Endocrine System Flashcards
Exocrine
Glands secrete into ducts that empty onto an epithelium that lines a surface
E.g. sweat, sebaceous, mucous and digestive glands
Endocrine
glands secrete into the interstitial fluid that then diffuses into blood capillaries
E.g pituitary and thyroid glands
What are hormones?
molecules that alter the physiological activity of other cells in the body
Powerful effects even when present in very low concentrations
How do hormones work?
The endcrine cells release the hormones into interstitial fluid(the fluid that surrounds the cells)
The hormones then diffuse into the blood stream
Then, hormones bind to the target cells that are located far away
What are some hormone secreting organs
pancreas
ovaries
testes
Nervous system features
neurotransmitters
released locally
close to site of release
short term effect and they release in milliseconds
targets muscle fibers, gland cells and other neurons
Features of endocrine system
hormones are delivered globally
far from site of release is the target
long term effects, takes a while to be released
targets cells throughout the body
Hypothalamus
It is inferior to the thalamus
neuroendcrine hormone
controls the pituitary gland
Pituitary gland
pea-shaped
lies in the sella turcica of the sphenoid bone
master endocrine gland
secretes several hormones that control other endocrine glands
What are the different parts of the pituitary gland?
anterior lobe-indirectly
-pars distalis-larger bulbar portion
-pars tuberalis-sheath around infundibulum
7 hormones
posterior lobe-directly
-pars nervosa-larger bulb portion
-infundibulum-stalk portion
2 hormones
-pars intermedia, not present in adults and it seperates the 2 lobes
Hypothalamic Regulation
transports 2 hormones to the posterior pituitary
then secretes releasing and inhibiting hormones to the anterior pituitary
Releasing hormone
turn it up
the hypothalamus sends out a releasing hormone, that hits the anterior pituitary, which then sends out hormones that turn up the action of the target hormone
Inhibiting hormone
the hypothalamus sends out inhibiting hormone
the anterior pituitary receives this and sends out inhibiting hormones to target organ
What is the portal veins
connect 2 capillary plexuses
What are the hormones of the anterior pituitary
Follicle stimulating hormone (FSH)
Lutenizing hormone (LH)
Adrenocrticotropic hormone (ACTH)
Thyroid-stimulating hormone (TSH)
Prolactin (PRL)
E MElanocyte-stimulating hormone (MSH)
Growth hormone (GH)
Growth hormone
stimulates body growth
increases protein synthesis
Thyroid stimulating hormone
the more hormone the less your thyroid has to work
Follicle-stimulating hormone
initiates oocytes development and indices estrogen secretions
and it stimulates sperm production in males
Luteinizing hormone
in females in stimulates ovulation and corpus luteum formation
stimulates the secretion of testosterone
Prolactin
initiates milk production in mammary lobes
Adrenocrticotropic hormone
increases glucose production (in kidney)
Melanocyte-stimulting hormone
excess of this causes darkening of the skin
Hormones of the posterior pituitary
antidiuretic hormone (ADH)
Oxytocin (OT)
Produced by the hypothalamus
Antidiuretic hormone
decreases urine volume
decreases sweating
constricts arterioles
to conserve blood volume and body water
this increases blood pressure
Oxytocin
mostly in wome
during delivery it enhances smooth muscle contraction in uterine wall
after delivery it stimulates milk ejection from the mammary glands
What are direct targets of posterior pituitary hormones
kidneys and uterus
Thyroid gland
butterfly-shaped
located inferior to the thyroid cartilage of the larynx
Thyroid hormones
T3
T4
Calcitonin
What does T3 and T4 hormones do?
oxygen use and basal metabolic rate
cellular metabolism
growth and development
What does calcitonin do?
regulates calcium homeostasis
Parathyroid glands
4 pea-sized glands that are embedded in the posterior surface of the thyroid gland
Parathyroid hormone
regulates calcium homeostasis
promotes the formation of the hormone calcitrol (active form of vitamin D)
Suprarenal gland
above the kidney
right=pyramidal
left=semi-lunar
Adrenal cortex
zona glomerulosa-produces mineral corticoids
Zona fasciculata-produces glucocorticoids
Zona reticularis-produces androgens and is involbed with growth and puberty
(Salt sugar sex)
Adrenal medulla
chromaffin cells (under the control of the autonomic nervous system) QUICK
secretes catecholamines-epinephrine and norephrine
pancreas
endocrine and exocrine
exocrine=pancreatic acini
endocrine=islets of langerhan
Islets of langerhans
alpha cell-secretes glucagon
beta cell-secretes insulin
delta cell-secretes somatostatin
