - primary/secondary OR deciduous/permanent
27
Define monophydont
Only one set of teeth
28
Define polyphydontous
Continuous shedding of teeth
29
Define periodontium
The tissues, both hard and soft, surrounding and supporting the tooth
30
Define primary dentine
Present at tooth eruption
31
Define secondary dentine
Laid down slowly and in an organized way in response to wear and tear
32
Define tertiary dentine
Laid down rapidly in a disorganized response to wear
It attracts food pigments and refracts light
33
Define the cementum
Bone-like tissue that covers the root of the tooth
34
What keeps the tooth in the socket
The periodontal ligament
35
What is the hardest tissue in the body and what produces it
The enamel, produced by ameloblasts
36
What is the name for the soft center of teeth
The pulp
37
What is the periodontal space
The space between the tooth and the tooth socket in the jaw bone
38
What is the furcation point
The area between the roots in multi-rooted teeth
39
What is the gingival sulcus
It relates to the degree of gum attachment around a tooth (should not be deeper than 3mm in dogs and 1mm in cats)
40
Define brachyodont
Short crown teeth
41
Define hypsodont
Long crown teeth (herbivores) with a 'reserve' crown that is seen upon gradual wear-down of grinding teeth
42
What is the full mammalian dental formula and what species has it
44 teeth
3/3, 1/1, 4/4, 3/3
The pig
43
Which are the 3 rooted teeth in the dog
The last 3 in the upper jaw
44
What is the only 3 rooted tooth in the cat
The carnassial tooth (the last pre-molar in the upper jaw)
45
What is the first upper premolar tooth of the horse called
The wolf tooth
46
What is the crown of the tooth
The part that is above the gum
47
What cell type produces the dentine
Odontoblasts
48
The pulp cavity is __ in young animals and __ in mature
Wide in young
Narrow in mature
49
What is the apex/apical point of a tooth
The tip of the root, i.e., the point furthest from the oral cavity)
50
What nerve supplies sensation to the dental arcades
The trigeminal nerve
51
What part of temporary teeth form first
The crown (root forms later)
52
What makes canine teeth difficult to extract
They are wider below the gingival margin than above it
53
What are the 4 salivary glands
1. Parotid
2. Submandibular
3. Sublingual
4. Zygomatic
54
What are the 3 phases of swallowing
1. Oral
2. Pharyngeal
3. Oesophageal
55
What are the 3 muscles involved in the 1st phase of swallowing (oral)
1. Masseter
2. Temporalis
3. Pterygoid
56
What are the 3 nerves involved in the 1st phase of swallowing (oral)
1. Trigeminal
2. Facial
3. Hypoglossal
57
What are the 2 nerves involved in the 3rd phase of swallowing (oesophageal)
1. Vagus
2. Sympathetic
58
What secretes bicarbonate
Pancreatic duct cells
59
What is the function of bicarbonate
Neutralizes acid entering the duodenum in gastric chyme
60
What is the precursor of bile acids
Cholesterol
61
What is the function of bile pigments
Breakdown products of hemoglobin
62
The ___ controls appetite
Hypothalamus
63
What is a pro-appetite hormone
Ghrelin
64
What hormone, produced by adipose tissue, acts on the hypothalamus to stimulate satiety
Leptin
65
In what portion of the brain is salivation controlled
Medulla oblongata
66
Parasympathetic stimulation ___ salivary production and sympathetic stimulation ___ salivary production
Increases; decreases
67
Define primary peristalsis
The continuation of the peristaltic wave that begins in the pharynx and spreads to the esophagus during the pharyngeal phase of swallowing
68
What is the difference between segmentation and peristalsis
Segmentation are mixing contractions that function to mix food with enzymes and secretions (no moving)
Peristalsis are contractions that move the contents along to intestine (no mixing)
69
The rate of gastric emptying depends on ___
Calorie density
70
What are house keeping contractions
Sweeping contractions that empty all swallowed saliva, gastric secretions and refluxed duodenal secretions back into the duodenum
71
What cells secrete pepsinogen
Chief cells
72
What activates pepsinogen (and into what)
Hydrochloric acid --> into pepsin
73
What produces hydrochloric acid
Parietal
74
How can the stomach withstand the action/presence of the all gastric secretions
Gastric mucosal barrier and bicarbonate
75
Name 3 liver secretions
1. Bile acids
2. Bicarbonate
3. Bile pigments
76
What are carrier proteins
Specific proteins found in the cell membrane of the enterocyte - they translocate end products of digestion from the intestinal lumen across the membrane
77
Why does carbohydrate digestion not start in the oral cavity in dog's and cats
Their saliva does not have amylase
78
Where is the major site of fat absorption
The small intestine
79
What makes up a micelle
Fat (hydrolyzed), lipase, bile acids
80
What is a chylomicron
Triglyceride + lipoprotein
81
What is the attachment of the liver to the stomach
The lesser omentum
82
What animals do not have a gallbladder
The horse and the rat
83
What are the 2 blood supplies of the liver
Hepatic artery and portal vein
84
What are the 2 divisions of the caudate lobe
The papillary and caudate process
85
What ligaments attach the liver to the diaphragm
Coronary and triangular ligaments
86
What ligament connects the diaphragmatic surface of the liver to the abdominal wall
The falciform ligament
87
In the spleen, hemoglobin is degraded into...
Heme and bilirubin
88
What vein (from the hepatic artery and portal veins) drains into the caudal vena cava
The hepatic vein
89
What makes up the portal triad
The hepatic artery, portal vein and bile duct
90
Define the hepatic acinus
All hepatocytes supplied by one triad
91
How is the histology of hepatic sinusoids different from capillary endothelium
It is fenestrated and lacks a basement membrane
92
In the dog, exocrine pancreatic secretions drain via the pancreatic duct into the duodenum via the ___
Pancreatic & accessory ducts
93
In the ruminant, exocrine pancreatic secretions drain via the pancreatic duct into the duodenum via the ___
Pancreatic duct
94
What artery(s) supplies the right lobe of the pancreas
The cranial pancreatoduodenal
95
What artery(s) supplies the left lobe of the pancreas
The splenic and caudal pancreatoduodenal
96
Where does the pancreatic vein drain
The portal vein
97
What are the 3 phases that control pancreatic secretion
1. Cephalic phase (smell/sight)
2. Gastric phase (distension)
3. Intestinal phase (acid/fat/protein in chyme in duodenum)
98
What are the 3 hormones that control pancreatic secretions and what are they secreted in response to
1. Gastrin (food in stomach)
2. CCK (protein/fat in the duodenum)
3. Secretin (acid in duodenum)
99
How is volume/composition of pancreatic secretions different between herbivores and carnivores
Herbivores - continuous/constant volume secreted over the day with low enzymes/bicarb
Carnivores - low volume secreted between meals, when secreted it has a high enzymes/bicarb
100
What are 3 signs of exocrine pancreas insufficiency
1. Large volume of fatty feces
2. Ravenous appetite
3. Weight loss
101
What is the difference between vomiting and regurgitation
Regurgitation is passive
102
Where is the vomiting center in the brain
The medulla oblongata
103
What is the shape of the pancreas in the dog
Y
Left and right limb, and the body
104
The pancreas arises from the ___, with connective tissue from the ___
Endoderm
Mesoderm
105
What are the endocrine cells of the pancreas
Islets of Langerhans
106
What are the 2 functions of the exocrine pancreas
1. Neutralize gastric contents as they enter duodenum
2. Deliver digestive enzymes to the small intestine
107
What are the 4 classes of diarrhoea
1. Osmotic
2. Secretory
3. Altered motility
4. Increased permeability
108
What is the rule of thumb for the eruption of deciduous central, middle and corner teeth in the horse
6 days, 6 weeks and 6 months
109
When are canine teeth present in the horse
In male horses - erupt at 5 years of age
110
What teeth in the horse are known as the cheek teeth
3 premolars (2nd-4th) and the 3 molars (1st-3rd)
111
How is the esophagus structure different in the horse than in the dog and ruminant
The esophagus in the horse is a mix of straited and smooth muscle
The esophagus in the dog and ruminant is all smooth muscle
112
What is the innervation of the esophagus in the horse
Striated: branches of vagus (motor)
Smooth: parasympathetic
113
What side of the body does the horse stomach lie on
The left
114
When do the wolf teeth erupt in the horse
At 1 year old
115
On what side of the horse can you find the small intestine
The right side
116
What key feature helps distinguish the small intestine from the large intestine in the horse
Taenial bands
117
On what side of the horse can you find the cecum
Right side
118
Where are impactions common in the large colon of the horse and why
The pelvic flexure because of a decrease in fluidity of ingesta, sudden change in direction and reduction in diameter of lumen
119
What is the caecocolic fold
Mesenteric attachment of large colon
Between RVC and lateral taenial band of caecum
120
What is the ascending mesocolon
Mesenteric attachment of large colon
Between RVC and RDC (short) and LVC and LDC (long)
121
On what side of the body is the pancreas
The right side
122
Where does digestion of non-structural carbohydrates, protein and fat occur in the horse
The foregut (stomach and small intestine)
123
Upper esophageal sphincter: function
Prevents esophagopharyngeal reflux and air distension
124
Esophageal body: function
Primary peristaltic wave propels food down esophagus
125
Lower esophageal sphincter: function
Closes in response to gastric distension and tone increases from vagal stimulation to stop food from coming back up
126
Define dysphagia
Difficultly swallowing - can be oral, pharyngeal or esophageal
127
Why should a horses diet be low in starch
They have limited amylase activity in the SI where it is digested
128
What are the 3 VFAs produced in the LI of the horse
1. Acetate (mostly)
2. Propionate
3. Butyrate
129
Butyrate: function
Respiratory fuel for colonic epithelial cells and suppresses muscosal inflammation
130
Propionate: function
Used by liver as precursors for gluconeogenesis
131
Acetate: function
Source of energy by peripheral tissues
132
What is responsible for the uptake of VFAs across the epithelial membrane
Moncarboxylate/H+ symporter
133
How long does it take to ween a foal
6 months
134
What is a haustral contraction and at what point in the GI tract do they occur
A kneading, non rhythmic contraction
Happen in the cecum and large colon
135
Where should you hear ileocecal sounds in the horse
In the right paralumbar fossa
136
What is the key process used in ruminants to digest plant cell wall material
Fermentation
137
What is the dental formula of a calf
0/3, 0/1, 3/3
138
What is the dental formula of a cow
0/3, 0/1, 3/3, 3/3
139
What are the 3 main salivary glands in the cow
Parotid, mandibular, sublingual
140
What side of the neck can you find the esophagus
Left side
141
What is the order of the stomachs in the ruminant
1. Rumen
2. Reticulum
3. Omasum
4. Abomasum
142
Describe the epithelium of the rumen
Keratinized, stratified, non-glandular epithelium
143
What stimulates the development of the forestomach's in the calf
The fiber diet
144
What stimulates rumen papillae growth
VFA production from concentrates
145
What is the reticular groove
The bypass of milk right to the abomasum
146
How many hours a day does the cow spend ruminating
8-10 hours
147
How much saliva does a cow produce a day
~150L
148
What is the optimum rumen pH
7.0
149
What are the 3 structural layers of the rumen contents
1. Free gas cap
2. Fibrous mat
3. Liquid layer
150
What is the main innervation of the rumen
The vagus nerve
151
Where do you auscultate for the A cycle
The left sublumbar fossa
152
What is primary bloat
When free gas cannot escape from the rumen
153
What is secondary bloat
When stable foam forms in the rumen
154
What are 4 end products of rumen fermentation
1. VFAs
2. Ammonia
3. Microbial cells
4. Gases
155
What part of the diet stimulates rumination
Fiber
156
What is the pH of the abomasum
3.0
