Hormones

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Slide 1

Gametes

Gametes… of the sexes

Females

Eggs Develop in the Ovaries

All the gametes an individual will ever produce are already present at birth and are stored as undeveloped follicles

Males

Sperm is produced in the male scrotum

Male gametes arise from undifferentiated stem cells that continually divide and regenerate over the male’s lifetime

Slide 2

Two Types of Feedback

Positive Feedback

Negative Feedback

Organ or Gland

Organ or Gland

Releases a substance to act on a system

Releases a substance to act on a system

System Acted

Upon

System Acted

Upon

Releases a secondary substance which acts on the gland or organ

Releases a secondary substance which acts on the gland or organ

Inhibits (stops) further release of the original substance

Promotes or encourages more of the original substance to be released

Slide 3

Three Primary Hormones of Sexual Development

Estrogen

Progesterone

Testosterone

Slide 4

Estrogen’s Effects on Female Sexual Development

Works with Progesterone through “Feedback Loops” to establish regular reproductive cycles

Growth and Maturation of Female Sex Organs

During Puberty, triggers lengthening of long bones, and changes in pelvic structure

Slide 5

Estrogen’s effects on Female Sexual Development (cont…)

Stimulates: the appearance of Axillary and Pubic hair, Hydration of the Skin and Female patterns of fat deposits

During pregnancy Estrogen also plays a major role (with Progesterone) in Embryonic Development and physical adaptations needed to accommodate Pregnancy and Child Birth

Slide 6

Testosterone’s Effects on Male Sexual Development

Growth and Maturation of Male Sex Organs, Must be held at Adequate levels to maintain functioning of Male Sex Organs

At puberty stimulates the growth of axillary, pubic, facial and chest hair.

Enlargement of Larynx (deepening voice)

Slide 7

Testosterone’s Effects on Male Sexual Development (cont…)

Thickens Skin and Increases Oiliness

Enhances Growth and Density of Bones

Increases Muscles in Size and Mass

Boosts the Basal Metabolic Rate and Influences Behavior (Sex Drive)

“Masculinizes” the Brain (Promotes Aggressiveness)

Slide 8

Summary of Hormonal Effects