Pituitary gland, Biology

Assignment Help:

PITUITARY GLAND (HYPOPHYSIS CEREBRI) -

  • It develops from ectoderm of the embryo.
  • The pituitary gland is located just below the hypothalamus. The pituitary gland is situated in a depression the sella turcica of sphenoid bone of the skull.
  • The pituitary gland is the smallest endocrine gland. It is about 1.3 cm in diameter and weighs about half a gram.
  • The gland is attached to the brain by a stalk the infundibulum which is continuous with the hypothalamus above.
  • Adenohypophysis or pars distalis and the posterior lobe or neurohypophysis or pars nervosa.
  • Adenohypophysis originates as Rathke's pouch from dorsal wall of stomodaeum in the embryo, but later its connection with the stomodaeum disappears.
  • The neurohypophysis originates as an outgrowth from the floor of the diencephalon.
  • A third lobe, called the intermediate lobe or pars intermedia is a part of adenohypophysis.

1108_pituitary gland.png

  • Adenohypophysis comprises about 75% part of the pituitary gland.
  • The hypophysial portal veins carry blood containing neurohormones (releasing factors) from the hypothalamus to tbe adenohypophysis.
  • Neurohypophysis comprises about 25% part of the pituitary gland. The axons of neurosecretory cells (secretory neurons) extend into the neurohypophysis where these axons terminate as axon terminals. These terminals are embedded in a neuroglial tissue formed of large and branched cells called pituicytes.
  • No hormones are synthesized in neurohypophysis but two hormones, synthesized in the hypothalamic neurosecretory cells remain stored in very small vesicles in the axons and terminals. These vesicles are called Herring bodies.

Related Discussions:- Pituitary gland

Define the ltlt pasteurization method, Define the LTLT Pasteurization Metho...

Define the LTLT Pasteurization Method? In LTLT pasteurization, the pasteurization time is in the order of minutes and related to the temperature used; two typical temperature/t

Which forms the inner walls of blood vessels, The kind of epithelium which ...

The kind of epithelium which forms the inner walls of blood vessels is : 1. cuboidal epithelium 2. columnar epithelium 3. ciliated columnar epithelium 4. squamous epith

Excreation, What is the excreatory organ in agama lizard

What is the excreatory organ in agama lizard

Lyme disease, Lyme disease It is a metazoonoses caused by a spirochaete, B...

Lyme disease It is a metazoonoses caused by a spirochaete, Borrelia burgdorferi. The disease based on the specific symptoms, is also known as erythema migrans (ECM) or lyme  arthr

Test hypothesis that vertebrates evolved from echinoderms, Q. Evolutionaril...

Q. Evolutionarily protochordates may be intermediate animals between invertebrates and vertebrates. Imagine a scientist is testing the hypothesis that vertebrates evolved from echi

What is xaxim, What is xaxim? Most pteridophytes have subterraneous ste...

What is xaxim? Most pteridophytes have subterraneous stems parallel to the substrate known as rhizomes. Xaxim is a type of pteridophyte with an aerial stem generally perpendicu

What is the senses explain their vision , What is the Senses explain their ...

What is the Senses explain their Vision ? Vision :  The human eye consists of structures which evolved together to focus light on a sensitive area called the retina. Light f

Which functional group ionization is stabilized by resonance, In which of t...

In which of the following functional groups ionization is stabilized by resonance? Select one: a. Carboxyl b. Hydroxyl c. Amine d. Aldehyde e. All of the above

Which of the vertebrate classes are warm-blooded, Which of the vertebrate c...

Which of the vertebrate classes (a) are 'warm-blooded', (b) reproduce by laying eggs?   (a) Birds and mammals are 'warm-blooded'. (b) Fish, Amphibia, Reptiles

Define conservation genetics and hybridization, Define Conservation genetic...

Define Conservation genetics and hybridization? Is the genetic integrity of European wolves threatened by hybridization along with free-ranging dogs? To ascertain the extent of

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd