Metabolism and homeostasis

Question 1

Define the term metabolism

Answer 1

the sum of chemical reactions that take place in each cell of a living organism

Question 2

What are the 4 main pathways through which dietary components are metabolised?

Answer 2

1) Biosynthetic
2) Fuel storage
3) Oxidative
4) Detoxification

Question 3

Define Anabolic metabolism and give an example

Answer 3

Synthesising larger molecules from smaller components

Eg. anabolic steroids are used by body builders to build muscle

Question 4

Which metabolic pathways are anabolic?

Answer 4

Biosynthetic pathway and fuel storage pathway

Question 5

Define Catabolic metabolism

Answer 5

The breakdown of larger molecules into smaller components

Question 6

Which metabolic pathways are catabolic?

Answer 6

Oxidative pathway and waste disposal pathway

Question 7

Explain a biosynthetic pathway

Answer 7

The sequence of enzymatic steps in the synthesis of a specific end product -> structural molecules (eg. proteins)

Question 8

Explain the fuel storage pathway

Answer 8

The synthesis of molecules that have a function to store energy (eg. ATP)

Question 9

Explain the oxidative pathway

Answer 9

Cells use enzymes to oxidize nutrients/energy rich molecules, releasing chemical energy

Question 10

Explain the detoxification pathway

Answer 10

The removal of waste products/products that are not useful and have no nutritional value

Question 11

What are cofactors? Give an example

Answer 11

What are cofactors? Give an example

Question 12

How is adipose tissue specialised?

Answer 12

It is approx. 85% fat and the storage site for fat (in the form of triglycerides)/energy rich molecules

Question 13

What percentage of body weight is water?

Answer 13

60%

Question 14

What percentage of total body water is intracellular fluid?

Answer 14

40%

Question 15

Is water freely permeable thought ICF and ECF?

Answer 15

Yes

Question 16

What is the predominant cation in ICF?

Answer 16

Potassium

Question 17

Sodium is the main contributor to ECF …….. and ………

Answer 17

osmolality and volume

Question 18

What else is present in the extracellular fluid?

Answer 18

1) anions chloride and bicarbonate
2) glucose & urea
3) protein (colloid osmotic pressure)

Question 19

What fluid surrounds the cells but does not circulate?

Answer 19

Interstitial fluid

Question 20

What fluid circulates as a component of the blood?

Answer 20

Plasma

Question 21

What is osmolality?

Answer 21

concentration of all small ions and molecules in the plasma

Question 22

How do we estimate plasma osmolality?

Answer 22

2[Na] + 2[K] + urea + glucose mmol/L

Question 23

Are intra and extracellular osmolality equal?

Answer 23

Yes

Question 24

Under ………… circumstances, fluid intake = fluid loss

Answer 24

normal

Question 25

What is our normal plasma osmolality?

Answer 25

275-295 mmol/kg

Question 26

What is our normal plasma osmolality?

Answer 26

275-295 mmol/kg

Question 27

3 causes of water depletion

Answer 27

1) Reduced intake 2) sweating 3) vomiting/diarrhoea/diuresis

Question 28

Clinical symptoms of dehydration

Answer 28

``` Thirst Dry mouth Inelastic skin Sunken eyes Raised haematocrit Weight loss Confusion Hypotension ```

Question 29

What are ascites?

Answer 29

accumulation of fluid in peritoneal space

Question 30

What is hypernatremia?

Answer 30

an increase in sodium ions (excess) in the blood plasma

Question 31

What is hyponatremia?

Answer 31

Loss of sodium ions due to renal loss

Question 32

What percentage of body water is found as extracellular fluid?

Answer 32

20% - split into intravascular and interstitial.

Question 33

Why we don't give water intravenously?

Answer 33

1) hypo-osmolar/hypotonic vs. cells 2) water causes blood cells to burst after entering 3) this only occurs in vicinity of intravenous cannula 4) instantaneous mixing would prevent this

Question 34

What is the condition where there is an excess accumulation of fluid in the interstitial space?

Answer 34

Oedema