ppt on digestive system

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PRESENTATION ON DIGESTIVE SYSTEM...
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(No Transcript)
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DIGESTION

• Phases Include
• Ingestion
• Movement
• Mechanical and Chemical Digestion
• Absorption
• Elimination

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TWO TYPE OF DIGESTION

• 1. Mechanical (physical)
• Chew
• Tear
• Grind
• Mash
• Mix
• 2. Chemical
• Enzymatic reactions to improve digestion of
• Carbohydrates
• Proteins
• Lipids

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DIGESTIVE SYSTEM ORAGNISATION
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1. MOUTH

• Teeth mechanically break down food into small
  pieces. Tongue mixes food with saliva (contains
  amylase, which helps break down starch).
• Epiglottis is a flap-like structure at the back
  of the throat that closes over the trachea
  preventing food from entering it. It is located
  in the Pharynx.

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Structure of mouth
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2. ESOPHAGUS

• Approximately 25cm long.
• Functions include -
• Adds mucus to food.
• Moves food from the throat to the stomach
  using muscle movement called peristalsis.
• If acid from the stomach gets in here
  thats heartburn.

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Movement of food esophagus
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3. STOMACH

• The stomach is wide J shaped muscular sac
  present on left side of the abdomen.
• Partially digested food reaches into the stomach
  from buccal cavity through pharynx and esophagus.
  
• Then the digestion of food takes place in
  stomach.

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• Mechanical churning of food
• Wall of the stomach undergoes
  periodic muscular contraction so that the
  food gets churned and mixes thoroughly with
  the gastric juice.

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• Partial digestion
• Stomach posses branched and tubular
  glands present on the inner surface of its
  wall. There are three types of glands which
  secrete hydrochloric acid protein digesting
  enzyme and mucus . All these secretions are
  collectively called gastric juice. The
  hydrochloric acid makes the medium acidic.
  Protein - digesting enzyme pepsin acts in
  acidic which breaks down the proteins into
  peptones. Gastric lipase which partially
  breaks down lipids. The gastric juice can
  also be secreted in the stomach by sight ,
  smell or thought of appetizing food.

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• The stomach serves four main functions -
  
• 1) Storage of food
• The food is stored in the stomach
  for variable duration. Carbohydrates continue
  to get digested food till the salivary
  enzyme ptyalin is destroyed by the HCl acid
  secreted in the stomach. Storage of food
  in stomach enables us to take food at
  intervals.

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• 4) Regulation of the flow of food into the small
  intestine The stomach regulates the flow
  of partially digested food into small
  intestine.

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STOMACH
Secretes mucus , HCl , gastric enzyme

• Gastric enzyme breakdown into lipids
• Sucrose glucose fructose
• Protein peptones
• Casein coagulates into
  insoluble
• calcium
  salts. Calcium
• 
  paracaesinate.

pepsin
rennin
pepsin
Peptone calcium

• Fat water fatty acids glycerol

lipase
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4. liver

• It produces bile.
• It stores as glycogen and breaks down glycogen to
  glucose.

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5. GALL BLADDER

• It stores bile juice secreted by liver .
• It emulsifies fat .
• Bile juice contains bile pigment , bile
  salts but no digestive enzyme . Bile juice
  neutralises the acidity of food to make it
  alkaline for the action of enzyme present
  in pancreatic juice .

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LOCATON OF GALL BLADDER
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6.PANCREAS

• Alpha cells produce glucagon hormone which
  converts glycogen into glucose in the liver.
• Beta cells produce insulin hormone which
  converts glycogen in liver and muscles.
• Delta cells secrete somatostain hormone .
• Pancreatic juice contains digestive enzymes like
  trypsin , amylase , and lipase.

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Location of pancreas
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7. Small Intestine

• Small intestines are roughly 7 meters long.
• Lining of intestine walls has finger - like
  projections called villi , to increase
  surface area.
• The villi are covered in microvilli which
  further increases surface area for
  absorption.

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• Nutrients from the food pass into the bloodstream
  through the small intestine walls.
• Absorbs
• 80 ingested water
• Vitamins
• Minerals
• Carbohydrates
• Proteins
• Lipids

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• Secretes intestinal juice enzymes which
  contains seven -
• Carbohydrases
• Two proteases
• Enterokinase
• Intestinal liphase
• Nucleic acid digesting enzymes
• Mucus
• Carbonates and water

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LOCATION OF SMALL INTESTINE
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maltase

• Maltose

Glucose
sucrase

• Sucrose

Glucose Fructose
lactase

• Lactose

Glucose Galactose

• Peptides
• dipeptides

Amino acids

• Nucleic
• acid

Nucleotides
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8. LARGE INTESTINE

• It arranged around the mass of small intestine in
  the form of question mark ( ? ) .
• It lacks villi but secretes mucus .
• The colon is followed by about 15 to 20 cm long
  vertical column called rectum .
• It has longitudinal folds and large blood vessels
  .
• The undigested food is collected as faeces in the
  rectum.

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• The rectum leads through 2 to 5 cm long canal to
  the exterior at anus .
• The faecal matter is egested out through canal
  opening by the activity of anal sphincter.

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Structure of large intestine
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Thank you
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Made by - Shruti Sahu X C