endocrine system Flashcards
(30 cards)
it t serve as effectors to regulate the activities of various cells, tissues, and organs in the body
hormones
- they r chemical messengers that promotes/ increase activity of certain organs or decreases the activity of certain organs (hence, same with CNS wherein the the nervous system deliver messages through AP, whereas the endocrine system delivers messages through hormones)
- possess no excretory ducts
- secretions are carried to specific destinations via the ECM of CT and vascular system
- endocrine glands are ductless and send hormones directly into your bloodstream/ lymphatics
what are the 2 functional components of pituitary gland or Hypophysis
Anterior lobe (adenohypophysis):
- regulates other endocrine glands and some nonendocrine tissues
- consists of cells that can SYNTHESIZE and produce hormones
Posterior lobe (neurohypophysis):
- extension of the CNS that stores and releases secretory products from the hypothalamus
- cells does not have the capability to synthesize hormones but rather able to STORE hormones that was produced by the hypothalamus
A structure in early development that forms parts of the anterior pituitary gland
Rathke’s pouch
What are the three parts derived from Rathke’s pouch?
Pars distalis
- hv 5 functional cell types based on immunocytochemical reaction
- almost 70% of the tissue in the adenohypophysis
- can be divided either based on
1. function-based division
- this divisions divides cells based on what they secrete
(insert ppt-watch recording)
- histochemical characteristics
chromophils
- acidophils
- basophils
chromphobes
Pars intermedia
- boundary between adenohypophysis tissue and the neurohypophysis tissue
- secretes alpha & beta endorphins and melaside stimulating factors
Pars tuberalis
- no secretory function
- it is continuous with the infundibulum or stalk leading to the hypothalamus
it is a storage site for neurosecretions of the neurons of the hypothalamus
neurohypophysis
- does not hv secreting characteristics but stores secretions coming from the hypothalamus
- consists of:
→ pars nervosa
neurosecretory bodies:
⤷ bundles of neurons
⤷ storage sites of the hormones from the hypothalamus
⤷ aka herring bodies
pituicytes:
⤷ support neurosecretory bodies and nerves that can be found in the herring bodies
⤷ function is similar w glial cells in the nervous system
→ infundibulum
what are the hormones that neurohypophysis secretes and its function
vasopressin/ ADH/ arginine vasopressin
- increases water permeability of renal collecting ducts
oxytocin
- stimulates contraction of mammary gland myoepithelial cells and uterine smooth muscle
this regulates pituitary gland activity
hypothalamus
- secretes hormones regulating the cells of adenohypophysis
*composed more of nerve tissue rather than ep tissue
what are the hormones that adenohypophysis secretes
(ppt-watch recording)
*secretes hormones regulating the cells of the adenohypophysis
it is a bundle of axons that courses into the neurohypophysis from two important hypothalamic nuclei
hypothalamohypophyseal tract
two important hypothalamic nuclei:
- Supraoptic nuclei
- Paraventricular nuclei
*these are the sources of the oxytocin and ADH
it is the blood vessels that carries the releasing hormones from the hypothalamus to the adenohypophysis
hypothalamohypophyseal portal system
- vascular and nervous tract networks that promotes the connection btwn pituitary gland and hypothalamus
- courses into the neurohypophysis from the hypothalamic nuclei
is a flattened, pine cone-shaped neuroendocrine gland that regulates daily body rhythm.
pineal gland or epiphysis cerebri
- regulates the circadian rhythm of the body during the normal day and night cycle
2 types of parenchymal cells of pineal gland
- Pinealocytes
- produces melatonin which regulates the body rhythms day-night cycle of the body
(ppt)
- secretion of melatonin is stimulated by dark environment - Interstitial cells
- same function role as the glial cells of the nervous system
- support pinealocyte, majority
-
these are calcified concretions derived from calcium phosphates and carbonates
corpora arenacea or brain sand
it is a bilobate endocrine gland consisting of two lateral lobes connected by isthmus.
thyroid gland
it constitute the functional units of the gland, covered by the follicular epithelium
Thyroid follicles
- Follicular cells (principal cells):
are responsible for the production of thyroid hormones T4 and T3. - Parafollicular cells (C cells):
secrete calcitonin, a hormone that regulates calcium metabolism.
(ppt)
these are small endocrine glands closely associated with the thyroid
parathyroid glands
what cells can be found in the parathyroid glands
Principal (chief) cells:
are the endocrine cells of the parathyroid glands, responsible for synthesis, storage, and secretion of parathyroid hormone (PTH).
Oxyphil cells:
constitute minor portion of the parenchymal cells.
no known secretory role.
it is a paired organs located in the retroperitoneal space of the abdominal cavit
adrenal glands
- covered with a thick CT capsule
what are the parenchymal cells of Adrenal Glands
it is is organized into two distinct regions:
1. Cortex: steroid-secreting portion
2. Medulla: catecholamine-secreting portion
what are the layers of the adrenal cortex and its secretions
(ppt)
Zona glomerulosa secretes mineralocorticoids
Zona fasciculata secretes glucocorticoids
Zona reticularis secretes androgens
what are adrenal medulla made of
- chromaffin cells
- large, pale-staining epithelioid cells
- main functional cells in the adrenal medulla
- secretes catecholamines – specifically epinephrine and norepinephrine
- pale staining - ganglion cells
function of epinephrine and norepinephrine
prepare the body for the “fight-or-flight” response (e.g., increased heart rate, energy, and alertness).
they constitutes the “master glands”/ switch of the endocrine system since they regulate the activities of all the endocrine organs
hypophysis and hypothalamus
[hypothalamus is like the brain behind the boss — it’s the part of your brain that controls the pituitary gland, which is the master gland of the endocrine system.
pituitary is the boss, the hypothalamus is the manager or command center that gives the boss instructions.]
differences btwn neurohypophysis and adenohypophysis
- Main Tissue Type
- Cells Present
- Function
- Connection to Brain
- Hormone Source
Neurohypophysis (Posterior Pituitary):
- Nerve tissue (nervous system)
- Neurons, axons, neuroglia (support cells)
- Stores & releases hormones from hypothalamus
- Direct extension of the hypothalamus (via axons)
- signals
Hormones come from the hypothalamus
Adenohypophysis (Anterior Pituitary):
- Epithelial tissue (glandular/secretory cells)
- Hormone-producing cells (endocrine cells)
- Makes and secretes its own hormones
- Controlled by hypothalamus through blood
- Hormones are made in the adenohypophysis
