CHAPTER – 1
HOMEOSTATIS
Definition
Home means same and statis means
state. So the regulatory mechanism which maintained the internal environment of
a organism is called homeostatis.
Important Aspects of Homeostatis
There are three important aspects of homeostatis.
Osmoregulation
Thermoregulation
Excretion
Thermoregulation
Excretion
Feed Back System
The check and balance system in a body is called feed back
system. In a feed back system three organs are involved.
1.
Receptor
The organ which receive any change in the internal environment
of the body are called Receptor.
2.
Effector
The central nervous system which send the message to a
particular organ are called effector. Take part in particular action.
3. Central
Nervous System
The receptor transfer message to a central nervous system such
as brain.
Types of Feed Back System
There are two type of feed back system.
Positive Feed Back System
Negative Feed Back System
1.
Positive Feed Back System
When there is a change in the internal environment and it is
further increase by the process are called positive feed back system.
2.
Negative Feed Back System
When there is a change in the internal environment and it is
further decreased by the process called negative feed back system.
Osmoregulation
Definition
The regulatory mechanism which
maintain the balance between water and solute context of a cell is called
osmoregulation.
Osmoregulation in Plant
Due to the availability of water there are four groups of plant.
Hydrophyte
Halophyte
Xerophyte
Mesophyte
Hydrophyte
The group of plant which is grow in fresh water are called
hydrophyte.
Characteristic
of Hydrophyte
§ The plant do not have layer of cuticle.
§ The leave have stomata in the upper surface with take part in
transpiration.
§ The root are either absent or poorly developed.
Example
Hydrilla, Lotus, Lily plant
Halophytes
The group of plant which is grow in marshy soil or salty soil
are called halophyte.
Characteristic
of Halophyte
§ These plant absorb water from such a soil, which is higher salt
concentration and low water potential.
§ Halophyte actively absorption salt into their roots.
§ In the leaves of plants salt glands are present which helps in
the removal of salt and water from the body.
§ Some halophytes absorb humidity by leave.
Example
Glass wort, Cord grass
Glass wort, Cord grass
Mesophyte
The group of plant which is grow in well watered soil are called
mesophyte.
Characteristics
of Mesophyte
§ Their roots are well developed.
§ Their body is covered by a layer called cuticle.
§ They contain stomata for evaporation of extra water.
§ Some mesophyte excrete out water in the form of drop this
process is called guttation.
Xerophyte
The group of plant which is grow in dry places such as desert are called Xerophyte.
The group of plant which is grow in dry places such as desert are called Xerophyte.
Characteristic
of Xerophyte
§ Some plants do not face dry consition and produce seed are
called ephemeral plant. During raining season seeds germinate.
§ Their root are well develop which go deep into the soil to
absorb water.
§ Some plant have horizontal root on the surface to absorb rain
water rapidly.
§ Some plant leaves are modified into spine to prevent
transpiration.
§ Stem and leave covered by cuticle.
§ Some plant store water in cell (succulent)
Example
Cacuts, Euphorbia.
Cacuts, Euphorbia.
EXCRETION
Definition
The removal of harmful substance
produce in the metabolic process from the body is called Excretion.
Excretion in Plant
In plant rate of catabolic process is very slow and waste
product are produce in less amount. They are used again in their anabolic
process.
Waste Substance of Plant
The substance which are produce in excess amount are
§ Water
§ CO2 and O2
§ Ions
Removal of Water
Extra water is removed from the body of plant by two methods.
Transpiration
The extra amount of water removed in the form of vapor through
stomata is called transpiration.
Guttation
When water is removed from plant in the form of drop this
process is called Guttation. Guttation occur special opening called hydathods.
Guttation take place in those plant which grow in tropical rain forest.
Release of Oxygen and Carbondioxide
§ In day time plant used CO2 for photosynthesis process and
released O2.
§ In night time plant released CO2 and inhale O2 gas.
Ions
Excess amount of ion are deposit into dead cell of plant body
such as bark.
Thermoregulation
The maintained the temperature of the body with in a range is
called thermoregulation.
Thermoregulation in Plant
The normal range of temperature in plant is 10oC to 35oC. The
adaption of plant to low and high temperature are as follows.
Low Temperature
§ At low temperature the nature of plasma membrane is changed and
produce crystalline structure due to which transport of solute is slow.
§ To control this condition plant cell produce unsaturated.
§ At freezing point ice crystal are formed in the cell. But the
plant of cold region change the composition of solute of cell so ice crystal
are not formed in cytoplasm they form in cell wall. This condition is known as
freezing tolerance.
High Temperature
§ High temperature has more harmful than low temperature for
plant.
§ Due to high temperature all enzyme are denature and metabolic
process stop. So plant increase rate of transpiration and cool the body.
§ At above 40oC plant produce heat shock protein. They protect the
enzyme from destroying.
§ In some plant shiny cuticle is present which protest them from
high temperature.
§ In some plant leaves are reduce in size.
OSMOREGULATION IN ANIMAL
Osmoregulation
in Terrestial Animal
In land animals excretion of water take place through body
surface so they have develop number of strategies to maintain Osmoregulation.
Water
Proof External Covering Epidemics present in reptile, mammal cuticle present
in insect which prevent the water loss from their body.
Storage
and Excretion of Solid Wastes
In birds, reptile and insect store nitrogenous waste uric acid.
Uric acid insoluble in water and help to reabsorption of water in cloeca. Uric
acid excreted the body in the form of paste and crystal.
Use of
Metabolic Water
Some mammal fat is converted into simple compound and during
this process water is produce which is reused in the body. Camel, Kangroo used
metabolic water.
Storage of
Harmful Waste
In mammal urea in kidney which is helps in reabsorption of
water.
Osmoregulation in Aquatic Animal
Osmoregulation in fresh water animal is maintained by two
methods.
1. By Contractile Vacuole
2. By producing dilute urine
1. By
Contractile Vacuole
Fresh water unicellular organism have contractile vacuoles.
Water with dissolved CO2 and uric acid is collected from the endoplasm into the
contractile vacuole, which increase in size up to a maximum and burst released
the extra substance in environment. In Amoeba and Paramicium the amount of
water and other substance remain in balanced by contractile vacuole.
2. By
Producing Dilute Urine
Fresh water fishes have hypertonic body fluid as compare to
surrounding water. Fisher released extra amount of water in the form of dilute
urine and absorb some essential ion from outside to maintain the salt and water
content in the body.
Osmoregulation in Marine Animal
Marine water fishes have hypotonic body fluid than surrounding
because sea water have high concentration of salt so these fishes drink water
continuously and the salt excreted out along with concentrated urine. They also
excrete salt through gills.
Excretion in Animal
In animal removal of nitrogenous waste from the body is very
essential. Animal have particular organ to excrete out nitrogenous waste.
Waste Substance of Animal
Animal produce different type of waste substance such as
1. Ammonia
2. Urea
3. Uric Acid
4. Creatinine
5. Hypozenthine
1. Ammonia
§ It is a small molecule of gas. Its formula is NH3.
§ It is highly soluble in water.
§ It is very toxic compound
§ It is dissolved in water and removes by simple diffusion method
through skin or by urine.
§ It is excretory substance of aquatic animal e.g. fishes.
2. Urea
§ Urea is less soluble in water.
§ Its formula is CO(NH2).
§ Urea is very less toxic substance because its 1,00,000 time less
toxic then NH3.
§ Urea is produce as a result of metabolism in the liver from
ammonia.
NH3 + CO2 ——> Citruline ——> Aginine ——> Urea
§ This process required energy.
§ Urea is the excretory product of mostly land animal like
mammals.
3. Uric
Acid
§ Its formula is C5O3N4H4.
§ It is not soluble in water.
§ Uric Acid is less toxic than urea.
§ Uric Acid released from the body in paste like substance or
urete crystal.
§ Urid Acid is the excretory product of insect, birds and reptile.
Excretion in Hydra
(Exetory Substance (NH3))
Hydra is a water living animal. In this body the excretory
products are produced in the form of NH3. It is excreted out the gastrovascular
cavity and then removed from the body along with water.
Excretion in Planaria
(Exetory Organs)
In planaria nitrogenous waste excrete out through skin and
special excretory organ called flame call or protonephridia.
Structure of Excretory System and
Functions
In the body of planaria there is a system of branch tube like
bodies. There are two longitudinal excretory trunks one on either side of the
body.
Nephredipores
They open to the out side by small pore called nephredipores.
Flame Cell
Internally these excretory trunk divide and redivide into number
of small branches at the end of the branch special cell are present are called
flame cell. The flame cells are club-shaped hollow cells. In their internal
cavity many cilia are attached which perform movement just like flame of
candle.
Functions
All the waste product of main branches absorb by flame cell
because the movement of cilia of flame cell. When the excretory product come
into the longitudinal excretory system they are removed out of the body through
the nephrediopore.
Excretory
Organs
The excretory system of earthworm consist of small, coiled tubes
called Metanephredia. It is present in each segment.
Structure of Nephredium
Each Nephredium consist of three part.
1.
Nephrostome
It is a rounded, ciliated funnel with the opening.
2. Bladder
Main body of nephridum consist of coiled tubular part and wide
part called bladder.
3.
Nephridiopore
The bladder opens outside by a small pore on the skin are called
nephridiopore.
Excretion
As fluid moves along the tubule, epithelium reabsorbs the salt
from lumen and send to blood vessels surrounding the nephridium. The left over
appears as urine containing nitrogenous waste.
EXCRETION IN COCKROACH
Excretory
Organs
Cockroach have special tube like excretory structure are called
“Malphighian Tubules”. It is present between the mid gut and hind gut. It is
embedded in the blood.
Excretion
Malphighian tubules absorb all nitrogenous waste from blood and pour
them into illium. The latter part of tubules reabsorbs important substance. The
uric acid when come into rectum, it also reabsorbs water and salt, so uric
became almost dry then it is excreted out of the body.
Liver
Liver is the large raddish brown glandular organ which is
central station of metabolism and consequently the body is central metabolism
clearing house.
Location
Liver located in the abdomen just below the diaphragm.
Functions of Liver
Liver is the main homeostatis organ which perform several
function.
1.
Metabolism of CHO and LIPIDS
Liver is the center of metabolism. Is take part in metabolism of
carbohydrate and lipid. It regulates the amount of glucose into the blood.
Excess glucose is converted into glycogen, which is reserve food. It amount of
glucose is decrease in the blood glycogen is broken into glucose. Glycogen is
reduce than liver convert amino acid into glucose.
Liver also help in oxidation of lipid. It is converted blood
lipid into simple fat which is stored in the body.
2.
Deamination and Urea Formation
Excess of protein can not be store in body. Protein are change
into amino acid. Amine group is removed from the amino acid this process is
called deamination of form NH3. Amonia combine with CO2 and convert into urea
by a cycle called ornithine cycle.
3.
Production of Bile
Liver produce a secretion called Bile. It is yellowish green
alkaline substance. Bile contain bile pigment biliverdin, bilirubin, salt such
as sodium-glycocholate, Na-taurocholate, Cholesterol, Phospholipid and mucous.
Functions of Bile
§ Bile neutralizes the acidic food
§ It kills the germs
§ It takes part in the emulsification of fat.
4.
Detoxification
Liver convert toxic substance into non toxic substance this
process are called detoxification.
For example a compound hydrogen peroxide H2O2 is a harmful compound. The liver secrete on enzyme catalase which convert H2O2 into H2 and O2 and became non poisonous substance.
For example a compound hydrogen peroxide H2O2 is a harmful compound. The liver secrete on enzyme catalase which convert H2O2 into H2 and O2 and became non poisonous substance.
5.
Formation of Cholesterol
Liver also forms cholesterol which is necessary for the body. Its
extra amount is always excreted along with water.
6.
Thermoregulation
Liver helps in regulation of body temperature by continue supply
of blood and metabolic process.
7. Storage
of Vitamins
Liver stores vitamins such as A1B and D.
Urinary System in Human Being
Urinary system of man consist of
Kidney
Kidneys are pair of dark red bean shaped structures which are
attached to the dorsal wall of the abdominal cavity.
Kidney are covered by a membrane are called peritoneum.
Ureter
Urine leaves the kidney through a pair of duct called Ureter.
Bladder
The ureters of both kidney drain into pear shaped thin walled
structure are called bladder.
Urethra
Urine leaves the body during urination from the bladder through
a tube called Urethra.
Sphincter
Sphincter muscles near the junction of the urethra and bladder
control the urine in bladder.
Kidney
Kidney are a pair of dark red bean shaped structures which are
attached to the dorsal wall of the abdominal cavity.
Structure of Kidney
Internally kidney consist of two part
1. Cortex is the outer and darker region.
2. Medulla is the inner and
lighter region in the kidney. It contain many cone like structure are called
pyramids.
NEPHRON
The basic structural and functional
unit of kidney are called Nephron.
OR
Kidney consist of million of
microtubules are called Nephron.
Structure of Nephron
Each nephron is sub-divided into
1. Renal Corpuscle
2. Renal Tubule
1. Renal
Corpuscle
Each renal corpuscle is divides into two
i. Bowman’s Capsule
ii. Glomerulus
i.
Bowman’s Capsule
In each nephron inner end forms a cup-shaped swelling called
Bowman’s
capsule.
ii.
Glomerulus
Each bowman’s capsule have a ball of capillaries called
glomerulus. Glumerulus circulates blood through capsule as it arrives through
Aferent Arteriole. Blood carried away from the capsule by a small vessel called
Efferent Arteriole. The blood vessel sub divide again into another network of
capillaries called Peritubular Capillaries.
2. Renal
Tubule
Bowman capsule continuous as extensively tubular system.
i. Proximal Convoluted tubule
ii. Loop of Henle
iii. Distal convoluted tubule
iv. Common collecting duct
i.
Proximal Convoluted Tubule
Bowman capsule gives out a coiled tubule called Proximal
Convoluted Tubule.
ii. Loop
of Henle
The proximal convoluted opens into a U-Shaped structure called
loop of Henle. Loop of Henle consist of descending and ascending limbs.
iii.
Distal Convoluted Tubule
The ascending limb of loop of Henle opens into another
convoluted tubule called Distal Convoluted Tubule.
iv. Collecting
Tubules
Distal tubule empties into collecting tubules which open into
pelvis.
Functions of Kidney
Urine formation take place in these following steps:
1. Ultra Filtration
2. Selective Reabsorption
3. Tubular Secretion
4. Counter Current Exchange
2.
Selective Reabsorption
All the important constituent of the glomerular filtrate are
reabsorbed when filtrate pass in tubular system.
§ Prominal convoluted tubule reabsorb salt amino acid, glucose and
water.
§ Descending limb of loop of Henle reabsorb Na and Cl inter in the
interstial fluid. Na and Cl reabsorbed by active transport. Water is not
reabsorb.
§ Distal convoluted tubule have hypotonic solution due to high
concentration of water. In this part by the action of hormones concentration of
various salt is adjust.
3. Tubular
Secretion
Tubular section is also very important process of excretion. The
tubular epithelium also secrete substances into teh lumen this secretion is
very selective and mainly of hydrogen into balance pH value of the filtrate passing
through the tubule.
4. Counter
Current Exchange
The exchange of solute and water in the medulla of kidney is
called counter current exchange. There are two counter exchanges:
i. Counter Current Multiplier
ii. Counter Current of Vasa Recta
i. Counter
Current Multiplier
When the filtrate passes through the descending limb of loop of
Henle water is reabsorbe due to this process the filtrate became hypertonic.
ii.
Counter Current of Vasa Recta
The blood vessels which run parallel to the loop of Henle are
called Vasa recta. Through these blood vessels only about 10% of blood of
kidney passes very slowly. This blood supplies oxygen and nourishment to the
cell of medulla and carries away the reabsorb water from the filtrate. The
system is regulate and maintained properly.
Reabsorption in the Nephron
Types of Nephron
There are two type of nephron
1. Cortical Nephron
2. Juxtamedullary Nephron
1.
Cortical Nephron
The nephron which have small length of loop of Henle and only
present in cortex region of kidney are called Cortical Nephron.
2.
Juxtamedullary Nephron
These nephron have long loop medullar of kidney reabsorb more
water are called juxtamedullary nephron.
Effect of Hormones on the Working of
kidney
Certain hormones control the working of kidney.
1. Andiurelic Hormones (ADH)
2. Aldosteron Hormones (AH)
3. Parathormon Hormone (PTH)
1.
Antidiurelic Hormones
Pituitary gland secrete ADH. It is also called vasopressin.
Functions
Hormones helps in reabsorption of water. Hormone is produce at
the time of dehydration. It causes shortage of water in the body due to rapid
loss of water. The osmotic pressure of blob increases. This hormone helps to
balance the amount of water.
2.
Aldosteron Hormones
Outer part of adrenal cortex secreted aldosteron harmine.
Functions
It control the concentration of Na+ in the bosy fluid. It
increase the reabsorption of sodium ion in nephrone.
3.
Parathormon Hormones
Parathyroid gland secrete parathormone.
Kidney Problem
Kidney is not perform properly due to different reason are
called Kidney problem or Kidney disease.
There are many problems of kidney
1. Kidney Stone
2. Renal Failure
1. Kidney
Stone
Stone solid materials are found in the kidney called Kidney
Stone.
Causes
Kidney stones are caused by metabolic disease.
70% of kidney stone are formed due to calcium oxalate and
phosphate oxalate. Oxalate are produced in the metabolic process and added in
the urine and deposit in kidney change into stones. Oxalates are present in
green vegetables and tomatoes therefore may be the source of oxalate stone.
Infective
Stone
20% stone are called as infective stone. Infective stone consist
of combination of calcium, magnesium and ammonium phosphate.
Uric Acid
Stone
5% stone are formed in uric acid.
Cure
Lithotripsy
The lithotripsy is used for non surgical removal of kidney
stone. It is a technique used to break up stones that form in the kidney,
ureter or gall bladder.
Method
There are several way to do it although the most common is shock
wave lithotripsy or ultrasonic lithotripsy. High concentration X-Ray or
ultrasound are directed from a machine outside the body to the stone inside.
The shock waves break the stone in tiny pieces or into sand which are passed
out of the body in urine.
2. Renal
Failure
Sometimes the working of kidney is badly damaged due to certain
reason or infection. They are not able to filter the harmful nitrogenous
substance it is called renal failure. In such condition the harmful substance
remain in blood.
Symptoms
§ Nausea
§ Vomiting
§ Loss of appetite
§ Weakness
§ Difficulty in breathing
In severe condition patient may suffer by pneumonia high blood
pressure coma and ultimately death.
TREATMENT OF KIDNEY FAILURE
Dialysis
A technique to remove nitrogenous wastes particularly the urea
from the blood of the patient is called Dialysis.
Type of
Dialysis
There are two types of dialysis
1. Haemodialysis
2. Peritoneal Dialysis
1.
Haemodialysis
Haemodialysis means “Cleaning the blood”. In this procedure
blood is circulated through a machine which contains a dialyzer also called on
artificial kidney.
Dialyzer has two spaces separated by thin membrance and dialysis
fluid on the other. The waste and excess water pass from the blood through the
membrane into the dialysis fluid. Dialysis take place 6 to 10 hours and 3 time
in a week.
2.
Peritoneal Dialysis
Abdomen has a peritoneal, lined by a thin epithelium called
peritoneum. Peritoneal cavity is filled with dialysis fluid that enters the
body through a catheter. Excess water and wastes pass through the peritoneum
into the dialysis fluid. This process is repeated several times in a day.
Kidney Transplant
Dialysis may be used as temporary measure. In high degree renal
failure also called as Uremia or end stage renal disease, the dialysis is done endlessly
thus the surgical transplantation of matching donor kidney is only the option
left as the permanent treatment.
THERMOREGULATION IN ANIMAL
Temperature Classification of Animal
According to the body temperature animals are divides into two
group.
1. Poikilotherms (Cold Blooded)
2. Homeotherms (Warm Blooded)
1.
Poikilotherms
Animal cannot maintain their body temperature and it can be
changed accordingto the climate are called Poikilotherms.
Example
Amphibians, Reptile, Fishes.
2.
Homeotherms
Animal can maintain their body temperature. It does not changed
according to their environment are called Homeotherm.
Example
Birds, Mammals
Many poikilotherm can maintain their body temperature and
homeotherm do not maintain their body temperature always. So there terms are
changed.
Modern Classification of Animal
The modern classification of animal according to the body
temperature.
1. Ectothermic
2. Endothermic
3. Heterothermic
1.
Ectothermic
Ecto mean outside thermic mean heat so those animal obtained
heat energy from their environment are called Ecotothermic.
Example
Invertibrate, Fish, Amphibian and Reptile.
2.
Endothermic
Endo mean inside thermic mean heat so those animals use internal
energy which is produced during their metabolism.
Example
Mammalia, Birds and Some Fishes.
3.
Heterothermic
Those animals are able to maintain their body temperature with
certain variation, so their body temperature can be changed upto certain limits
are called Heterothermic.
Example
Bat, Humming birds.
Method of Thermoregulation in Animals
In animal thermoregulation occurs by two ways.
1. Behavioral Regulation
2. Physiological Regulation
1.
Behavioral Regulation
When temperature is maintained by the activity of animal body,
it is called behavior regulation, such as animals change their position to
increase or decrease the temperature.
2.
Physiological Regulation
When temperature of the body is maintained by
inter-physiological process it is called physiological regulation, such as
change in blood circulation etc.
Thermoregulation in Cold Temperature
In cold temperature animal regulate their body temperature by
two methods.
1. Physiological Process
2. Behavioral Process
1.
Physiological Regulation
This is the internal process of the body to maintain body temperature.
It take place by two way
i. Non-shivering thermogenesis
ii. Shivering thermogenesis
i. Non-Shivering Thermogenesis
Hormones trigger the heat production as do thyroid hormones are
called Non-shivering thermogenesis.
Mechanism
In this mechanism heat is produce by three methods.
In this mechanism heat is produce by three methods.
§ Erection of hairs
§ Reduction of blood flow toward skin
§ Sub cutaneous fat accumulation
Erection
of Hairs
In cold season the hair become in erect position. In furry
animals air is trapped between the space of hairs and loss of body heat is
stopped.
Reduction
in Blood Flow toward Skin
In cold season the blood vessels of skin are reduced. It is
called Vasoconstriction. Due to this process blood flow towards skin become
slow and loss of heat through skin is reduced.
Sub
Cutaneous Fat Accumulation
In mammals below skin fat is deposited in adipose cell. It
prevent the loss of body heat. It is common in aquatic animals such as Seal,
Whale.
ii. Shivering Thermogenesis
The rate of heat production is increased y increased muscle
contraction by movement or shivering so called as shivering thermogenesis.
Mechanism
In very cold weather shivering occur in the muscles of the body.
It produce heat Rate of Metabolism become faster. In this mechanism hormones
are involved one hormone adrenaline is produce by adrenal gland. It increases
the supply of glucose in blood so respiration become fast and energy is
produce.
Thyroid gland also secreted thyroxin hormone in blood. This
hormone also increased respiration to produce heat.
2.
Behavioral Process
In this mechanism the animals produce heat by their body
activities.
Movement
toward Hot Place
Animals move toward hot places during cold season.
Gathering
of Animals
The animals come close to each other, so energy is produced.
Use of
Warm Cloths
Man used warm clothes for protection and to get heat.
Thermoregulation in Hot Temperature
In hot season the animal produce less heat and also released
heat from their body. It take place by two method.
1. Physiological Mechanism
2. Behavioral Mechanism
1.
Physiological Mechanism
This process take place by following method.
Less Fats
Deposition
In hot season fat is not deposit in below the skin. It loss the
body heat.
Increase
in Blood Flow toward Skin
In hot season the blood vessels of skin are dilated and
vasodialation occur to released body heat.
Softness
of Hair
Hair of skin not erect in hot season not prevent the loss of
heat energy.
Sweet
Gland
Sweet glands become active and water is excreted out through
skin. The blood becomes cold and internal temperature is maintained. It is
called physiological temperature regulation.
2.
Behavioral Mechanism
In this mechanism the animal released heat by their body
activities.
Movement
toward Cold Places
Animal move from hot to cold places. They remain in shade or
moist place to reduce their body heat.
Use of
Thin Clothes
Man use thin clothes during summer season.
Role of Brain in Thermoregulation
The body temperature regulation in human is based on complex
homeostatic system facilitated by feedback mechanism.
The
Control Center
The homeostatic thermostate is present in the hypothalamus, a
brain part. It respond to the changes in the temperature above and below 37oC.
Warm
Temperature
Incase of increase in temperature above 37oC certain warm temperature
sensitive thermoreceptors in skin, hypothalamus and other parts of nervous
system send the signals to the system that increase the blood flow to the skin
and also cause sweat gland activation and sweat is evaporated for the cooling.
Cold Temperature
In cold temperature, the cold receptor send the impulse to
hypothalamus to inhibit heat loss mechanism and activate the heat conservation
mechanism.
Fever
When the temperature of the body is increased beyond a set point
it is called Fever or Pyrexia.
Cause of Fever
The main cause of fever is the viral or bacterial infection.
These germs in blood vessels produce a chemical substance called pyrogen. It
increases the body temperature than normal.
Importance
§ Fever helps to kill the germs
§ It indicates any abnormal condition in the body or infection.
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