Neroendocronoligy final

What are the major endocrine glands?

The hypothalamus, pituitary, thyroid, adrenal glands, pancreas, gonads, pineal gland, and placenta (during pregnancy).

What is a hormone?

A chemical messenger released into blood or extracellular fluid that acts on target cells at a distance.

What is a neurohormone?

A hormone produced by a neuron and released into the bloodstream.

What is a neurotransmitter?

A chemical messenger released at synapses that acts locally between neurons.

What is a neuromodulator?

A chemical that modifies a neuron's response to other inputs, often via metabotropic receptors.

What is the difference between peptide and steroid hormones?

Peptides are water-soluble and act through membrane receptors; steroids are lipid-soluble and cross membranes to act on nuclear receptors.

Why can steroid hormones pass through the cell membrane?

They are lipophilic (fat-soluble).

What are the main steroid-producing glands?

The adrenal cortex (glucocorticoids, mineralocorticoids) and gonads (estrogens, progestins, androgens).

What is alternative splicing?

A process generating multiple protein isoforms from one gene by altering exon inclusion.

What hormone does the hypothalamus release to regulate reproduction?

GnRH (gonadotropin-releasing hormone).

What is the median eminence?

A neurovascular interface where hypothalamic neurons release hormones into the portal system to reach the anterior pituitary.

What does the anterior pituitary secrete?

TSH, ACTH, prolactin, GH, FSH, LH.

What does the posterior pituitary release?

Oxytocin and vasopressin (ADH).

Main function of oxytocin?

Stimulates uterine contractions, milk ejection, and plays roles in bonding.

Main function of vasopressin?

Regulates water retention in kidneys; involved in pair bonding in some species.

What do thyroid hormones regulate?

Metabolism, growth, development.

Symptoms of hyperthyroidism?

Heat intolerance, weight loss, anxiety, increased heart rate.

Symptoms of hypothyroidism?

Cold intolerance, lethargy, weight gain.

What does insulin do?

Promotes glucose uptake and storage and lowers blood glucose.

What does glucagon do?

Stimulates glycogen breakdown and raises blood glucose.

Type 1 vs Type 2 diabetes?

Type 1 = no insulin production (autoimmune); Type 2 = insulin resistance.

What does the adrenal medulla secrete?

Epinephrine and norepinephrine (fight-or-flight).

What does the adrenal cortex secrete?

Cortisol and aldosterone.

Main role of cortisol?

Mobilizes energy and mediates stress responses.

Main role of aldosterone?

Promotes sodium retention and blood pressure regulation.

What does the pineal gland secrete?

Melatonin for circadian and seasonal rhythms.

What hormone does the placenta produce for pregnancy maintenance?

hCG, which maintains the corpus luteum.

What are the three domains of a membrane receptor?

Extracellular domain, transmembrane domain, intracellular domain.

What is the cAMP second messenger pathway?

A GPCR activates adenylyl cyclase, increases cAMP, activates PKA, phosphorylates proteins.

What is the IP3/DAG pathway?

PIP2 cleavage produces IP3 (releases Ca²⁺) and DAG (activates PKC).

What are the four main domains of steroid receptors?

NTD (AF-1), DBD, hinge region, LBD (AF-2).

What do steroid receptor co-activators do?

Bridge receptors with transcription machinery and often acetylate histones to open chromatin.

How do steroid antagonists work?

Bind the receptor but prevent co-activator recruitment and transcription activation.

What is a Western blot used for?

Protein detection and quantification with no spatial resolution.

What is IHC used for?

Detecting protein expression with cellular resolution in tissue.

What is siRNA used for?

Knocking down gene expression by degrading specific mRNAs.

What is CRISPR used for?

Gene editing or knockout via DNA cuts at targeted sequences.

What is a conditional knockout?

A gene deletion restricted to specific tissues or times using Cre-lox recombination.

What is optogenetics?

Control of neuron firing using light-sensitive ion channels expressed via viral vectors.

What is the difference between sex and gender?

Sex = biological traits; gender = social and cultural identity and expression.

What is sexual dimorphism?

A trait that shows two non-overlapping forms between sexes.

What is a sex difference?

A trait with overlapping distributions between sexes.

Which CNS disorders are more common in AMAB?

Autism, ADHD, schizophrenia, Parkinson's.

Which CNS disorders are more common in AFAB?

Depression, anxiety, Alzheimer's, eating disorders.

Why may AMAB brains be more vulnerable early in development?

Greater susceptibility to early injury or disruption during critical periods.

What ducts form female internal organs?

Müllerian ducts (uterus, oviducts, fimbria).

What ducts form male internal organs?

Wolffian ducts (epididymis, vas deferens, seminal vesicles).

What hormone causes Müllerian duct regression?

AMH (anti-Müllerian hormone) from Sertoli cells.

What hormone stabilizes Wolffian ducts?

Androgens (testosterone).

What happens to ducts in typical female development?

No AMH so Müllerian structures develop; no androgens so Wolffian structures regress.

What is the SRY gene?

A Y chromosome gene that initiates testis development.

What is AIS (Androgen Insensitivity Syndrome)?

XY individuals with nonfunctional androgen receptors; testes present but external female genitalia.

What is Persistent Müllerian Duct Syndrome?

Failure of AMH or its receptor; XY individuals retain Müllerian ducts along with male ducts.

What is Turner syndrome?

XO individuals with streak ovaries, short stature, infertility, normal female internal and external anatomy.

What is CAH (Congenital Adrenal Hyperplasia)?

Usually 21-hydroxylase deficiency; low cortisol, high ACTH, high androgens; virilization of XX fetuses.

Why are XX individuals affected more strongly by CAH?

Excess androgens alter external genital development in XX, but XY are already masculinized.

What enzyme is defective in most CAH?

21-hydroxylase.

What is the result of 21-hydroxylase deficiency?

Low cortisol, high ACTH, increased androgen synthesis.

What determines male-typical brain organization in rodents?

Fetal or neonatal testosterone surge, aromatization to estradiol, masculinization and defeminization.

What is aromatization?

Conversion of testosterone to estradiol via aromatase.

Why doesn't maternal estrogen masculinize female brains?

α-Fetoprotein binds maternal estrogen and prevents its entry into the fetal brain.

What is the SDN-POA?

A hypothalamic nucleus larger in males due to estradiol exposure during development.

What hormones masculinize the SDN-POA?

Testosterone (via aromatization) and estradiol.

Which androgen does NOT masculinize the SDN-POA?

DHT, because it cannot convert to estradiol.

How does estradiol enlarge the SDN-POA?

By reducing apoptosis during the critical period.

What protein mediates apoptosis in this region?

Bax (pro-death protein).

What happens to SDN size in Bax KO mice?

Both sexes have large SDN-POA due to reduced apoptosis.

What happens in a TFM rat's SDN-POA?

SDN-POA is still masculinized because estradiol, not androgens, drives this change.

When are ER levels higher in females?

Postnatal day 7 in females

When are AR levels higher in males?

Postnatal day 7 in males

When is the critical period for brain sexual differentiation in rats?

Perinatal period, approximately the first 10 days after birth.

What is an organizational effect?

A permanent developmental effect of hormones.

What is an activational effect?

A reversible adult effect of hormones.

What happens if you castrate a male rat at birth?

He shows female sexual behavior in adulthood with E+P (lordosis).

What happens if you give neonatal testosterone to a female rat?

She is masculinized and defeminized; later shows mounting with testosterone, not lordosis with E+P.

What is lordosis?

A sexually receptive posture in female rodents controlled by estrogen and progesterone.

Which brain region controls lordosis?

VMN (ventromedial nucleus of the hypothalamus).

Evidence that the VMN regulates female sexual behavior?

Lesions eliminate lordosis; stimulation induces behavior; E+P implants restore behavior.

What region inhibits female sexual behavior?

The MPOA.

Which ER subtype is essential for lordosis?

ERα.

What happens in PRKO mice?

PR-A/B knockout results in little or no lordosis.

Which PR isoform is more important for behavior?

PR-A is more critical than PR-B.

What is the Lee-Boot effect?

Female cycle lengthening when housed together without males.

What is the Whitten effect?

Male urine induces estrus and synchrony in females.

What is the Vandenbergh effect?

Male odor accelerates puberty in females.

What is the Bruce effect?

Pregnancy block after exposure to unfamiliar male odor.

What structure detects pheromones?

The vomeronasal organ (VNO).

VNO pathway

VNO → accessory olfactory bulb → amygdala → hypothalamus.

What happens if the VNO is lesioned?

Pheromone-driven reproductive effects disappear.

What hormone increases libido in AFAB individuals?

Testosterone more than estrogen.

What evidence suggests this?

TAH/BSO studies where androgen replacement increased sexual desire.

What did McClintock show?

Donor underarm secretions can alter menstrual timing.

What are candidate male/female pheromone responses in humans?

AMAB attracted to AND and AFAB attracted to EST, linked to hypothalamic activation patterns.

What is the birth order effect?

More older brothers increase likelihood of homosexuality in AMAB.

Findings about INAH in sexual orientation?

INAH-3 larger in straight AMAB and smaller in gay AMAB and AFAB.

Limitations of early brain-sexuality studies?

Correlation not causation, small sample sizes, confounds such as AIDS.

What is stress?

Any disturbance of homeostasis that elicits physiological and psychological responses.

What is the HPA axis sequence?

Stress → CRH → ACTH → cortisol → negative feedback.

What does acute stress do?

Increases heart rate, blood pressure, glucose; sharpens cognition; suppresses reproduction.

What does chronic stress do?

Causes hippocampal atrophy, impaired memory, immune suppression.