Digestive system Flashcards

(95 cards)

1
Q

List in sequence the sections of the digestive tract

A
  1. Oral cavity (mouth/jaws/lips/tongue/teeth)

2. GI tract - Oesophagus, Stomach, SI, cecum, LI (colon), rectum, anus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Most important feeding structure of vertebrates?

A

Jaw

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define crown

A

Part of tooth visible above gum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define dentin

A

mineralised substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define root

A

anchor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define dental pulp

A

connective tissues, nerves & blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define enamel

A

hard outer substance of tooth.

Inorganic crystals, irreplaceable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Dental formula of dog (upper & lower)?

A

3142

3143

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Dental formula of sheep (upper & lower)?

A

0033

4033

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Tongue properties…?

A

muscle mass covered in mucous membrane

stratified, squamous epithelium covered in papillae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Different forms of papillae?

A
filiform
fungiform
foliate
vallate
conical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define prehension and structures involved

A

Act of getting food into mouth - lips, tongue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define mastication

A

1st act of digestion
initiates mechanical breakdown
Motility of mouth enables slicing, tearing, grinding & mixing food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does mastication stimulate?

A

Secretion of saliva, gastric juices, bile, pancreatic juices

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define deglutition

A

Swallowing - relaxed upper oesophageal sphincter & closed soft palate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Draw micro-anatomy of the SI

A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 2 levels of control of the GIT?

A

Extrinsic - ANS

Intrinsic (enteric) - unique to GIT; nervous & endocrine components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

T or F - ANS nerves form link with enteric NS

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

T or F - extrinsic nerves originate within the GIT

A

false - outside the GIT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

ANS influences GIT motility how?

A
  1. modifies ongoing activity thru intrinsic plexus
  2. alters levels of GIT hormone secretion
  3. Acts directly on SM & glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Properties & functions of the oesophagus?

A

To push boluses of food from pharynx to stomach

Contains mucus -> prevents damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Muscle type in dog & ruminant oesophagus

A

entirely striated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Muscle type in bird & human oesophagus

A

entirely smooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Muscle type in horse, cat & pig oesophagus

A

striated at origin then to SM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Draw stomach & label
...
26
Learn and distinguish differences between GIT of ruminant & non-ruminant...
4 compartments vs 1 compartments much greater number of bacteria to aid in digestion See illustrations
27
List the structures in the horse large intestine
Caecum, ascending colon, transverse colon, descending colon, rectum
28
Name the accessory digestive organs
Salivary glands Pancreas Liver
29
Name the salivary glands
Parotid Mandibular Sublingual Buccal
30
Endocrine portion of pancreas contains ... & secretes ...?
Islets of Langerhans & insulin/glucagon
31
Exocrine portion of pancreas contains ... & ... cells which secrete... & ...?
Acinar cells - digestive enzymes | Duct cells - sodium bicarb solution
32
Functions of the liver...?
``` Bile secretion Metabolic processing RBC breakdown Waste elimination Plasma protein synthesis Secretion/modification of hormones/growth factors Gluconeogenesis ```
33
Liver stores what?
glycogen, fat, iron, copper, vitamins
34
Know how to label structures of liver
... slide 47 & 48
35
Know components of the avian digestive tract
...slide 51 (lec objective)
36
Characteristics of motility?
Mixing ingested material with secretions Peristalsis - circular muscle contracts & longitudinal muscle relaxes and vice versa Rate of movement varies bwn feed/spp
37
Characteristics of secretion?
Release of useful substances in GIT lumen | Secretions: enzymes, buffers, bile, lubrication, solvent
38
Characteristics of digestion?
Breakdown into smaller molecules - mechanical/enzymatic | Aided by secretions
39
Characteristics of absorption?
nutrient uptake & use uses specialised cells lining GIT lumen passive or active
40
Segmentation (haustration) involves what?
Random, localised contraction of smooth muscle Occurs in SI & colon non-propulsive; instead mixes digesta
41
Most saliva secretion comes from where?
Parotid glands mandibular glands sublingual glands
42
2 types of saliva secretions?
viscous - mucous rich (small glands) | serous - (parotids)
43
Which salivary glands secrete both (viscous & serous) saliva?
madibular & sublingual
44
T or F - Starch digestion begins in mouth due to amylose
False - amylase
45
Amylase digestion is high, low and absent in which animals?
High - pigs Low - horses Absent - ruminants
46
T or F - saliva provides alkaline buffer & fluid bicarbonate in the rumen
True - very important for ruminant digestion
47
T or F - salive provides evaporative cooling and oral protection
true - oral protection is due to buffer, lysosomes & antibacterial properties
48
Salivary center in medulla is stimulated by which factors?
``` Pressure receptors & chemoreceptors (mouth) Cerebral cortex (sight of food ->'mouthwatering') ```
49
Cascade of events to stimulate saliva secretion...?
Visual/chemo-/pressure cues -> + salivary center -> + ANS -> + salivary glands -> + saliva secretion
50
Mucous cells secretions & role?
Alkaline mucous & protect mucosa
51
Chief cells secretions & role?
pepsinogen & protein digestion
52
Parietal cells secretions & role (2 secretions)?
Hydrochloric acid & activates pepsinogen | Intrinsic factor & facilitates absorption of vit B12
53
Enterochromaffin like cells (ECL) secretions & role?
Histamine & stimulates parietal cells
54
G cells secretions & role?
Gastrin & stimulates parietal, chief & ECL cells
55
D cells secretions & role?
Somatostatin & Inhibits parietal, G & ECL cells
56
Pancreatic enzyme properties...?
Potent enzymatic secretions Aqueous alkaline secretions VERY important in non-ruminants Synthesised as zymogens (inactive enzymes)
57
3 principle types of pancreatic enzymes?
proteolytic (protein catabolism) amylase (starch catabolism) lipase (fat catabolism)
58
Describe the control of pancreatic sodium bicarb secretion
+acid in duodenum -> + secretin release (mucosa) -> +secretion of bicarb (pancreatic duct cells) -> duodenal lumen -> neutralises acid in duodenum
59
Describe the control of pancreatic digestive enzyme secretion
Fats & proteins in duodenum -> +CCK (mucosa) -> + secretion digestive enzymes (acinar cells) -> digests fats & proteins
60
Bile...
Stored in gall bladder (not stored in horse) | Emulsifies fats
61
Know SI anatomy diagram on slide 22 (lec 2)
...
62
In the small intestine, what impairs digestion & absorption?
Loss of surface area (villous atrophy)
63
Why is physical breakdown of food important?
Reduces particle size | Enlarges surface area
64
Reduction of food particles occurs where?
stomach
65
Chemical digestion involves...?
Complex nutrients -> simple ones | Via hydrolysis
66
Chemical digestion of CHO breaks which bonds?
glycosidic linkages
67
Chemical digestion of proteins breaks which bonds?
peptide bonds
68
Chemical digestion of fats breaks which bonds?
ester bonds
69
Chemical digestion of nucleic acids breaks which bonds?
phosphodiester bonds
70
Describe luminal phase of monogastric digestion (non-fibrous CHO)
Dietary polysaccharides such as starch & glycogen broken down in GI lumen by salivary & pancreatic AMYLASE into maltose & sucrose.
71
Describe membraneous phase of monogastric digestion (non-fibrous CHO)
Maltose, sucrose & lactose -> monosaccharides by brush border enzymes -> glucose & galactose absorbed apical membrane by Na+ cotransport. Fructose by facilitated diffusion
72
Describe monogastric protein digestion & absorption (3 steps)
1. Dietary & endogenous protein ingested -> hydrolysed by pepsin & pancreatic proteolytic enzymes 2. AAs across apical membrane via Na+/K+ pump 3. Small peptides absorbed by different carrier -> AAs by aminopeptidases or intracellular peptidases
73
Consider drawing monogastric protein digestion (3 steps)
slide 27...
74
Consider drawing monogastric CHO digestion
slide 26...
75
Describe lipid digestion & absorption in monigatrics
1. TGs emulsified in SI by bile (duodenum) 2. Pancreatic lipases hydrolyse TGs -> monoglycerides & FFAs 3. Micelles formed by lipase & bile carry monoglycerides & FFAs -> luminal surface 4. Micelles release monoglycerides & FFAs near epithelial surface -> passive diffusion thru lipid bilayer
76
Consider drawing monogastric lipid digestion
slide 28...
77
Properties of large intestine...?
absorb water & electrolytes microbial CHO & protein digestion mucosal glands -> buffer & mucous
78
What does hind gut fermentation in horses produce?
VFAs = energy
79
Draw diagram of rumen and label compartments
slide 31-32...
80
Role(s) of the rumen...?
fermentation - anaerobic, pH, temp, removes indigestible material & products of digestion
81
Role of reticulum?
'Honeycomb' appearance - movement of material, fluid etc.
82
Role of omasum?
Spherical shape - laminae grind roughage & squeeze fluid out of ingesta
83
Role of abomasum?
True 'glandular' stomach - enzymatic digestion
84
2 main types of motility in the rumen?
Primary contractions - mixing | Secondary contractions - eructation of gas
85
T or F - regurgitation is not considered a motility pattern
true
86
3 main steps to ruminate...?
1. Regurgitate - rumen & reticulum contract -> recently eaten food away from oesophagus replacing it with semi-liquid partially fermented -> reverse peristalsis up oesophagus 2. Remasticate - only some matter ->reinsalivate 3. Reswallow
87
What is fermentation? Briefly describe...
Metabolic action of bacteria & other microorganisms | Microbial enzymes hydrolyse large molecules
88
What are the key features of ruminant & hindgut fermentation?
CHO most important E source 37 degrees osmolality (ionic strength) optimum range anaerobic (-ve red-ox potential) removal of ingestible material rate of microbial removal = microbial regeneration VFAs buffered or removed
89
5 major groups of microbes?
``` Bacteria Protozoa Fungi Archael (methanogens) Bacteriophage ```
90
CHO digestion in the rumen...?
Microbial fermentation -> Acetate, Butyrate, Propionate
91
T or F - SCFA account for between 30 - 50% digestible E intake
False. 50 - 70%
92
Why is propionate important?
glucose production
93
Increased roughage -> ?
increased acetate
94
Protein digestion in the rumen...?
Proteins -> AAs -> microbial protein prod. & ammonia prod. | Can -> VFA prod.
95
Lipid digestion in the rumen...?
Microbes release extracellular lipases -> meat & milk products to become saturated