Describe the structure of the villus in small intestines and its role.

Describe the role of capillaries and lacteals in absorption.

Station 1 (15 mins):

Experiment on Absorption of Digested Food

Station 2 (15 mins):

Tablet PC

& Case Study

Doc, I have recently gotten back my blood test. The results show

that I have been diagnosed with coeliac disease.

Coeliac disease is a a digestive disease that

damages the villi in the small intestines.

Surface area to volume ratio for absorption will

decrease.

Lack of nutrients will be taken into

the body

Weight loss?

May suffer from deficiencies in iron, vitamins

and other nutrients.

Easily tired?

Osteoporosis?

Adaptions of Villi in Small Intestines

• Villi provide efficient absorption surface by having:

(1) rich supply of blood capillaries

(transporting amino acids, simple sugars, vitamins, mineral salts) and lymphatic capillaries (fats & fat-soluble vitamins).

2) thin membrane of epithelium. ( 1 cell thick )

3) moist and large surface area of villi bearing numerous microvilli.

4) continual transport of digested substances help to maintain diffusion gradient for absorption.

• Nutrients are taken into the body cells by diffusing into the blood capillaries in villi and circulated via the bloodstream to other parts of the body.

Absorption of glucose and amino

acids:

Read up your textbook page 105 – 108 on the function of liver.

Assimilation:

• Transport and utilization of nutrients.

• Nutrients are transported to liver through hepatic portal vein for processing, storage and distribution to other body parts.

Small Intestines Hepatic Portal Vein Liver

Liver functions in Digestion & Assimilation

• Production of bile.• Food Storage:(i) Regulate blood glucose concentration: Glucose (after meal): Store glycogen with

the help of hormone insulin released from pancreas.

Glucose (starving): Convert glycogen back to glucose.

(ii) Vitamins(A, B, D), minerals copper and potassium, as well as iron to make red blood cells.

• Heat Production by liver is carried around body to keep warm.

• Chemical Factory:(i) Detoxification of harmful substances

(alcohol, medications, micro-organisms, fats) absorbed into blood stream from gut.

(ii) Synthesis of proteins ( e.g fibrinogen for clotting blood, albumins)

(iii) Deamination of excess amino acids form to be excreted as urea.

• Which of these diagrams represent a healthy liver?

• What are the consequences of a fatty liver?

Ans: Liver is not able to filter and cleanse the blood stream efficiently and the blood stream will become overloaded with toxins and fat.

What happened to the excess amino acids

in our body?

Excess A.A

Ammonia Carbohydrate

Urea

Deamination by liver

+ CO2

Glycogen

stored as

EXCRETION

Ans:________________________________