PSYCH 230 Exam 3

Hormones

chemicals, secreted by a group of cells (i.e., gland), that travel through the bloodstream to act on targets

endocrine glands

release hormones within the body

exocrine glands

use ducts to secrete fluids such as tears and sweat outside the body

Endocrinology

the study of endocrine glands and their associated hormones

The first formal study of endocrinology

Conducted by Arnold Berthold in 1849

Castration

removal of the gonads (testes) → results in behavioral and physiological changes

Berthold demonstrated experimentally that…

a product released from testes into the blood is necessary for an immature chicken to develop into a normal male rooster, both behaviorally and physically

exposure to hormones early in life

The brain and body are “organized” by ____________, and these changes can be dramatic and long-lasting

hormones “activate” behaviors

Later in life, ____________, but their effects tend to be less dramatic and short-lived

Synaptic communication

involves chemical release into the synaptic cleft for action on the postsynaptic membrane

Endocrine communication

a hormone released into the bloodstream to act on target issues

Neuroendocrine (or neurosecretory) cells

neurons that release hormones into the blood

Synaptic communication:

• travels only across a synaptic cleft to act on receptor

• signal travels along a laid path (circuit)

• very fast

Endocrine communication:

• Spreads anywhere throughout the body if there is a blood supply; can act on cells with the appropriate receptor

• Relatively slower

Paracrine function

the released chemical diffuses to nearby target cells (e.g., synaptic transmission)

Autocrine function

a released chemical acts on the releasing cell

Pheromone function

hormones can be used to communicate between individuals of the SAME species; pheromones are released into the environment

Allomone function

Allomones are chemicals released by one species to affect the behavior of ANOTHER species

gradual

Hormones act in a _________ fashion

probability or intesity

Hormones act by changing the ____________________________ of a behavior

DO NOT

Hormones _______ make you do anything

reciprocal, or bidirectional relationship

Hormones can affect behavior, and behavior can affect hormones

multiple; several

A hormone may have ____ effects, and one behavior can be affected by ______ hormones

pulsatile

Hormones often act in a _______ secretion pattern (i.e., bursts)

change their affects

Hormones can interact with other hormones and…

with a receptor for that hormone

Hormones can only affect cells…

Peptide hormone, Amine hormones, Steroid hormones

Chemical structure of hormones:

Peptide hormone

a string of amino acids

Amine hormones

modified amino acids, called monoamine hormones

Steroid hormones

four rings of carbon atoms (derivatives of cholesterol)

neurotransmitters AND hormones

Some chemicals can act as both…

→ It depends on the cells that release them, and where they are released

peptide hormones

most common type of hormone found in animals

peptides hormones

Only a few amino acids in length

protein hormones

larger ones (>50 amino acids)

peptide hormones

Can be stored within the cell (in vesicles)

peptide hormones

LARGE (can’t pass through cell membranes)

oxytocin, insulin, leptin

examples of peptide/protein hormones

Indoleamines (e.g., serotonin) and catecholamines (e.g., epinephrine, dopamine)

two classes of amine hormones affect behavior

they don’t affect behavior

Thyroid hormones are also monoamines, but…

within the cell membrane; which brings about changes in cellular function

Protein and amine hormones bind to specific receptors embedded _______________and cause the release of a second messenger…

FAST

peptide hormone action is relatively _______(effects on order of ms to min)

Steroid hormones

Most come from the adrenal glands and gonads

Steroid hormones

Small and lipophilic (passes through cell membrane)

Steroid hormones

Never stored and some require carrier proteins, or cofactors

estrogens, androgens

examples of steroid hormones

bind to receptors inside the cell

Steroid hormones pass through the cell membrane and…

transcription factor

The steroid-receptor complex binds to DNA in the nucleus and acts as a…

steroid hormone action → transcription factor

controlling gene expression and protein production—hence, effects are longer-lasting

SLOW

steroid hormone action relatively ______ (effects usually on order of hours to days)

Genomic action

steroid hormone action is called…

nongenomic action

Estradiol (steroid hormone) can have a rapid, brief effect involving neuronal membrane receptors

Neurosteroids

steroids made in the brain, including testosterone and estrogens

combining an enzyme with a different hormone

Many steroid hormones are made by…

aromatase

an enzyme that can convert testosterone into estrogens inside a cell

positive feedback and negative feedback

Hormones are regulated by feedback systems:

negative feedback

output feeds back and inhibits further secretion

positive feedback

output feeds back and increases further secretion

negative feedback

more common feedback in terms of hormone regulation

autocrine negative feedback loop

involves endocrine cells releasing a hormone whose presence feeds back on the endocrine cells

target cell feedback

the hormone acts on its target cells and has a biological effect

further release is inhibited

The biological effect is detected by the endocrine gland and…

example of target cell feedback

insulin release in response to glucose after eating

hypothalamus

A more complex endocrine system involves the brain, usually the _________

releasing hormones; tropic hormones; the pituitary and the hypothalamus

• First the hypothalamus uses _________ to act on the anterior pituitary

• Then the pituitary releases _________ that affect other endocrine cells

• Negative feedback from the endocrine cells goes to both _____________

direct hormone release from endocrine glands (one of which is the pituitary gland)

Brain regulation involves the hypothalamus which can…

negative feedback on the hypothalamus

The brain detects the hormone’s effects and exerts…

Posterior pituitary, Anterior pituitary

The pituitary gland releases hormones, and has two main but separate parts:

oxytocin and vasopressin

The posterior pituitary secretes two principal hormones:

supraoptic nuclei and paraventricular nuclei

Neurons in the _________ and ___________ of the hypothalamus synthesize oxytocin and vasopressin

pituitary stalk

oxytocin and vasopressin travel along the ________ and into the blood supply in the posterior pituitary

posterior pituitary hormones

Because oxytocin and vasopressin are released into the blood supply of the posterior pituitary, they are called…

releasing hormones

Some hypothalamic neuroendocrine cells synthesize _____________

anterior pituitary

The hypothalamus communicates with the ________ differently, requiring additional steps

median eminence

Axons from hypothalamic neuroendocrine cells converge on the __________, above the pituitary stalk

hypophyseal portal system

Releasing hormones are secreted into blood vessels called the ____________, and are carried to the anterior pituitary

tropic hormones

The releasing hormones stimulate specific cells in anterior pituitary to release _________ into general circulation, where they’ll travel through the body to their targets

Circulating messages, such as other hormones, blood sugar, immune system products, and synaptic inputs from other brain areas

The hypothalamic neuroendocrine cells that synthesize releasing hormones are influenced by:

Hypothalamic-pituitary-thyroid axis

Example of Complex Endocrine Regulation

Secretions of the Anterior Pituitary

physiology; behavior

Hormones can affect both _______ as well as ________

hormones affecting physiology

Oxytocin stimulates uterine contractions and is involved in milk letdown (nursing)

hormones affecting behavior

Oxytocin is released during nursing interactions and during O to facilitate bonding; in female prairie voles, it promotes pair-bonds; Vasopressin facilitates the formation of pair-bonds in male prairie voles

Sex

biological sex, the physical body

• Essentially the “biological and physiological characteristics that distinguish females from males”

Gender

social concept, self-identification

• This includes “socially constructed roles, relationships, behaviors, relative power, and other traits societies ascribe to women and men”

Sex determination

the process by which the decision is made for a fetus to develop as a male or a female

chromosome driven

Sex determination is…

Sexual differentiation

the process by which individuals develop either male or female bodies and behaviors

hormone driven

Sexual differentiation is…

the offspring will become male

If the sperm that enters the egg has an Y chromosome…

the offspring will become female

If the sperm that enters the egg has an X chromosome…

bipotential

When the gonads are first made, they are _________

the SRY gene, or sex-determining region of the Y chromosome

The Y chromosome has a gene (_____________) that codes for the development of testes from the bipotential gonad

an ovary forms

Without an SRY gene…

product of gametes and production of steroid hormones

The gonads serve two purposes:

steroid hormones are required for…

gamete production, development of secondary sex characteristics, behaviors that bring gametes together

testes

Male gonads =

androgen

primary steroid produced is testosterone, which is an __________

in utero

Testosterone production begins as soon as the testes are formed ________

masculine development

testosterone production helps guide…

ovaries

Female gonads =