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Homeostatis

2nd Year Biology Notes

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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

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

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.
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.
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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.
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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.

5. Formation of Cholesterol
Liver also forms cholesterol which is necessary for the body. Its extra amount is always excreted along with water.

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.

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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.
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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.

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.

• 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.