Transcript Digestive System
Slide 1
Digestive system
For XII standard
EXIT
Slide 2
Digestive system: Anatomy
Digestive
system
comprises the
alimentary canal,
associated
glands and
regions of
absorption of
food.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 3
Digestive system: Physiology.
Food provides us with fuel to live, energy to work and play,
and the raw materials to build new cells.
All the different varieties of food we eat are broken down by
our digestive system into simple components
and transported to every part of our body by our circulatory system.
Digestive system serves to transfer organic molecules,
salts and water from the external environment to the
body’s internal environment.
Digestion is accomplished by the enzymes produced
from the glands associated with the digestive system.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 4
Digestive system: Physiology.
Digestion in Mouth
In mouth digestion starts with chewing.
Chewing breaks up large pieces of food into smaller
particles that can be swallowed without choking.
It is accompanied by teeth, tongue, jaws and saliva.
Chewing is controlled by the somatic nerves to the skeletal
muscles of mouth and tongue.
Saliva is secreted by 3 pairs of
salivary glands, namely
Parotid gland
Sub lingual gland
Sub mandibular gland
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 5
Digestive system: Physiology.
Daily secretion of saliva ranges from 1000 ml to 1500 ml.
Saliva contains the salivary amylase and Mucin.
Salivary amylase or ptyalin is
an enzyme which converts
cooked starch into maltose.
Mucin is a glycoprotein helps
in the lubrication of food.
The lubricated, swallowable form of food is called the bolus.
Salivary secretion is controlled by reflex activities.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 6
Digestive system: Physiology.
Swallowing
It is a complex reflex process
controlled by the medulla
oblongata.
Oesophageal phase begins with
relaxation of upper oesophageal
sphincter.
In oesophagus the food is moved
towards stomach by a progressive
wave of muscle contraction proceed
downward to the stomach.
During swallowing;
the soft palate is elevated,
larynx gets raised,
Such waves are known as
Peristaltive waves. One peristaltive
wave takes 9 seconds to reach the
stomach.
tongue forces food back into
the pharynx,
the epiglottis closes the
glottis
and the food slowly passes
into the osesophagus.
Due to peristaltive waves, swallowing
can occureven when a person is
upside down.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 7
Digestive system: Physiology.
Digestion in Stomach
During feeding the volume of stomach may
increase up to 1.5 litre.
Stomach’s contractile action will produce peristaltic
waves proceed towards the pyloric region.
In the wall of stomach there are 40 million glands
producing the gastric juice.
The parietal (Oxyntic) cells produce HCl to create
the acidic medium for enzymes.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 8
Digestive system: Physiology.
Digestion in Stomach
Enzymes of stomach are pepsin and renin.
Pepsin is secreted as inactive pepsinogen, which is
converted as active pepsin by the Hydrochloric acid.
Pepsin hydrolyses the proteins into short polypeptides
chains and peptones.
Renin acts on soluble milk protein caesinogen and converts
it into insoluble caesin.
In the presence of ca+ ions caesin is precipitated to
insoluble calcium-caesin compound (curd).
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 9
Digestive system: Physiology.
Digestion in Stomach
(Inactive) pepsinogen + HCl → Pepsin (Active)
Proteins
pepsin
→ polypeptides + peptones.
Caesiongen
Renin
→ caesin.
caesin + ca+ → calcium-caesin
Repeated peristaltic waves in the stomach help to
soften the food.
The food leaves the stomach in the form of chyme and
enters the upper small intestine at periodic intervals
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 10
Slide 11
Digestive system: Physiology.
Digestion in Small intestine
The food in the small intestine is mixed with 3 juices namely
bile juice, pancreatic juice, intestinal juice.
Bile juice: It is a brownish green, alkaline secretion of the
liver and stored in the gall bladder and pored into
duodenum via the bile duct.
Bile salts emulsify fats and helps enzymes like lipase to act upon fats.
Bile salts convert bigger fat particles into smaller fat
globules called chilomicrons.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 12
Digestive system: Physiology.
Digestion in Small intestine
pancreatic juice: It is an alkaline [pH 7-8] fluid transported to
duodenum through the pancreatic duct.
It contains water, mineral salts and enzymes.
Important enzymes are trypsin, chymotrypsin, amylase,
lipase, carboxypeptidase and nuclease.
Proteins + trypsin → polypeptides + peptones.
Proteins
chymopepsin
→ large peptides.
polypeptides Carboxypeptidase → di peptides + tri peptides + fatty acids
Emulsified fat (Tri glycerides)
Starch
Pancreatic Amylase
lipase
→ fatty acids + monoglycerides
→ Maltose
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 13
Digestive system: Physiology.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 14
Digestive system: Physiology.
Digestion in Small intestine
Changes take place in succus entericus
Erypsin converts poly peptide into aminoacids.
Maltase acts on maltose and converts into glucose.
Sucrase (Invertase) acts on sucrose and converts
into glucose and fructose.
Lactase acts on lactose and converts into glucose
and galactose.
Lipase acts on fats and converts into fatty acids and
glycerol.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 15
Digestive system: Physiology.
Absorption and Assimilation
Carbohydrates are broken into Glucose or fructose.
Lipids are broken into glycerol and fatty acids.
Proteins are broken into Amino acids.
Along with this simpler molecules minerals, vitamins,
water etc. are absorbed through the intestinal villi.
Fatty acids absorbed through the lymph vessels. Vitamins by
diffusion process. Glucose by active transport.
From the lumens of the intestine absorbed food constituents are
carried to the liver through the hepatic portal vein.
From the liver food materials are transported to all other regions
of body for utilization.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 16
Digestive system: Physiology.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 17
Digestive system: Physiology.
Absorption and Assimilation
From the lumens of the intestine absorbed food
constituents are carried to the liver through the
hepatic portal vein.
From the liver food materials are transported to
all other regions of body for utilization.
This conversion of food into energy and cellular
organization is called assimilation.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 18
Digestive system: Physiology.
Digestion in Large intestine
Any useful substances in the leftovers, such as spare water and body
minerals, are absorbed through the walls of the large intestine.
The remains are formed into brown, semi-solid faeces, ready to be
removed from the body.
In Rectum and Anus
The end of the large intestine and the next part of the tract,
the rectum, store the faeces.
These are finally squeezed through a ring of muscle, the
anus, and out of the body.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 19
Digestive system: Physiology.
Egestion
The indigestible material is known as roughage.
The removal of faecal material is known as
defecation (or) egestion.
Defaecation takes place through anus
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 20
Digestive system: Physiology.
End
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Digestive system
For XII standard
EXIT
Slide 2
Digestive system: Anatomy
Digestive
system
comprises the
alimentary canal,
associated
glands and
regions of
absorption of
food.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 3
Digestive system: Physiology.
Food provides us with fuel to live, energy to work and play,
and the raw materials to build new cells.
All the different varieties of food we eat are broken down by
our digestive system into simple components
and transported to every part of our body by our circulatory system.
Digestive system serves to transfer organic molecules,
salts and water from the external environment to the
body’s internal environment.
Digestion is accomplished by the enzymes produced
from the glands associated with the digestive system.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 4
Digestive system: Physiology.
Digestion in Mouth
In mouth digestion starts with chewing.
Chewing breaks up large pieces of food into smaller
particles that can be swallowed without choking.
It is accompanied by teeth, tongue, jaws and saliva.
Chewing is controlled by the somatic nerves to the skeletal
muscles of mouth and tongue.
Saliva is secreted by 3 pairs of
salivary glands, namely
Parotid gland
Sub lingual gland
Sub mandibular gland
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 5
Digestive system: Physiology.
Daily secretion of saliva ranges from 1000 ml to 1500 ml.
Saliva contains the salivary amylase and Mucin.
Salivary amylase or ptyalin is
an enzyme which converts
cooked starch into maltose.
Mucin is a glycoprotein helps
in the lubrication of food.
The lubricated, swallowable form of food is called the bolus.
Salivary secretion is controlled by reflex activities.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 6
Digestive system: Physiology.
Swallowing
It is a complex reflex process
controlled by the medulla
oblongata.
Oesophageal phase begins with
relaxation of upper oesophageal
sphincter.
In oesophagus the food is moved
towards stomach by a progressive
wave of muscle contraction proceed
downward to the stomach.
During swallowing;
the soft palate is elevated,
larynx gets raised,
Such waves are known as
Peristaltive waves. One peristaltive
wave takes 9 seconds to reach the
stomach.
tongue forces food back into
the pharynx,
the epiglottis closes the
glottis
and the food slowly passes
into the osesophagus.
Due to peristaltive waves, swallowing
can occureven when a person is
upside down.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 7
Digestive system: Physiology.
Digestion in Stomach
During feeding the volume of stomach may
increase up to 1.5 litre.
Stomach’s contractile action will produce peristaltic
waves proceed towards the pyloric region.
In the wall of stomach there are 40 million glands
producing the gastric juice.
The parietal (Oxyntic) cells produce HCl to create
the acidic medium for enzymes.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 8
Digestive system: Physiology.
Digestion in Stomach
Enzymes of stomach are pepsin and renin.
Pepsin is secreted as inactive pepsinogen, which is
converted as active pepsin by the Hydrochloric acid.
Pepsin hydrolyses the proteins into short polypeptides
chains and peptones.
Renin acts on soluble milk protein caesinogen and converts
it into insoluble caesin.
In the presence of ca+ ions caesin is precipitated to
insoluble calcium-caesin compound (curd).
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 9
Digestive system: Physiology.
Digestion in Stomach
(Inactive) pepsinogen + HCl → Pepsin (Active)
Proteins
pepsin
→ polypeptides + peptones.
Caesiongen
Renin
→ caesin.
caesin + ca+ → calcium-caesin
Repeated peristaltic waves in the stomach help to
soften the food.
The food leaves the stomach in the form of chyme and
enters the upper small intestine at periodic intervals
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 10
Slide 11
Digestive system: Physiology.
Digestion in Small intestine
The food in the small intestine is mixed with 3 juices namely
bile juice, pancreatic juice, intestinal juice.
Bile juice: It is a brownish green, alkaline secretion of the
liver and stored in the gall bladder and pored into
duodenum via the bile duct.
Bile salts emulsify fats and helps enzymes like lipase to act upon fats.
Bile salts convert bigger fat particles into smaller fat
globules called chilomicrons.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 12
Digestive system: Physiology.
Digestion in Small intestine
pancreatic juice: It is an alkaline [pH 7-8] fluid transported to
duodenum through the pancreatic duct.
It contains water, mineral salts and enzymes.
Important enzymes are trypsin, chymotrypsin, amylase,
lipase, carboxypeptidase and nuclease.
Proteins + trypsin → polypeptides + peptones.
Proteins
chymopepsin
→ large peptides.
polypeptides Carboxypeptidase → di peptides + tri peptides + fatty acids
Emulsified fat (Tri glycerides)
Starch
Pancreatic Amylase
lipase
→ fatty acids + monoglycerides
→ Maltose
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 13
Digestive system: Physiology.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 14
Digestive system: Physiology.
Digestion in Small intestine
Changes take place in succus entericus
Erypsin converts poly peptide into aminoacids.
Maltase acts on maltose and converts into glucose.
Sucrase (Invertase) acts on sucrose and converts
into glucose and fructose.
Lactase acts on lactose and converts into glucose
and galactose.
Lipase acts on fats and converts into fatty acids and
glycerol.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 15
Digestive system: Physiology.
Absorption and Assimilation
Carbohydrates are broken into Glucose or fructose.
Lipids are broken into glycerol and fatty acids.
Proteins are broken into Amino acids.
Along with this simpler molecules minerals, vitamins,
water etc. are absorbed through the intestinal villi.
Fatty acids absorbed through the lymph vessels. Vitamins by
diffusion process. Glucose by active transport.
From the lumens of the intestine absorbed food constituents are
carried to the liver through the hepatic portal vein.
From the liver food materials are transported to all other regions
of body for utilization.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 16
Digestive system: Physiology.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 17
Digestive system: Physiology.
Absorption and Assimilation
From the lumens of the intestine absorbed food
constituents are carried to the liver through the
hepatic portal vein.
From the liver food materials are transported to
all other regions of body for utilization.
This conversion of food into energy and cellular
organization is called assimilation.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 18
Digestive system: Physiology.
Digestion in Large intestine
Any useful substances in the leftovers, such as spare water and body
minerals, are absorbed through the walls of the large intestine.
The remains are formed into brown, semi-solid faeces, ready to be
removed from the body.
In Rectum and Anus
The end of the large intestine and the next part of the tract,
the rectum, store the faeces.
These are finally squeezed through a ring of muscle, the
anus, and out of the body.
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 19
Digestive system: Physiology.
Egestion
The indigestible material is known as roughage.
The removal of faecal material is known as
defecation (or) egestion.
Defaecation takes place through anus
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT
Slide 20
Digestive system: Physiology.
End
An illustration from …T. MADHAVAN,
M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..
EXIT