Pineal, Hypothalamus, Pituitary Flashcards
Pineal gland
Located in the 3rd ventricle. It regulates the circadian rhythm, regulates seasonal biorhythms, and suppresses gonadal functions
Melatonin
Produced at night by the pineal gland
Seratonin
Produced during the day by the pineal gland
HIOM (hydroxyindole-o-methyltransferase)
Converts seratonin to melatonin
Superior cervical ganglion
Promotes melatonin synthesis. By direct autonomic sympathetic imput
Suprachiasmatic nucleus (hypothalamus)
Inhibits melatonin synthesis. By visual input through here
Pinealocytes
main cells of the pineal gland producing the serotonin and melatonin
Corpora arencacea
unique feature of the pineal gland, called “brain sand”
Nuclei
used to describe the cluster of cell bodies of neurons in the hypothalamus
Ventro-medial nucleus
Projects to median eminence. Regulates appetite, sleep and wake center; emotions, behavior
Supraoptic nucleus
Projects to the pars nervosa. They secrete vasopressin (ADH) to regulate water reabsorption in the kidney
Paraventricular nucleus
Projects to the pars nervosa. They secrete oxytocin to regulate milk ejection in mammary gland and uterine contraction
Medial eminence
Vascular bed that is a termination point for the medial nuclei. This is where the hormones drain into the pars distalis
Primary capillary plexus
Fenestrated capillaries of the median eminence located within the pars tuberalis
Pars nervosa
Termination point of the supraoptic and paraventricular nuclei. Contains the herring’s bodies
Superior hypophyseal artery
Supplies the median eminence
Herring’s bodies
Terminal dilations (secretory vesicles) of the inferior hypophyseal artery located within the neurohypophysis. Store oxytocin and vasopressin.
Sella turcica
small cup-like portion of bone that contains the pituitary gland
Neurohypophysis (neuronal)
Posterior pituitary containing the pars nervosa and infundibular stalk (stem and median eminence). It contains unmyelinated axons
Adenohypophysis (epithelial)
Anterior pituitary containing the pars distalis, pars intermedia, and pars tuberalis
Pars distalis
Main portion of the adenohypophysis
Pars intermedia
Small section of the adenohypophysis that separates the pars distalis from the pars nervosa. Stains like basophils. Secrete MSH
Pars tuberalis
Tube-like structure of adenophypophysis that wraps around the neuronal portion of the infundibular stalk. Stains like basophils. Secretes mostly LH and FSH
Pituicytes
Highly branched glial cells in the neurohypophysis
Chromophobes
Do not stain or stain poorly and they lack granules
Chromophils
Stain intensely with different dyes and they contain secretory cells (acidophils and basophils)
Acidophils
stain with eosin and orange G (stain yellow/orange) (simple proteins)
Basophils
stain with hematoxilin and PAS (stain purple/blue) (glycoproteins)
Hormones secreted by acidophils
Growth hormone and prolactin
Hormones secreted by basophils
TSH, FSH, LH, ACTH, lipotropin, endorphin, MSH
Rathke’s cysts
Located within the pars intermedia. Filled with colloid and lined by cuboidal epithelium
Posterior hypothalamus
regulates sympathetic autonomic NS (↑heart rate, vasoconstriction)
Anterior hypothalamus
regulates parasympathetic autonomic NS (↓heart rate, vasodilatation), and body temperature
Epiphysis
Pineal gland
Hypophysis
Pituitary gland
