objectives - mans metabolism - 1st.pdf · objectives by the end of lecture the student should:...
TRANSCRIPT
![Page 1: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/1.jpg)
![Page 2: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/2.jpg)
Objectives
By the end of lecture the student should:
Identify importance of lipids in food.
Describe digestion of different types of lipids.
Illustrate absorption of lipids from intestine.
Summarize transport of dietary lipids from intestine.
![Page 3: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/3.jpg)
• Source of energy: 1 gm
supplies 9.1 calories
• Minimal amount of fat is essential in our food to: Essential fatty acids Help Fat-soluble
vitamins absorption
![Page 4: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/4.jpg)
Digestion of lipids
1- Triglycerides
2- Phospholipids
3-
Cholesterol esters
![Page 5: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/5.jpg)
A- Emulsification
B- Enzymatic hydrolysis by lipase enzymes
1- Digestion of triglycerides
![Page 6: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/6.jpg)
• Breakdown of large fat globule small ones
A-Emulsification
![Page 7: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/7.jpg)
• Breakdown of large fat globule small ones
• Occurs in:
Mouth by chewing
Stomach by peristaltic contractions
Intestine by peristaltic movement,
bile salts
lysophospholipids
A-Emulsification
![Page 8: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/8.jpg)
Types:
1- lingual lipase
2- gastric lipase
3- pancreatic lipase
4- intestinal lipase
the most active is pancreatic lipase.
B- Lipase enzymes
![Page 9: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/9.jpg)
secreted by the dorsal surface of the tongue (Von-Ebner’s glands)
Is not of much significance in humans
compared to rat or mouse
1- Lingual lipase
![Page 10: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/10.jpg)
physiological significance in :
Infants: adults:
2- Gastric lipase (pH 3-6)
![Page 12: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/12.jpg)
F.A
F.A
F.A
F.A
F.A F.A
lipase
F.A
Isomerase
F.A lipase
TG
β MAG
α MAG
Glycerol
F.A
F.A P N B
PL A2 F.A
P N B F.A
PL
lyso PL
Chol. F.A
Chol.estrase
Chol. F.A
72%
28%
22%
6%
![Page 13: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/13.jpg)
Act within intestinal mucosal cells hydrolyse the absorbed primary (α) monoglycerides forming glycerol and FFA
4- Intestinal lipase
![Page 14: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/14.jpg)
Phospholipids lysophospholipids
Intestinal phospholipase may complete the hydrolysis of lysophospholipids
Phospholipase A2 activated by trypsin & requires bile salts for activity
2- Digestion of phospholipids
![Page 15: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/15.jpg)
Cholesterol esters by cholesterol esterase FA & free cholesterol
3- Digestion of cholesterol esters
![Page 16: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/16.jpg)
• The end products of lipid digestion are : monoglycerides, FA, glycerol, cholesterol
& lysophospholipids
1- Glycerol and short chain FA :
water soluble carried through portal circulation
Absorption of lipids
2- Long chain FA, monoglycerides,cholesterol & lysophospholipids : need bile salts to be absorbed
![Page 17: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/17.jpg)
• Bile salts surround these component (by their unpolar end while their polar endings directing outward) water soluble micelles (0.1 –0.5 μ in diameter)
How
![Page 18: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/18.jpg)
![Page 19: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/19.jpg)
How
• Micelles soluble in water, enter microvilli of mucosal cells by endocytosis where fat digestion may be completed through action of intestinal lipase:
![Page 20: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/20.jpg)
Enterocyte
Lumen
Baso-
lateral
border
Lymph
F.A MG
Chol
LPh.L
Unstirred water layer
Passive diffusion
F.A Gly
Resynthesis TG
Ch.E
PL
TG Chol.E
Ph.L
Chylomicrons Micelle
Lipid absorption
Blood
![Page 21: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/21.jpg)
• In the mucosal cells triglycerides and other lipids are resyntheiszed once again as follow:
1- FA activated to acyl-CoA
![Page 22: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/22.jpg)
2- Reesterification of absorbed β-monoglyceride with 2 Acyl-CoA triglycerides
3- Re-esterification of glycerol 3p with 3 Acyl-CoA triglycerides
Glycerol 3p is derived from: Glycerol by Glycerokinase, present in liver, kidney
& to small degree in small intestine but deficient in adipose tissue
DHAP derived from glucose by glycolysis.
![Page 23: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/23.jpg)
- Resynthesis of phospholipids & cholesterol esters by combination of cholesterol and lysopholipids absorbed with acyl-CoA
![Page 24: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/24.jpg)
• The triglycerides, phospholipids & cholesterol
bind with a protein (Apolipoprotein B48) forming
chylomicrons lacteals & pass with lymphatic
drainage the thoracic duct systemic
circulation.
![Page 25: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/25.jpg)
• Immediately after absorption of lipids there is turbidity of plasma due to circulating chylomicrons (appear in plasma 2 hours after meals)
• This turbidity is soon cleared by lipoprotein lipase enzyme (clearing factor)
Fate of absorbed lipids
![Page 26: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/26.jpg)
Lipoprotein lipase
Chylomicrons
(TG)
FFA Glycerol Glycerol liver
FFA adipose CT, liver
![Page 27: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/27.jpg)
Summary
![Page 28: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/28.jpg)
Questions
![Page 29: Objectives - Mans METABOLISM - 1st.pdf · Objectives By the end of lecture the student should: Identify importance of lipids in food. Describe digestion of different types of lipids](https://reader031.vdocument.in/reader031/viewer/2022022119/5d03d15a88c993c8248bde31/html5/thumbnails/29.jpg)