Module 11: Hormones, Sex, and Sleep

Endocrine System

A collection of organs in the body that secrete chemicals (hormones) that alter the body in some manner

Pituitary Gland

Controls most of the function of the others; "master gland"; primary control center for releasing hormones

Types of Hormones

Amino-acid based, large proteins, or steroids

Functions of the Endocrine System

Metabolism, Blood Sugar, Fight or Flight Response, Immune Response

Metabolism

Thyroid

Blood Sugar

Pancreas

Fight or Flight Response

Adrenal Glands

Immune Response

Thymus

Biological Sex

Physical characteristics that differentiate men from women; male and female

Primary Sexual Characteristics

Changes that occur that allow individuals to reproduce

Male Primary Sexual Characteristics

Lowering of testes, maturation of sperm, ejaculation

Female Primary Sexual Characteristics

Monthly ovulation, menarche, maturation of uterus and vagina

Male biology

maturation of the testes and ability to produce sperm

Female biology

menarche and the ability to host an embryo

Secondary Sexual Characteristics

Changes that differentiate males from females, unrelated to the reproduction of the species

Male Secondary Sexual Characteristics

Growth spurts, increase in lean muscle mass, growth of body hair, growth of facial hair, lowering of voice pitch

Female Secondary Sexual Characteristics

Growth spurts, widening of hips, growth of breasts, growth of body hair, increase in body fat

Sex Hormones

Cause sexual development in individuals, and trigger differences in sex characteristics

Male Sex Hormones

Testosterone & Androgen

Female Sex Hormones

Progesterone & Estrogen

Sexual Genitalia in Embryonic Development

This process depends on the sex hormones the fetus is exposed to in-utero

Male Sexual Genitalia Development

Mullerian and Wolfian Ducts - Mullerian Duct = Wolffian Ducts

Wolffian Duct

Becomes epididymis and ductus (vas) deferens

Female Sexual Genitalia Development

Mullerian and Wolfian Ducts - Wolffian Duct = Mullerian Ducts

Mullerian Ducts

Becomes uterine tubes and uterus

Differentiation of Genitalia

Overstimulation or understimulation of sex hormones on embryonic development may lead to sexually ambiguous genitalia

Klinefelter's Syndrome (XXY)

Poor beard growth, breast development, under-developed testes (male)

Turner's Syndrome (XO)

Characteristic facial features, web of skin, constriction of aorta, poor breast development, under-developed breasts

Melatonin

For sleep; synthesized by the pineal gland from the neurotransmitter serotonin

Facilitates the Circadian Rhythm

Release of melatonin

3 stages of sleep

measured by EEG; stages repeat across the duration of the entire night

REM Sleep

Subsequent Stage 1s of sleep

REM Sleep

Dreams often occur during this stage of sleep

Stage 1 of sleep

NREM Alpha

Stage 2 of sleep

NREM Theta

Stage 3 of sleep

NREM Delta

Activation-Synthesis Hypothesis

Brain gets a lot of neural impulses in brainstem, which is sometimes interpreted by the frontal cortex. Our brain tries to find meaning from random brain activity--> explanation that dreams may not actually have meaning.

Theories on Sleep

Recuperation Theory and Adaptation Theory

Recuperation Theory

Being awake disrupts our body's homeostasis or balance in some way; sleeping resets this balance

Adaptation Theory

Sleeping is not a physiological need to balance, but an evolutionary adaptation to conserve energy

Parasomnia

"Disorder of sleep"

Insomnia

An inability to enter or maintain a sleeping state

Narcolepsy

An excessive amount of drowsiness, often at inappropriate times