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

Explain the nervous system characterized in echinoderms, How are the symmet...

How are the symmetry and the nervous system characterized in echinoderms? Adult echinoderms, with cnidarians, are the animals that present radial symmetry, i.e., their body str

Peak flow velocity, Peak Flow Velocity  fs  derived  from Doppler  shift by...

Peak Flow Velocity  fs  derived  from Doppler  shift by  rearranging Doppler equation: V = C/2 x ΔF/Fo Various  information can be obtained from spectral display

What is a ph meter, What is a pH meter? A pH meter is a device used for...

What is a pH meter? A pH meter is a device used for measuring. pH of any unknown solution. It is composed of: a) A reference electrode b) Glass electrode whose potential

Prophase of karyokinesis, 1. This is very prolonged phase, and differs from...

1. This is very prolonged phase, and differs from the prophase of mitosis, because in this Chromosomes behave as homologous pairs. 2. Each diploid cell has two chromosomes of ea

What is the function of the iris and of the pupil, What is the function of ...

What is the function of the iris and of the pupil? The iris works like the diaphragm of a photographic camera as it has muscles that contract or relax varying the pupil diamete

Explain phenotypical characteristics of alleles of a gene, What are few exa...

What are few examples of phenotypical characteristics that present two or more varieties and of phenotypical features that do not vary? In relation to the genes correspondent to th

Organs in animal - excretion, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Ruminal tympany (bloat), R uminal tympany (Bloat) It is the over-diste...

R uminal tympany (Bloat) It is the over-distension of the rumen with gases which may be either frothy or free gas. The disease is characterized by change in silhouette of the

What is the function of the plant cell wall, Q. What is the function of the...

Q. What is the function of the plant cell wall? The plant cell wall has protective and structural functions. It plays an significant role in the constraint of the cell size, pr

Stages of aerobic respiration, Stages of Aerobic Respiration: Glycoly...

Stages of Aerobic Respiration: Glycolysis (cytoplasm) Process 2ATP used for Glucose -> Fructose 1,6 bisphosphate Fructose splits into G3P and DHAP. DHAP

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