BI459 Lecture Notes - Lecture 5: Paraventricular Nucleus Of Hypothalamus, Supraoptic Nucleus, Median Eminence
Document Summary
The activities of the pituitary are mainly controlled by the hypothalamus. Formed by a collection of nuclei (12) and fiber tracts. 3 main divisions posterior; middle (tuberal); anterior. Anterior nuclei: preoptic (pr), supraoptic (so), suprachias matic (sc) Middle nuclei: paraventricular (pvn), dorsomedial (dmn), ventromedial (vmn), lateral (l), arcuate (ar) Posterior nuclei: dorsal (dn), posterior (pn), mammillary bodies (mb), Endocrine, autonomic, somatic and emotional functions: control of body temperature, control of blood circulation/pressure, regulation of food and water intake. Maintenance of internal environment in a physiological range homeostasis. Functions of the hypothalamus mechanisms: neural signals. Autonomic modulation: anterior hypothalamus parasympathetic effects, posterior hypothalamus sympathetic effects. Allows control of heart rate, vasoconstriction, digestion, sweating, etc: endocrine signals, releases neurohormones into general circulatory system via the posterior pituitary/neurohypophysis, releases neurohormones to portal system regulated function of anterior pituitary/adenohpophysis. Magnocellular (large neurons: somas in son (supraoptic nucleus) and pvn, axon terminals in neurohypophysis. Parvocellular (small neurons: somas in different nuceli, axons reach median eminence.
