here you find information about solar system, but it is in brief, we shall update it soon with more information.

There are many planetary systems like ours in the universe, with planets orbiting a host star. our planetary system is named the “solar” sytem because our sun is named Sol , after the latin word for sun, “solis”, and anything related to the sun we call “solar.”

Age 4.568 billion years

our solar system formed about 4.5 billion years ago from a dense cloud collapsed, possibly due to the shockwave of a nearby exploding star, called supernova. when this dust cloud collapsed. it formed a solar nebula – a spinning, swirling disk of material. As is typical of molecular clouds, this one consisted mostly of hydrogen, with some helium, and small amounts of heavier elements fused by previous generations of stars.

The solar system consists of the Sun, planets, dwarf planets, moons, and numerous smaller objects such as comets and asteroids. 194 moons, 3,583 comets and 796,289 asteroids have been found in the solar system. 99.86% of the solar system’s mass is found in the Sun.

The Sun is our nearest star. It is, as all stars are, a hot ball of gas made up mostly of Hydrogen. The Sun is so hot that most of the gas is actually plasma, the fourth state of matter. The sun is classified as a G-type main-sequence star, or G dwarf star, or more imprecisely, a yellow dwarf. The planets in order from the Sun based on their distance are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Approx distance between neptune (8th) planet and sun is 4.476 billion km.
It is 143.73 billion km from the Sun, thus giving the Solar System a diameter of 287.46 billion km approx.

Based on where the planets end, you could say it’s Neptune and the Kuiper Belt. If you measure by edge of the Sun’s magnetic fields, the end is the heliosphere. If you judge by the stopping point of Sun’s gravitational influence, the solar system would end at the Oort Cloud. The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars, that is occupied by a great many solid, irregularly shaped bodies, of many sizes but much smaller than planets, called asteroids or minor planets.
The asteroid belt formed from the primordial solar nebula as a group of planetesimals.
Planetesimals are the smaller precursors of the protoplanets. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitationally perturb each other’s orbits and collide, gradually coalescing into the dominant planets.

The Kuiper belt, occasionally called the Edgeworth–Kuiper belt, is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger – 20 times as wide and 20–200 times
as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed.
The Kuiper belt is home to three officially recognized dwarf planets: Pluto, Haumea and Make make. Kuiper belt contain comets, mostly ice comets with black colour. When the orbit of the comet brings it close to the Sun, the ice evaporates into space, leaving some of the fine dust sitting on the surface. The dust is fine like talcum powder because comets are too small to have
enough gravity to squeeze the dust together into larger particles. The surface is very black.

The sun sends out a constant flow of charged particles called the solar wind, which ultimately travels past all the planets to some three times the distance to Pluto before being impeded by the interstellar medium. This forms a giant bubble around the sun and its planets, known as the heliosphere.

The heliosphere is the vast, bubble-like region of space which surrounds and is
created by the Sun. In plasma physics terms, this is the cavity formed by the Sun in the
surrounding interstellar medium. The “bubble” of the heliosphere is continuously “inflated”
by plasma originating from the Sun, known as the solar wind.
The heliosphere acts as a shield that protects the planets from interstellar radiation.

The Oort Cloud lies far beyond most distant edges of the Kuiper Belt. While the planets of our solar system orbit in a flat plane, the Oort Cloud is believed to be a giant spherical shell surrounding the Sun, planets and Kuiper Belt. The outer limit of the Oort cloud defines the cosmographic boundary of the Solar System and the extent of the Sun’s Hill sphere. The outer Oort cloud is only loosely bound to the Solar System, and thus is easily affected by the gravitational pull both of passing stars and of the Milky Way itself. The Oort Cloud is made up of icy pieces of space debris.
In short, gravity from the planets shoved many icy planetesimals away from the Sun, and gravity from the galaxy likely caused them to settle in the borderlands of the solar system, where the planets couldn’t perturb them anymore. And they became what we now call the Oort Cloud.
The Oort cloud is thought to occupy a vast space from somewhere between 2,000 and 5,000 au .
The outer limit of the Oort cloud defines the cosmographic boundary of the Solar System and
the extent of the Sun’s Hill sphere.

to be continue…



ENDOCRINOLOGY in short and if we get more information then we’ll update this post.



  1. Adrenaline hormone
  2. Cortisol hormone
  3. Steroid hormone

Adrenaline –

             Action of the adrenalin include increasing the heart rate ,increasing blood pressure , expending the air passage of the lunge entering of the pupil in the eye.


         Increases the gluconeogenesis in the liver.

Inhibitory effect on insulin which stop transport of glucose into the cells

Cortisol has diurnal variation.

No diurnal change In cushings syndrome.


                   Steroid hormones play an important role in    –

Carbohydrate regulation (glucocorticoids)

Mineral balance (mineralocorticoide)

Reproductive function (gonadal steroids)

Steroid play a important role in inflammatory responses stress responses bone metabolism, cardiovascular fitness, behavior


A pink gland with two lobes located in the thoracic cavity posterior to the sternum.

It is large during the child hood and puberty but shrinks during adulthood.


         Its primary function is to stimulate the production of T Cells which are an important part of the immune system.

Thymosin also assists in the development of B Cells to plasma cell to produce antibodies.

 Over production of thymosin- Lymphocytosis


HORMONE     Insulin 


           Insulin is the only hormone that reduce blood glucose levels and it does this by activating the glucose transport mechanism and glucose utilizing metabolic pathway in different tissues of the body.


4) Testes

Hormone -androgen (testosterone)


  1. Growth development and maintenance of male reproductive organs.
  2. Sexual differentiation and secondary sexual characteristics.
  3. Spermatogenesis
  4. Male pattern of aggressive behavior.
  5. pubertal transformation.
  6. Enlargement of testes ,penis and scrotum.
  7. Pubic and axillary hair.
  8. Bone growth
  9. RBC mass increase
  10. Skeletal muscle mass increase
  11. Larynx enlarges -deeping increase
  12. Development of beard.

5) Ovaries-

Hormone – Estrogens  and progesterone


  1. Maturation growth and development of the reproductive organs
  2. Stimulation of normal physiological process of the tubular reproductive tract.
  3. Growth of the uterine tube
  4. Development of the endometrial lining of the uterus
  5. Increase the vascularity of the uterus
  6. Induction of the behavioral estrus
  7. Dilation of the cervix liquefaction of mucous plug.
  8. Under the influence of the estrogens the uterus is less susceptible to infection.


Function of thyroid gland-

  1. Role in growth
  2. It has role in development
  3. It stimulate heart rate and contraction.
  4. Stimulate synthesis of proteins and carbohydrates
  5. It encreases vit. Requirements.

Function of thyroid hormone

  1. Maturation of bone
  2. Maturation of skeletal system
  3. Maturation of nerves in CNS
  4. Regulation of growth hormone
  5. Regulation of body temperature
  6. Generation of heat
  7. Metabolic function
  8. It  influence mood and behaviour

Disorders of thyroid gland – Hypothyroidism             


Hormone  Calcitonin

Function of PTH

             Bone  Parathyroid hormone stimulates the release of calcium from large calcium stores in the bone into the bloodstream.

This increases bone destruction and decreases the formation of new bone.

Kidney Pth reduces loss of calcium in urine.

Pth stimulate the production of active vitamin D in the kidney.

Intestine  pth indirectly increases calcium absorption from food in the intestine via its effects on vitamin D metabolism.


Posterior pituitary

Hormone     ADH

Function        Stimulate water reabsorption by kidney.

Hormone   Oxytocine

Function   Stimulate uterine muscle contraction release of milk by mammary gland.

Anterior pituitary

Hormone   TSH

Function     Stimulate thyroid gland.

Hormone    ACTH

Function      Stimulate adrenal cortex.

Hormone    PRL

Function      Milk production

Hormone   GH

Function      Cell division , protein synthesis ,and bone growth.

Hormone   MSH

Function Unknown function in humans regulates skin color in lower vertebrates.