Question

1. Write very briefly about following:
(i) Kolliker's pit​

Answer 1

Answer: It is explained as follows:

Explanation:

• Kollicker's pit is a sensory organ present in the nerve cord of chordates.
• The anterior area of the cerebral vesicle contains a depression called Kollicker's pit, which is made up of ciliated ectodermal cells on the roof.

• It designates the spot where the larval neuropore closes as the adult neural tube develops. Despite lacking sensory cells, it is regarded as an olfactory chemoreceptor because of its location next to cyclostome's single nostrils.

#SPJ2

Answer 2

Kolliker's pit is a depression of ciliated ectodermal cells on the roof in the anterior region of the medulla

Kolliker's pit

• Kolliker's pit is a depression of ciliated ectodermal cells on the roof in the anterior region of the medulla. This marking indicates the point at which the larval neural tube closes up.
• This organism lacks sensory cells, but it is considered an olfactory chemoreceptor because it is located near the single nostril of cyclostomes.
• Prior to 'hearing initiation', the development of cochlear inner hair cells (IHCs) and primary auditory neurons undergo experience-independent activity, which is thought to be important in retaining and refining connections in the absence of sound.
• A major hypothesis regarding the origin of this activity involves the group of columnar epithelial supporting cells that make up the Kölliker organ, which exists only during this critical period of auditory development. There is evidence that a purinergic signalling mechanism is involved in such activity.

(#SPJ2)