Alimentary Canal Flashcards
(103 cards)
1
Q
Where does digestion of carbohydrates begin ?
A
In the mouth
2
Q
Where does digestion of proteins occur ?
A
In the stomach
3
Q
Which organ makes digestive enzymes ?
A
Pancreas
4
Q
What is the role of bile salts ?
A
Digestion and absorption of lipids
5
Q
What is the role of the small intestine (2) ?
A
Chemical digestion and nutrient absorption
6
Q
What is the role of the stomach (3) ?
A
- Storage
- Chemical digestion
- Sterilisation
7
Q
What 3 roles does the large intestine have ?
A
- Water absorption
- Formation of faeces
- Bacterial fermentation
8
Q
What is the mucosa made up of ?
A
The epithelium, lamina propria and the muscular mucosae.
9
Q
Where are glands in the submucosa found ?
A
Duodenum and oesophagus.
10
Q
Which two plexuses make up the enteric NS ?
A
Myenteric and submucosal plexuses.
11
Q
What type of epithelium and the mouth and anus made of ?
A
Stratified squamous epithelium
12
Q
What is found in the lamina propria ?
A
Blood vessels and glands
13
Q
What is found in the submucosa ?
A
Blood vessels, glands, lymphatics and nerves.
14
Q
What type of plexuses are the submucosal and myenteric ?
A
Parasympathetic plexuses
15
Q
Which nerves control salivation ?
A
Facial and glossopharyngeal
16
Q
What is sympathetic innervation via ?
A
Splanchnic nerves
17
Q
What vein does the stomach blood drain into ?
A
Gastric vein
18
Q
What vein does blood from the pancreas drain into ?
A
Splenic vein
19
Q
Which veins does blood from the liver drain into ?
A
Hepatic veins
20
Q
Is the hepatic portal circulation in parallel or in series with the gut circulation ?
A
In series
21
Q
What type of sugars are monosaccharides ?
A
Hexose sugars
22
Q
Give 3 examples of monosaccharides ?
A
Glucose, Fructose and Galactose
23
Q
What is the name of the bond that holds two monosaccharides together ?
A
A glycosidic bond
24
Q
Which enzymes break down glycosidic bonds between disaccharides and where are they found?
A
Brush border enzymes in the small intestine
25
What is Lactose broken down into ?
Glucose and Galactose
26
What is Sucrose broken down into ?
Fructose and Glucose
27
What is Maltose broken down into ?
Glucose and Glucose
28
What is starch made up of ?
A-Amylase and Amylopectin
29
Does A-Amylase have a straight or branched structure ?
Straight
30
Does Amylopectin have a straight or branched structure ?
Branched
31
In starch what are the bond between the monosaccharides ?
A 1-4 glycosidic bonds
32
What are A 1-4 glycosidic bonds broken down by ?
Amylases
33
Where are amylases produced ?
By salivary glands and the pancreas
34
What is the structure of cellulose ?
Unbranched straight chains of glucose linked by B 1-4 glycosidic bonds.
35
Can humans break down cellulose ?
No because they cannot make cellulase
36
How are glucose monomers linked in glycogen ?
By A 1-4 glycosidic bonds
37
What is the name of the membrane that faces the lumen ?
Apical membrane
38
What is the name of the membrane on the opposite site of the cell to the apical membrane ?
The Basolateral membrane
39
What type of junctions are found between the cells ?
Tight junctions
40
Define transcellular transport
Transport through the cells
41
Define paracellular transport
Transport between cells through the tight junctions
42
Define vectorial transport
Unidirectional movement through cells
43
How is glucose transported across the membrane ?
Via SGLUT1 along with sodium ions. Sodium moves down its concentration gradient.
44
How is glucose pumped out of the basolateral membrane ?
Via GLUT2
45
Which way does water move ?
Water moves down its osmotic gradient into the blood following glucose
46
How do galactose and fructose move through the cells ?
Galactose follows the same path as glucose but fructose moves through the apical membrane via GLUT5 and through the basolateral via GLUT2.
47
What difference is there between the glucose/galactose pathway and the fructose pathway in terms of sodium movement ?
Sodium doesn't move into the blood in the fructose pathway.
48
Where do endopeptidases work ?
On peptide bonds in the middle of a protein
49
Where do exopeptidase work ?
They act on the end of the protein
50
How do amino acids move into cells ?
They move through the apical membrane via transport proteins using sodium ions.
51
How do amino acids move out of cells ?
Through protein channels
52
How do di- and tri-peptides move through cells ?
Using PEPT1 with hydrogen
53
What is the most common type on ingested fat ?
Triglycerides
54
Where is all fat digested and by which enzyme ?
In the small intestine by pancreatic lipase
55
What are triglycerides broken down into ?
Monoglyceride and 3 fatty acids
56
Is lipase water or fat soluble ?
Water soluble
57
Define emulsification
The division of larger lipid droplets into smaller ones
58
What is the job of an emulsifying agent ?
Prevents large lipid droplets reforming from smaller ones
59
What is the emulsifying agent found in the human body ? (2 components)
Bile salts and phospholipids
60
Define amphipathic molecules
Have a polar and non-polar end
61
What are micelles made up from ?
Bile salts, fatty acids, phospholipids and monoglycerides
62
What happens to monglycerides and fatty acids that are taken up into cells ?
They enter the SER and triglycerides are reformed, these droplets are then coated in protein and move through the cell.
63
How do triglycerides leaves cells ?
Via exocytosis
64
What does triglycerides become ones outside the cell ?
Chylomicrons
65
Where do chylomicrons pass into ?
Lacteals
66
What do Chylomicrons contain ?
Triglycerides, cholesterol, phospholipids and fat soluble vitamins.
67
What do water soluble vitamins require to pass through cells ?
Transport proteins
68
What transport protein moves iron into duodenal enterocytes ?
DMT1
69
What is iron incorporated into for storage ?
Ferritin
70
How is unbound iron transport in blood ?
Via transferritin
71
How are iron levels measure in blood tests ?
Using ferritin levels. If there is low ferritin then body stores of iron are low.
72
Define Hyperaemia
Too much iron. High blood ferritin.
73
Define Anemia
Too little iron. Low blood ferritin.
74
What are the components of saliva ? (5)
- Mucins
- Water
- Lysosomes
- Electrolytes
- A-amylase
75
What do mucinous alveoli secrete ?
Mucus
76
What do serous alveoli secrete ?
Digestive juices
77
What type of secretion does sympathetic innervation cause ?
Thick salivary secretion with a high amylase content.
78
What type of secretion does parasympathetic innervation cause ?
Profuse watery secretion
79
Describe the oral phase of swallowing
Bolus is pushed to the back of the oral cavity by the tongue
80
Describe the pharyngeal phase of swallowing
Bolus moves into oropharynx and this causes a reflex contraction of the pharyngeal muscles. Co-ordination of this reflex is via the swallowing centre in the medulla.
Soft palate moves upwards and epiglottis clovers larynx and it moves upwards. Bolus moves down the pharynx , the UOS relaxes.
81
Describe the oesophageal phase of swallowing
UOS contracts and bolus moves down oesophagus, it is propelled towards the stomach by the process of peristalsis. The LOS then relaxes.
82
What is the stomach lumen lined with ?
Rugae
83
What are the 3 layers of stomach muscle from the inside out ?
1) Oblique
2) Circular
3) Longitudinal
84
Which layers form the rugae ?
The mucosa and submucosa
85
What cells are found in the gastric pits/gastric glands ?
- Mucous cells
- Chief cells
- Parietal cells
86
How does Upper GI bleeding present ?
```
Melena
Haematemesis
Elevated blood urea
Pain
Dysphagia/dyspepsia
```
87
What is Upper GI bleeding associated with ?
NSAID use
88
How does lower GI bleeding present ?
Painless
Large amounts of fresh blood
Diarrhoea
Normal blood urea levels
89
Name some of the most common causes of Upper GI bleeding
Peptic ulcers
Malignancy
Oesophagitis
Gastritis
90
Which drug classes cause peptic ulcers ?
Anti-platlets
Anti-coagulants
Steroids
NSAID's
91
What other causes that drugs are linked to peptic ulcers ?
Alcohol and Stress
92
What does Zollinger-Ellison Syndrome present as ?
Recurrent duodenal ulcers that do not heal well.
93
What may cause a Mallory-Weiss tear ?
Period of retching/vomiting
94
What is dieulafoy ?
A large tortuous arteriole most commonly in the stomach wall that erodes and bleeds.
95
What is angiodysplasia ?
Small vascular malformation of the gut.
96
How is radiation colitis treated ?
- Analgesics
- Diet
- Laxative/anti-spasmodics
- Blood transfusions
97
What does APC stand for and what is it used for ?
Argon plasma coagulation - used to treat bleeding in the GI tract e.g. Haemorrhages due to radiation colitis
98
How is Meckel's diverticulum investigated ?
Nuclear Scintigraphy
99
Define shock
Circulatory collapse resulting in inadequate tissue perfusion
100
How does shock present ?
```
Pale, clammy skin
N/V
Tachycardia
Tachypnoea
Confusion
```
101
How is Upper GI bleeding classified ? (2)
Rockhall score
| Blatchford score
102
What is the name of the tube used for uncontrolled bleeding ?
Sengstaken-Blakemore tube
103
What other procedure can be used for uncontrolled bleeding ?
TIPS
