Learning with Mixture

SEPARATING LIQUID/LIQUID MIXTURES
Oil and water do not mix easily. They are said to be immiscible
1.LIQUIDS WHICH ARE MISCIBLE
If miscible liquids are to be separated, then this can be done by fractional distillation. Fractional distillation relies upon the liquids having different boiling points. When an ethanol and water mixture is heated,the vapours of ethanol and water boil off at different temperatures and can be condensed and collected separately. Ethanol boils at 78 °C whereas water boils at 100 °C. When the mixture is heated the vapour produced is mainly ethanol with some steam. Because water has the higher boiling point of the two, it condenses out from the mixture with ethanol. This is what takes place in the fractionating column. :The water condenses and drips back into the flask while the ethanol vapour moves up the column and into the condenser, where it condenses into liquid ethanol and is collected in the receiving flask as the distillate. When all the ethanol has distilled over, the temperature reading on the thermometer rises steadily to 100 °C, showing that the steam is now entering the condenser. At this point the receiver can be changed and the condensing water can now be collected.
2.LIQUIDS WHICH ARE IMMISCIBLE
If two liquids are immiscible they can be separated using a separating funnel. The mixture is poured into the funnel and the layers allowed to separate...The lower layer can then be run off by opening the tap.

Villi
Cells lining glands called the crypts of Lieberkuhn in the walls of the duodenum also secrete a number of enzymes collectively called the succusentericus:
A. lipase catalyses the hydrolysis of lipids to fatty acids and glycerol
B. maltase catalyses the hydrolysis of maltose to glucose
C. lactase catalyses the hydrolysis of lactose to glucose and galactose
D. sucrase catalyses the hydrolysis of sucrose to glucose and fructose
E.enterokinase converts trypsinogen to trypsina peptidase catalyses the hydrolysis of peptides to amino acids.
The enzymes released into the small intestine do not digest the intestine wall, which is made of proteins and lipids, because the wall has special-mucus secreting cells. The mucus protects the lining of the small intestine.
Also, the enzymes are only secreted when food is present.Absorption in the small intestine
Absorption is the process by which the small soluble molecules produce by the digestion of food enter the blood and lymph from the lumen of the gut. Absorption takes place mainly in the ileum, which is adapted to the function in several ways:
l. It is the longest part of the gut, ensuring that most of the soluble food are absorbed.
2. It has an inner surface folded into thousands of microscopic flnger-like projections called villi. These produce an enormous surface area for the absorption of the products of digestion. The villi are in constant motion. Each slowly contracts and expands

Biology 🍰🍞🍞🥯🤰👀👻🗣️
The small intestine
The small intestine, at 7 m long in humans, is the longest part of the ali-mentary canal. It is divided into two sections: the duodenum, the first 25cm, and the ileum.In the small intestine, the digestion of proteins, starch and lipids is completed. The duodenum secretes a hormone secretin, which in turn triggers the gall bladder to eject stored bile, made by the liver, and the pancreas to secrete pancreatic juice. These enter the duodenum through a duct. Bile is an alkaline green watery fluid which contains: *inorganic salts, mainly sodium hydrogencarbonate, which neutralise the acidic chyme coming from the stomach
*organic salts, which emulsify lipids, breaking them into small droplets;this emulsiflcation increases the surface area on which lipid-digesting enzymes can work
*no enzymes
Pancreatic juice is also an alkaline fluid with a pH of 7-8. It contains:
1.sodium hydrogencarbonate to neutralise the acidic chymea
2. Pancreatic amylase, which catalyses the hydrolysis of starch to maltose
3. Trypsin, a protease, secreted as an inactive molecule, trypsinogen.which catalyses the hydrolysis of proteins to peptides
4. Lipase, which catalyses the hydrolysis of lipids to fatty acids and glyc-erol.

The human gut🤰🤰🤰
The human gut consists of a number of discrete parts, each adapted to perform a particular function.
The mouth cavity🗣️🗣️🗣️👅👅👄👄
The mouth or buccal cavity contains the teeth, tongue and salivary glands. Food is chewed in the mouth (masticated) breaking the large food particles into smaller pieces (mechanical digestion). Food is also mixed with saliva produced by three pairs of salivary glands. Saliva:
* moistens food, dissolving soluble food molecules such as glucose
* contains mucin, important in lubricating the food so it can be swallowed easily
* contains an enzyme called salivary amylase or ptyalin, which starts the digestion of starch to maltose
* contains salts, such as sodium hydrogencarbonate, which act as a buffer,providing a very slightly alkaline pH in the mouth
Swallowing😋😋😋🦷
After chewing, a sausage-shaped bolus of food is formed by the tongue.This is then swallowed and enters the oesophagus, a muscular tube which runs from the mouth to the stomach. Swallowing is a reflex action - it occurs without being under voluntary control. As the food is swallowed, a flap of tissue called the epiglottis seals the trachea, preventing food from entering, the lungs.
The oesophagus 👻👻👻
It contains two layers of stnooth muscles, a circular and a longitudinal layer. Contraction of the circular muscle layer behind the Ioad forces it down the oesophagus. The same sorts of contractions, called peristalsis, produced by these two layers of muscle are responsible for moving food through the whole of the alimentary canal.Starch digestion continues in the oesophagus until the food enters the stomach.