Endocrine and Reproductive Systems Flashcards
Hormones are _______________
Chemicals, secreted by one cell group, that travel through the bloodstream to act on targets
Neurotransmitters vs hormones. What are the traits of neurotransmitters?
- Secreted by neurons
- Travel short distances through the synapse
- Travel to precise destinations (receptors on the postsynaptic neuron)
- Rapid messages
Neurotransmitters vs hormones. What are the traits of hormones?
- Secreted by endocrine glands
- Travel long distances through the blood
- Spread throughout the body, but only picked up by cells with the proper receptors
- Slower messages
Classic early endocrinology study by ____________________ suggested the nature of hormones
Berthold in 1849
What were the finding of the nature of hormones by Berthold in 1849?
- Uncastrated roosters had secondary sex characteristics
- Castrated roosters had no secondary sex characteristics
- Roosters with testes reimplanted in abdomen (not connected by nerves)….
-had secondary sex characteristics
-indicated signal traveling through blood- hormone
Endocrine is the system that _____________________
Secretes hormones into the blood stream
Glands are ___________________
Organs that secrete substances, such as hormones
Neuroendocrine is when _____________
Signaling molecules are secreted by a neuron into the blood, where they function as hormones
How do peptide hormones (proteins or peptides) work?
They bind extracellular receptors
What are steroid hormones synthesized by?
Cholesterol
What are amino acid-derived hormones synthesized from?
Tryptophan or tyrosine
What do amino acid-derived hormones bind?
-Some bind cell membrane receptors (similar to peptide hormones)
-Some bind intracellular receptors (similar to steroid hormones)
Hormones are regulated by _______________________
Negative and positive feedback loops
Negative feedback loops _______________
Hormone inhibits further hormone secretion, and it maintains homeostasis
Example of negative feedback loops is when __________
Thyroid hormone inhibits production of thyroid hormone
Positive feedback loops _________________
are rare, and hormone release causes additional hormone release, and it amplifies signaling
Example of positive feedback loop is when ____________
Oxytocin release leads to uterine contractions, which cause additional oxytocin release
Thyroid hormones, produced by a butterfly-shaped gland in your _________ increase ___________________
-Neck
-Alertness and metabolism
The manufacturing of thyroid hormones depends on the ________________ and without it, the thyroid swells in an attempt to produce more __________ (called a goiter)
-Supply of iodine
-Iodine
The pineal gland is a
Single gland on top of the brainstem
What does the pineal gland secrete?
An amino acid-derived hormone, melatonin, almost exclusively at night.
Melatonin provides a signal that _________________
Tracks day length and the seasons
Where are the adrenal glands located and what do they do?
They are at the top of each kidney and secrete hormones
In mammals, the outer 80% of the gland is the _____________, and the core 20% is the ________________
-Adrenal cortex
-Adrenal medulla
