Lecture 11 Flashcards
What are the 2 things essential physiological processes require?
Energy, raw materials.
What can autotrophs and heterotrophs subsist on?
Aututrophs - inorganic nutrients alone.
Heterotrophs - complex organic compounds from other organisms.
What 6 nutrients are required?
Carbohydrates, lipids, proteins, vitamins, inorganic salts, water.
How much energy is released by protein, lipids and carbohydrates per gram?
Carbohydrates: 17kJ/g.
Lipids: 22 kJ/g.
Proteins: 39kJ/g.
5 functions of water?
Solvent, transportation, hydrostatic support (e.g. eyeball), evaporative cooling, cleaning agent (e.g. eyes).
What are the 8 essential amino acids that must be obtained from food?
Trp, Met, Val, Thr, Phe, Leu, Ile, Lys.
How much energy (x10^6J/day) is required for light work (woman), light work (man), medium work (man) and heavy work (man)?
- 5,
- 5
- 3
- 9
How many calories is 1 joule?
0.239 calories.
How much water is lost per day? (and therefore must be consumed)
2.5l.
How long is the GI tract?
4.5m.
What 3 basic digestive processes occur in the GI tract?
digestion, absorption, motility.
What word describes the way muscle moves food along GI tract?
Peristaltic.
What digestive process occurs in Accessory glands?
Secretion.
What 4 glands make up accessory glands?
Salivary glands, pancreas, liver, gall bladder.
What are the 8 digestive organs that food passes through in the digestive system?
Mouth, pharynx, oesophagus, stomach, small intestine, colon, rectum, anus.
Three functions of the mouth in digestion?
Mechanical breakdown,
Mixing food with saliva,
Initiation of chemical digestion of carbohydrates by salivary amylase.
4 layers of GI tract surrounding the lumen, from inside to outside.
Mucosa, submucosa, muscularis(circular layer, longitudinal layer), serosa.
What 3 layers is the mucosa made of?
Mucous membrane,
Lamina propria, (CT, capillaries, nerves, lymphoid tissue),
Muscularis mucosae.
What is the submucosa made of?
connective tissue, blood, lymphatic vessels.
What is the series made up of?
Connective tissue.
What layers of the GI tract does the nerve plexus span?
Submucosa to serosa.
What are the epithelial cells in mucous membrane of mucosa called?
Absorptive cells, exocrine cells, goblet cells, endocrine cells.
What are the 3 salivary glands?
parotid gland, sublingual gland, submandibular gland.
How much saliva is secreted by salivary glands per minute?
0.5ml/min.
What 2 enzymes are secreted by the salivary glands?
Salivary amylase, lingual lipase.
What does salivary amylase digest?
Glycogen and starch.
What are the 6 other functions of saliva (apart from digestion)?
Lubrication, Buffering and diluting noxious substances, Antibiotic action, Taste, Clean teeth, Fluoride, calcium uptake into teeth.
How long is the oesophagus, and what type of muscle does it consist of?
25cm long.
Upper 1/3rd skeletal muscle, lower 2/3rds smooth muscle.
What does the oesophagus connect?
Pharynx to stomach.
Which sphincters are usually closed in the oesophagus?
Upper and lower oesophageal sphincters.
What causes heartburn?
Back flow up oesophageal sphincters.
What is the stomach’s minimum and maximum volumes roughly?
~50mls to 1-2 litres.
What cells do gastric glands in the stomach contain, and what do they secrete?
Parietal cells, (secrete HCl)
Chief cells, (secrete pepsinogen).
How much HCl can be secreted in the stomach in one day, and at what concentration/pH?
2 litres HCl/day.
10mM A.K.A pH2.
What is a zymogen?
An inactive substance converted into an enzyme when activated by another enzyme.
What’s secreted from the neck cells in the stomach?
Mucus.
What coagulates milk and is found in the stomach?
Rennin.
What is the mechanism for gastric acid secretion?
H+ ions made from CO2 and water from carbonic anhydrase, actively transported into lumen in exchange for K+.
Bicarbonate ions exchanged for chloride ions, diffuse into lumen.
Causes accumulation of HCl in lumen.
How is chymotripsinogen activated?
Tripsin converts it into π-Chymotripsin.
Chymotrypsin then converts π-chymotripsin into α-chymotrypsin, removing 2 dipeptides in the process.
What activates pepsinogen?
HCl and a current pepsin, creating pepsin.
What does pepsin do?
Degrade proteins into smaller polypeptides.
