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Endocrine system (2)
-controlling system of the body that works with the N.S
-coordinates and integrates the activity of the body's cells
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Endocrine glands can be..(4)
-isolated structure or organ
-part of a larger organ
-few cells or a single cell
-widely distributed throughout the body
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What are hormones?
chemical messengers synthesize by the cells of the endocrine system
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What do hormones influence?
The metabolic activity of other cells
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What are the target cells or organs of hormones?
The cells they affect
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Significant difference between rapid nervous system and hormones?
hormone effects take longer to begin than the rapid nervous system but they have prolonged effects
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Endocrine cell arrangement) (2)
-endocrine organs have cells arranged in cords, clusters, or follicles
- -surrounded by numerous blood vessels
- *to empty their contents into blood stream
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Difference between exocrine and endocrine?
Endocrine are doubtless glands while exocrine release product into a duct system
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How are glandular epithelium developed?
By ingrown of epithelial tissue that will form ducts
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What is a gland?>
- One of more cells that produce a product
- *exocrine or endocrine
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Exocrine
Release into ducts still connected to surface of the epithelium
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Endocrine (2)
No ducts
secrete into blood vessel located near the cells
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Pathway from endocrine to target organs
-endocrine glands relaxes hormones into blood vascular system surrounding it, then blood distributes the hormones, then hormones act on target organs
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examples of target cells
-bone marrow
-skeletal msucle
-osteobalsts
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paracrine cells
affect immediately surrounding cells
*I give heart to my valentine
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autocrine cells
- Affect themselves
- *same cell
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hypophysis
Pituitary gland
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Where is the pituitary gland housed?
Within sella turcica of the sphenoid bone
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What does pituitary gland release?
Growth hormone
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Neurohypophysis
Posterior lobe of the pituitary gland
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Which 2 hormones does the posterior lobe of the pituitary gland store?
-antidiuretic hormone
-oxytocin
**these are produced in hypothalamus
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Which lobe of pit gland an extension of hypothalamus?
Post lobe
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What forms the hypothalamic-hypophyseal tract?
Axons of paraventricular and supraoptic nuclei which descend down through infidibulum and post lobe
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Sequence to how both hormones end up in postlobe (3)
-ADH and oxytocin produced in the hypothalamus in the paraventricular and supraoptic nuclei
-transported to posterior lobe pit gland via the hypothalamic-hypopheseal tract
-ADH and oxytocin stored in axon terminals till they receive signals to be released
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adenohypophysis
Anterior lobe of pit gland
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What is anterior lobe composed off?
Glandular tissue that manufactures and releases a number of hormones
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hypophyseal portal system , what is it?
- Vascular network which transports releasing and inhibiting hormones from hypothalamus to anterior lobe
- *stop and go signals
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What controls the hormonal secretions of the anterior lobe?
Hypothalamus
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Linear sequence of hypophyseal portal system
-arteries > primary cap plexus > veins > secondary capillary plexus > veins
***usually arteries> cap plexus > veins
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Sequence of hypophesyeal portal system
- Artery delivers blood to primary cap plexus. Chemical signals of body arrive in nerve terminals and are relaxed into primary cap plexus as they travel to secondary cap plexus through veins. At 2nd cap plexus, inhibiting/releasing factors may interact with glandular tissue of adenohypophysis. Hormones relaxed here are delivered to blood by veins that leave ant lobe
- *look at picture
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Function of intermediate lobe?
- No function in adults
- *located between ant and post lobe
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Description of thryiod gland
Butterfly shaped gland in anterior neck
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2 hormones thyroid gland produces?
-thyroid hormone
-calcitonin
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Where does thyroid gland produce thyroid hormone?
From fluid filled follicles
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Where does thyroid gland produce calcitonin?
From parafollicular cells located between the follicles
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What are thyroid hormones invoked in?
General metabolic rate
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Role of calcitonin ?
Involved in calcium balance
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What are parathyroid glands
2-8 small glands located on the posterior side of the thyroid gland
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What procures parathyroid hormone?
Chief cells/principle cells in parathyroid glands
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What is parathyroid hormone invoked in?
Calcium balance
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Function of larger oxyphil cells?
Unclear
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Parathyroid hormone antagonist to
calcitonin
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What does the thymus secrete?
- Hormones involved in maturation of the immune system
- *t-lymphocytes
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Thymus AND chidlren
Very large in children after puberty it starts to become a fatty mass
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Where are adrenal glands located?
Paired glands that sit on top of the kidneys
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2 layers of adrenal gland
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3 zonas in cortex of adrenal medulla
-zona glomerulosa
-zona fasciculata
-zona reticularis
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Zone in medulaa
Adrenal medulla
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adrenal cortex) what does each layer produce?
Different type of corticosteroid
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Zona glomerulosa
mineralocorticoids; aldosterone (water balance)
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Zona fasciculata
glucocorticoids; cortisol (stress and metabolism)
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Zona reticularis
gonadocorticoids ; androgens (puberty)
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Medulla of adrenal gland is part of
Sympathetic ANS branch
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Medulla from adrenal gland secretes
80 epinephrine to 20 Norepinephrine
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Where is the pancreas located?
Partially behind the stomach, elongated shape
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Pancreas has
Both endocrine and exocrine functions
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Pancreas ) cells of pancreas
Pancreatic islets or islets of Langerhans
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Endocrine of pancreas )What do pancreatic islets secrete ?
- Insulting and glucagon
- *glucose metabolism
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What are pancreas cells related to endocrine?
Pancreatic islets
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Pancreas, endocrine portion: alpha cells secret
glucagon
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Pancreas, endocrine portion: beta cells secxret
insulin
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Pancreas, endocrine portion: delta cells secrete
somatostatin
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Pancreas, exocrine portion for digestion
acinar cells and duct cells
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2 functions of gonads
- -hormones
- *test or EST/progest
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master controller of endocrine systems?
hypothalamus
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What is hypothalamus composed of?
Several clusters of neurons or nuclei
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How does hypothalamus controls the ant lobe pit gland regarding released of hormones?
Portal system allows hypothalamus to send stop&go factors signals to ant lobe for control of master gland activity
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Small intestine and stomach ) what do they contained?
contain gut-associated endocrine cells (enteroendocrine cells) to regulate digestion
***may be paracrine in nature or relaxed into vascular system
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What do enteroendocrine cells release?
Several peptide hormones to regulate digestive functions
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Kidneys: unidentified cells produce
Erythropoietin
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Kidneys: what does Erythropoietin do?
Increases RBC production
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Heart: what do specialized cardiac muscle cells produce?
atria natriuretic peptide (ANP)
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Heart: what does ANP do?
Functions in controlling blood pressure
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Placenta: what fdoees it produce?
- -estrogen/progesterone and human chronic gonadotropin (hcG)
- *temp endocrine organ
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What is recognized by pregnancy tests
hcG
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