Human Endocrine System Summary

HUMAN ENDOCRINE SYSTEM
Endocrine system =
endocrine
glands
→
hormones ( chemical messengers)

uctless glands =
release hormones directly into bloodstream .
>
target organs
Exocrine glands =
secrete viaducts to cavity or outside e.
g salivary glands

chemical coordination : control i. co -
ordination of hormones in blood .




HORMONES
ENOCRINENERVT
-




chemical
>
Organic chemical messenger message electrochemical
message
>
proteins or steroids slower response Fast response
>
secreted small ↳ doesn't last
quantities Response long lasting
:

long
>
Target organs have receptors for specific hormone Bloodstream Nerves
>
Regulatory function -




>
Regulated by negative or positive feedback mechanisms



Negative feedback mechanism :
Any deviation from normal levels elicits a response that restores normal levels .




ENDOCRINE GLANDS & their HORMONES


Hypophysis Pituitary gland
' '

Master gland

location : Base of brain attached to hypothalamus in
cavity
'
,
=
cranium


>
2 lobes →
Anterior adenohypophysis
Posterior neuro
hypothesis)

Relationship between hypothalamus & hypo physics
> controls pituitary gland function link between nervous { endocrine system
↳ secretes
releasing factors via neurons / blood Stimulates .

hypophysis to produce/ release hormones

hypophysis
>
Hypothalamus connected to

→
blood vessels →
anterior lobe
→
neurons →
posterior lobe

Hypothalamus produces hormones posterior lobe storage
> →
neurons → =




sapper
Kappa

, ANTERIOR LOBE HORMONES

TSH (Thyroid hormone)
stimulating
>
Target organ Thyroid gland :




Thyroid secretes thyroxine
→




5TH (so Matotropic hormone / growth hormone)
>
Target organ :
muscles i. skeleton ( stimulates synthesis of proteins)
Promotes growth
→




0
Disorders :



>
under secretion
-
:
hyposecretion
children pituitary dwarfism
• =




>
over -
secretion :
hypersecretion
•
children =

gigantism
•
Adults =
Acromegaly

FSH (
Follicle-stimulating hormone)
Target organ ovaries
>
±
:



testes
→
development of primary follicle into mature G-raafian follicles
→
activates germinal epithelium that produces sperm cells


LH ( lutein ising hormone)


Target organ ovaries
>
±
:



testes
stimulates ovulation (release secondary oocyte) + development of Corpus luteum
→



→
stimulates cells of Leydig to produce testosterone


Prolactin

>
Target organ mammary glands :


stimulates to produce milk
mammary glands
→
.