Question

Pharyngeal pouches which are reduced gills are found in
(a) Birds
(b) Mammals
(c) Reptiles
(d) Fishes

Answer 1

Hint In the embryonic development of vertebrates, pharyngeal pouches arise between the pharyngeal arches on the endodermal side. The pharyngeal grooves (or clefts) separate the arches on the lateral ectodermal surface of the neck.

Complete step by step answer:
The very first pouch: The future auditory tube (Pharyngotympanic Eustachian tube), the middle ear, the mastoid antrum, and the inner layer of the tympanic membrane are all lined with endoderm. Mandibular nerve provides derivatives of this pouch.
The second pouch is: The palatine tonsils, which are supplied by the facial nerve, contribute.
The third pouch is: Dorsal and ventral wings are found in the third pouch. The inferior parathyroid glands are derivatives of the dorsal wings, while the ventral wings merge to generate the cyto reticular cells of the thymus. Cranial Nerve IX, glossopharyngeal neural, is the principal nerve supply to the pouch's derivatives.
The fourth pouch is: Superior parathyroid glands and the ultimobranchial body, which forms the thyroid gland's parafollicular C-Cells, are derivatives. Laryngeal musculature and cartilage (along with the sixth pharyngeal arch). Superior laryngeal nerve is the nerve that supplies these derivatives.
The fifth pouch is: Thyroid C-cells are found in the fourth pouch, which has a rudimentary structure.
This is the sixth pouch: The musculature and cartilage of the larynx are formed in part by the fourth and sixth pouches. The recurrent laryngeal nerve provides nerve supply.
The endoderm between the pharyngeal arches forms pharyngeal pouches during embryonic development. In fish, the pouches align with the clefts, and these thin segments produce gills.

As a result, option D is the proper response.

Note: The thyroid begins towards the base of the tongue, between the first and second pharyngeal pouches. The thyroid diverticulum is formed when endodermal cells of the primitive pharynx proliferate in the third week of pregnancy, around day 20-24.