1. Integumentary System:

• It includes skin, hair, nails, swet glands and oil glands
• The skin is the heaviest organ of our body and weighs about 7 kg.

Functions of skin

• Protects the inner parts of the body
• It works as an excretory organ by sweating
• It acts as a sense organ

2. Skeletal System

• The Skeletal System is made up of 206 bones.

Function

• Skeletal System provides a frame work to the body and helps inmovements.
• It protects many internal organs such as brain, heart, lungs etc.
• It produces blood cells like Red Blood Cells, White Blood Cells and Platelets.

3. Muscular System

• The Muscular System is made up of three types of muscles. They areskeletal muscles, smooth muscles and cardiac muscles.

Function

• Skeletal muscles give shape to the body and makes possible the movementsinour body.
• These muscles generate heat required for maintaining our bodytemperature.
• Other muscles bring out movement in the internal orgens

4. Circulatory System

• The Circulatory System transports substances from one part of the body toanother.

Functions

• Blood transports nutrients oxygen,wastes, hormones.
• It regulates water level and body temperature.
• Blood vessels are f three types: arteries, veins and capillaries
• Nervous System is composed of the brain, spinal cord and nerves.

5. Endocrine System

• A group of ductless glands form a system called Endocrine System in ourbody.
• Hormones regulate body functions

6. Reproductive System

• The Reproductive System is composed of mainly testes in males and ovariesin females.
• The testes produce male gametes called sperms. The ovaries produce femalegametes called eggs.
• Health Care is the prevention and treatment of illness.

Skin

The skin is composed of three major tissues.

1.Epidermis

Epidermis is the upper layer of the skin. The outer most layer consists of flat, thin and scale-like dead cells.

2.Dermis

The dermis is the middle layer. It is thick but elastic. The dermis consist of nerves, blood vessels, hair follicles, sweat glands and sebaceous glands(oil glands). The sweat glands separate sweat from blood vessels.

The sebaceous glands secrets sebum which keeps the skin smooth and shiny.

3.Hypodermis

It is the lowest most layer, which contains large amount of adipose tissue.

Functions of the Skin

Skin can prepare vitamin D with help of sunlight.

Skin acts as an excretory organ and excretes sweat.

Skin colour of women is determined by the melanocytes of the basement membrane. The formation of melanocytes is by hereditary. Even then there is some impact of colour by external factors like temperature, sunlight, wind and contumes,

Skeletal Muscles

• The skeletal muscles are attached to the body by tendons.
• These muscles are covered by sheets of connective tissues called fascia.

Tendons

• These are connective tissue structure showing slight elasticity. They are like cords or straps strongly attached to bones.

Fascia

• These are assemblages of connective tissue lining skeletal muscles as membranous sheets.
• The fascia may be superficial or deep. The Superficial is a layer of loose connective tissue found in between skin and muscles.
• cm of muscles can lift 3.5kg.

Facial Expressions

• Facial expression, such as looking, shocked and smiling, are tiny voluntary movements made by more than 30 different muscles.

Digestive system

Generally two major types of digestion are encountered

1.Intra cellular digestion

2.Extra cellular digestion

1.Intra cellular digestion

• Amoeba like unicellular organisms digest its prey inside the food vacuole and expels the undigested food.This type of digestion is called intracellular digestion e.g.Amoeba

2.Extra Cellular digestion

• Various glands secrete enzymes into the cavity and digest the food extra cellularly .This kind of digestion outside  the cell,but within the cavity is extracellular digestion e.g Human

The alimentary canal

• It is a coiled muscular tube extending from the mouth to the anus.It is about 6-9 meters long and consists of many specialized sections
• Arranged sequentially these are mouth ,buccal cavity, Pharynx, oesophagus, stomach, small intestine, Large intestine ,rectum and anus

Mouth

• It is an oval shaped cavity bounded in front by lips and laterally by the jaws. The roof of the cavity is lined by the palate. The floor contains a tongue.
• The upper jaw and lower jaw are lined by the tooth. Mouth helps ingestion

Teeth

• In man teeth are 32 in number. 4 incisors, 2 canines, 4 premolars and 6 molars in each jaw. The last set of molar tooth grow after the age of 20; Hence they are named as wisdom tooth.

Types of Teeth

• The first set of teeth grows when a baby is about one year old. This set ofteeth is called milk teeth.
• They are twenty in number.
• When the milk teeth fall off, a new of teeth grow . They are calledpermanent teeth. They are thirty-two in number
• Incisors: These are chisel shaped teeth at the front of the mouth. They areeight in number. Four are present in each jaw .These are used for biting thefood.
• Canines: These are sharp teeth and pointed teeth . They are four in number andtwo are present in ea are used for cutting and tearing offood.
• Premolars: These are large teeth behind canines on each side. They have large surface.They are eight in number and four are present in each jaw. They help in chewing and grinding the food.
• Molars: These are very large teeth present just behind the premolars. Theyhave more4 surface area than premolars. They are used for chewing andgrinding of food like premolars. ‘They are twelve in number, and six arepresent in each jaw.
• Birds have no teeth.
• Rats have continuously growing teeth.
• The tusks of elephants are actually incisors that have become very long.
• Very few adult humans have all the 32 teeth.

Ruminants

• In fact they eat grass hurriedly and swallow quickly and store it in the first
• chamber of the stomach called rumen.
• The process of chewing the cud is called rumination.
• Grass is rich in cellulose which is a kind of carbohydrate.
• There is a sac – like structure called caecum between the small and largeintestine in ruminants. This sac contains some bacteria which produce anenzyme called cellulose which digest the cellulose

Tongue

• It is the organ for the sense of taste. lt is attached to the floor at the mouth.Its tip is thin and narrow. The upper surface of the tongue contains several papillae or Sensory buds.
• The hardest part of the human body is the tooth

Salivary gland

• Parotid glands – It is the largest gland of the three pairs.It is found below the air.
• Submaxillary gland –it is found below the jaw and irregular in shape.
• Sublingual gland – it is smallest gland. It is found at the base of the tongue.
• Parotid gland is the only salivary gland affected by mumps virus.
• The three pairs salivary glands secrete approximately 1.5 liters of saliva every day.
• The saliva has the following

1. Ptyalin (Amylase) – enzyme

2.Bicarbonate – salt

3. Mucus – carbohydrate
4. Lysozyme -enzyme

Pharynx

Pharynx is found below the nose and mouth. It is about 11 cm in length.This region has 7 openings. They are 2 intemal nostrils, 2 eustachiantubes, mouth, larynx and oesophagus.

Oesophagus

 It is a musculo-membranous canal about 22 cm length. It extends frompharynx to the stomach. The inner lining has a mucus coat and it is lined by epithelium.

Stomach

• Since stomach is the main organ of digestion,it is the most dilated part ofthe alimentary canal. Stomach is a horizontal chamber containing 3 conspicuous regions. They are cardiac,funduspyloric. The stomach secretes gastric juice.
• The gastric juice contains the following:

1. Pepsin
2. Rennin
3. Hydrocloric acid

Small intestine

The stomach opens  into the small intestine through pylorus. The small intestine is divisible into 3 regions duodenum, jejunum and ileum.

Duodenum

 Duodenum is around 22 cm in length. In this region where the liver and pancreas are connected to the alimentary canal,

Liver

• Liver is the largest glandular organ in human. It weighs about 1500 gms. Itcontains two unequal lobes.
• The right lobe is larger.
• Liver secrete-s bile juice which is greenish yellow in colour.
• The bile is temporarily stored-in gall bladder.
• The gall bladder in attached to the bile duct. The duct opens into theduodenum. Bile juice helps the digestion of fat.
• It does not have any enzyme. It has bile salts and bile pigments,
• Excess, of eating fatty foods leads ho the formation of bile stones in the gallbladder.

Pancreas

• Pancreas is a long, leaf like transparent gland. It is 15 to 20 cms long. Pancreas secretes pancreatic juice and it is connected with duodenum through pancreatic duct. .
• Pancreas acts as an exocrine gland and endocrine gland. The gland’s upper surface bears the islets of Langerhans
• The pancreatic alpha cells secrete the hormone glucogon, and the pancreatic beta cells secrete the harmone insulin.

As an exocrine it secretes the following enzymes:

1. Trypsin
2. Chymotrypsin
3. Carboxy peptidase
4. Amylase
5. Lipase

Jejunum

 Jejunum constitutes 2/5^th  of the small intestine. It starts from theduodenum and ends with ileum.

 The secretion of small intestine is intestinal juice. The intestinal juice contain the enzymez

1. Sucrase

2, Maltese

3. Lactase

4.Lipase

Ileum

• It is a coiled tube-like structure which constitutes 3/5^th of the small intestine.It contains numerous minute finger-like projections called villi(1 mm) in length
• They are approximately 4 million in number .Internally each villus contains fine blood capillaries and lacteal tubes. Food absorption takes place here

Large intestine

• It extends from the ileum to the anus. It is about 1.5 metres in length. It is divided into caecum, colon and rectum

Caecum

 Caecum is a large blind pouch and measures about 5 cm in length. The terminal part of caecum is vermiform appendix.

Claude Bernard

• The French scientist Claude Bernard (1813-78) was one of the first people to study physiology. He discovered that glucose, the main source of energy for the body is stored in the liver as glycogen and released as and when it is needed.
• He also studied digestion, how drugs change the way the body works and the nervous system.

Kidneys

• Kidney is a chief excretory organ. It is a pair of dark red, bean shaped organ placed behind the abdomen, on each side of the vertebral column
• The average adult kidney measures about 12 cm in length, 6 cm in width and 3 cm in thickness. The outer surface of the kidney is convex and the inner surface is concave and it faces the vertebral column. The right kidney is just lower than that of the left kidney because the right side of the body is occupied by the liver.
• Each kidney is surrounded by a fibrous membrane called capsule.
• Urinary bladder the temporary storage organ of urine. Urine is expelled through the urethra to the exterior.

Nephron

Kidneys are made up of millions of nephrons, which are the structure and functional unit of  kidneys. Each kidney consists of about one million of nephrons.

Other excretory organs in human body

• Lungs: Lungs excrete CO2 and water from the blood.
• Skin: Skin excretes sweat, the sweat consists of dissolved urea, uric acid and lactic acid.
• Liver: Liver excretes bile pigments, formed during the breakdown of haemoglobin. It is incharge for the formation of urea through ornithin cycle.

Other information

• Kidney functions are the basis of blood pressure
• There are approximately 1 milion nephrons in each kidney. At least4,50,000 of them must remain functional to ensure survival.
• Every minute kidneys receive 1/5^th blood of the cardiac output that is approximately 1.250 liters every minute.
• Among reptiles only the crocodiles have a four chambered heart

Circulatory system or Blood vascular system

Circulatory system is a special system which contains heart, blood vessels and blood. This system makes the blood to circulate around the body because of the contraction and expansion of heart

Open blood vascular system

• In open type, the blood is pumped by the heart into the blood vessels that opens into blood spaces(cavities).There is no capillary system. e.g. most arthropods. These cavities are called haemoccoel. The pressure of the blood here is very low e.g Cockroach

Closed blood vascular system

• The blood is circulating through the blood vessles and it creates blood pressure inside the blood vessels e. g. human blood vascular system.
• The heart is a hollow, muscular organ. It is somewhat conical in shape,The heart is covered with double walled membrane called pericardium. The space between the pericardial membrane is called pericardial space, which is filled with pericardial fluid.
• The pericardial fluid protects the heart from shock. The heart is placed inside the thoracic chamber in between the two lungs in the mediastinum
• The total volume of blood in blue whale is 12 tonnes. It can be pumped by its heart

Animals and their hearts

Internal structure of human heart

• Human heart consists of four chambers.Two upper thin chambers are called artria(singular –artrium)and two lower thick chambers are called ventricles.The right side of the heart is separated from the left side by a longitudinal wall named inter artrio-ventricular septum

Blood vessels connected with heart

Valves in heart

1.Tricuspid valve: Located in between right atrium and right ventricle

2.Bicuspid Valve(Mitral valve):Lies in between left  atrium and left ventricle

3.Semi lunar valves :Present near the mouth of pulmonary artery and aorta

Arteries

• The blood vessels carrying blood away from the heart are the arteries .Generally ,the arteries carry oxygenated blood except pulmonary artery

Veins

• Generally,the veins carry deoxygenated blood except pulmonary veins

Capillaries

• Capillaries are fine, small tubes found spreading in the midst of the cells. They perform all the functions of blood vascular system. It is considered as a vital tube of the blood vascular system

Human blood

• Human blood consists of two components

1.Plasma

2.Blood corpuscles

Difference between artery and vein

1. Plasma

It is an extra cellular fluid of about 55 per cent of the blood volume. It is a faint yellow colour fluid, which isalkaline in nature. Plasma contains  proteins, enzymes, hormones, wastes and elements.

2. Blood corpuscles

Nearly 45 per cent volume of blood contains corpuscles. The blood corpuscles are of three types.

1. Erythrocytes or red blood corpuscles (RBC)
2. Leucocytes or white blood corpus (WBC)
3. Thrombocytes or blood platelets.

1.Erythrocytes

• They are red, biconcave and disc shaped cells.The red colour of the RBC is due to the presence of respiratory pigment haemoglobin
• Haemoglobin helps in transporting oxygen and carbon di-oxide in our body.One cubic mm of blood contains 5 millions of RBC
• The life span of RBC is 120 days.They are destroyed in the liver and spleen RBC’s are prepared by red bone marrow

2. Leucocytes

• They are colourless, irregular and nucleated cells. The WBC’s are fewer innumber compared to RBCs and they are larger in size.
• One cubic mm of blood contains 8000 WBC’s. There are 5 types of WBCwhich are monocytes, lymphocytes, neutrophils, eosinophils and basophils, The life span of WBC is 4 weeks.
• They are prepared by yellow bone marrow and lymphatic tissue. WBC’sattack the invading germs and protect our body.

Thrombocytes (Blood Platelets)

• These are small, non-nucleated and colourless structures floating in the plasma. In one cubic mm of blood there are 2,00,000 to 4,00,000 thrombocytes.
• Whenever there is an injury, the thrombocytes disintegrate to give rise to thromboplastin, which helps in the clotting of blood.

Functions of Blood

1. Blood distributes the digested food
2. Blood carries the metabolic wastes to excretory organs
3. Blood carries hormones, which are the secretions of endocrine glands.
4. Blood distributes the heat evenly body.
5. Blood keeps all the tissues

Respiratory system

Respiration

• The phenomenon of release of energy by oxidation of various organic molecules is known as respiration

 Respiration is of   o types on the basis of usage of oxygen

1. Aerobic Respiration
2. Anaerobic Respiration

Aerobic Respiration

• Respiration with saturated amount of oxygen. This type of respiration is found in higher animals.

Anaerobic Respiration

• Respiration, without oxygen. In this process little amount of energy liberated. For example Bacteria.

Breathing

• Breathing is entirely different from that of respiration. It is an initial step in respiration.Inhaling of atmospheric air and exhaling of carbon-di-oxide is called breathing.

Animals and their mode or Respiration

1. Amoeba – simple diffusion
2. Cockroach – through tracheoles
3. Sea cucumber – through respiratory trees
4. Fishes – through gills
5. Frog – a.Cutaneous respiration(skin)

                        b.Pulmonary respiration(lungs)

                        c.Buccal cavity respiration(buccalcarity)

Human Respiratory System

• The respiratory organs include nasal cavity, pharynx, larynx, traehea, bronchi and lungs
• The nasal cavity follows the external nose. The nose is a visible prominent structure. The nasal passage opens outside through external nostrils.opens inside the internal nostrils at pharynx.
• The trachea (or wind pipe) is membranous tube supported by ‘C’ shaped cartilage rings. The inner wall is lined by mucous membrane. It consists of ciliated columnar epithelium.
• The cartilage ring found at the basal region is called carina. Foreign objects reaching Carina stimulate a powerful cough.

Respiratory area

• The total surface of the alveoli will be around 80 100 metre square and equals the size of the tennis court
• The pair of lungs are the actual orans of respiration It is conical in shapeand placed inside the thoracic chamber
• The base of the lungs rests on the diaphragm .The right lung has three lobes and left lung has two lobes
• Each lung is surrounded by a double wall membrane called pleura. The region inside the pleural membrane is named as the pleural cavity. The Cavity is filled with pleural fluid

Nervous System

• Coordination is the process through which two or more organs interact and compliment the functions of one or the other.
• In our body the neural or nervous system and the endocrine system dothe function of coordinating and integrating all the activities of the organs so that the body works efficiently by synchronizing the functions.

Nervous System

• The nervous system of an animal is composed of
• Specialized cells called neurons or nerve cells,
• The nerve fibres

Nerve cells

• Billions of nerve cells make up our brain.
• A nerve cell is a microscopic structure consisting of three major partsnamely cell body, dendrites and axon.

Cell body

• It is the cell structure irregular in shape or polyhedral structure, it is also called as cyton.

Dendrites

• Shorter fibres which branch repeatedly and project out of the cell body.Dendrites transmit electrical impulses towards the cyton.

Axon

• One of the fibres arising from the cell body is very long with a branched distal end and it is called as Axon
• The distal branches terminate as bulb like structure called synaptic knob filled with chemicals called neuro transmitters.
• Neurilemma encloses the axon except at the branched distal ends.
• In some neurons called rnyelinated neurons an additional white fattyfibre called myelin sheath covers the neurilemma.
• The gaps left by the myelin sheath on the axon are called Nodes, ofRanvier.
• Over the rnyelin sheath are found certain cells called Schwann cells.

Types of nerve cells

• Myelinated or Medullated or While neurons:
• When the axon is enclosed by the white fatty myelin cover
• This forms the cerebral cortex of our brain.
• Non-Myelinated or Non-Medullated or Grey neurons:
• It appears grayish in colour. The axon is covered by only neurilemmaandSchwarm cells.
• Found in the white matter of cerebrum.

Unipolar neurons:

• The embryonic nervous tissue con unipolar neurons

Bipolar neurons

• The sensory hair cells of the sense organs like rods and cones of retina are made up of bipolar neurons

Multipolar neuron:

• The cerebral cortex contains the multipolar neurons;eachmutipolar neuron has a cell body
• Synapse: The dendritesthe synaptic knobs of the axons of neighbouring neurons are in physical contact with one another without fusing.
• This point of contact between ‘the neighboring nerve cells iscalledsynapse.

Nerve impulse:

• The conduction of stimuli by the nerve cells is called nerve impulse.

Human nervous system

• The human nervous system is divided into’
• The Central Nervous System (CNS) and
• The Peripheral Nervous System (PNS)
• The Autonomic Nervous System (ANS)
• The CNS includes the brain and spinal cord and it is the site
• The PNS comprises of the nerves of the body associated witl1 the centralnervous system.

Central Nervous System

• Organized of two organs namely the brain and the Spinal cord.
• The CNS is accommodated in the protective bony  structures namelyskull and vertebral column
• Meninges: The central nervous system is covered by three protectivecoverings or envelops collectively called meninges.
• The outermost cover
• is called Durameter
• The middle covering is called Arachnoid membrane.
• The innermost cover is a very thin delicate membrane and is closelyapplied on the outer surface of brain and spinal cord and it called Piamater.

The Brain

• Man is a vertebrate and a mammal belonging to the animal kingdom.
• The human brain as in the case of other vertebrates, is divided intothree major paris:

1. Fore brain b. Mid brain c. Hind brain

Fore brain

• Fore brain consists of cerebrum, thalamus and hypothalamus.

Cerebrum

• Median cleft divides the cerebrum longitudinally into two halves asright and left cerebral hemispheres, which are united at the base by a sheet of nervous tissue called corpus callosum.
• The outer region of the cerebrum is distinguished as, the grey matter orcerebral cortex and the inner region is called White matter.

Cerebral cortex

• called as grey matter.
• thrown into a pattern of convolutions consisting of ridges and furrows.

Cerebral cortex contains

1. motor areas
2. sensory areas
3. association areas(a region that is neither sensory nor motor).

Motor areas

• Motor areas e the sites of order or command of the cerebrum, fromwhere the order arises to control the activities of the different organs of our body.
• Initiation of voluntary activities takes place here.

Sensory areas

• These are the sites where the sensory functions of the various organs are received through the sensory nerves.

Association areas

• These are responsible for complex functions like intersensoryassociatios, memory and communication.
• White matter of cerebrum: The inner part of the cerebrum lying belowthe cerebral cortex is called white matter and it consists of bundles of nerve fibres with myelin sheath giving the white colour.
• Functions of cerebrum: Cerebrum is the seat of consciousness,intelligence, memory, imagination and reasoning.
• It receives impulses from different parts of the body and initiatesvoluntary activities.
• Specific areas of cerebrum are associated with specific functions.
• Thus there is a centre for hearing, another for seeing, another for tasting, another for smelling another for speaking and so on
• A damage in a specific centreofcerebrum will deprive the particular faculty from doing its functions.

Thalamus

• Cerebrum wraps around a structure called thalamus – a major conducting centre for sensory and motor signaling.

Hypothalamus

• It lies at the base of the thalamus. It controls body temperature, urge toeat and drink, regulation of sexual behaviour, express emotional reactions like excitement, anger.

Mid brain

• A canal called cerebral aqueduct passes through the mid brain.
• mid brain consists of four hemispherical bodies called corpora quadrigemina which controls and regulates the various visual reflexes and optical orientation.

Hind brain

 Hind brain comprises of ports, cerebellum and medulla oblongata.

Cerebellum

• Cerebellum regulates and coordinates the group movements of voluntary muscles as in walking or running.

Pons

It relays the information from from the cerebrum to cerebellum. It alsocontains sleep centre and respiratory centre

Medulla oblongata

• Medulla is the centre for several reflexes involved in the regulation of heartbeat, blood vessel contraction,breathing, etc,.
• The ventricle of the medulla remains connected with the ventricles of the cerebral hemisphere

The Spinal cord

• This is a tubular structure, a continuation of the brain lying in theneural canal of the vertebral column.
• The lower end of the spinal cord is filamentous and is called Filumterminale.
• Running through the center of the spinal cord is the central canal, anextension of the ventricle filled with cerebro spinal fluid.

Peripheral nervous system (PNS)

• The nerves arising from the brain and spinal cord constitute the PNB.

Cranial nerves:

• Twelve pairs of cranial nerves arise from the brain.

Spinal nerves:

• Thirty one pairs of spinal nerves arise from the spinal cord.

The Autonomic Nervous System (ANS)

In controls the functions of the vital organs of the body through its twoantagonistic divisions namely, sympathetic and parasympatheticnerves.

Endocrine System in Man

• The chemical coordination of the vital organs of the body processes to maintain thehomeostasisisthe work of endocrine system
• Endocrine system consists of a number of endocrine glands and theirhormones

Head                – a. Pitutary gland

               b.pineal gland

Neck                – a. Thyroid gland

1.     parathyroid gland

Thorax              – thymus gland

Abdomen         – a. pancreas – Islets of Langerhans

1. adrenal glands – adrenal cortex and adrenal medulla
2. gonads – testes in man and ovaries in women

Hormones

• Chemically hormones are proteins or amino acids or steroids.

Pituitary gland

• It is called as the conductor of endocrine orchestra.
• is differentiated into an anterior lobe called adenohypophysis and a posterior lobe called neurohypophysis.

The hormones of neuro Hypophysis namely, oxytocin and vasopressin are secreted by hypothalamus and are

released on specific stimuli.

Thyroid gland

The bilobed thyroid gland is located in the neck, one lobe on each sideof larynx, which secretes a hormone called thyroxine

Functions of thyroxine

• It increases the rate of metabolism
• It stimulata a rise in the body temperature
• It promo growth and differentiation of tissues.
• called personality hormone

Thyroid disorders

• Hypothyroidism- less secretion of thyroxine causes manyabnormalities like simple goitre, myxoedema and cretinism.
• Simple goiter – It is due to the deficiency of iodine in our diet.
• Myxoedema – It is caused in the adults, the symptoms are, lowmetabolic rate, loss of mental and physical vigour, increase in weight.
• Cretinism – This is produced in children and the symptoms are stuntedgrowth, retarded mental development, defective teeth.
• Hyperthyroidism – The excess production of thyroxinecausesexophthalmic goiter or Grave’s disease.

The islets of Langerhans

• Pancreas is a dual role playing endocrine gland. The exocrine parts produce pancreatic juice. The endocrine portion is called islets of Langerhans.
• Alpha cells produce a hormone called glucagon and Beta cells produceinsulin and amylin.

Insulin

• It promotes the uptake of glucose by the cells for tissue oxidation
• It favours conversion of glucose,into glycogen and its storage in theliver and the muscles.
• It prevents the formation of glucose from protein ad fat.
• It maintains normal blood glucose level at 80 – 120 mg/ 100 ml of blood.

Diabetes mellitus

• Less production of insulin causes diabetes mellitus, in which the excess unused glucose is excreted in the urine

Glucagon

• It is secreted when glucose level in the blood is low.

Adrenal gland (Supra renal gland)

Adrenal cortex

• It secretes two hormones namely, Aldosterone and Cortisone

Aldosterone (Mineralocorticoid)

• It maintains mineral metabolism, by favouring reabsorption of sodiumand water and excretion of potassium and phosphate ions.

Cortisone (glucocorticoid)

• It stimulates the breakdown of glycogen into glucose raising the bloodglucose level.

Adrenal medulla

• It secretes two hormones, namely adrenaline- (epinephrine) and noradrenaline (norepinepthrine). They are together called emergencyhormones or hormones of flight and fight as they rapidly mobilize thebody to face as stress or emergency situation.

Testes

• The endocrine part secretes male sex hormone called testosterones (androgen).
• Testosterone stimulates the growth of reproductive organs and the production of male sex cell,the sperms

Ovaries

• Ovaries are both cytogenic (Producing egg cells) and endocrine (producing reproductive hormones ,such as oestrogen, progesteroneand relaxin0 in functioning
• Oestrogen is responsible for growth of female reproductive organs andthe appearance of secondary sexual characters in female, such as growth of public hairs, soft voice, feminine body, etc.,
• Progesterone maintains pregnancy and regulates menstrual cycle.

Parathyroid gland

These are found within thyroid and produce the hormones mainly parathormone and calcitonin which maintain the mineral metabolism.

Thymus gland

• It’s a lymphoid mass, present above the heart. It secretes thymosin.

Pineal gland

• It lies under the corpus callosum in the brain. It produces melationin,causing concentration of pigments in some specific areas like areola,scrotal sacs

Skeletal system

• The skeletal system consist of bones, cartilages and ligaments. It is a frame on which all organs are arranged.
• The human skeletal system is divided into two categories

1. The axial skeleton
2. The appendicular skeleton.

Axial skeleton

• Skull consist of 22 bones. Among 22 , 8 are head bones and remaining 14 are facial bones.
• The skull is divided into head bones and facial bones.
• The cranium is covered by 8 bones. All are flat bones. They are joined with immovable joints. It protects the brain.

Thoracic cavity

• The thoracic cavity consists of three different types of bones.
• The front portion has single bone named sternum.
• The back portion has a long vertebral column.
• Both the bones are connected by ribs on the lateral side.

Rib cage

• There are 12 pairs of ribs.
• In the front, the first ten pairs are attached with sternum.
• The first seven pairs are directly attached with sternum. They are called as the true ribe.
• Cartilages of 8^th ,9^th and 10^th are fused and attached to the sternum indirectly. They are called false ribs.
• They are called floating ribs.

The vertebral column vertebrae

• Actually back bone consist of 33 vertebrae. They are divided into five regions.

Vertebral column of a human

They are

1. Cervical vertebrae – 7
2. Thoracic vertebrae – 12
3. Lumbar vertebrae – 5
4. Sacral vertebrae – 5
5. Cocygeal vertebrae – 4

Upper limb or hands

• Upper arm has a long bone named humerus. The distal end of the upper arm is articulate with two fore arm bones named ulna and radium.
• The frame work of the hand if formed of five metacarpels. Each hand have five digits. They include one thumb and four fingers. Each digit has small long bones called phalanges.

The pelvic girdle and leg

• The pelvic girdle is a ring of bones in the hip region formed by scarum and paired bones called coxae or hip bones.
• Each coxa is formed by the fusion of three bones namely ilium, ischium and pubis. The thigh region contains the longest bone called femur.
• The ankle consist of seven tarsal bones. The ankle articulates with tibia and fibula through talus.

Number of bones in human body

• In the human body, there are 206 bones of those 80 are in the axial skeleton, 126 are in the appendicular skeleton 28 bones are in the skull, 26 are in the vertebral column, 25 bones are in the thoracic cage and one remains as the hyoid bone.