The human reproductive system
This presentation is the property of its rightful owner.
Sponsored Links
1 / 26

The Human Reproductive System PowerPoint PPT Presentation


  • 109 Views
  • Uploaded on
  • Presentation posted in: General

The Human Reproductive System. Male Reproductive System. urinary bladder. seminal vesicles. prostate gland. urethra. penis. rectum. epididymis. Cowper’s gland. testis/testes. vas deferens. scrotum. Male Reproductive System (frontal view). See p. 62 in Review book.

Download Presentation

The Human Reproductive System

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


The human reproductive system

The Human Reproductive System


Male reproductive system

Male Reproductive System

urinary bladder

seminal vesicles

prostate gland

urethra

penis

rectum

epididymis

Cowper’s gland

testis/testes

vas deferens

scrotum


Male reproductive system frontal view

Male Reproductive System (frontal view)

See p. 62 in Review book


Male reproductive system1

Male Reproductive System

  • Scrotum – sac of skin that holds testes. Hangs below body to keep testes cool. Sperm cannot be produced if body is too warm. Testes move into scrotum just before birth.

  • Testis/testes – male gonads. Made up of small, coiled tubes – seminiferous tubules. 300-600 per testis. Immature sperm made here.

    Secrete testosterone


Male reproductive system2

Male Reproductive System

  • Epididymis – storage area in upper rear of testis. Immature sperm move here to mature – takes 18 hours.

  • Vas deferens – tube that leads upwards from each testis into lower part of abdomen from epididymis.

  • Cowper’s gland – produces fluids that nourish sperm and protect them from the acidity of female.

    Combination of sperm and fluids - semen


Male reproductive system3

Male Reproductive System

6. Rectum – holds wastes

7. Seminal vesicles – same job as Cowper’s gland

8. Urinary bladder – stores urine

9. Prostate gland – same job as Cowper’s gland and seminal vesicles

10. Urethra – passageway for excretion of urine and for sperm to leave body. Vas deferens empties into urethra


Male reproductive system4

Male Reproductive System

11. Penis – male reproductive organ. Facilitates internal fertilization

Ejaculation – muscular contractions force semen through urethra. Before, during and after ejaculation reflex actions keep outlet of bladder closed


Hormones and negative feedback in males

Hormones and Negative Feedback in Males

  • Negative Feedback – change that leads to a response that causes something to counteract that change

  • Luteinizing Hormone (LH) – stimulates testes to produce testosterone

  • Testosterone – stimulates development of sperm. Once there is a large number of sperm, puberty is complete.


The human reproductive system

What is the effect of high levels of LH?

Testosterone is produced

What is the effect of high levels of testosterone?

Slows production of LH which in turn slows production of testosterone

What is the overall outcome of this on-off negative feedback system involving LH and testosterone?

Nearly constant level of both hormones - homeostasis


Male reproductive system and hormones

Male Reproductive System and Hormones

  • Explain how LH stimulates the testes to produce testosterone.

    Circulates in the blood- reaches the testes target cells – stimulates them to produce testosterone

  • What happens when the levels of testosterone are too high in the body?

    LH level drops

  • What is negative feedback and how does it maintain homeostasis?

    Change in conditions triggers response in body to counteract that condition. Keeps hormones in balance


Female reproductive system

Female Reproductive System

oviduct

ovary

Urinary bladder

uterus

urethra

rectum

cervix

vagina


Female reproductive system frontal view

Female Reproductive System (frontal view)

See p. 61 in Review book


Female reproductive system1

Female Reproductive System

  • Ovary – female gonads. Secrete estrogen – produces secondary characteristics, menstrual cycle

    Produces eggs – 2 ovaries 4cms long, 2 cms wide


The human reproductive system

Follicles – each ovary contains 200,000 egg sacs called follicles. In each follicle is an immature egg.

All the eggs are present at birth. During the woman’s lifetime 500 eggs mature

When an egg matures, follicle moves to surface of ovary.

Follicle breaks & releases the egg – ovulation

Egg can be fertilized for about 24 hours after ovulation


Female reproductive system2

Female Reproductive System

2. Oviduct (fallopian tube) – Each ovary is near but not connected to oviduct. Tube with funnel-like opening. Cilia line it to create a current that draws the egg into the tube. Egg is fertilized in the oviduct

3. Uterus – thick, muscular, pear-shaped organ. Once egg is fertilized it finishes its development in uterus attached to uterine wall


Female reproductive system3

Female Reproductive System

4. Urinary bladder – storage of urine

5. Urethra – passage of urine to outside of body

6. Vagina (birth canal) – leads to outside of body

7. Cervix – narrow neck of uterus

8. Rectum – passage for wastes


The menstrual cycle

The Menstrual Cycle

What is the menstrual cycle?

Cycle during which an egg develops and is released from the ovary and the uterus is prepared to receive a fertilized egg

Menarche: first menstrual period – usually occurs between 11 and 12

Menopause: time when a woman stops menstruating, usually between 45 & 55 and is no longer able to conceive.


The menstrual cycle1

The Menstrual Cycle


The menstrual cycle2

The Menstrual Cycle

1. Menstruation: Loss of egg and uterine tissue via vagina if fertilization does not occur

2. Follicle Stage (follicular stage): lasts 10 days, FSH & LH levels increase, egg matures, follicle secretes estrogen to prepare uterus


The menstrual cycle3

The Menstrual Cycle

3. Ovulation: High level of estrogen detected by hypothalamus, increased LH, decreased FSH, follicle bursts – egg released

4. Corpus Luteum Stage (Luteal Phase): LH converts follicle to corpus luteum – secretes estrogen & progesterone. Progesterone prepares uterus. Increased progesterone keeps LH & FSH low


The human reproductive system

Another Way of Looking at Negative Feedback in the Female Reproductive System (Hormones of the Menstrual Cycle)

Brain

Pituitary gland

FSH (causes egg to mature in follicle)

LH (causes to egg to be let go = ovulation)

ovary

Estrogen (causes uterine lining to thicken & build up to prepare for egg)

uterus

Progesterone (helps maintain uterine lining)


Hormones of menstrual cycle

Hormones of Menstrual Cycle

What happens if fertilization occurs?

Corpus luteum keeps producing progesterone to maintain pregnancy. After 5 weeks the embryo produces progesterone – this inhibits LH & FSH so no menstrual cycle

What happens if fertilization does not occur?

There is no implantation – the corpus luteum breaks down. Progesterone level drops, uterine lining breaks down – menstruation.

FSH & LH are produced again – new cycle

Average Menstrual Cycle is 28 days long


Ovulation to implantation

Ovulation to Implantation

oviduct

uterus

egg from ruptured follicle

cervix

ovary

follicle

vagina

sperm


Ovulation to implantation1

Ovulation to Implantation

  • Ovary – produces estrogen & progesterone – meiosis occurs & egg develops

  • Egg matures in follicle of ovary

  • Ovulation – egg released from follicle – may live for 24 hours

    - egg moves into fallopian tube by cilia


Ovulation to implantation2

Ovulation to Implantation

  • Events in fallopian tube

    • Fertilization occurs here. Sperm lives 4-5 days (egg lives 1 day)

    • Zygote undergoes mitosis & travels down fallopian tube within 6-10 days. Zygote is ready to implant into uterus.


Ovulation to implantation3

Ovulation to Implantation

  • Events in uterus

    • Implantation – embryo implants/embeds into uterine lining & secretes hormone HCG to signal its arrival

    • Cell Differentiation – cells divide by mitosis & become different due to gene expression. Different embryo parts will form.


  • Login