Lecture 14 2/13/24 Flashcards
What are the general characteristics of the endocrine system?
-ductless gland system
-epithelial in origin
-highly vascular
-utilizes hormones
-endocrine signaling mechanism/action on distant cells
What is the major goal of the endocrine system?
maintain homeostasis
What are the characteristics of hormones?
-travel via bloodstream
-bind to receptors
-produce slow, sustained responses
-highly controlled via tiered setups and neg. feedback loops
What is the hypothalamus?
area of the brain that links the CNS to the endocrine system
What are the two main parts of the pituitary?
-anterior pituitary
-posterior pituitary
What are the two parts of the anterior pituitary?
-pars distalis
-pars intermedia
What is the main part of the posterior pituitary?
pars nervosa
Why is the anterior pituitary also known as the adenohypophysis?
it is the glandular portion of the pituitary
Why is the posterior pituitary also known as the neurohypophysis?
it is an extension of the hypothalmus/brain
What is the sella turcica?
recess of skull in which the pituitary lives
Which hormones produced by the hypothalamic neurons are released into the pars nervosa?
-antidiuretic hormone
-oxytocin
What are the characteristics of the posterior pituitary?
-cell bodies are large neurons within the hypothalamus
-axons comprise pars nervosa
-supported by pituicytes
-axons terminate on blood vessels to release ADH and oxytocin
What is the purpose of the releasing hormones produced by the hypothalamic neurons?
to stimulate the anterior pituitary pars distalis cells
What are the characteristics of the pars distalis?
-largest part that secretes majority of hormones
-requires releasing hormone from hypothalamus
-cell types include chromophobes, acidophils, and basophils
Which hormones are produced by the pars distalis basophils?
-ACTH
-TSH
-FSH
-LH
Which hormones are produced by the pars distalis acidophils?
-GH
-PRL
How can basophils producing LH be distinguished using IHC staining?
those producing LH will stain brown
What are the characteristics of the pars intermedia?
-made up of a single cell population
-produces melanocyte stimulating hormone
-right up against pars nervosa
What are the main components of the adrenal gland?
-capsule
-cortex
-medulla
What are the three components of the adrenal gland cortex?
-zona glomerulosa
-zona fasciculata
-zona reticularis
Which hormone type is produced by the zona glomerulosa?
mineralocorticoids (salt)
Which hormone type is produced by the zona fasciculata?
glucocorticoids (sugar)
Which hormone type is produced by the zona reticularis?
weak androgens (sex)
What are the characteristics of the thyroid?
-composed of follicles
-activity regulated by TSH
What are the characteristics of thyroid follicular cells?
-simple cuboidal/columnar
-produce thyroglobulin, which is stored as colloid in the lumen
What are the characteristics of thyroid parafollicular cells?
-in interstitium between follicles
-secrete calcitonin in response to high blood calcium to lower levels
What are the characteristics of parathyroid gland chief cells?
-tightly packed
-secrete parathormone/PTH in response to low blood calcium to raise levels
What are the characteristics of the pineal gland?
-stimulated by light perceived by retina
-thought to have a role in circadian rhythm and seasonal repro.
-pinealocytes produce melatonin
What are the characteristics of pancreatic islets?
-98% exocrine to 2% endocrine
-contain alpha, beta, delta, and other cells
Which hormones are produced by pancreatic alpha cells?
-glucagon
-CCK
-GIP
Which hormones are produced by pancreatic beta cells?
-insulin
-IAPP
Which hormone is produced by pancreatic delta cells?
somatostatin
Which hormone is produced by other pancreatic cells?
gastrin
