Hypothalamus and temp Flashcards
Supraoptic nucleus
anterior hypothalamus. above optic chiasm
Tuberal nucleus
medial. Above pituitary
Mammillary nucleus
posterior. Above and including the mammillary bodies
Dorsal longitudinal fasciculus
To autonomic nuclei in brainstem reticular system and spinal cord
Medial forebrain bundle
To brainstem reticular formation
Mammillotegmental tract
from mammillary bodies to midbrain reticular formation
Somatic motor response pathway
hypothalamus –> UMN in brainstem reticular formation –> LMN –> skeletal muscle
Actions involving hypothalamic somatic motor response pathway
vomiting, laughing, crying, and facial expressions. Chewing and swallowing
Direct hypothalamus regulation of endocrine function
Posterior pituitary. SON and paraventricular nuclei –> vasopressin and oxytocin –> posterior pituitary. Action potentials –> release to general circulation
Indirect hypothalamus regulation of endocrine function
Anterior pituitary. Hypothalamic hormones –> hypothalamo-pituitary portal circulation –> regulated release of hormones from anterior pituitary –> regulated release of hormones from peripheral endocrine organs
Hypothalamus role in emotion and motivation
Somatic = escape, fighting, biting, hissing, facial expressions Autonomic = blushing, drymouth, sweating, GI effects, fainting Endocrine = activated adrenal cortex and medulla
Sham rage
dissociation of rage response from appropriate environmental context. Remains intact if hypothalamus is disconnected from higher brain areas. Disconnection from brainstem –> abolished sham rage
Fever
REGULATED increase in body temp
Fever mechanism
exogenous pyrogen –> cytokine (IL-1, -6, TNF) release to OVLT in hypothalamus –> PGE2 –> POAH thermoreceptors –> increased set point –> vasoconstriction, shivering –> fever
Hypothalamus role in heat response
warm receptors –> excited preoptic anterior hypothalamus, inhibited posterior hypothalamus –> heat loss (skin vasodilation, sweat, seek cold environment)
