pituitary gland function

Digestive organsFunctions of digestive systemMouthKeeps food between teeth; Foods uniformly chewed during mastication.TeethSolid foods reduced to smaller particles for swallowing.TongueFood maneuvered for mastication.Salivary GlandsSecrete saliva; lining of mouth and pharynx lubricated; Salivary amylase splits starch into smaller fragments.PharynxMoves bolus of food from pharynx into esophagus; closes air passage ways.EsophagusPermits entry of bolus from pharynx into esophagus; pushes bolus down esophagus; permits entry of bolus into stomach; lubricates esophagus for smooth passage of bolus.StomachMaceration of food; Mixes it with gastric juice; reduce food to chime; Kills many microbes in food; Activates Pepsin.PancreasContains enzymes that digest carbohydrates, proteins, triglycerides and nucleic acids.LiverProduces bile; Emulsification and absorption of lipids in small intestine.Gall BladderStores and concentrates bile and releases it into small intestine.Small IntestineMixes chyme with digestive juices; Completes the digestion of carbohydrates, proteins, lipids and nucleic acids; Absorption of 90 % of nutrients and water.Large IntestineDrives the contents of colon into rectum; Absorption of some water, ions and vitamins; defecation.

reactive metals

Reaction with oxygenSulphur's most prominent chemical property is that it burns. When it does so, it gives off a pale blue flame and sulphur dioxide (SO 2 ) gas. Sulphur dioxide has a very obvious strong, choking odor.When heated in air or oxygen, sulphur first melts and then burns with a blue flame to form sulphur dioxide and some traces of sulphur trioxide.Reaction with nonmetalswith hydrogen gas:The compound formed in this reaction is hydrogen sulphide (H 2 S). Hydrogen sulphide has one of the best known odors of all compounds. It smells like rotten eggs. Hydrogen sulphide is added to natural gas (methane) used in homes for cooking and heating. Methane is odorless. So the unique smell of hydrogen sulphide makes it easy to know when there is a methane leak.When hydrogen is passed through boiling sulphur, both hydrogen and sulphur combine to form hydrogen sulphideWith CarbonVapors of sulphur is passed over white-hot charcoal. They combine to form carbon disulphideWith chlorineWhen chlorine is bubbled through boiling sulphur, it forms sulphur monochloride Reaction with acidsSulphur does not react with hydrochloric acid. Dilute sulphuric acid and dilute nitric acid also do not affect sulphur.Reaction with hot concentrated Sulphuric acidWith hot concentrated sulphuric acid d is added to sulphur it oxidises to sulphur dioxide. During the reaction sulphuric acid undergoes thermal decomposition and in the process water, sulphur dioxide and nascent oxygen are formed.Nascent oxygen reacts with sulphur to form additional sulphur dioxide.ORReaction with hot concentrated nitric acidHot concentrated nitric acid oxidises sulphur to sulphuric acid.Sulphur is further oxidised by the nascent oxygen to sulphur trioxide.Sulphur trioxide then combines with water to form sulphuric acid.ORReaction with metalsWith most of the metals the reaction of sulphur is highly exothermic. Sulphur combines with metals under varying conditions of temperature to form the respective sulphides.With mercurySulphur is very reactive with mercury and can combine even at the temperature of liquid air (-200oC). Usually both are rubbed together to make them combine. With sodiumThe reaction of sulphur with sodium is as follows: With IronIron and sulphur combine on heating to form iron (II) sulphide, evolving a large quantity of heat energy. With CopperOn heating to about 400oC, copper combines with sulphur to form cuprous sulphide. If the temperature is above 400oC, then cupric sulphide is formed.With zincThe reaction of sulphur with zinc is as follows:Reaction with oxidizing agentsWhen sulphur is mixed with potassium nitrate, potassium chlorate etc., it forms an explosive mixture. When struck or heated or ignited, the mixture explodes e.g. gun powder.

latent heat of ice

Put equal quantities of crushed ice into two identical filter funnels P and Q (see Fig. 14.5). If the ice has been taken out. of a freezer, it must be left until it attains a temperature of 0 °C and starts to melt. Place an immersion heater connected to an ammeter, voltmeter and rheostat in P, making sure that it is completely covered with ice. At the same time as you switch on the immersion heater, place dry empty beakers of known mass under P and Q. Note the readings of the ammeter and voltmeter, and if necessary adjust the rheostat to keep them constant throughout the experiment. After several minutes, when a reasonable amount of water is in the beaker under P, note the time, remove the beakers and switch off the heater. Find the masses of the beakers and their content.

define mass communication

An artificial satellite revolving in a circular orbit round the earth in the equatorial plane, in the same sense as that of the rotation of the earth and with the same period of revolution as the period of rotation of the earth (i.e. 24 hours or 86400 seconds), is called a communication satellite (Fig. 2.6). Such a satellite always appears stationary from the surface of the earth and hence it is also called a geostationary satellite or a geosynchronous satellite.In order to launch a communication satellite in its orbit, it is first raised to a certain height above the equator and then projected with a certain velocity in the same direction as that of the sense of rotation of the earth. The height and the velocity of the satellite are determined as follows.(1) If r is the radius of the orbit of the satellite, the period (T) of the satellite is given byT = 2n J-; \GMT2 GM' r3 = —...(2.37)AnNow, M = mass of the earth = 5.98 x 1024 kg and G = constant of gravitation = 6.67 x 10"11 Nm2/kg2. For the communication satellite, 7=24 hours = 86400 s. Substituting these values in the above equation, we get(86400J2 x6.67xl0~n x5.98 x 1024^ = 4 x (3.14 J2= 7.55 x 1022r = (7.55 x 1022)1/3 = 4.227 x 107 m = 42.27 x 106 mIf h is the height of the satellite above the surface of the earth and R is the radius of the earth,r = R + hh = r-RNow R = 6400 km = 6.4 x 106 mh =r-R = 42.27 x 106 - 6.4xl06 = 35.87 x 106 m= 35870 km(2) The velocity of projection ( vc) of the satellite is given byIGM lGM~ 16.67 xlO"11 x 5.98 x 1024~ vc= ]lR + h=i= V 4.227 xlO7= 3.072 x 103 m/s = 3.072 km/s The above consideration shows that the height of the communication satellite above the surface of the earth is about 36000 km and its speed is about 3.1 km/s.

organelle functions

Cell Wall           This is the layer that surrounds the plant cell which is made  up of  fibres of cellulose , hemi cellulose,   pectin and proteins.  This outer protective layer is very thick and rigid that provide  strength to the plant body.Cell Membrane             This is the thin layer inner to the cell wall.   It is made up of lipids and proteins that surrounds the cytoplasm  and is semi permeable .Cytoplasm           The plant cell anatomy reveals the appearance of cytoplasm.  It is fluid in which cell organelles like endoplasmic reticulam, golgi apparatus, mitochondria, plastids etc... are distributed  and also acting as the site for various cellular activities.Endoplasmic reticulam:  It is a network of tiny tubular structures  scattered in the cytoplasm acting as a channel for transporting materials.There are two types of endoplasmic reticulam- ribosome bearing -Rough Endoplasmic Reticulam (RER)   and without  ribosome-Smooth Endoplasmic Reticulam(SER).Golgi apparatus-It is  flattened ,disc-shaped sac or cisternae arranged parallel to each other.Its function is packaging and delivery of materials  inside or out side the cells.Lysosomes-They are membrane bound vescicular structures  containing highly active hydrolytic enzymes capable of digesting  carbohydrates,proteins,lipids and  nucleic acids.But found rarely in plant cells..Vacuoles-These are membrane bound organelles containing  water,sap, excretory products and other  useful substances needed  for the cellular activities. Its outer  membrane is called tonoplast.In young plant cells small vacuoles are  present  while the  older plant cells are identified with a big vacuole.Mitochondria-Cylindrical or sausage shaped organelles act as sites for cellular respiration.It is with a  double membrane and the  outer membrane is the smooth  limiting membrane  and inner membrane  form infoldings  called  cristae  in to the  matrix  to increase the surface area for respiration. Here energy is produced in the form of ATP molecules  and stored . Hence they are called  ' power houses' of he cell.It contains a circular DNA  in its matrix.PLASTIDS-Three types of plastids present-chloroplast,chromoplast and leucoplast.Chloroplasts  contain chlorophyll pigments that trap light  energy for photosynthesis. Chromoplasts  are  the plastids   that give colour to the  flowers and other parts.Leucoplasts are the colourless plastids present   in roots.Plastids are also double membraned structures contain the matrix called  stroma in which flattened  membranous  sacs   called thylakoids ,arranged  as stalks called grana.This also contains circular DNA.Ribosomes-Granular structures composed of   RNA and act as sites  for protein synthesis.Cytoskeleton-Plant cell anatomy  shows some proteinaceous filamentous net work in the cytoplasm which provides mechanical support and maintain the shape of the cell.Nucleus--In the study of plant cell anatomy the important  structure locating as the centre for controlling  cellular activities is the nucleus. The nuclear membrane is  double  layered   that  covers  the nucleoplasm which contains  chromatin fibres (chromosomes) and nucleolus.  Chromosomes  are the structures  made up of  DNA  -- the heriditary units.

is one a prime number

            A prime number is a natural number; it means which number is divisible by 1 and itself only. Based on some criteria prime numbers are classified as followings:Twin prime numbers: A pair of prime numbers is given in brackets.Cousin prime numbers: Which prime numbers of a pair differ by digit four is known as cousin prime numbers.Balanced prime numbers: It has a balanced distance to its previous and next prime number.Palindromic prime numbers: the reverse of the prime number is same as the original prime number.Reversible prime numbers: the reversal of one prime number gives another prime number.Permutable prime numbers:  This prime number’s permutation should give a prime.Pythagorean prime numbers: Which number’s square is equal to the sum of square of any two prime numbers. Centered square prime numberMersenne prime numbers

electrical conductivity of metals

The response of a metal to electromagnetic radiation is determined by the frequency dependent conductivity. This in turn depends on the available mechanisms for energy absorption by the conduction electrons at the given frequency. The electronic excitation spectrum in the superconducting state is characterised by an energy gap 2Eg. So we expect the AC conductivity to differ substantially from its normal state form at frequencies small compared with 2Eg Ifi, and to be essentially the same in the superconducting and normal states at frequencies large compared with 2Eg / h. The value of 2Eg /h, is typically in the range between microwave and infrared frequencies. In the superconducting state, an AC behaviour is observed which is indistinguishable from that in the normal state at optical frequencies. Deviations from normal state behaviour first appear in the infrared. At microwave frequencies AC behaviour fully displaying the lack of electronic absorption characteristic of an energy gap becomes completely developed.