VPB 121: Veterinary Physiology - II (2+1)

HYPOTHALAMUS

• Responsible for involuntary internal response of body systems and prepares for appropriate action in a particular emotional state. It occupies the ventral portion of the brain stem.

 

• It serves as the major control of visceral motor activity namely CONSUMMATORY MOTOR BEHAVIOUR.
• The hypothalamus contribute to rage behaviour, affects emotions like fear response, arousal, exploration and orientation.
• The hypothalamus and its    related structures control many internal conditions of the body such as body temperature, osmolality of the body fluids, the drive to eat and drink etc. known as "the vegetative functions of the body".
• It receives connection from amygdala, hippocampus, dorsomedial nucleus of thalamus septal area, ascending recticular formation, globus pallidus and cerebral cortex.

• Hypothalamus sends output signals downward through the brain stem reticular formation of mesencephalon, pons and the medulla as autonomic outflow and upward to the areas of the anterior thalamus and limbic cortex.
• It regulates emotional and visceral motor activity by passing efferent fibres to dorso medial nucleus of thalamus, anterior group of nuclei, superior colliculus and tegmentum (mid brain).
• The hypothalamus includes optic chiasma, tuber cinereum, mamilary bodies, median eminence, infundibulum and neurohypohysis.

It forms that portion of  the rhinencephalon  (limbic system) which are closely related to the behaviour.