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

What is the parasite that causes toxoplasmosis, What is the parasite that c...

What is the parasite that causes toxoplasmosis? How is the disease transmitted and what are its typical manifestations? Toxoplasmosis is caused by the protozoan Toxoplasma gond

Explain the term- pedon and polypedon, Explain the term- pedon and polypedo...

Explain the term- pedon and polypedon The characteristics of soil do not change vertically downwards only, there are lateral variations also as soil is a three dimensional body.

Explain about doubling earth''s human population, Identify three possible c...

Identify three possible consequences of doubling Earth's human population. Increased CO2 in the atmosphere and globalwarming; increased use of resources to producehomes, schoo

Define determinants of food security - food utilization, Define Determinant...

Define Determinants of Food Security - Food Utilization? It is the proper biological use of food, requiring a diet providing sufficient energy and essential nutrients, potable

MACRO TAXONOMY, WHAT IS CHARACTER SELECTION CRITERI

WHAT IS CHARACTER SELECTION CRITERIA

What is atom, What is atom? Atoms are the smallest component of matter ...

What is atom? Atoms are the smallest component of matter that determine its unique chemical and physical properties. They are composed of negatively charged electrons, positive

What are the factors which influence the spoilage of meat, Q. What are the ...

Q. What are the factors which influence the spoilage of meat? Can you list a few? Ans. Sure enough, you should be able to enumerate these having learnt about them earlier

Long lasting vaccine against common cold, Q. Why does not a long lasting va...

Q. Why does not a long lasting vaccine against common cold exist yet? Viruses that present a high mutation rate like the virus that causes the common cold escape easily from th

Digestion, Digestion The nutritional requirements and the various way...

Digestion The nutritional requirements and the various ways used by heterotrophic organisms to obtain nutrition. Whether food is used to give energy or to build the body, the

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