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Lion Track icon Lion Den » A&P » AP2 Lec » Outlines » Reproductive

Learning Outline

Reproductive Systems

A&P 2

traffic light warningWarning — This part of the course includes graphic sexual content. If you can't handle that, then don't come to class. And seriously reconsider whether you even want to work in a health profession—if that's the path you are on.
Because some graphic images will appear on Previews and online tests and exams, it is also important that you are sensitive to your surroundings. Avoid viewing these materials in inappropriate circumstances (for example, where others may be startled or offended by such graphics).
Links marked with ! are particularly graphic in content.

The importance and nature of sexual reproduction

Survival of genes

Despite what you've heard, the prime importance is not survival of the individual or species

In The Selfish Gene , biologist Richard Dawkins explains the theory that reproduction, indeed all the mechanisms of life in general, can be explained in terms of the continued survival of genes tv icon

Genes are information —NOT strands of nucleotides (any more than the information contained in these notes is a string of letters; the information in the notes can be copied [multiplied] and even changed to another form such as speech or digital code or Swahili)

Thus genes build organisms to live in just as humans build houses to live in

Individuals come & go—species come & go—genes can remain forever

Sexual mode of reproduction

Sexual / two-parent (rather than asexual/one-parent) reproduction allows more variation among offspring

Individual genes want to survive and through sexual reproduction can form coalitions with different genes to improve their chances that at least some gene copies will survive (those genes that end up in combinations that turn out to be successful)



Gametes — reproductive cells

Similarity of reproductive tract

Both systems have paired gonads and tubes to carry gametes from the gonads and out of the body

Both systems have gonads and tubes in a Y-shaped structure

Many reproductive organs (male/female) are derived from the same tissue and thus are analogous structures activity

Life's Greatest Miracle , a film from PBS's Nova series, is required as a preview/review of the structure and function of human reproduction and development.
lion trackYou can click on NOVA to view it online (free) or you can view a DVD.

Male Reproductive System

Functional anatomy

Testes (sing. testis)

Reproductive tract

Accessory glands

Penis activity


Germinal epithelium image

Development of sperm cells

Seminal fluid (semen)

Combined secretions of epididymes, vesicles, prostate, bulbourethral glands

pH 7.5

Highly viscous and slippery to aid swimming of sperm

Ball park (no pun intended) figures (but highly variable)

Release of semen


Stages of development of sperm after ejaculation and before fertilization

Complete development of the sperm does not occur until (and unless) the sperm nucleus joins with the egg nucleus to form the first cell of a new offspring (first cell is called the zygote)

Endocrine regulation

Gonadotropin releasing hormone (GnRH) from hypothalamus (to the anterior pituitary)

Controlled by long and short loop negative feedback

Female reproductive system

Functional anatomy


Uterine (fallopian) tubes


Vagina (literally "sheath")

Vulva activity


Meiotic division activity

Primary follicles

Secondary follicles


Ovum that is released is surrounded by layers of cells activity

Some studies now challenge the notion that oogenesis cannot begin in the adult ovary and the notion that ovulation only occurs once per cycle

ovary with corpus luteum

Corpus luteum.

Section of ovary with fully developed corpus luteum at top of photo.

Click image to enlarge it.


Hormonal regulation

Gonadotropin releasing hormone (GnRH) from hypothalamus


Pregnancy tv iconFree A&P image

Labor and delivery

Mammary glands

Integumentary vs. reproductive

Anatomically, mammary glands are integumentary (skin) structures, NOT reproductive structures

However, mammary glands have a reproductive function in the sense that they provide nutrients to offspring during early development (birth to a year or so)

Functional anatomy

Breasts are mammary glands plus surrounding/supporting fat and ligaments, and skin activity picture icon

Both males and females have breasts (with mammary glands)

Nipple — central bump with multiple openings of lactiferous ducts (literally "milk-carrying ducts")

Areola is circle of thin skin surrounding nipple

Mammary glands activity

Hormones regulate breast function / lactation

Estrogen stimulates breast development at puberty and then more during pregnancy

Placental lactogen promotes milk production

Prolactin (adenohypophysis) promotes milk secretion

Oxytocin stimulates milk ejection (from ducts)

Human sexual response

Masters and Johnson picture icon

It has essentially 4 parts (in this order) image image! image!

This is a Learning Outline page.
Did you notice the EXTRA menu bar at the top of each Learning Outline page with extra helps?

This page updated on 23-sep-16