BIOL125 - Feeding and Digestion
0.0 / 5
- Created by: Katherine
- Created on: 19-05-16 12:12
What do process of life require?
Energy and raw material
1 of 108
What is an autotroph?
Something that can subsit on inorganic nutrients alone (self sustaining) whereas heterotrophs require complex organic compounds in their diet.
2 of 108
What do heterotrophs require?
They require complex organic compounds from other organisms.
3 of 108
What are the types of nutrient required?
Carbohydrates, Lipids, Proteins, Vitamins, Inorganic salts and water
4 of 108
Why do we need lipids?
We need them to make cell membranes.
5 of 108
Why we need proteins?
For structural components like collagen and elastin.
6 of 108
Why do we need vitamins?
They are co-factors for enzymes
7 of 108
Why do we need water?
It is a solvent
8 of 108
What are the different functions of water?
To act as a solvent for transportation, for hydrostatic support, for evaporative cooling, and as a cleaning agent.
9 of 108
How many essential amino acids are there, and what are they?
8 - Trp, Met, Val, Thr, Phe, Leu, Ile, Lys - These must be obtained in the diet as we can't make them
10 of 108
How many calories can a heavy manual working man have?
4,500
11 of 108
How many calories can a moderately worknig man have?
3,400
12 of 108
How many calories can a light working man have?
2,500
13 of 108
What are the four basic digestive processes?
Digestion, absorption, motility and secretion
14 of 108
What is digestion?
It is the physical and chemical breakdown of food
15 of 108
What is absorption?
Transport of digestive end products in to bloodstream
16 of 108
What is motility?
It is peristaltic activity of muscle propelling food along GI tract. We have accessory glands which secrete things into the lumen of the GI tract
17 of 108
What is secreton?
Transport of digestive fluids into the GI tract
18 of 108
What are the accessory glands?
Salivary glands, pancrease and liver and gallbladder
19 of 108
What is the function of the Pharynx?
Conduction of food to esophagus
20 of 108
What is the function of the stomach?
Mechanical breakdown of food;secretion of acid, pepsiongen and intrinsic factor; initiation of chemical digestion of proteins by pepsin; secretion of gastrin into blood stream; transforamtion of food into chyme
21 of 108
What is the function of the small intestine?
Chemical digestion of all nutrient classes by pancreatic enzymes and membrane bound enzymes; absorption of digestive end products, water, ions and vitamins; secretion of enterogastrones into blood stream. Secretion of bicarbonate rich fluid
22 of 108
What is the function of the colon?
Absorption of ions and water; transformation of chyme into feces; storage of feces.
23 of 108
What is the function of the rectum?
Storage of feces prior to elimination
24 of 108
What is the function of the anus?
Control of defecation
25 of 108
What is the function of the salivary glands?
Secretion of saliva (contains amylase, bicarbonate, and lysozyme)
26 of 108
What is the function of the pancreas?
Secretion of pancreatic juicss (contains digestive enzymes and bicarbonate)
27 of 108
What is the function of the liver?
Secretion of ble (contains bile salts and bicarbonate); processing of absorbed nutrients
28 of 108
What is the function of the gall bladder?
Storage and concentration of bile
29 of 108
What does the general structure of the GI tract consist of?
Duct of accessory gland, lumen, mucosa, submucosa, muscularis, serosa, Nerve plexus
30 of 108
What does the mucosa consist of?
Mucuous membrane, lamina propria (connective tissue, capillaries, nerves, lymphoid tissue) and muscularis mucosae
31 of 108
What type of cells make up the mucous membrane?
Epithelial cells or enterocytes which include absorptive cells, exocrine cells, goblet cells (secret mucus) and endocrine cells
32 of 108
What is saliva secreted by?
It is secreted by salivary glands
33 of 108
What does saliva contain?
Salivary amylase (digests glycogen and starch) and lingual lipase
34 of 108
What are the other functions of saliva?
Lubrication (mucus), buffering and diluting noxious substances, antibiotic action (lysozyme, lactoferrin), taste, cleans teeth, fluoride/calciium uptake into teeth.
35 of 108
What does the Oesphagus do?
It is a muscular tube the connects the pharynx to the stomach.
36 of 108
The upper and lower esophageal sphincters are usually closed, but back flow can occur, what does this result in?
Heartburn
37 of 108
The upper 1/3 has what type of muscle?
Skeletal
38 of 108
The lower 2/3 has what type of muscle?
Smooth muscle
39 of 108
The stomach can exand from 50mls to what?
1-2 litres
40 of 108
The stomach gastric glands (mucosa) contain what type of cells?
Parietal cells and chief cells
41 of 108
What do parietal cells do?
They secrete hcl
42 of 108
What do chief cells do?
They secrete pepsiongen.
43 of 108
How much HCL can the stomach secrete each day?
2 litres
44 of 108
If pepsinogen is an inactive zymogen, what is its active form?
Pepsin
45 of 108
What is also secreted from the stomach?
Mucus and gastric lipase
46 of 108
Parietal cells are an intrinsic factor required for absorption of what?
Vitamin B
47 of 108
Wht coagulates milk?
Rennin
48 of 108
What is the mechanism of gastic acid secretion?
H+ ions, made from CO2 and water by carbonic anyhdrase, are actively transported into the lumen in exchange for K+ ions. Bicarbonate ions are exchanged for chloride ions which diffuse into lumen.
49 of 108
What is the nett result of this?
The accumulaton of HCL in the lumen?
50 of 108
How can you tell if something is a zymogen?
If it ends in "inogen"
51 of 108
Why are zymogens a thing?
They a better in the inactive form so they only start digesting things when they're released into the lumen of the digestive tract.
52 of 108
How is chymotrypsinogen activated?
The zymogen is cleaved between the 15 and 16th amino acids by trypsin. This forms 3 chains (ABC) which are linked by interchain disulphide bonds
53 of 108
When is pepsinogen activated?
When it comes into contact with HCL in the stomach.
54 of 108
Once activated, Pepsin can activate what?
More pepsinogen
55 of 108
What does the pepsin then do?
It starts to degrade proteins into smaller polypeptides.
56 of 108
How long is the small intentsine?
2.5-5 m long
57 of 108
What are the names of the 3 sections of the small intestine?
Duodenum, jejenum and ileum
58 of 108
What does the duodenum do?
It receives chyme from stomach, enzymes from pancreas and bile from liver and gall bladder.
59 of 108
Which section if responsible for digestion?
The duodenum
60 of 108
Which section is responsible for absorption?
All 3 sections - absorption of nutrients, water, vitamins and minerals.
61 of 108
The crypts of Liberkuhn do what?
Secrete copious amounts of bicarbonate rich fluid.
62 of 108
The epithelial wall of the mucosa are covered in what?
Villi
63 of 108
Each cell has numerous...
Microvilli = brush border
64 of 108
The villi have...
Capillaries and lymphatic vessels
65 of 108
The total surface area available for absorption and digestion is
300m ^2
66 of 108
The brush border has associated enzymes, which include...
Lactase, maltase, sucrase and nucleases, peptidases
67 of 108
How long is the pancrease?
It is about 20cm long, weighs 100g
68 of 108
What type of cells make digestive enzymes
Acinaar cells (exocrine cells) - they release digestive enzymes into duodenum via the secretory duct.
69 of 108
In the pancreas, waht else is made?
Chymotrpypsin, trypsin, carboxylpeptidase, elastase, made as zymogens.
70 of 108
What else is made?
Pancreastic amylase, lipase, proteases, DNAse, RNase
71 of 108
What else do Acinar cells make?
Bicarbonate
72 of 108
What do Islets of Langerhans (endocrine cells) make?
Hormones which are secreted into the blood.
73 of 108
What do B cells make?
Insulin - stimulates glucose - glycogen
74 of 108
What do A cells make?
Glucagon - stimulates glycogen - glucose
75 of 108
What do d cells make ?
Somatostatin - regulates digestion, absorption and release of other hormonse
76 of 108
What is type one diabetes?
It is early onset, insulin dependent - an autoimmune disease caused by loss of insulin secretion from the islets of Langerhans. Treated with insulin administration
77 of 108
What is type two diabetes?
It is late on set diabetes, it is non insulin dependent - it is associated with obestity, sedentary lifestyle, and is due initially to loss of responsivness to insulin.
78 of 108
How can type 2 diabetes be avoided?
Through diet and exercise, but may require insulin in advanced stages.
79 of 108
What do both types of diabetes cause?
Evelation in blood glucose
80 of 108
Monosaccarides and amino acids are transported into what...
Blood capillaries of villi, then to the liver via the hapatic portal vein.
81 of 108
Fats are emulsidied into fat droplets by the action of ...
Bile salts, they are then susceptible to digestion by pancreatic lipase.
82 of 108
Resulting fatty acids and monglycerides are converted into...
chylomicrons (small particles) which enter the lymphatic capillary system.
83 of 108
How do monosaccharides, amino acids, electrolytes, water, absrobed from the intestine travel to the liver?
Via mesenteric veins and the hepatic portal vein. They can then enter the general cirulation via the hepatic vein
84 of 108
What does the liver do?
It makes bile pigments (waste products of red blood cells) and bile salts
85 of 108
Where are bile salts stored?
In the gall bladder
86 of 108
What does the liver do?
It detoxifies absorbed materials and regulates blood composition, produces many proteins found in blood plasma, regulates blood glucose levels 9stored as glycogen), conversion of glucose to glycogen stimulated bt insulin - reverse of glucagon
87 of 108
What type of structures are bile saltes?
They are amphipathic structures - so cholesterol derivatives
88 of 108
Do bile salts digest fats?
No, they act as detergents to break them down into small droplets or micelles.
89 of 108
What are the droplets then able to do?
They are then amenable to digestion by lipases
90 of 108
Are bile salts destroyed after use?
No, they are recirculated
91 of 108
How are chylomicrons formed?
Fatty acids and monoglycerides from fat digestion are absorbed and synthesised into trigylcerides, which are then packed into chylomicrons
92 of 108
What happens to the chylomicrons after exocytosis?
They enter the lacteals and into the lymphatic ststem
93 of 108
What is the colon?
It is the last metre of the GI tract
94 of 108
What is the colon composed of?
Ascending, transverse, descending and sigmoid colons
95 of 108
Is there digestion and absorption of nutrients in the colon?
No
96 of 108
Which 3 segments absorb water and inorganic ions?
The first 3
97 of 108
The sigmoid colon is the...
Strorage depot
98 of 108
What happens to ***** matter?
It is ejected through rectum and anus
99 of 108
What is the souce of main digestive enzymes?
Stomach enzmes (pepsin) are optimally active at very acidic pH, whereas those found in the small intestine are active at slightly alkaline pH.
100 of 108
What is enterokinase?
It is a protease that converts trypsinogen into trypsin.
101 of 108
What are the names of the phases responsible for regulation of gastric secretion?
Cephalic or Reflex phase (a few mins) and gastric phase (A few hours), Intestinal phase
102 of 108
What is the cephalic or reflex phase?
The nervous system stimulates salivary and sastric secretions (olfactory receptors, taste buds -brain)(hypothalamus - vagus nerves) in response to aroma, taste, sight or thought of food.
103 of 108
What is the Gastric phaes?
Involves acetylcholine, histamine and gastrin (polypeptide hormone made by stomach G cells) which together stimulate secretion of HCL and pepsinogen.
104 of 108
What controls the gastric phase?
It is controlled by stomach distension and rising pH, as proteins in food ' mop up' H+ ions.
105 of 108
What is the intestinal phase?
Release of chyme from stomach into duodenum briefly stimulates gastric activity via release of intestinal gastrin.
106 of 108
What does continued release of chyme do?
It inhibits gastric activity due to secretion by duodenum of gastric inhibitory peptide (GIP), vasoactive intestinal peptide (VIP), cholecytostokinin (CCK), and secretin
107 of 108
What are the major GI hormones?
Gastrin, Chyme, GIP, Secretin, CCK, VIP,
108 of 108
Other cards in this set
Card 2
Front
What is an autotroph?
Back
Something that can subsit on inorganic nutrients alone (self sustaining) whereas heterotrophs require complex organic compounds in their diet.
Card 3
Front
What do heterotrophs require?
Back
Card 4
Front
What are the types of nutrient required?
Back
Card 5
Front
Why do we need lipids?
Back
Related discussions on The Student Room
- A&P revision recommendations »
- AQA Biology essay »
- Recognition of prior learning (rpl) »
- Human foods for dogs »
- What happens when a person with anorexia has a baby? »
- Sample digestion method in food testing »
- Life as a student nurse at Bradford »
- What life science degree should I do? »
- Investigation on the effect of bile on fat digestion. »
- Biology help please »
Similar Biology resources:
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
Comments
No comments have yet been made