https://youtu.be/TEhEAkH6dYE
DIGESTIVE SYSTEM NOTES
1.parts of digestive system in humans are
Buccal cavity
Pharynx
Oesophagus
Stomach
Duodenum (liver and pancreas open here)
Small intestine
Large intestine
Rectum
Anus
2.Buccal cavity
Space inside mouth is called buccal cavity
A.consists of
tongue ,
teeth ,
salivary glands and
saliva
B.tongue
helps in swallowing,speech, and taste
Swallowing scientifically called deglutition
C.teeth
helps in mastication(chewing food)
D.salivary glands
They are 3 in number secret saliva
They are submaxillary
Sub mandibular
Parotid glands
E.saliva
Saliva has enzyme PTYALIN or salivary amylase
Salivary amylase converts cooked starch in food to maltose
Conclusion is digestion begins in buccal cavity itself with help of saliva
2.pharynx
It is common passage for both food and air and water
3.oesophagus
It shows PERISTALTIC MOVEMENTS
Which is rhythmatic contraction and relaxation of oesophagus
Which help food to pass in one direction only to stomach
Reverse peristalsis only occurs during vomiting which is under control of brain.
4.STOMACH
It is j shaped structure
Food is stored here for 3 to 4 hrs
Slowly released into duodenum
Stomach has many folds called RUGAE
they help in expansion and contraction of stomach according to food intake
Stomach has mucosal lining which prevents self digestion of stomach
The secretions of stomach are called as
GASTIRC JUICE
Gastric juice consists of HCL and enzymes
Two important functions of stomach are
It help in release of HCL and enzymes
Hcl functions are
A.kills microbes in food
B.activates enzyme pepsinogen to pepsin
And
other function of stomach is
Stomach has 3 important enzymes
Pepsin
Renin
Lipase.
Pepsin helps in digestion of proteins
Renin helps in digestion of milk protein
Lipase helps in digestion of fats
Two sphincter muscles are present
Cardiac sphincter
Pyloric sphincter
Sphincter muscles helps in
One way passage of food
4.DUODENUM
first part of small intestine is duodenum
Duodenum releases sodium and potassium ions
As they are metal ions
Metals are basic
Neutralise acidic food coming from stomach
Duodenum itself dont release any enzymes
But liver and pancreas ducts opens into duodenum
5.LIVER
2imp function of bile
A.neutralise acidic food
B.emulsification of fats
Liver us largest gland in body
Liver secretes BILE JUICE
Bile JUICE consists of
Bile salts and bile pigments
Bile salts are sodium and potassium glycocholates and tarchocholates which help in making food alkaline
Bile pigments are bilirubin and biliverdin.
Which are formed by break down of blood.
Liver secretes bile JUICE into gall bladder
Gall bladder concentrates bilejuice
By removing water in bile juice
And scrtes bile JUICE into duodenum
Through bile duct
6.pancreas
Pancreas is dual gland
Acts as both exocrine and endocrine glands
Endocrine because
It secretes harmones
Exocrine because
It release enzymes
Trypsin
Amylase
Lipase
Trypsin digest proteins
Amylase digest carbohydrates
Lipase digests fats
Pancreas release pancreatic juice
Through pancreatic duct
Into duodenum
7.illeum and jejunum
These are other 2 parts of small intestine
In small intestine complete digestion takes place
Digested food is absorbed by finger pike structures called VILLI
villi absorb digested food and gives it to blood
Blood gives digested food to all cells of the body
In each cell food is oxidized in mitochondria
Mitochondria is power house of cell
Mitochondria release energy ,co2 and water
Energy in the form of ATP
it is used in doing metabolic activities
8.caecum and appendix
First segment of large intestine is caecum
Rudimentary appendage called appendix is present at junction of caecum
Appendix is vestigial in humans
But useful in lower organisms for digesting cellulose present in grass
9.large intestine
Main function of large intestine is to absorb water from undigested food
10.rectum
All undigested and waste matter get settled in rectum
11.anus
Waste excreta is passed out through anus
Passing out waste is called DAFEACATION
12.this is how digestion takes place
Enzymes acts as bio catalysts which enhance speed of digestion
After digestion
Carbohydrates are converted to glucose
Fats are converted to fatty acids and glycerol
Proteins are converted to amino acids
Glucose is stored in body glycogen
Glycogen is also often called as ANIMAL STARCH
during starvation stored glycogen again gets converted to glucose and gives instant energy
1.parts of digestive system in humans are
Buccal cavity
Pharynx
Oesophagus
Stomach
Duodenum (liver and pancreas open here)
Small intestine
Large intestine
Rectum
Anus
2.Buccal cavity
Space inside mouth is called buccal cavity
A.consists of
tongue ,
teeth ,
salivary glands and
saliva
B.tongue
helps in swallowing,speech, and taste
Swallowing scientifically called deglutition
C.teeth
helps in mastication(chewing food)
D.salivary glands
They are 3 in number secret saliva
They are submaxillary
Sub mandibular
Parotid glands
E.saliva
Saliva has enzyme PTYALIN or salivary amylase
Salivary amylase converts cooked starch in food to maltose
Conclusion is digestion begins in buccal cavity itself with help of saliva
2.pharynx
It is common passage for both food and air and water
3.oesophagus
It shows PERISTALTIC MOVEMENTS
Which is rhythmatic contraction and relaxation of oesophagus
Which help food to pass in one direction only to stomach
Reverse peristalsis only occurs during vomiting which is under control of brain.
4.STOMACH
It is j shaped structure
Food is stored here for 3 to 4 hrs
Slowly released into duodenum
Stomach has many folds called RUGAE
they help in expansion and contraction of stomach according to food intake
Stomach has mucosal lining which prevents self digestion of stomach
The secretions of stomach are called as
GASTIRC JUICE
Gastric juice consists of HCL and enzymes
Two important functions of stomach are
It help in release of HCL and enzymes
Hcl functions are
A.kills microbes in food
B.activates enzyme pepsinogen to pepsin
And
other function of stomach is
Stomach has 3 important enzymes
Pepsin
Renin
Lipase.
Pepsin helps in digestion of proteins
Renin helps in digestion of milk protein
Lipase helps in digestion of fats
Two sphincter muscles are present
Cardiac sphincter
Pyloric sphincter
Sphincter muscles helps in
One way passage of food
4.DUODENUM
first part of small intestine is duodenum
Duodenum releases sodium and potassium ions
As they are metal ions
Metals are basic
Neutralise acidic food coming from stomach
Duodenum itself dont release any enzymes
But liver and pancreas ducts opens into duodenum
5.LIVER
2imp function of bile
A.neutralise acidic food
B.emulsification of fats
Liver us largest gland in body
Liver secretes BILE JUICE
Bile JUICE consists of
Bile salts and bile pigments
Bile salts are sodium and potassium glycocholates and tarchocholates which help in making food alkaline
Bile pigments are bilirubin and biliverdin.
Which are formed by break down of blood.
Liver secretes bile JUICE into gall bladder
Gall bladder concentrates bilejuice
By removing water in bile juice
And scrtes bile JUICE into duodenum
Through bile duct
6.pancreas
Pancreas is dual gland
Acts as both exocrine and endocrine glands
Endocrine because
It secretes harmones
Exocrine because
It release enzymes
Trypsin
Amylase
Lipase
Trypsin digest proteins
Amylase digest carbohydrates
Lipase digests fats
Pancreas release pancreatic juice
Through pancreatic duct
Into duodenum
7.illeum and jejunum
These are other 2 parts of small intestine
In small intestine complete digestion takes place
Digested food is absorbed by finger pike structures called VILLI
villi absorb digested food and gives it to blood
Blood gives digested food to all cells of the body
In each cell food is oxidized in mitochondria
Mitochondria is power house of cell
Mitochondria release energy ,co2 and water
Energy in the form of ATP
it is used in doing metabolic activities
8.caecum and appendix
First segment of large intestine is caecum
Rudimentary appendage called appendix is present at junction of caecum
Appendix is vestigial in humans
But useful in lower organisms for digesting cellulose present in grass
9.large intestine
Main function of large intestine is to absorb water from undigested food
10.rectum
All undigested and waste matter get settled in rectum
11.anus
Waste excreta is passed out through anus
Passing out waste is called DAFEACATION
12.this is how digestion takes place
Enzymes acts as bio catalysts which enhance speed of digestion
After digestion
Carbohydrates are converted to glucose
Fats are converted to fatty acids and glycerol
Proteins are converted to amino acids
Glucose is stored in body glycogen
Glycogen is also often called as ANIMAL STARCH
during starvation stored glycogen again gets converted to glucose and gives instant energy
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