Reproductive System

Reproductive System

Meiosis

Special type of cell division that creates 4 genetically unique haploid gametes from 1 diploid cell

How does that differ from mitosis?

Meiosis I (Reduction Division)

Before meiosis, Interphase - replicate all chromosomes Goals

• Crossing over - during Prophase I
• PMAT to divide homologous chromosomes to create 2 genetically unique, haploid cells

Meiosis II (Equational Division)

Goals:

• Repeat PMAT to divide sister chromatids -> create 4 genetically unique, haploid gametes

Reproductive Endocrinology: Hypothalamus

• GnRH

• Oxytocin (production only)

Reproductive Endocrinology: Pituitary

Anterior Pituitary

• FSH

• LH

• prolactin

Posterior Pituitary

• oxytocin (secretion only)

Reproductive Endocrinology: Gonads

Ovaries

• Estrogen

• Progesterone

• Relaxin

Testes

• Testosterone

Reproductive Endocrinology: HPG Axis

Reproductive Endocrinology: Placenta

• hCG

Male Reproductive System

Chapter 16

Testosterone Production

Testosterone Production

Begins when male reaches _____________ & continues through their life

• Hypothalamus produces ______________________

• This stimulates the release of _______ & _______ from the __________________________.

• Those hormones target the testes. What is their primary action?
• LH
• FSH

• Testosterone production is regulated by ______________ feedback.

puberty

GnRH

FSH

LH

anterior pituitary

negative

Female Reproductive System

Anatomy of Female External Genitalia

vulva

clitoris

labia minora

urethral orifice

labia majora

vaginal introitus

perineum

Supports the development of embryo/fetus

Tubes that act as bridge b/t ovaries and uterus. Transports egg from ovaries to uterus.

end of fallopian tube closest to ovary that is fringed with fimbriae

Finger-like projections that swell and sweep back & forth across the ovary to draw egg into fallopian tube.

produces, stores, matures, and releases follicles containing female gametes (ova/egg). Also produ ces estrogen & progesterone.

Middle layer of uterus. Made of smooth muscle that contracts during labor.

Facilitates intercourse and provides a channel for childbirth as well as menstrual blood & tissue to be removed.

inner lining of uterus that responds to hormonal changes to prepare for embryo implantation. If implantation doesn't occur, it slughs off during menstruation.

lower 2-3 cm of uterus. Produces mucus that changes during a woman's ocarian cycle that can either block or enhance sperm transport.

Female Reproductive Anatomy -Sagittal Section

Ovarian Cycle

Ovarian Cycle

The process by which ovarian follicles mature, rupture (ovulate), and degenerate. Begins when the female reaches puberty -> hypothalamus secretes __________ which drives the production of FSH and LH. 3 Phases of the Ovarian Cycle

1. Follicular phase
2. Ovulation
3. Luteal phase

GnRH

Regulation of Ovarian Cycle by FSH and LH

Follicular

• During the ______________ phase (~ days 0-13), FSH and LH remain relatively low.

• Just before ______________(~days 13-14), FSH and LH will spike.
• FSH causes the follicle containing the oocyte to ____________________.
• LH causes the follicle to ____________________ and release the ____________________. This process is called _______________________.

• During the _________________ phase (~days 15-28), LH and FSH return to low levels. The _____________________________ develops during this phase.

ovulation

grow and mature

rupture

egg/oocyte

ovulation

luteal

corpus luteum

Estrogen & Progesterone Production

• During the _________________ phase (~days 0-13), the follicle containing an oocyte is growing and maturing. As it grows, it produces _________________________.

• Following ovulation, the tissue that remains of the follicle will form a new structure called the ________________________________________. This structure produces a large amount of ________________________ and some ________________________.

follicular

estrogen

corpus luteum

progesterone

estrogen

Development of Ovarian Follicle

Immature follicles - egg is paused in Prophase I. You're born with about 1 million primordial follicles and will not produce any more after birth.

After about 2 weeks, the corpus luteum degenerates further and becomes the corpus albicans which is essentially a scar formed on the ovary from ovulation

At puberty, each month during the follicular phase, 1 follicle will begin maturing due to rising FSH levels. Within the maturing follicle is an egg (oocyte) that is also maturing and continuing through the process of meiosis (development stops at Metaphase II). As the follicle matures, it secretes estrogen.

mature egg that has ruptured out of it's follicle ithin the ovary (ovulation) due to a peak in LH. This egg will remain in Metaphase II until shortly after fertilization.

After ovulation, the remaining tissue of the follicle becomes the corpus luteum. This structure secretes high levels of progesterone which helps maintain the lining of the uterus to prepare for implantation. The corpus luteum degenerates if implantation does not occur, but will remain for about 12 weeks if implantation does occur.

Uterine (Menstrual) Cycle

Uterine (Menstrual) Cycle

Changes that occur in the uterus during the ovarian cycle. Driven by 2 hormones: __________________ & _____________ 3 Major Phases

1. Menstrual phase
2. Proliferative phase
3. Secretory Phase

estrogen

progesterone

Uterine (Menstrual) Cycle

menstrual

• The first phase is called the ___________________ phase (days ~0-5). During this phase, estrogen and progesterone levels are _________________ which causes the __________________ to shed (a process called ______________________________)

• The second phase is called the ____________________ phase (days ~5-14). Increasing ____________________ causes the endometrium to _____________________.

• The third phase is called the ____________________ phase (~days 14-28). Increasing progesterone & estrogen keep the endometrium ________________ and cause glands in the endometrium to secrete ______________________ to prepare for possible implantation of a fertilized egg.

low

endometrium

menstruation (menses)

proliferative

estrogen

thicken

secretory

thick

nutrients

Part II

Childbirth Disorders of the Reproductive System

Disorders of the Reproductive System

Prostatitis

• Inflammation of prostate gland
• Usually caused by cancer or infection
• Treatment depends on the cause
• Main symptom - difficulty urinating

Testicular Torsion

• Testicle twists and cuts off blood supply
• Sometimes occurs after injury or vigorous exercise; usually happens spontaneously in teenagers
• Main symptom: severe pain
• This is a medical emergency that requires surgery

Priapism

• Prolonged erection (>4 hours); usually without arousal
• Some meds (erectile dysfunction meds, antidepressants) can make you more susceptible
• Treatment: remove blood -> vasoconstrictors, needle aspiration, larger surgery
• This is a medical emergency that must be treated before tissue death occurs

Polycystic Ovarian Syndrome

• Hormonal imbalance (increased androgens like testosterone)
• Characterized by enlarged ovaries with many cysts
• Often also causes insulin resistance - those affected need to manage blood glucose
• Symptoms: pain, irregular menses, irregular ovulation, infertility
• Treatment: manage blood sugar, birth control pills, fertility meds

Endometriosis

• Endometrium grows outside of uterus
• it responds to estrogen and progesterone - thickens and sheds
• Causes scar tissue/adhesions to develop
• Symptoms: severe pain, heavy menses, infertility

• Treatment: surgical removal of lesions, birth control pills, GnRH antagonists

Ectopic Pregnancy

• Pregnancy that occurs outside of the uterus -> usually the fallopian tube
• This is a medical emergency - requires medical attention (termination of pregnancy with meds or surgery) immediately. No treatment = hemorrhage and death

Sexually Transmitted Infections (STI's)

Gonorrhea

• AKA "the clap"
• Caused by a bacterial infection (Neisseria gonorrheae) spread from sexual contact
• Signs/Symptoms:
• Thick yellowish discharge from penis/vagina; tingling
• Can also cause throat infections (if contracted via oral sex)
• Treatment: antibiotics

Syphilis

• Caused by a bacterial infection (Trepenoma pallidum) spread through sexual contact
• Signs/Symptoms:
• development of chancre -> painless ulcer where bacteria entered
• Eventual body-wide rash that comes and goes
• Brain damage and death if not treated
• Treatment: antibiotics

Chlamydia

• Caused by a bacterial infection (Chalmydia trachomatis) spread through sexual contact
• Signs/Symptoms:
• Large amount of light-colored discharge
• Often no other symptoms (silent disease). Sometimes will experience burning
• Treatment: antibiotics

Human Papillomavirus (HPV)

• Viral infection spread through sexual contact.

• Many different strains cause different symptoms:
• warts
• cervical, penile, anal, and throat cancer

• Treatment - removal of warts/lesions. Treatment of cancer if it develops. No specific cure.

• Prevention - in addition to safe sex, Guardasil vaccine.

Human Immunodeficiency Virus (HIV) Aquired Immunodeficiency Disease (AIDS)

Human Immunodeficiency Virus (HIV)

• This virus attacks T-cells (a type of immune cell)
• The photo you see is of a T-cell rupturing from an infection with HIV
• Leaves the person extremely susceptible to other infections
• If uncontrolled, can develop into AIDS (acquired immunodeficiency syndrome) -> severe immune deficiency which makes even minor infections potentially deadly.
• Treatent - antiretroviral therapy (helps, but cannot cure)

Herpes Simplex Virus (HSV)

Herpes Simplex Virus (HSV) Two types exist

• Type 1 - usually causes blisters around mouth (oral herpes)
• Type 2 - usually causes blisters around genitalia (genital herpes)
• Treatment - valtrex and acyclovir (helps, but cannot cure)

Protozoan STDs

• Trichomoniasis
• Causes by a protozoan infection
• Protozoa are microorganisms that are neither bacteria, viruses, nor fungi
• Characterized by frothy green discharge with a foul fish-y odor
• Treatment - metronidazole (cures the infection)

• Trichomoniasis

STDs and Infertility

• If left untreated, many sexually transmitted diseases/infections can render you infertile.
• Photo on left - extreme PID (pelvic inflammatory disease) caused by prolonged STD
• Photo on right - epididymitis - inflammation of epididymis caused by prolonged STD

Vas deferens

Tube that transports mature sperm from epididymis to ejaculatory duct during ejaculation. This is the tube that is cut during a vasectomy

Cervix

lower 2-3 cm of uterus. Produces mucus that changes during a woman's ocarian cycle that can either block or enhance sperm transport.

Primordial follicle

Immature follicles - egg is paused in Prophase I. You're born with about 1 million primordial follicles and will not produce any more after birth.

Epididymis

• coiled tube on top of each testicle.
• stores and matures sperm made by the testicles
• Maturation takes about 1 week

Infundubiulum

end of fallopian tube closest to ovary that is fringed with fimbriae

Ovum

mature egg that has ruptured out of it's follicle ithin the ovary (ovulation) due to a peak in LH. This egg will remain in Metaphase II until shortly after fertilization.

Urethra

• Tube that runs through center of penis
• Transports semen and urine to the outside of body

Corpus Spongiosum

• Erectile tissue found below the corpus cavernosum.
• Contains only 10% of blood in penis during an erection
• Surrounds the urethra and prevents urethral collapse during erections

Fallopian Tubes

Tubes that act as bridge between ovaries and uterus. Transports egg from ovaries to uterus.

Ovary

produces, stores, matures, and releases follicles containing female gametes (ova/egg). Also produ ces estrogen & progesterone.

Ejaculatory Duct

• tube formed by the union of the seminal vesicle duct and vas deferens and passes through the prostate gland.
• The prostate gland contracts around the ejaculatory duct to propel semen during ejaculation.

Endometrium

inner lining of uterus that responds to hormonal changes to prepare for embryo implantation. If implantation doesn't occur, it slughs off during menstruation.

Corpus albicans

After about 2 weeks, the corpus luteum degenerates further and becomes the corpus albicans which is essentially a scar formed on the ovary from ovulation

Corpus Luteum

After ovulation (during the luteal phase) the remaining tissue of the follicle becomes the corpus luteum. This structure secretes high levels of progesterone which helps maintain the lining of the uterus to prepare for implantation. The corpus luteum degenerates if implantation does not occur, but will remain for about 12 weeks if implantation does occur.

Cowper's Gland

• Secretes clear, alkaline fluid rich in nutrients into the urethra BEFORE ejaculation
• Lubricates the urethra to prevent sperm damage

Testis

• Plural: testes
• gland that produces sperm and testosterone.
• Each has many coiled tubes called siminiferous tubules - where sperm are made
• Leydig cells between tubules are what create testosterone

Fimbriae

Finger-like projections that swell and sweep back & forth across the ovary to draw egg into fallopian tube

Seminal Vesicle

• 2 glands located behind and below the bladder
• Supplies most of the fluid that makes up semen.
• This fluid alkaline to neutralize the acidic vagina (which would otherwise kill sperm)
• Also rich in nutrients to support sperm

Corpus Cavernosum

• Spongy erectile tissue that engorges with blood to stiffen the penis, creating an erection.
• 90% of blood in penis is found here during an erection

Myometrium

Middle layer of uterus. Made of smooth muscle that contracts during labor.

Vagina

Facilitates intercourse and provides a channel for childbirth as well as menstrual blood & tissue to be removed.

Scrotum

• suspended sac of skin and smooth muscle that holds testes outside of body
• Keeps testes cooler than core body temp > prevents sperm damage

Penis

External male sex organ that: 1. facilitates intercourse 2. expels sperm 3. removes urine

Prostate gland

• produces an alkaline fluid that makes up about 30% of semen.
• Also contains smooth muscle which contracts to propel semen through ejaculatory duct during ejaculation

Uterus

• Supports the development of embryo/fetus

Glans penis

• Head of penis
• Rich in nerves that contribute to sexual pleasure
• covered by foreskin in uncircumcised males/exposed in circumcised males

GnRH - Gonadotropin Releasing Hormone

• Produced by hypothalamus when puberty is reached
• Targets anterior pituitary
• Causes anterior pituitary to secrete FSH and LH

FSH - Follicle Stimulating Hormone

• Produced by anterior pituitary (in response to GnRH)
• Targets gonads
• Testes - stimulates sperm production
• Ovaries - stimulates egg production which leads to estrogen production

LH - Luteinizing Hormone

• produced by anterior pituitary (in resonse to GnRH)
• Targets gonads
• Testes - stimulates testosterone production
• Ovaries - triggers ovulation which stimulates progesterone production

Prolactin

• produced by anterior pituitary
• targets mammary glands to stimulate breastmilk production

Oxytocin

• Produced by hypothalamus
• Stored and secreted by posterior pituitary
• Target:
• Uterus: causes contractions during childbirth and female orgasm
• Penis: stimulates contractions during ejaculation
• Mammary glands: stimulates ejection (release) of breastmilk
• Brain: "bonding hormone" for both males and females

Testosterone

• Primary sex hormone produced by testes (males)
• Helps sperm mature
• Also causes development of secondary sex characteristics (body hair, voice change, increased muscle and bone mass

Estrogen

• One of the primary female sex hormones produced by ovaries
• Helps eggs mature
• Helps maintain pregnancy
• Contributes to secondary sex characterstics - widening hips, breast development, pubic hair

Progesterone

• One of the primary female sex hormones produced by ovaries
• Helps maintain uterine lining to prepare for and maintain pregnancy

Relaxin

• Production increases significantly during pregnancy (by ovaries)
• Targets connective tissue to help pelvis relax to make room for growing fetus
• Also helps cervix soften and dilate closer to delivery

hCG (human chorionic gonadotropin)

• pregnancy hormone
• produced by cells that will become placenta (shortly after fertilization) and eventually produced by placenta (organ that develops during pregnancy)
• Helps maintain the pregnancy by targeting the ovaries to cause an increase in estrogen and progesterone (keep the uterine lining thick for good embryo implantation)

Vulva

external female genitalia

Labia majora/minora

External skin folds that protect the openings to the urethra and vagina Majora - larger and more superficial; characterized by pubic hair growth Minora - smaller and deeper to the majora; mucous membrane with no pubic hair

Labia major/minora

External skin folds that protect the openings to the urethra and vagina Majora - larger and more superficial; characterized by pubic hair growth Minora - smaller and deeper to the majora; mucous membrane with no pubic hair

Perineum

tissue between vaginal introitus and anus. This is the area most prone to tearing during childbirth

Clitoris

small mound of sensitive erectile tissue (similar to penis).Functions to aid in sexual pleasure only

Urethra orifice

external opening of urethra which transports urine from bladder to external world

Vaginal Introitus

"entrance" to vagina