MT Review (Final) Flashcards
(43 cards)
What do hormones do?
short term effects: - change membrane potential, affects APs - change protein expression long term effects: - activate gene expression (think puberty) - slower, but coordinates organism
Why is timing important during castration?
before puberty: no facial hair, long arms, higher pitched voice, no sex drive
after puberty: no effect on physical appearance
What did the Berthold baby chick experiment show?
- testes were transferable
- no specific nerves control secretory function
- effects are only seen when chicks were castrated prepubescently
How can you determine if there is a relationship between hormones and behavior?
- if you remove the hormone, it removes the behavior
- if you reintroduce the hormone, it reintroduces the behavior
- hormone concentration and behavior covaries
What are proximate causes of behavior?
the HOW immediate causation - change in [hormone] - reaction to stimuli developmental - learned behavior
What are the ultimate causes of behavior?
the WHY
evolution: what has been naturally selected
adaptive function: what makes it more likely for the genes to be spread to offspring
Describe the process of knockout genetics
- mutate DNA in stem cells
- put them into of the blastocyst of one mouse and take the embryo and put it into a surrogate
- give birth to a recessive chimeric baby
- have chimeric babies mate, produce offspring with total knockout of gene
What is the role of the hypothalamus in the endocrine system?
serves as the regulator between the brain and endocrine system
- receives input from higher brain regions
- works to control and regulate endocrine glands of the body
What is the structure of the anterior pituitary like?
contains a portal system
- closed blood circuits between the hypothalamus and AP
- hypothalamus sends releasing factors that tells AP to release hormones
- these trophic hormones go to other endocrine glands and tells them to release hormones
What is the structure of the posterior pituitary like?
axons from the hypothalamus project directly onto the posterior pituitary
- much faster than the AP
- releases vasopressin and oxytocin
Describe peptide hormones
created from proteins
- do not need carriers in the blood, water soluble
- released by exocytosis
- largest class of hormones
- structurally different across species
- hypothalamic and pituitary hormones
Describe steroid hormones
all made from the precursor cholesterol
- not soluble in water, require vesicles
- small, diffusible across membranes
- intracellular and membrane receptors
- adrenals, gonads, brain
What governs [steroid hormone]?
rate of synthesis
rate of inactivation/catabolism
affinity for binding to receptor
How are steroid hormones regulated?
they are never stored, once synthesized they are released
- bind to water soluble carrier proteins
- regulated by the regulation of the enzymes that convert cholesterol into hormones
What is a prohomone?
a hormone that itself can act as a hormone or be converted into another active hormone
What are androgens important for?
spermatogenesis male secondary sexual development muscle mass courtship behavior aggression
What do androgens do in women?
in the ovaries, enzymes convert androgens into estrogen
- rate of transformation depends on the amount of enzyme available
What do estrogens do in women?
stimulates formation of the corpora lutea secondary sex characteristics bone mass metabolism sexual behavior has role in almost all tissues
What is the difference between the different hormones in males and females?
androgens and estrogens are found in both males and females
difference occurs in the relative concentrations
- this is driven by the different enzymes present in the organism
What are neurosteroids?
steroid hormones in the brain
- produced by CNS glial cells from cholesterol
- function: modulates NT receptors
Where are steroid hormones receptors typically located?
intracellular - within the cytosol or the nucleus
the complex formed between the receptor and the hormone can stimulate gene transcription
What are the three domains of a hormone receptor?
C domain - where the hormone binds
Center domain - where the hormone-receptor complex binds to the DNA
N domain where DNA binding proteins can attach
Why do we believe there are non-genomic actions of steroids?
there are some effects of steroid hormones that are much faster
can include:
- modulating ion channels
- interacting with NTs
- membrane receptors
evidence: expose show that injection of estradiol has immediate effects of AP rates
How are hormones regulated?
positive feedback loop - stimulates more hormone
negative feedback loop - inhibits/slows hormone production
