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MBCHB1 exam > phase 1 week 9 > Flashcards

phase 1 week 9 Flashcards

1
Q

Describe what is recommended from the “eat well” plate

A

plenty of fruits and vegetables
plenty of starchy foods such as bread, rice, potatoes and pasta
some meat, fish, eggs, beans and other non-dairy sources of protein
some milk and dairy foods
just a small amount of foods or drinks that are high in fat or sugar

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2
Q

What is metabolism?

A

the sum of all chemical reactions in which energy is made available and consumed in the body

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3
Q

Give some uses of energy in the body

A

Contraction of muscle and hence for all movement
accumulation of ions and other molecules against concentration gradients
biosynthesis and hence for the building of tissues
waste disposal and hence for getting rid of the end products of bodily function
generation of heat and hence maintenance of body temperature

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4
Q

Describe ATP

A

It is often stated that ATP is the energy currency of living organisms, since hydrolysis to give ADP and Pi liberates large amounts of energy
In metabolism, ATP is continually made and broken down

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5
Q

How is glucose converted into Acetyl CoA?

A

glycolysis

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6
Q

How are fatty acids converted into Acetyl CoA?

A

beta oxidation

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7
Q

How are amino acids converted into Acetyl CoA?

A

transamination, oxidative deamination

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8
Q

What are the major common pathways that are the main producers of ATP?

A

TCA (Krebs) cycle

oxidative phosphorylation

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9
Q

Describe glycolysis

A

glucose is turned into 2 pyruvate
occurs in cytosol
ATP investment and ATP generation stages

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10
Q

Describe what happens to pyruvate in anaerobic conditions

A

pyruvate is converted into lactate, this regenerates NAD+ to keep glycolysis going
overall glucose + 2ADP +2Pi > 2lactate + 2 ATP

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11
Q

Describe what happens to pyruvate in aerobic conditions

A

pyruvate is transported to the mitochondria and converted to acetyl CoA by the action of pyruvate dehydrogenase
NADH produced

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12
Q

Describe the breakdown of fatty acids

A

released from triglyceride stores in adipose tissue via the action of lipase enzymes
transported in the blood as a complex with albumin and are taken up by cells for oxidation
They are then attached to CoA, driven by ATP and catalysed by acyl CoA synthase
Acyl groups are joined to carntitine which allows them to translocate into the mitochondria
In each reaction of the cycle the fatty acid is shortened by 2 carbon atoms, with NADH and FADH2 and acetyl CoA being produced.
Acetyl CoA enters the TCA cycle and NADH and FADH2 enter the election transport chain

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13
Q

What is the ATP yield from the TCA cycle and electron transport chain?

A

In the TCA cycle 1 GTP, 3NADH and 1FADH2 are produced
NADH yields 2.5 ATP and FADH2 yields 1.5 ATP
Total yield per acetyl CoA is 10ATP

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14
Q

How is glycolysis regulated?

A

high levels of citrate and ATP inhibit phosphofructokinase which is an important enzyme in glycolysis

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15
Q

Describe protein metabolism

A

9 amino acids are essential and must be obtained from the diet
transamination - 1 amino acid is converted to another
oxidative deamination - the amino acid of an amino acid is lost as ammonia, which can enter the urea cycle

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16
Q

Describe energy requirements

A

Basal energy expenditure (BEE) / basal metabolic rate (BMR) represent the energy required to maintain basic functions when a person is lying down, relaxed, in a normal ambient temperature

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17
Q

What is BMI?

A

Body mass index

weight/height squared

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18
Q

What are the ranges for BMI?

A

30 obese

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19
Q

Describe anorexia

A

self induced weight loss
low body weight
body image distortion
endocrine disorder

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20
Q

Describe the psychological presentations of anorexia

A

overvalued idea re weight
dysphoria
abnormal behaviours - food fads, odd eating, drink in excess or too little, secretiveness, avoidance of social eating

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21
Q

Describe some compensatory behaviours in anorexia

A

excess exercise to burn energy

use laxatives, induce vomiting

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22
Q

Describe some of the personality traits involved in anorexia

A 
premorbid perfectionism
introversion
poor peer relationships
low self esteem
"perfect" child becomes angry, deceptive, manipulative, withdrawn
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23
Q

Describe the treatment for anorexia

A 
inpatient / outpatient
psychological intervention
physical monitoring
diet plan
SSRIs when clear obsessional component
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24
Q

Describe bulimia

A 
cravings
binge eating
counteractive behaviour
body image symptoms 
physical effects to purging
also malnourished
can be overweight
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25
Q

Describe the management of bulimia

A 
outpatient based
self help resources
CBT - 16-20 sessions
high dose SSRI
periodic biochemistry monitoring
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26
Q

Describe the 2 groups of organs in the alimentary system

A

digestive tract

accessory organs - salivary glands, gallbladder, liver, pancreas

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27
Q

Describe the structure of the GI system

A

mucosa
submucosa
muscularis propria
adventitia

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28
Q

What is in the mucosa?

A

epithelium, lamina propria, mucularis mucosae

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29
Q

What is in the muscularis mucosa?

A

inner circular, outer longitudinal

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30
Q

Describe the pharynx

A

muscular tube
conducts air
muscles direct food to oesophagus
3 parts - nasopharynx, oropharynx and larynnopharynx

31
Q

Describe the oesophagus

A 
muscular tube - pharynx to stomach
lies in neck, thorax and abdomen
posterior to the trachea and heart
pierces diaphragm
sphincters
32
Q

Describe the stomach

A

found ion the left hypochondriac / epigastric region
endocrine cells produce gastrin
parietal cells produce HCl and intrinsic factor
chief cells produce pepsinogen

33
Q

Describe the small intestine

A

Comprises duodenum, jejunum and ileum

primary site for digestion and absorption

34
Q

describe the deodenum

A 
receives chyme
short length
contains Brunner's glands - alkaline secretion
receives common bile duct (sphincter of Oddi)
major duodenal papilla
bile
pancreatic "juice"
Ends a deodenojejunal junction
35
Q

deserve the pancreas

A

Dual purpose
exocrine gland - 99%
endocrine gland - islets of Langerhans

36
Q

What does the exocrine portion of the pancreas produce?

A

many digestive enzyme

bicarbonate ions

37
Q

What does the endocrine portion of the pancreas produce?

A

hormones - insulin, glucagon, somatostatin

38
Q

Describe the liver

A 
metabolism - storage of glycogen and release of glucose
protein synthesis
inactivation of hormones, drugs
excretion of waste
produces bile
39
Q

Describe the large intestine

A

Caecum - appendix
Colon - ascending, transverse, descending, sigmoid
rectum

40
Q

What is the blood supply to the GI tract?

A

3 vessels all arising from the abdominal aorta
coeliac trunk
superior mesenteric artery
inferior mesenteric artery

41
Q

Describe the divisions of the abdomen

A

Right and left hypochondriac, epigastric
right and left lumbar, umbilical
Right and left iliac, suprapubic

42
Q

What nervous system influences digestive processes?

A

enteric

43
Q

What does the myenteric plexus do?

A

GI motility

44
Q

What does the submucous plexus do?

A

sensing environment in the lumen
regulating GI blood flow
controlling epithelial cell function

45
Q

Describe the mouth, pharynx and salivary glands

A

start digestion by physically chewing food and breaking it down with saliva

46
Q

What are the functions of saliva?

A

Maintaining healthy oral tissues - contain thiocyanate ions, proteolytic enzymes and antibodies
starts digestion of carbohydrates
contributes to digestion of fats
its absence provides the urge to drink
provides mucous
keeps mouth moist for speech, oral comfort, chewing and swallowing

47
Q

Describe salivary amylase

A

produced by acini glands
pH optimum 6.9
activity continues for 15-30 minutes in mouth and stomach
breaks down alpha 1,4 glucosidic bonds
starch, glycogen > maltose, maltotriose and alpha limit dextrins

48
Q

Describe the functions of the stomach

A

storage of food
churn and mix with gastric secretions
acid and pepsin secretions
slow emptying of digestive contents into small intestine

49
Q

What are the gastric secretions?

A

mucous secreting cells
acid secretion
chief cells produce pepsinogen
intrinsic factor

50
Q

Why is mucous important in the stomach?

A

protects stomach from damage by gastric acids

51
Q

What do acid secretions in the stomach do?

A

breakdown of connective tissue, activates pepsin, solubilises calcium and iron, acts as a barrier to microbes

52
Q

What does pepsinogen do?

A

converted into pepsin, digests proteins

53
Q

What is intrinsic factor important for?

A

absorption of vitamin B12

54
Q

Describe pancreatic juice

A 
made of aqueous and enzymatic component
 alkali - contains bicarbonate
buffers acidic secretion of stomach
protects mucosa
enters small intestine
provides right pH for proteolytic enzymes
55
Q

What are the two types of pancreatic secretions?

A

proteolytic and non-proteolytic

56
Q

Give examples of proteolytic enzymes

A 
trypsin
yhromotrypsin
carboxypeptidase
elastase
phospholipase
secreted by acinar cells as zymogens
57
Q

Give examples of non-proteolytic enzymes

A 
amylase
lipase
ribonuclease
deoxyribonuclease
released in active form
58
Q

Describe pancreatic amylase

A

endoamylase, similar to salivary
digests alpha 1-4 glucose bonds
digests starch and glycogen to maltose maltotriose and dextrins

59
Q

Describe pancreatic lipase

A

acts of water insoluble triglycerides

releases fatty acids and 2-monoglycerides

60
Q

Describe liver bile

A

synthesised in the hepatocyte
stored in the gall bladder
released into duodenum after meal

61
Q

What is bile composed of?

A 
bile acids
phospholipid
cholesterol
bilirubin
electrolytes
detoxified drugs
62
Q

What are the functions of bile?

A

emulsification of fat particles

helps in absorption of fats by forming complexes called micelles

63
Q

What is the function of the duodenum?

A

mixing secretions from pancreas, liver and its own with food, neutralising the acid, further digestion, absorption

64
Q

What is the function of the jejunum?

A

completing breakdown, nutrient absorption

65
Q

What is the function of the ileum?

A

nutrient absorption

66
Q

What is chylomicron formation?

A

if a fatty acid has more than 12 carbons, then triglyceride reformed in a cell coated protein, phospholipid and cholesterol enclosed in vesicles

67
Q

What do the absorptive cells of the small intestine release?

A

digestive enzymes

68
Q

What do goblet cells in the small intestine produce?

A

mucous

69
Q

What do granular cells in the small intestine produce?

A

enzymes

70
Q

what do endocrine cells in the small intestine produce?

A

hormones

71
Q

Give examples of brush border enzymes

A

peptidases
lactase
lucrase
maltase

72
Q

Describe protein digesition

A

starts in the stomach - pepsin
continues in small intestine - trypsin, chymotrypsin, carboxypeptidase
continues at brush border amino peptidases
amino acids and peptides absorbed by active transport vis 7 sodium linked carriers

73
Q

Describe the digestion of fats

A

pancreatic lipase, collapse
mixed with emulsified fat and bile acid
triglyceride > 2-monoglyceride and fatty acids

74
Q

Describe fatty acid absorption

A

at brush border lower pH at mucosa reduces solubility of lipid in micelles
fatty acids are absorbed by micelles

MBCHB1 exam (28 decks)

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