6.5 absorption and assimilation of digested food
TRANSCRIPT
Starch +
waterMaltose
Protein+
waterPolypeptide
Caesinogen
+ waterCaesinPeptides
+ waterAmino
acids
Maltose
+ waterGlucose
Sucrose
+ water
Glucose +
Fructose
Lactose + water
Glucose +
Galactose
Lipid +water
Fatty acids
+ glycerol
Starch +
water
maltose
Polypeptide
+ water peptide
Lipid +
water
Fatty acids
+ glycerol
Secretes bile
Stores bile
Secretes pancreatic juices
Salivary
amylase
Pepsin
pH 2.0
RenninErepsin
pH 7.5
Maltase
Sucrase
Lactase
Lipase
Pancreatic
amylase
Trypsin
Lipase
Cud (chewed and
reswallowed)
• Largest part of the stomach
• Mutualistic microorganisms secrete
cellulase to digest cellulose Water is removed from cud
• True stomach
• Gastric juice
secreted
• Digestion of
proteins
Digestion of Cellulose by a Ruminant
Microorganisms secrete
cellulase to digest
cellulose
Glucose
Amino acids
Fatty acids
+ glycerol,
Vitamins A,
D, E and K
Structure of a villus
LOCATION
• Assimilation takes place in the cells (digestion takes place in the alimentary canal)
• Simpler form of nutrient is used to form complex compounds or structural components
• Liver acts as checkpoint and control centre for the release of appropriate amount of nutrients in the circulatory system.
ASSIMILATION OF GLUCOSE
• Most of glucose is converted into glycogen and
stored in the liver.
• Glycogen will be converted to sugar when the body
needs energy
• Glucose is distributed throughout the body by
circulatory system.
• Cells oxidise glucose to release energy during
cellular respiration.
ASSIMILATION OF GLUCOSE
• Excess of glucose is
converted into lipids by
the liver.
ASSIMILATION OF AMINO ACIDS
• Amino acids have to pass through the liver before
they reach blood circulatory system
• Amino acids are used to synthesized plasma
proteins.
• Function of plasma proteins: blood clotting and
osmoregulation
• When there are short supply of glucose, amino acids
are converted to glucose by the liver through
gluconeogenesis process.
ASSIMILATION OF AMINO ACIDS
• Amino acids that enter the cell are used for
synthesizing protoplasm and repair the damaged
tissue.
• Amino acids are also important blocks to synthesis
hormones and enzymes.
• Excess of amino acids will be broken by deamination
process. The waste product of this process is
commonly the urea.
• Urea is transported to the kidneys and secreted out
through urine.
LIPIDS• Lipids such as fats
represent the major energy
store of the body
• Excess lipids are stored in
the adipose tissue.
• Some lipids; ex:
phospholipids and
cholesterol are major
components of plasma
membranes
OTHER FUNCTION OF LIVER
• Liver acts as the detoxicification site
• In this process, the liver removes harmful
substances from blood and convert them to less
toxidic compounds.
• The detoxicification products are eliminated from the
body through bile or urine.
Glucose – for cellular respiration
Amino – synthesis of hormones, plasma acidsmembranes, enzymes
Glucose - respiration
Excess glucose – glycogen
Amino acids – plasma protein
Excess amino acids - urea
Formation of Faeces and Defaecation
• Reabsorbs water and minerals
• Elimates undigested food
• Escherichia coli are found
• Secretes mucus to bind faeces and
lubricates movement of feaces
along the colon
• Temporary storage of faeces
Faeces is expelled from here when
the rectum is full, contraction of the
muscles of the rectum propels the
faeces out