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ELECTRICAL MEASURING INSTRUMENTS For the detection or measurement of electric current, potential difference, and resistance certain instruments have been devised viz. The galvanometer for the detection of small currents measurements of small currents of the order of micro amperes or mili amperes the voltmeter or potentiometer for the measurement of potential difference (and voltage) between two points of a circuit are the EMF of a source the ammeter for the measurement of large currents the wheatstone bridge the meter Bridge the post office box and the ohmmeter for the measurement of resistance. THE MOVING COIL GALVANOMETER The moving coil galvanometer is a basic electrical instrument it is used for the detection (and Measurement) of small currents. Its underlying principle is the fact that when a current flows in a rectangular coil placed in a magnetic field it experiences a magnetic torque. If it is free to rotate under a controlling torque, it rotates through an angle proportional t...
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DIGESTION OF FOOD

The food of animals and men consists of complex organic substances such as carbohydrate, fats, proteins etc. Theses substances as such cannot be absorbed by cells hence it is necessary that our body mechanism must change these complex molecules into simple absorbable by cells hence it is necessary that our body mechanism must change these complex molecules into simple absorbable form.

DIGESTION :

It is the process of breaking down of food mechanically and chemically into simple water soluble units, suitable of being absorbed into the body fluids.

            In man digestion and absorption of food occur in the alimentary canal which is about 9 meter long.The digestion is extracellular within the gut cavity and mainly is the enzymatic hydrolysis of food.

           Different parts of alimentary canal perform their specific action in digestion as follows:

(a) DIGESTION IN MOUTH (BUCCAL DIGESTION):- 

The digestion of man starts in moth.Mastication and chewing of food by teeth break the food into smaller particles and the tongue blends them.SALIVARY GLANDS in buccal cavity are stimulated by sight, smell and taste of food,which secrete saliva.It is slightly alkaline fluid containing 90% water, a lubricant MUCIN and enzymes AMYLASE  also called PTYALIN,

The saliva performs the following functions:

(i) It lubricates the food
(ii) Its enzymes PTYALIN  hydrolysis starch to maltose.

Starch ------------- > Maltose 

No digestion of lipid and protein occurs in mouth.The action of tongue and cheeks mould the food into a ball (the bolus) and pushes it towards pharynx from where it is swallowed into the aesophagus ,The food moves down the aesophagus by peristalsis towards the stomach.

(b) DIGESTION IN STOMACH (GASTRIC DIGESTION) :-

The stomach is the first region of gut where any significant digestion of food takes place.

It is a muscular bag with inner folded membrane called GASTRIC MUCOSA which secretes GASTRIC JUICES which contain:
(i) 0.5% HCl
(ii) Enzymes 

(a) Inactive PEPSINOGEN which is
(b) Gastric LYPASE
(c) RENIN only in young children

(iii) Lunricant MUCIN it lubricates gastric mucosa and prevents it from corrosive action HCl.

Hydrochloric acid performs the following functions:

(a) It provides necessary pH (1 to 2) for enzyme action.

(b) It acts as a antiseptic enzyme, PEPSINOGEN to its active form,PEPSIN.

(c) It changes inactive enzyme, PEPSINOGEN to its active form, PEPSIN.

(d) It dissolves collagen, splits nucleoproteins and some other complex molecules and makes the food soft.

DIGESTIVE ACTION OF GASTRIC JUICE:-

Except for a limited hydrolysis of sucrose, no major digestion of carbohydrates takes place in stomach.Enzyme lypase acts upon small amount of lipids to produce saturated fatty acids and glycerine.Due to low pH, Lypase can not play any important role in hydrolysis of fat.

Enzyme PEPSIN commences the breakdown of protein into simple proteins i.e Proteoses and peptones called peptides.

Protein + H2O + Proteoses + Peptones 

RENIN is active in stomach of babies.It changes soluble milk protein CASEINOGEN into insoluble curd protein, CASEIN which then combines with calcium ion (Ca2+) in milk to form insoluble semisolid CALCIUM CASEINATE.It is then converted to POLYPEPTIDE by the action of PEPSIN.

The churning movements of the wall of stomach thoroughly mixes the food with gastric juice and changes it into a semi liquid form called CHYME which gradually enters the duodenum.The chyme is periodically allowed to live the stomach by way of pyloric sphincter muscles.

 

(c) DIGESTION IN SMALL INTESTINE : INTESTINAL DIGESTION :-

Duodenum is the first part of small intestine,It is the main seat of digestion It receives three digestive juices.

  1. BILE from liver 
  2. Pancreatic Juice 
  3. SUCCUS Entericus from the duodenum walls




    

Hope you will understand after reading this article :

Digestive system process
Digestive system organs and function
Human digestive system parts and functions
Digestion in the stomach
Digestion in the small intestine
Which type of food is digested in the stomach?
Food digestion process
Digestion definition
what is digestion in biology ?
what is chemical digestion in biology ?
What is digestion ?





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