CHAPTER 6 - NUTRITION

6.5 - THE PROCESSES OF ABSORRTION AND ASSIMILATION OF DIGESTED FOOD

Absorption of digested food in small intestine

In ileum, 2 processes occur : Digestion Absorption

Process of digestion is completed in the ileum to produce simple sugars ( ______, _______ and _______) amino acids Glycerol and fatty acids

Process of absorption (occur in ileum) – to absorb the products of digestion into the blood capillaries and to be used bt the cells in the body

Absorption of digested food in small intestine

Finger-like projection (villi)

Products of digestion = absorbed into body by small finger-like projections called villi (singular : villus)

Absorption of digested food in small intestine

Villus Structure in the

walls of small intestine

Villus contains: Networks of blood

capillaries Lymphatic vessel

called lacteal ( center of the villus)

Villus Adaptation of small intestine to aid absorption

Long and coiled – increase the surface area for absorption

Lining of the intestine is folded – increase the surface area for absorption

Epithelial cells lining the villus is very thin – to facilitated of digested food.

Many villi and microvilli to increase the surface area for absorption

Each villus has network of blood capillaries – to transported digested food that has been absorbed

Villus has lacteal to transport glycerol and f.a

Structure of villusVillus

Blood capillaries Lacteal

• Glucose • amino acid• minerals• vitamin B and C

Carried by hepatic portal vein to liver(distributed to body cell by circulatory system

Via simple diffusion through epithelium of the villus

Diffuse across thin epithelial of villus

• fatty acids• glycerol• vitamins A, D, E and K

Carried by thoracic duct into blood stream via the left shoulder vein liver(distributed to body cell by circulatory system

absorb absorb

Absorption of Water and Minerals in Colon Large intestine consists of :

Caecum = part where small intestine joins with large intestine

Colon = longer part of large intestine Rectum = the last part of large intestine

Intestinal contents (has not been absorbed in ileum) pass into caecum to colon

Colon absorb much of the water from indigestible food residue become more solid as it passes along.

Colon absorb : 90% water and mineral

Absorption of Water and Minerals in Colon

Label the villus

Answer

Assimilation Process where the products of

digestion are utilised in the body cell to form complex compounds or structural components.

Glucose – oxidised in body cells during respiration to produce energy

Excess glucose converted to glycogen and stored in the liver and muscles.

Assimilation Amino acids – synthesise various proteins

such as enzymes, antibody, plasma membrane and protoplasm.

Excess a.a – broken down in the liver and converted into urea(urine)

Lipids(fats droplets) – to build plasma membrane and cholesterol

Excess lipid- stored as adipose tissue below skin, abdomen and around internal organ.

Assimilation Mineral – calcium- strong bones and

teeth Iron – synthesise hemoglobin in r.b.c

Liver Largest gland Carries out assimilation and acts as

storage organ Receives the products of digestion

dissolved in the blood via hepatic portal vein

Main fx of liver: Storage nutrient – glycogen, fat, iron Processing the products of digestion-

convert excess glucose to glycogen and vice versa

Liver Fx:

Detoxcification- toxic substances –alcohol and drugs into less toxic in body. The product of detoxcification excreted in urine.

Breaks down of lipids in storage to provide energy

Production of bile Removal of damaged rbc Synthesise vita A and blood clotting

substances