oRGANS AND SYSTEM
ORGANS AND SYSTEMS
Two or more kinds of tissues organised in such a way that the tissues can together perform a more complex function. Heart, lungs, brain ,liver and the examples of these organs .
A system is a group of organs which together carry out one of the essential functions of the body .
There are 11 major organs system of the body , which are listed below . All of the system work harmoniously together in a healthy body.
System of the body
1 ) skeletal system
2). Muscular system
3) Nervous system
4) Endocrine system
Or
Glandular system
5). Circulatory system
6). Respiratory system
7). Digestive system
8). Excretory system
9). Reproductive system
a)Male reproductive system
b) Female reproductive system
10). Lymphatic system
11). Integumentary system
1* SKELETAL SYSTEM
The skeleton is the bony framework of the body. It is made in such a way that it can support the body in the erect position and help the body to move freely . The skeleton is made up of 206 seperate bones in the adult . The cartilage and ligaments help to unite the bones at a joint.
The parts included in the skeleton
* Skull made up of. 29 bones
* Spine. 26 bones
* Thorax. 25 bones
* Upperlimb each
32 bones. 64 bones
*. Lower limb each
31 bones. 62 bones
✓ 206 total bones.
Types of bones are:
* Long bones - are in arms, legs and fingers.
* Short bones - are in wrist and ankles.
* Flat bones - include rib , shoulder blades and bones of cranium.
* Irregular bones - in face and spines.
Functions of the skeleton
* Supports and gives shape to the body.
* Protect internal organs.
*. Movement with the help of muscles.
*. Forms blood cells.
Joints
A joint is a point at which two or more bones meet .bones are held together at the joints by cartulage , ligaments and tendons.
Types of joint
1 fibrous joint-
Those joints in which there is no movement of sutures of the skull .
2 cartilaginous joint -
Those joints in which two bones are joined by a pad of fibro cartilage which allow slight movement. They are found in vertabra column and pelvis.
3 synovial joint-
Those joints which are freely movable. They are found in the limbs and jaw.
2* THE MUSCULAR SYSTEM
The function of a muscle is to contract and produce movement. This muscles are made up of bundles of fibres held together there are three types of muscles.
Voluntary muscles-
Found with skeletal system causing joints to mive .
Involuntary muscles -
Work without conscious control. They are found in internal organs.
Cardiac muscle -
A special type found only in heart. They are not under control.
3* THE NERVOUS SYSTEM
This functions like a telephone system with the brain as the head office and nerves like the telephone wires for communication with other parts of the body.
Nervous system has two parts:
The central nervous system -
Made up of brain and cranial nerves, spinal cord and spinal nerves. It controls voluntary muscles of hand , trunk and limps.
The autonomus nervous system-
It is made up of sympathetic and para sympathetic nerves. It controls involuntary musces and gland secretions.
THE SPECIAL SENSES
there are five sense organs with special senses which are listed below:
*Eye. - to see
* Ear -. To hear
* Nose - to smell
* Tongue - to taste
* Skin - to touch
The Eye
Eyes are two in number. It is very precious and delicate organ. Each eye is protected in the orbital cavity of the skull with a pad of fat behind .
Accessory organs help to protect the eyes which are:
Eye brow -
It protects from too much light and sweat of the forehead.
Eyelids-.
Upper and lower - each with a row of eyelashes on the edge-help to keep dust and insects away.
Conjunctiva-
Layer of mucous membrane which lines the eyelid.
Tear gland and ducts-
Tear from tear gland in the upper outer corner of the eye wash over the front of the eye- keep it moist and clean . Excess of tear is removed by tear duct into the nose.
Muscles of eyeball-
The eyeball is attached to the bony orbit by six muscles. They work in harmony to move the eyeball up and down, side to side and obliquely.
THE EAR
The ear consists of following parts:
The external ear.
The middle ear.
The internal ear.
The auditory nerve and hearing center in the brain.
The external ear
It consists ear :
Pinna -
The part which is attached to the side of head. It's function is to collect sound and direct them inside the ear.
Auditory canal -
A curved tube 3 cm. Long leading to the eardrum. It protects the eardrum from insects and foreign bodies.
Eardum -
It is a membrane attached across the hold in the bone . When sound waves hit it, eardrum vibrates . It is performed - deafness may occur.
The middle ear
It is a tiny cavity filled with air inside the temporal bone. The middle ear is lined with mucous membranes and connected by eustactrian tube with upper part of throat.
The internal ear
It is also inside the temporal bone, but it is filled with fluid.
The parts of internal ear are:
Cochlea-
It look like the shell of a small snail। It contains nerve endings for hearing
Vestibule-
A small cavity behind the oral window
Semicircular canals -
Curving upward, backward and sideways, all connected with the vestibule fluid in this canal moves as we change our position this helps to keep our balance
The auditory nerve
This takes the messages from the internal ear to the centre for hearing and balance in the brain
The sense of smell and taste
Smell is conveyed to the brain by the olfactory nerve olfactory nerve endings are situated in the upper part of the nose and help in getting the smell
Taste is one of the functions of the tongue the taste buds are located in the rough surface of the tongue the nerve endings are in these taste buds different taste buds are for different taste sensation- which are:
Sweet
Sour
Bitter and salt
4 *THE ENDOCRINE SYSTEM
The endocrine system is composed of specialized glands that secret chemicals known as hormones directly into the blood. Sometimes called ductless glands, the organs of Endocrine system perform the same general function as the nervous system , communication, integration and control. The endocrine system provides slower but longer lasting control by hormone secretion- for example secretion of growth hormone control the rate of development over long periods and gradual growth.
Endocrine gland are widely distributed throughout the body. The pitiuatory gland, pineal gland, hypothalamus are located in the skull. The thyroid and parthyroid gland are in the neck. The thymus gland is the thoracic cavity. The adreanal gland and pancreas found in abdominal cavity.
5 * CIRCULARY SYSTEM
The circulary system is the system by which food, oxygen , water and other requirements are conveyed to the tissue cells and there wast product are carried away.
The parts of circulary system
The blood
The heart
The blood vessels .
The primary function of the Circulatory system is transportation. It also helps to regulate body temperature by distributing heat through out the body and by assisting in retaining or releasing heat from the body by regulating blood flow near the body surface.
6 * RESPIRATORY SYSTEM
The respiratory system provides the blood with oxygen and gets rid of carbon dioxide. It consists of:
The nose
The pharynx
The larynx
The trachea
The bronchi
The lungs .
These organ form a lifeline for air to pass in and out of the body. The air passage are mostly lined with ciliated epithelium . Tigether these organs permit the movement of air into the tiny thin walled section of the lungs called alveoli. In the alreati oxygen from air is exchange for the waste product, carbon dioxide which is carried to the lungs by the blood so that it can be eliminated from the body.
7 * DIGESTIVE SYSTEM
The organs of digestive system are often seperated into two groups. The primary organs
Consisting of mouth, pharynx, oesopharygus , stomach, small and large intestine, rectum and anal canal.
The primary organs of digestive system from a tube open at both ends called gastro intestinal or gi tract. Food that enters the tract is digested. It's nutrients are absorbed and undigested residue is eliminated from the body as waste material called faceas.
The accessory organs assist in mechanical or chemical breakdown of ingested food.
8 * The Excretory SYSTEM
The organs of excretory system include:
Right and left kidneys - excretory gland.
Right and left ureters-. The ducts of kidney.
The bladder - the reservoir of urine.
The urethra - the passage from bladder to the outside.
The kidneys clear or clean the blood of the wast e products continuously produced by the metabolism of food stuff in the body cell. It also manintains electrolyte, water, acid base balance in the body.
9 * THE REPRODUCTIVE SYSTEM
The normal function of reproductive system ensure survival not of the individual but of the species - the human race. The production of hormones that permit the development of sexual characteristics, occur as a result of normal reproductive system activity.
The male reproductive structure includes the gonades called which produce sex cell or sperms.
The female gonades are ovaries .
female reproductive system
The accessory organs both in male and female reproductive system helps in the process of reproduction.
10 * THE LYMPHATIC SYSTEM
Lymphatic system is composed of:
The lymph
The lymphatic vessel
The lymph glands or nodes
Lymph is a fluid like plasma and the tissue fluid but in cases of infection it may contain bacteria.
Specialized lymphatic organs are such as tonsils , thymus and spleen.
* The lymphatic vessels are:
The thoracic duct which collects lymph from legs, trunk, left arm, left side of chest and left side of the head .
The right lymphatic duct which collects lymph from right arm, right side of chest and right side of the head.
Functions;
Lymph gland help to protect the body from infection by:
. Filtering the lymph to prevent germs from getting into blood stream and fighting to overcome them.
. Producing new lymphocytes for the blood.
The spleen is 121/2 cm. Long and 8 cm . broad and is protected by lower ribs . In some diseases such as typhoid fever, malaria it becomes enlarged and can be palpated at the upper abdomen.
. It produces new lymphocytes for the blood.
. It helps to fight the infection.
. It acts as a reservoir of RBC. 
11 * THE INTEGUMENTARY SYSTEM
It includes the skin and it's appendages which include hair, nails , sweat and oil producing glands. In addition highly specialized sense organs are embedded in in the skin. They permit the body to respond to pain, pressure, touch and changes in temperature. 
It's primary function is protection against invasion of harmful bacteria, bars entry of most chemicals, minimizes the chances of mechanical injury. It regulates body temperature by sweating, synthesizing important chemicals and harmones and functions as a sophisticated sense organ . As we study more details about the functions of the organ system we will see no one body system functions entirely independently of other system . Instead we will see they are functionally , structurally interrelated and interdependent.
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