Liver Functions Part II

8/15/2019 Liver Functions Part II

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Liver Functions Part II

3E1


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From where we left off…


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In the small intestines

• Complete digestion occurs in the smallintestines

• End products (glucose, amino acids, fattyacids, glycerol) diffuse into the blood vesselslining the small intestines.

• This process is called Absorption.


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Some animal samples

• Guess what is the organ

shown!

• From which animal?


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Adaptation of the

small intestine forabsorption


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Structure of small intestine


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What do you see in the intestinal walls?


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How do the folds and villi help

in absorption?

• The presence of folds and villi

in the intestinal wall increase

surface area


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More adaptations from the small

intestine

• the epithelial cell of the intestinal wall

• One-celled thick epithelial wall and microvilli

further increases

surface area


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The small intestines• What makes the small intestines suitable for Absorption?

1) Elongated ileum, Innersurface of the ileum is folded

These features provide large surface area:vol for absorption

2) Villi andmicrovilli


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The small intestines• What makes the small intestines suitable for Absorption?

3) Many blood

vessels lining thesmall intestines


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Absorption• Absorption occurs by: – Diffusion

– Active transport

• After absorption,

Glucose and

amino acids enter

the blood

capilliaries

Glycerol and

fatty acids enter the

lacteals


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How does absorption takes

place in the intestines

Absorption of fatty acids and glycerol

• Glycerol and fatty acids diffuse into theepithelium where they combined to formminute fat globules and enters the lacteals

•Fat globules mix with lymph in the lacteals toform chyle

• Liver is not involved *


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Assimilation

and

function of the liver


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Overview

Role of Digestion Mouth & Oesophagus

Gall Bladder &Pancreas

Stomach

Large Intestine & Others Small Intestine


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Overview – 4 Stages

Ingestion Digestion

AbsorptionAssimilation

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Lesson objectives:

• Describe the fate of glucose, amino acids and fats inthe blood that leaves the intestines, after a meal.

• Describe the 5 major roles that the liver plays in the

human body – Regulation of blood glucose concentration

– Deamination of amino acids

– Production of bile

–

Detoxication – Iron storage


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Fate of

glucose and

amino acids


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Transport and utilization of absorbed foods

In the Liver!

Types of absorbed food products

Glucose

Amino acids

Fats


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From the small intestines to the

liver! How??

Connected by a

vein called Hepatic

Portal Vein!


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Guess which part the vein connects

to the intestine?

A

B

C

D


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Carbohydrate metabolism

Hepatic portal veintransports sugars like glucose from

the intestines to the liver


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Question!

Receives 5 glucose

molecules from the

intestines

Requires only 3

glucose molecules for

breathing

h l l f l d


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how many molecules of glucose do you

think the liver would transport to the

lungs?

Receives 5 glucose

molecules from the

intestines

Requires only 3

glucose molecules for

breathing


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Liver in Glucose metabolism

Hepatic portal vein


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In the liver….

1. Some glucose carried in the blood to bedistributed to the rest of the body

- Tissue respiration

Carbohydrate metabolism


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In the liver….

-Glucose (excess) Glycogen (stored)Hormone : Insulin

- If the glucose level is too low in the blood

Glycogen (stored) Glucose

Hormone: Glucagon

Insulin and glucagon


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What about the amino acids

absorbed by the small intestines?

Similar route as sugars:

Intestines hepatic portal vein

liver general blood

circulation


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Liver in Protein metabolism

Hepatic portal vein


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Fate of amino acids

Amino acid metabolism

•Converted into

protoplasm•Used for growth

& repair of worn-

out parts•Formation of

enzymes &

hormones

•Excess amino

acids cannot bestored :

Deamination


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Deamination

—N— H

H

C—OH||O

R

|—C—

|

H

Amino group Carbon residue

Ammonia (toxic)

Urea (non-toxic)

glucose

glycogen


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Intestines lacteal lymphatic vessels blood rest

of the body

Fat metabolism

Fate of Fats

• maintenance of cell

membranes

•Production ofhormones

• Excess fats stored in

adipose tissues

When glucose supply is low,

fats will be oxidised in the liver

to provide energy

(Liver not involved)


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Summary:

5 major roles that the liver plays

– Regulation of blood glucose

concentration

–

Deamination of amino acids – Iron storage

– Production of bile

– Detoxication


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True/False

• Liver is part of the alimentary canal


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True/False

• Carbohydrates are digested in the liver


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True/False

• Excess amino acids are deaminated


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True/False

• Fats are absorbed in the liver and

transport to other parts of the body for

usage.

Liver Functions Part II

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Transcript of Liver Functions Part II