Changes

==Thymus==

==Thymus==

Reptiles usually have two pairs of thymus glands located cranial to the [[Snake Cardiovascular System|heart]]. They are closely associated with the common carotid artery, jugular vein and vagus nerve.  In snakes there are significant species differences with some [[Boidae|boids]], [[Colubridae|colubrids]] and crotalids having only a single bilateral lobe.  The thymus decreases in weight with age.

Reptiles usually have two pairs of thymus glands located cranial to the [[Snake Cardiovascular System|heart]]. They are closely associated with the common carotid artery, jugular vein and vagus nerve.  In snakes there are significant species differences with some [[Boidae|boids]], [[Colubridae|colubrids]] and [[Crotalinae|crotalids]] having only a single bilateral lobe.  The thymus decreases in weight with age.

==Parathyroids==

==Parathyroids==