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Flashcards in Digestion & Absorption 2 Deck (17)
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1
Q

Two types of lipids?

A

Saturated & unsaturated

2
Q

Where in the body are lipases produced

A
  1. Pancreas 2. Stomach 3. Mouth
3
Q

What is the role of Bile salts?

A

Emulsifiers. Large fat droplets made smaller

4
Q

What are the two effects of failure to secrete bile?

A
  1. Lipid malabsorption- steatorrhoea 2. 2ndary vitamin deficiency cos of failure to absorb lipid vitamins
5
Q

Why can’t lipase work on lipids in the presence of bile

A

bile blocks access of enzyme to the lipid

6
Q

Role of co-lipase?

A

Binds to bile and lipase, allows access of lipase to tri, diglycerides

7
Q

What is the main enzyme used in digestion?

A

Pancreatic lipase Triglyericeride–> free fatty acids

8
Q

What are the products of pancreatic lipase breakdown of lipids?

A
  1. 2- Monoglyceride 2. Fatty acids (2X)
9
Q

What is the principal form of transport in lipid absorption?

A

Passive diffusion. From micelles to the apical membrane

10
Q

Where are the products of digestion stored and later released from?

A

Mixed Micelles. Micelles take up lipids and solubilises them, allowing their transport into the enterocytes of the GI tract.

11
Q

Short chain fatty acids can transport through enterocytes into the capillaries, Long chain fatty acids cannot. What happens to these?

A

Incorporated into chylomicrons

12
Q

Chylomicrons are carried in lymph vessels into the systemic circulation by what cells?

A

Lacteals

13
Q

Chylomicrons are metabolised into _ and _ by which enzyme?

A

Free fatty acids & glycerol

Lipoprotein lipase

14
Q

How is cholesterol absorbed?

A

Endocytosis by Neimann-Pick-C1 Like 1 protein (NPC1L1). NPC1L1- drug target in Ezetimibe

15
Q

How is Ca absorption regulated?

A

Absorption can be passive or active Regulated by - 1,25-dihydroxyvitamin D3 - Parathyroid hormone (produces the above)

16
Q

How is Iron absorption regulated?

A

Hepcidin. Inhibits ferroprotein to prevent Fe absorption

17
Q

How is Vitamin B12 regulated?

A

By haptocorin.