TABLE OF CONTENTS
CHAPTER 16 - REPRODUCTIVE SYSTEM
1. Human Life Cycle
a. Mitosis and Meiosis
2. Male Reproductive System
a. Orgasm
b. Testes
c. Hormonal regulation
3. Female Reproductive System
a. Genital tract
b. External genitals
c. Orgasm
4. Female Hormone Levels
a. Ovarian cycle - non pregnant
b. Estrogen and progesterone
c. Uterine cycle - non pregnant
d. Fertilization and pregnancy
5. Control of Reproduction
a. Birth control
b. Fertilization and pregnancy
c. Infertility
6. Sexually Transmitted Diseases (STDs)
a. Caused by virus
b. Caused by bacteria
c. Two other infections
CHAPTER 17 - DEVELOPMENT AND AGING
7. Fertilization
a. Steps
8. Pre-embryonic Development
a. Processes
b. Extraembryonic Membranes
c. Stages
9. Fetal Development
a. Events
b. Development of male and female sex genitals
10. Pregnancy and Birth
a. Birth
b. Stage 1
c. Stage 2
d. Stage 3
11. Development After Birth
a. Hypothesis of aging
b. Effects of age
CHAPTER 16 - REPRODUCTIVE SYSTEM
HUMAN LIFE CYCLE
In our human life cycle 2 types of cell division is required. Mitosis and Meiosis.
Mitosis is growth and repair of tissues.
Meiosis is gamete production.
MALE PRODUCTIVE SYSTEM
The external genitals of males are the penis and the scrotum.
Spermatogenisis is production of sperm in the seminiferous tubules of the testes. Mature sperm is stored in the epididymides. Sperm pass from the vasa deferentia to the urethra. The seminal vesicles, the prostate gland, and bulbourethral glands add fluids to the sperm. These are referred to as semen and seminal fluid. Orgasm in males results in ejaculation of semen from the penis.See illustration.*
The hypothalamus, the anterior pituitary and the testes regulate hormones, they maintain a fairly constant level of testosterone. See illustration.*
The hypothalamus, the anterior pituitary and the testes regulate hormones, they maintain a fairly constant level of testosterone. See illustration.*
FSH form the anterior pituitary promotes spermatogenesis.
LH from the anterior pituitary promotes testosterone production by interstitial cells.
FEMALE REPRODUCTIVE SYSTEM
FEMALE REPRODUCTIVE SYSTEM
Oogenesis occurring within the ovaries typically produces one mature follicle each month.
The follicle releases an egg that enters an oviduct. Oviducts lead to the uterus, where implantation and development occur.
The external female genital area includes the vaginal opening, the clitoris, the labia minora and the labia majora. The vagina is the organ of sexual intercourse and the birth canal.
See illustration.*
Orgasm in females culminates in uterine and oviduct contractions.
FEMALE HORMONE LEVELS
Ovarian Cycle: Non-pregnant
The hypothalamus and the anterior pituitary control hormones in the ovarian cycle.
The hypothalamus and the anterior pituitary control hormones in the ovarian cycle.
During first half of cycle, FSH from the anterior pituitary causes maturation of a follicle that secretes estrogen and progesterone. After ovulation and during the cycle's second half, LH from the anterior pituitary converts the follicle into the corpus luteum, which secretes progesterone and some estrogen.
Uterine Cycle: Non-pregnant
First of all, estrogen and progesterone regulate the uterine cycle. Estrogen causes the endometrium to rebuild. Ovulation occurs on day 14 of a 28 day cycle. See illustration.*
Progesterone produced by the corpus luteum causes the endometrium to thicken and become secretory.
A low level of hormones causes the endometrium to break down as menstruation occurs.
Fertilization and Pregnancy
If fertilization takes place, the embryo implants itself in the thickened endometrium.
The corpus luteum is maintained because of HCG production by the placenta, and therefore, progesterone production does not cease. Menstruation usually does not occur during pregnancy.
CONTROL OF REPRODUCTION
There are numerous birth control methods and devices are available. A few include: birth control pill, diaphragm, and condoms. Effectiveness varies.
Here in this illustration it shows two surgical ways of birth control.*
Infertility is the failure of a couple to achieve pregnancy after one year of regular, unprotected intercourse. Infertility can be caused by low sperm count and/or a large proportion of abnormal sperm. Infertility in females can be caused by being overweight, or due to pelvic inflammatory disease and endometriosis.
There are assisted reproductive technologies like: artificial insemination by donor (AID), gamete intrafallopian transfer (GIFT), and intracytoplasmic sperm injection (ICSI).
SEXUALLY TRANSMITTED DISEASES
STDs are caused by viruses, bacteria, protists, fungi, and animals.
STDs caused by viruses include: HIV, genital warts, genital herpes, hepatitis.
STDs caused by bacteria include: chlamydia, gonorrhea, syphilis.
Two other infections include: bacterial vaginosis, and trichomoniasis.
CHAPTER 17 - DEVELOPMENT AND AGING
FERTILIZATION
Fertilization is the union of a sperm and egg to form a zygote, the first cell of the new individual. The acrosome of a sperm releases enzymes that digest a pathway for the sperm through the zona pellucida. The sperm nucleus enters the egg and fuses with the egg nucleus. See illustration.*
PRE-EMBRYONIC AND EMBRYONIC DEVELOPMENT
Cleavage, growth, morphogenesis and differentiation are the processes of development.
Cleavage is immediately after fertilization, the zygote begins to divide.
Growth - during embryonic development, cell division is accompanied by an increase in size of the daughter cells.
Growth - during embryonic development, cell division is accompanied by an increase in size of the daughter cells.
Morphogenesis refers to the shaping of the embryo and is first evident when certain cells are seen to move, or migrate, in relation to other cells. These movements, the emvbryo begins to assume various shapes.
Differentiation is when cells take on a specific structure and function, differentiation occurs. The first system to become visibly differentiated is the nervous system.
The extraembryonic membranes, chorion, allantois, yolk sac, and amnion, function in internal development.
STAGE DEVELOPMENT
Pre-embryonic development encompasses the events of the first week. See illustration.*
Embryoinc development begins with the second week and lasts until the end of the second month of development. In this stage the major event called gastrulation starts, turns the inner cell mass into the embryonic disk. This is where 3 primary germ layers are formed. See illustration.*
Third week - the nervous system is the first system to develop and the heart starts to develop.
Fourth week and fifth weeks - blood vessels become umbilical blood vessels. Umbilical cord is fully fored. Limb buds appear. 5th week head enlarges, and sense organs become more prominent. See illustration.*
Sixth through eight weeks - Form is easily recognizable as a human being. brain development, head achieves its normal relationship with the body, nervous system is developed enough to permit reflex actions, 38 mm long at end of this period and weighs no more than an aspirin tablet, all organ systems have been established.
FETAL DEVELOPMENT
The umbilical cord stretches between the placenta and the fetus. It is the lifeline of the fetus because it contains the umbilical arteries and vein. See illustration.*
Third and fourth month - the skeleton is becoming ossified. The sex of the fetus becomes distinguishable. If an SRY gene is present, testes and male genitals develop. If not, ovaries and female genitals develop. See illustration.*
Fifth through the ninth months - the fetus continues to grow and to gain weight.
PREGNANCY AND BIRTH
Major changes take place in the mother's body during pregnancy.
Weight gain occurs as the uterus occupies most of the abdominal cavity. Many complaints, such as constipation, heartburn, darkening of certain skin areas, and pregnancy- induced diabetes, are due to the presence of placental hormones.
During birth, a positive feedback mechanism that involves uterine contractions and oxytocin explains the onset and continuation of labor.
During stage 1 of birth the cervix dilates.
During stage 2 of birth the child is born.
During stage 3 of birth the afterbirth is expelled.
DEVELOPMENT AFTER BIRTH
Development after birth consists of infancy, childhood, adolescence, and adulthood.
Aging encompasses progressive changes from about age 20 on that contribute to an increased risk of infirmity, disease and death.
Aging may have a genetic basis, may be due to changes that affect the whole body, and may be due to extrinsic factors(diet and exercise)
Deterioration of organ systems can possibly be prevented or reduced in part by utilizing good health habits.
No comments:
Post a Comment