HUMAN REPRODUCTION

Chapter 3

MALE Reproductive

System

FEMALE Reproductive

System

Reproductive Engineering

Fertilization, Implantation, and Birth

THE MALE REPRODUCTIVE SYSTEM

TESTES It arise early in the embryonic development, these remain in the lower part of abdominal cavity

Descends through the body wall into a sac called Scrotal Sac or Scrotum

Failing to descend is the condition called Cryptorchidism

Each testis consist of Seminiferous Tubules, its lining walls are called Spermatogonia that produce the sperms

Sperms produced are collected by tiny ducts called Vasa Efferentia which lead to a long (20 ft) coiled Epididymis

Interstitial cells that produces male sex hormones are called Androgens

Testosterone is the responsible androgens for developing secondary male characteristics such as deep voice and facial hair

CRYPTORCHIDISM Derived from the Greek κρυπτός, kryptos, meaning hidden and ὄρχις, orchis, meaning testicle

The absence of one or both testes from the scrotum Can only be corrected through surgery

ABNORMALITIES OF MALE REPRODUCTIVE SYSTEM

1. Cryptorchidism - First type of male sterility that occurs at the time of birth of a baby boy.

2. Abnormal Sperm Morphology - Men with abnormal sperm morphology are still capable of fathering children; however, it may take longer than normal to do so.

3. Reduced Sperm Counts -Having a low sperm count decreases the probability that one of your sperm will fertilize your partner's egg. Nonetheless, many men who have a low sperm count are still able to father a child.

SPERM MORPHOLOGY OR TERATOZOOSPERMIA

It is the shape and size of sperm, head should be oval in shape, have a mid-section, and have a long, straight tail

CROSS-SECTION OF THE SEMINIFEROUS TUBULES

A normal ejaculation is equivalent to 3.5 ml semen containing 400 million sperms.

1 ml semen contains 60 million sperms. Lower than 60 million is considered abnormal condition.

THE FEMALE REPRODUCTIVE SYSTEM

Gonads - an organ that produces gametes; a testis or ovary.- gonads of the female are the 2 ovaries, where eggs are produced.

Oogonia- an immature female reproductive cell that gives rise to primary oocytes by mitosis.

Oocyte- cell in an ovary that may undergo meiotic division to form an ovum.

Mitosis- a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus.

Puberty (9-15 years) - No further development takes place until a girl reaches this period.- During this stage, eggs mature and grows larger once in a month.- Eggs completes its 1st meotic division within a follicle.

Follicle- A fluid-filled envelope of cells surrounding the egg.- Serves as an endocrine gland and produces a mixture of female sex hormones called Estrogen.

Estrogen- Hormone repsonsible for developing secondary sexual characteristics of a woman such as development of breast and broadening of the pelvis.- Plays important role in monthly menstrual cycle.

Menstruation- The process where a small amount of blood and other products of tissue disintegration are discharged from the Vagina.- It continues for 4-5 days.- Estrogen stimulates an increase in the thickness an blood supply of the inner lining of the Uterus.

Ovulation- Occurs 2 weeks onset of menstruation in which the egg cell is being released when the follicle ruptures.

Fallopian Tube- Also called oviduct, where the egg is being swept until reaching the end of it with the help of the constant moving of Fimbria.

FEMALE UTERUS

Corpus Luteum- The yellow body being developed when the old follicle undergoes a reorganization of its cells.- It also functions as an endocrine gland by secreting another female hormone called Progesterone.

Progesterone- For 10 days high level of this hormone in blood stream stimulates the development of the lining of uterine wall and causes slight enlargement of breasts.- Without fertilization occuring, the production of this hormone drops off at about 26th day of cycle, Corpus Luteum shrinks and linings of the uterus breaks down. On the 28th day, the menstrual flow begins.- Withdrawal of this hormone results in uterine contraction, the ”cramps” usually associated with the 1st and 2nd day of menstruation.

ABNORMALITIES OF FEMALE REPRODUCTIVE SYSTEM

1. Hypogonadism- Characterized by reduce or less secretion of ovarian hormones leading to infantile uterus, uterus didn’t develop, remained small with the size of an infant’s, and failed to attain adult characteristics.- could undergo an operation but its purpose is just to be able to have a sexual intercourse with her partner. Unfortunately, it is impossible to bear a child.

2. Irregular Menstruation- Associated with failure of ovulation.- Only 30 to 40 percent accounts to infertility. Chances are women can still get pregnant even when having irregular periods.

ABNORMALITIES OF FEMALE REPRODUCTIVE SYSTEM

3. Excessive Estrogen-It decreases the production of gonadotopins limiting the production of ovarian hormone.- This condition often results to cell tumor in the ovary after menopause. Bleeding is the 1st symptom that indicates such tumor exists.

4. Endometriosis- The development and growth of endometrium or the uterine wall or linings.- It causes pelvic pain. It is painful and may be a hint to other problems.- Most likely to affect women during their childbearing years.

FERTILIZATION, IMPLANTATION, AND BIRTH

- Sperms must be deposited to the vagina near the time of ovulation.- Due to Sexual arousal the arteries supplying blood to the penis became wider resulting to pressure that causes it to become erect and thus able to penetrate the vagina.- Further arousal results to ejaculation of semen.

Semen- Are mixture or sperms and secretion.- Only 1 sperm fertilizes the egg but 60 million sperms must be present in 1 ml if fertilization is to occur because most sperms die due very acidic trip through the female genital tract.

- Embryonic development begins while the zygote is still within the Fallopian tube.- The embryo continues to travel down the tube reaching the Uterus within just a week.- Implantation on the thickened lining of the uterus takes place.- The extra-embryonic membranes develop forming the amniotic cavity, placenta, and umbilical cord. Pregnancy then is established.- During first 3 months of pregnancy, embryo produces chorionic gonadotropin which is usually spilled in the urine of the mother giving postive results during Pregnancy Test.- After 5 months of pregnancy Corpus Luteum can not produce enough progesterone anymore. Placenta then becomes an endocrine that produces extra amount of progesterone called Placental Progesterone.

- Before the ”labor”, ovaries and placenta produce a hormone called Relaxin that causes the ligaments between the pelvic bones to loosen providing more flexible passage way for the baby during birth.- Other hormones which cause strong contraction are Oxytocin and Prostaglandins.

Oxytocin - Some evidence shows that the baby itself is the main source of this hormone

Prostaglandins - a group of related substance that also appears in the mother’s blood an in the amniotic fluid at the time of birth and causes strong contraction of uterus allowing the rupture of amniotic cavity producing labor pains.

- Later, Cervix opens and amniotic fluids flow out.- Continuous contraction of the uterus expels the baby through the cervix and out of the vagina.- Umbilical cord is then severed and the baby can be touched or spanked lightly to effect its first cry.- Shortly after the baby arrived, the placenta and remains of the umbilical cord are expelled.

First Cry- This allow the lungs to be fully

functional and to start breathing.

REPRODUCTIVE ENGINEERING

- Refers to the technology related to improve species whether be of plants or animals.- Also reffered to as gene slicing or inserting the desired gene to a particular species - It is an integral part of biotechnology

Biotechnology- exploitation of biological processes

for industrial and other purposes, esp. the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc.

APPROACHES TO REPRODUCTIVE ENGINIEERING:

1. Development of Sperm Bank among animals and gene bank among plants. - Animals including man, semen are thawed and put into the reproductive tract of a woman. - This was originally done in pigs and cows in artificial insemination but now, this is also possible among human beings if natural process is not applicable. - Plants, hybridization among species is done through establishment of gene bank, it is a designated area where different species are planted and produced whether be of natural or artificial hybridization .

APPROACHES TO REPRODUCTIVE ENGINIEERING:

2. Embryo Transfer or Surrogation. - This the transfer of fertilized egg or early embryo from a female who produced it to a foster mother who will carry the child until birth.

- This is a case where the mother or wife is unable to carry the child herself due to health problems such as heart failure or diseases of the uterus

APPROACHES TO REPRODUCTIVE ENGINIEERING:

3. Test Tube Babies.- This is a process that leads to

the development of an environment for the in-vitro baby because the mother is not capable of sexual act due to heart disease or other ailments.

4. Amniocentesis.- A very senstive process that

allows couple to determine any abnormality of the baby inside uterus.

- Abnormality such as Down Syndrome and enzymatic defects can be detected.

APPROACHES TO REPRODUCTIVE ENGINIEERING:

5. Tetraparental mice.- Applicable only for mice, this is

the production of offspring with 4 parents.

6. Cloning.- This is the newest type of

reproductive engineering that doesn’t involve any sperms but only egg.

- One example of cloning is the cloned lamb named Dolly.

THATS ALL! THANK YOU!

PREGNANCY STAGES