Carbohydrates of biological and clinical significance and Absorption of glucose

Moderator:

Group member names:

Dr.Krishnanda Prabhu

Vinod.R.S

Ravi Teja.CH

Nagendra.K

Introduction

Classification of carbohydrates

Biological significance CHO

Clinical significance of CHO

Glucose absorption

Summary

MCQs

References & Additional information Sources.

Contents of the seminar

Objective

• Add your objective here

Results

• Add your results here

Procedure/Methodology

BIOLOGICAL IMPORTANCE OF CARBOHYDRATES:

• Chief source of Energy

• Structure

• Storage

• Protein sparing

• Antigen properties

• Role as Dietary Fiber

• Prevention of ketosis

• Role in biosynthesis

• ECM

• Hygroscopic nature

STRUCTURAL FORMS CARBOHYDRATES:

Role of Glycoconjugates:

• Glycoproteins

• GAGs

• Glycolipids

Clinical significance of carbohydrates:

• Nutritional significance of carbohydrates

• Glucose homeostasis & Glycaemic Index

• Glycated haemoglobin

• Significance of fibre

• Significance of Dextran's and Inulin’s

• Dental caries due to carbohydrates

• MCQ’s

Phase ORIGIN OF BLOOD

GLUCOSE

TISSUES USING GLUCOSE MAJOR FUEL OF BRAIN

1 Exogenous All

Glucose

2 Glycogen

Hepatic gluconeogenesis

All except liver.

Muscle and adipose tissue

at diminished rate Glucose

3 Hepatic

gluconeogenesis

Glycogen

All except liver.

Muscle and adipose tissue

at rate intermediate

between 2 and 4

Glucose

4

Gluconeogenesis,

Hepatic and Renal

Brain, RBCs, renal medulla.

Small amount by muscle.

Glucose,

Ketone bodies

5

Gluconeogenesis,

Hepatic and Renal

Brain at a diminished rate,

RBCs ,Renal medulla

Ketone bodies,

Glucose

Five way mechanism of homeostasis:

Glycaemic index:

Glycated haemoglobin:

Functions of fibre:

• Role in Maintenance

• Blood Cholesterol Regulation

• Weight Management

• Colon health

• Easy passage of stool

• Increases peristaltic movement in the bowel

Potential effects of DF consumption:

It is a fructosan

Low MW substance (5 KDa) Inulin

fructose units joined by β-1,2 bond

present in various bulbs, tubers (dahlia, onion, garlic,

dandelions, artichoke etc.)

A complex, branched polysaccharide of glucose

MW varies from 3-2000 KDa Dextran

The straight chain consists of α-1,6 bond

Branches begin with α-1,3 linkage

Clinical significance of Dextran’s:

• Antithrombotic , Anti-platelet role

• Plasma volume expander

Used to reduce blood viscosity

As lubricant

• Used in intravenous fluid to solubilize other factors: eg. Iron

OK MAMA…………

Fructose

Sucrose

Starch

Lactose

FOOD

DIGESTION ABSORPTION

(Small Intestine)

Glucose

Galactose

Fructose

Digestion of Glucose Digestion in mouth,

Digestion in stomach, Digestion in small

intestine

Absorption – General Aspects

Absorption of substances into mucosal cells involves

the passage across the plasma membrane

simple diffusion carrier-mediated transports

passive

(no energy expenditure)

No carrier protein

facilitated transport

(passive)

(requiring energy expenditure)

active transport

it is carrier mediated mechanism

involving transporter proteins and the process called

Na+ dependent transporter /

Na+ Glucose co transport /

SGLT

from the small

intestinal lumen

SGLT1

(Absorption)

into the intestinal

epithelial cells

From the PCT

SGLT2

(Reabsorption)

In to the brush border

cell of PCT

ACTIVE TRANSPORT:

Facilitated diffusion andtransporters :

• Diffusion?

• Facilitated diffusion?

• Types Of transporter :

GLUT1(All most all the cells mostly on CNS & RBCs)

GULT2 (It’s a two way transporter, Liver & Kidney)

GULT3 (BBB,RBCs)

GULT4 (Insulin dependent, Skeletal muscle & Adipose tissue)

GULT5( Mainly the Fructose transporter, Lumen of SI)

Intestinal

Epithelial Cell

Absorption of Glucose

Glucose

Glucose

Glucose

GLUT-5

Intestinal Lumen Na+

Na+

Na+ K+

K+

Na+-dependent transporter

(SGLT)

GLUT-2

Portal Capillary Blood

ATP

Na+–K+ ATPase

ADP + Pi

secondary active transportfacilitated transport

Inhibitors of glucose transporters:

• OUABAIN: Inhibiting sodium dependent glucose

transport by inhibiting Na-K ATPase

• Phlorhizin: Inhibiting coupling of sodium to

the cotransporter

• Cytochalasin B: 2 glucose transporter, GLUT2

LZHS

A number and a colon

1 $100

Which of the following statements about dietary fiber is/are correct?

Insoluble fiber increases stool bulk & decrease transit time

All of the aboveMucilaginous fiber slows the rate of digestion and absorption of cho

Water soluble Fiber helps to lower serum

cholesterol

LZHS

A number and a colon

2 $200

Against a conc. Gradient if the transporter is Na+ dependent

By a Na+ independent trans. (GULT2) across d contraluminal membrane

Monosaccharides are absorbed from the intestine

By a Na+-dependent cotransp. For glucose n galac

Na+ independent facilitated transport for fructose

LZHS

A number and a colon

3 $300

The following polysaccharide is composed of beta glycosidic bonds

Starch Dextrin

CelluloseGlycogen

Summary of the seminar

Introduction of carbohydrates and classification of CHO

Biological importance

Important of Glycoconjugates

Clinical significance of CHO mainly how glucose homeostasis is

maintained, Significance of fiber and etc..

Digestion of carbohydrates

Absorption by Na+ glucose cotransport

Glucose transporters

Important glucose transporters

MCQ’s

References & Additional information sources.

Text book of Biochemistry—T. M. Devlin

Text book of Biochemistry– Aroor

Lehninger text book of biochemistry

Text book of biochemistry –Satyanarayana

Marks

Vasudevan

Baynes

A C Deb

Wikipedia

www.fao.org

http://www.konjacfoods.com/fiber.html

Google images