Endocrine System
Collection of cells, tissues, and glands that release chemical messengers (HORMONES) into the bloodstream. Compared to the Nervous System (NS), the Endocrine System sends out slower stimuli, but it produces widespread effects that last longer than Action Potential. |
What are the similarities of the endocrine and nervous systems? Both control systems (homeostasis and other) |
Endocrine System vs Nervous System
What are the similarities of the endocrine and nervous systems?
Both control systems (homeostasis and other)
Control and coordinate body activities through chemical messengers |
Differences of NS and ES
Mode: NS - Neurotransmitters | ES - Hormones
Speed: NS - fast | ES - slow
Duration of stimuli: NS - short-lived | ES - long-term |
Endocrine Glands and Their Functions
Hypothalamus (control/integrator) |
releasing hormones to the anterior pituitary (blood communication) and direct connection to posterior pituitary (nerve communication) |
Pituitary gland |
"Master Gland"; The Anterior produces hormones that regulate other endocrine glands, and the Posterior stores and releases vasopressin (ADH) and oxytocin. |
Pineal gland |
Sleep, thru release of Melatonin |
Thyroid gland |
follicular cells, high blood calcium, storage of calcium in bone, release Thyroid Hormone (T3 & T4) to increase metabolism and body temperature |
Parathyroid gland |
low blood calcium, Parathyroid Hormone (PTH), release calcium into blood from bone |
Adrenal glands |
stress response, blood pressure response, blood osmolarity/concentration, Sex Hormones (FSH & LH) |
Pancreas |
Insulin and Glucagon |
Ovaries |
make and release Oestrogen and Progesterone |
Testes |
make and release Androgens (e.g. testosterone) |
Thymus |
Thymosin - programs T-cells |
3 Types of Hormones
Amino Acid (Tyrosine) |
hormones from the Adrenal Medulla, Thyroid Gland (T3 & T4) |
Protein / Peptide |
most abundant; derived from Amino Acids; Pituitary hormones and Pancreas hormones |
Steroids |
hormones from the Adrenal Cortex and Gonads - the Ovaries & Testes |
Proteins (>100 Amino Acids)
Peptides (<100 Amino Acids)
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Hormones
GLAND |
HORMONE |
FUNCTION/S |
Hypothalamus |
TRH |
release TSH |
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CRH |
release ACTH |
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GnRH |
release of FSH & LH |
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GHRH |
release of GH & TSH |
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Somatostatin |
inhibits secretion of GH |
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Dopamine |
inhibits secretion of Prolactin |
Pituitary (Anterior) |
GH |
growth of bones, muscles, & tissues |
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TSH |
release T₃ and T₄ |
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ACTH |
production and release of cortisol |
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FSH |
sperm production and follicle dev. |
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LH |
triggers ovulation and testosterone prod. |
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Prolactin |
milk production |
Pituitary (Posterior) |
Oxytocin |
uterine contractions and milk ejection; promotes bonding |
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ADH |
water reabsorption in kidneys; constricts blood vessels |
Pineal |
Melatonin |
regulates sleep-wake cycles |
Thyroid |
T3 & T4 |
metabolism, growth, and development |
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Calcitonin |
lowers blood calcium |
Parathyroid |
PTH |
raises blood calcium |
Adrenal Cortex |
Mineralocorticoid (Aldosterone) |
sodium and potassium balance; maintains blood pressure |
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Glucocorticoid (Cortisol) |
body response to stress; regulates metabolism |
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Androgens |
sex drive and development of secondary sex traits |
Adrenal Medulla |
Epinephrine |
increases heart rate, breathing, and energy during stress (“fight or flight”) |
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Norepinephrine |
works with epinephrine |
Pancreas |
Insulin |
lowers blood glucose |
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Glucagon |
raises blood glucose |
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Somatostatin |
inhibits secretion of insulin and glucagon |
Overies |
Oestrogen |
regulates menstrual cycle |
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Progesterone |
maintains uterine lining and supports pregnancy |
Testes |
Testosterone |
supports sperm production |
Thymus |
Thymosin |
dev. and activation of T-cells for immune response |
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3 Types of ES Stimuli
Neural |
nerves (Action Potential - AP) stimulate hormone release |
Humoral |
blood substances (e.g. calcium, glucose, or sodium) stimulates release of hormones |
Hormonal |
hormones stimulate the release of other hormones |
When a hormone ends with -tropin or -tropic it is usually a hormone that stimulates others, which means it is not the end of the cascade.
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