Class 3: Hormones Flashcards
Definition of Hormone
A hormone is a chemical messenger secreted by glands that act elsewhere in body
What are hormones secreted by?
Hormones are secreted by Endocrine Glands
What is included in endocrine system?
A complex network of glands and organs that uses hormones.
What is Endocrinology?
The field that studies hormones & the effects it has on the body
Who discovered hormones and when?
A. A. Berthold in 1859 (rooster testicle experiment)
What does the word hormones translate to?
“to set in motion”
What is the hierarchy of hormone release (4 levels)
- Hypothalamus
- Pituitary Gland
- Target Endocrine Glands
- Target organs or tissues
What is the HPA Axis and what does it stand for?
The Hypothalamic-Pituitary-Adrenal Axis is the major neural system activated during stress
What are the 3 major classes of hormones?
- Peptide hormones
- Monoamine hormones
- Steroid hormones
What are peptide hormone?
Strings of amino acids (such as insulin and leptin)
What are monoamine hormones?
Modified amino acids (often found in brain as NT as well)
What are steroid hormones?
Hormones synthesized from cholesterol and have four ringed structure
Do hormones have receptors like NTs or not?
Hormones do have receptors just like NTs
Are hormone receptors (like NTs receptors) ion channels?
Hormone receptors are not ion channels, they induce intracellular set of events which cause physiological changes inside of the cell
What are the three basic ways that hormones act throughout the body
- Promote growth, proliferation and differentiation of cells
- Modulate cell activity & metabolism
- Modulate secretion of other hormones from endocrine glands
What are the two parts of the pituitary gland?
Anterior pituitary (AP) and Posterior pituitary (PP)
What is the anterior pituitary responsible for?
The anterior pituitary gland is connected to the hypothalamus by veins (i.e portals) Similar to the HPA axis method of stress activation.
What is the posterior pituitary responsible for?
The posterior pituitary gland is connected to the hypothalamus by neurons. A neural signal will be received by the posterior pituitary to release the hormones.
What is the negative feedback-loop (in relation to hormones)?
Hormones can control their own release to maintain a predetermined balance (homeostasis)
What are the 6 general principles of hormones?
- Hormone levels vary of time
- Hormones affect probability of a behaviour not directly cause said behaviour
- The relationship between hormones and behaviour is reciprical (hormones affect behaviour and behaviour affects hormones)
- Hormones can interact with out hormones
- Hormones act in a gradual fashion
- A Hormone can have multiple effects (1 to many and many to 1)
What is the difference between synaptic signaling and endocrine signaling?
Synaptic signaling diffuses across synaptic cleft while endocrine signaling involves release of hormones into bloodstream
What are 4 difference between hormonal and neural signaling?
- Neural signals have precise targets
- Neural signals are rapid
- Neural signals are all or nothing
- Neural communication are sometimes voluntary control
What are 3 similarities between hormonal and neural signaling?
- Neurons and endocrine glands produce and store chemicals which they release on stimulation
- NTs and hormones bind to receptors on target cells
- Some chemicals can be a hormone or a NT
