Digestive System Flashcards
1
Q
What are the 6 digestive activities?
A
- Ingestion
- Propulsion
- Mechanical digestion
- Chemical digestion (involves secretion)
- Absorption
- Defecation
2
Q
What sensory receptors are found in the GI tract?
A
Mechanoreceptors (respond to stress)
Chemoreceptors (respond to osmolarity and pH changes, and digestive substrates and end products)
3
Q
What reflexes do sensory receptors in he GI tract initiate?
A
- Activate or inhibit digestive glands
Stimulate smooth muscle to mix and move lumen contents
4
Q
What is an example of extrinsic control?
A
Thought/smell of food
5
Q
What is an example of intrinsic control?
A
Stretch/chemoreceptors
6
Q
What do both intrinsic and extrinsic factors control?
A
Motility and secretion of enzymes/ hormones
7
Q
What are short reflexes?
A
Enteric nerve plexuses (gut brain) respond to stimuli in GI tract
8
Q
What are long reflexes?
A
Respond to stimuli inside or outside of the GI tract (autonomic (CNS) control)
9
Q
What are the 4 digestive processes?
A
1.motility
2. Secretion
3. Absorption
4. Digestion
10
Q
What helps increase surface area for absorption?
A
Villi and microvilli
11
Q
How is starch (carbohydrates) digested?
A
Amylase breaks it down into maltose - maltase breaks maltose into glucose which is absorbed into blood
12
Q
What does amylase break down?
A
Starch
13
Q
Where is amylase from?
A
Salivary glands and pancreas
14
Q
Where does amylase from salivary glands act?
A
Month
15
Q
Where does amylase from the pancreas act?
A
Small intestine
16
Q
Where does carbohydrate digestion start?
A
Mouth (amylase from salivary glands)
17
Q
Where are lactase, maltase and sucrase from and where do they act?
A
From SI wall, act in SI
18
Q
True/false: humans have the enzyme to completely digest complex carbohydrates
A
False
19
Q
True/false: fibre is a complex carbohydrate
A
True
20
Q
What happens to complex carbohydrates if we can’t fully digest them?
A
Fibre moves to Li for E. coli digestion where it ferments which leads to gas production
21
Q
How much protein per day is needed?
A
50- 60g
22
Q
Why do we need protein?
A
They have essential amino acids
23
Q
Where does protein digestion start?
A
Stomach (pepsin)
24
Q
What enzymes from the pancreas act in SI on proteins?
A
-Trypsin/chymotrypsin
- carboxypepsidase
- aminopeptidase
25
Where is dipeptidase from?
Small intestine (acts in si)
26
Why are so many enzymes needed to break down proteins?
To break the bonds between the different amino acids
27
True/false: fat is non-polar
True
28
Truelfalse: bile is an enzyme
False! (Its an emulsifier)
29
What does bile do?
Increase surface area of fat for lipase by emulsifying
30
What enzyme aides in fat digestion?
Lipase
31
Where is lipase from, where does it act?
From pancreas, acts in SI
32
What does lipase break fat into?
Monoglycerides and fatty acids (these can enter absorptive cells or form micelles)
33
Where does chylomicron form?
Within cell
34
What is chylomicron absorbed into?
Lymph
35
What digests nucleic acids?
Nucleases
36
Where is nucleases from and where does it act?
From para crease acts is SI, SI enzymes
37
True/false: vitamins get broken down
False (get absorbed full)
38
What is secreted in the mouth?
Mucous for lubrication, salivary amylase for starch digestion
39
What triggers the swallowing reflex?
Food in pharynx
40
What coordinates swallowing reflex contractions?
Medulla
41
What separates the esophagus and the stomach?
Castroesophageal (cardiac) sphincter
42
What causes heart burn?
Faulty gastroesophageal valve (acid refluxe)
43
What is a hiatal hernia?
Part of stomach moves into chest
44
What are the 4 functions of the stomach?
1. storage
2. Mixing
3. Secretion
4. Absorption
45
How much can your stomach expand?
20x (50ml → 1L)
46
What cells secrete acid?
Parietal
47
What cells secrete pepsin?
Chief cells
48
What is the role of mucous in the stomach?
Protect wall from acid
49
What helps in absorption of B12 in the SI?
Intrinsic factor
50
What is the inactive form of pepsin?
Pepsinogen
51
What converts pepsinogen to pepsin?
HCI secreted by parietal cells
52
What can the stomach's pt drop to?
2-3
53
What does hydrochloric acid do?
- Activates pepsin
- creates down connective tissue and muscle
-Kills pathogens
54
How does the stomach wall protect itself?
Mucous, tight junctions, and high cell replacement
55
What are the 2 things that can be absorbed through the stomach wall?
- Aspirin
- alcohol
56
What does gastric do?
-inc HCI secretion
-Inc pepsinogen
-Inc motility
57
What is gastric stimulated by?
Proteins, distension, smell
58
What are peptic ulcers?
Hole caused by inflammation and necrosis caused in part by pepsin (stomach und duodenum)
59
What are symptoms of peptic ulcers?
- pain
-Bleeding (hematemesis (blood in vomit), melena (blood in poop))
60
How do you treat peptic ulcers?
- Reduction of contributory factors
-Antacids
- surgery in severe cases
61
How long is the small intestine?
21 ft long (1cm diameter)
62
What are the 3 parts of the small intestine?
Duodenum, jejunum, ileum
63
what happens in the small intestine?
Digestion, secretion, absorption
64
What is secreted into small intestine from the gall bladder?
Bile
65
What is secreted into the duodenum from the pancreas?
- Amylase
- trypsin, chymotrypsin
-Pepsidases
-Lipase
- nucleases
-Bicarbonate (neutralizer)
66
Where do pancreatic enzymes act?
Duodenum (SI)
67
What is CCK?
Cholecystokinin
68
What triggers CCK?
Bolus of food entering SI (in duodenum) or if fat content in SI increases
69
What does CCK do?
Acts on pancreas and gall bladder to increase release of enzymes and bile
70
What is gastric inhibition?
Distension of duodenum inhibits gastric emptying allowing time for digestion and absorption in SI
71
True/ false: secretin is a hormone
True
72
When is secretin released?
If SI is acidic
73
What are the effects of secretin?
- Causes pancreas to release bicarbonate (neutralizes acid)
- increase bile formation in liver
-Inhibits gastric motility
74
What does motilin do?
Promotes motility in SI
75
What does motilin do?
Promotes motility in SI
76
What is absorbed in the SI?
-amino acids
-sugars
- fatty acids
-Carbohydrates
- fats
- proteins
77
How are amino acids and sugars absorbed in SI?
Via carriers into villi capillaries
78
How are fatty acids absorbed into the SI?
Via carriers into lacteals of lymph vessels then into blood
79
How are carbohydrates absorbed into the SI?
Quickly absorbed in first half of jejunum (2-3 hrs to empty stomach)
80
How are fats and proteins absorbed into the SI?
Slower to digest (8-10 hrs to empty stomach)
81
How are fat-soluble vitamins absorbed in the SI?
With micelles
82
How are water-soluble vitamins absorbed in the SI?
By carriers
83
Where does electrolyte and water absorption occur?
- Along length of SI
84
Where does iron and calcium get absorbed?
In duodenum
85
What is Na absorption coupled with?
Glucose and amino acids
86
What is Ca absorption regulated by?
By vitamin d and parathyroid hormone
87
What is Crohn's disease?
Type of inflammatory bowel disease in SI (can go into remission, genetic pre-disposition)
88
What are symptoms of Crohn's disease?
- Anorexia
-Flatulence
-Pain
-diarrhea and constipation
89
What are some supportive treatments for Crohn's disease?
- Low-residue diet (food, that will be absorbed in SI)
-Medications
- surgery
90
What type of movement occurs in the large intestine?
Haustral contractions (slow movements)
91
What is reabsorbed in the LI?
Na, water
92
True/false: fibre is partially digested by E. coli in the large intestine
True
93
What is the defecation reflex?
- distention of rectum
- parasympathetic response (relaxes sphincters, contracts rectal walls)
- can over-ride with higher brain centres
94
How much food/drink is secreted daily?
2L
95
How much saliva is secreted daily?
1.5 L
96
How much is secreted into the stomach daily?
2L
97
How much bile is secreted daily?
0.5L
98
How much pancreatic juice is secreted daily?
1.5L
99
What is the daily intestinal secretions (SI)?
1.5 L
100
How much is absorbed daily in the SI?
8.5L
101
How much is absorbed daily in the LI?
400 0ml/day
102
How much feces is excreted daily?
100ml
103
What are hemorrhoids?
Varicose reins in rectum
104
What causes hemorrhoids?
- pressure in anal area
- Constipation
-Prolonged standing
- pregnancy and childbirth
105
How do you prevent hemorrhoids?
- Good bowel habits (fluids, fibre)
-Exercise
- avoid laxatives
106
How do you treat hemorrhoids?
Medications
Warm sits baths
Manual reduction
Cryosurgery
Hemorrhoidectomy
107
True/false: the pancreas has both exocrine and endocrine function
True
108
What do duct cells secrete?
Bicarbonate
109
What do acinar cells secrete?
Enzymes
110
What do endocrine cells secrete?
Insulin/glucagon
111
What is pancreatitis?
Inflammation of pancreas
112
What are symptoms of pancreatitis?
- pain radiating to back
-nausea/vomiting
- foul feces
- necrosis, bleeding
113
What causes pancreatitis?
- Alcohol
- female over 40
114
What are hepatocytes arranged in?
Sinusoid s
115
Name functions of the liver not related to digestion:
-Metabolic processing of the major nutrients
- detoxifying or degrading body wastes and hormones, drugs, and other foreign compounds
- synthesize plasma proteins
- stores glycogen, fats, iron, copper, vitamins
-Makes clotting factors
-Activates vitamin D
- removes bacteria and work-out red blood cells
- excretes cholesterol and bilirubin
116
How much bile is produced a day?
900ml
117
True/false: formation of bile is cholesterol based
True
118
What gives bill its yellow colour?
Bilirubin (porphyrin rings form hb)
119
What is bile made up of?
-Bilirubin
-Cholesterol
- lecithin
- bile salts (important in fat digestion, derived from cholesterol)
-Water
120
True/false: bile salts are recycled
True
121
True/false: gall bladder contracts with CCK
True
122
What is hepatitis?
Inflammation of liver
123
What causes hepatitis?
- Chemical actions of drugs
-Toxic substances
- chronic alcoholism
- group of viruses
124
What are symptoms of hepatitis
-Jaundice and liver enlargement
- myalgia and abdominal pain
- clay or light colored stools
- date colored urine
-Malaise
-anorexia
-Fever
-Ascites
125
Hepatitis prevention:
- Good hygiene
-Vaccination
- special cure when handling needles and body fluids
126
Hepatitis treatment:
- Rest
- good nutrition
-Anti-virals
-Transplant
127
What are the 5 types of viral hepatitis?
A,B,C, D, E
128
What is hepatitis A (infectious hepatitis)?
- Benign
- incubates for 2-6 weeks
- oral-fecal spread
- contaminated food
129
What is hepatitis b?
Serum hepatitis
- can lead to chronic hepatitis or cirrhosis
- spread by blood, urge, feces, saliva, semen (incubates 2-6 months)
130
What is hepatitis c?
- Spread by blood or sexual contact
- persists for months or years (can lead to cirrhosis, may require transplant)
131
What is hepatitis D?
- Delta virus (needs hepatitis b to replicate, spreads like hepatitis b)
- leads to chronic disease
132
What is hepatitis e?
- uncommon in N.A
- oral-fecal spread (often water contamination)
