Reproductive Systems (Chapter 41, Pages 770-792) 41.1 How Animals Reproduce 771 41.2 Human Male Reproductive System 773 41.3 Human Female Reproductive System 777 41.4 Control of Human Reproduction 781 41.5 Sexually Transmitted Diseases 785

For an animal species to survive, individuals must reproduce. There are 2 types of reproduction: 1. Sexual reproduction 2. Asexual reproduction

Male Reproductive system (Fig.41.4 & Table 41.1 page 773) The male gonads are paired testes, which are suspended within the sacs of the scrotum. The scrotum helps regulate testicular temperature. The testes Produce sperm and male sex hormones. Sperm produced in the seminiferous tubules of the testes, and mature within the epididymides. After maturation, the sperm enters the vas deferens, also called ductus deferens for storage.

Each vas deferens passes into the abdominal cavity, where it curves around the bladder and empties into an ejaculatory duct. When a male becomes sexually aroused, the sperm enter the ejaculatory ducts and then the urethra, part of which is located within the penis. The interstitial cells (Leydig cells) produce the androgens (mainly the testosterone). Testicular cancer is the most common type of cancer in young men between the ages of 15 and 34.

The Male Reproductive System

Production of Sperm (Fig.41.5 page 774). Each testis is composed of compartments called lobules. Each lobule contains 1-3 tightly coiled seminiferous tubules, which are packed with cells undergoing spermatogenesis, the production of sperm. Sertoli cells, support, nourish the developing sperm, and regulate spermatogenesis. It takes approximately 74 days for a spermatogonium to develop into sperm.

Mature sperm (spermatozoa) have 3 distinct parts: 1.The head 2.The middle piece 3.The tail

Testis and Sperm

The penis (Fig.41.6 page 775) Is the male organ of sexual intercourse. Has a long shaft and an enlarged tip called the glans penis. The glans penis is normally covered by a layer of skin called the foreskin. 3 cylindrical columns of spongy, erectile tissue containing distensible blood spaces extend through the shaft of the penis. During sexual arousal, nervous reflexes cause an increase in arterial blood flow to the penis.

This increased blood flow fills the blood space in the erectile tissue, and the penis, which is normally limp (flaccid), stiffens and increases in size. These changes are called erection. Erectile dysfunction (formerly called impotency) is the inability to achieve or maintain an erection suitable for sexual intercourse. It may have a number of causes, including any condition that affects blood flow, certain medications or illicit drugs, and psychological factors. Can be treated by drugs as Viagra.

Penis Anatomy

Semen (Seminal fluid) Is a thick, whitish fluid that contains sperm and secretion from 3 glands: 1.The paired seminal vesicles Secrete a thick, viscous fluid containing nutrients (fructose). The fluid also contains prostaglandins. 2.The prostate gland It secretes a milky alkaline fluid believed to activate or increase the motility of sperm. By the age of 50, over half of all men experience a benign enlargement (hypertrophy) of the prostate gland that can result in an increased frequency of urination, and a weak urinary stream. Also, after skin cancer, prostate cancer is the most common type of cancer among men.

3.Bulbourethral glands Produce a clear, viscous secretion known as pre-ejaculate. An average male releases 2-5 ml of semen during orgasm. The ejaculated semen of a normal human male contains between 50-150 million sperm/ml, meaning there may be more than 400 million sperm released in one ejaculation. If less than 25 million sperm/ml are released, infertility may result. Fewer than 100 ever reach the vicinity of the egg, however, and only one sperm normally enters an egg. With contractions of the female uterus, it takes sperm about 2hrs to reach the egg traveling approximately 12.5 cm/hr.

Hormonal Regulation in Males (Fig.41.7 page 776) The hypothalamus has the ultimate control of the testes’ sexual function. The anterior pituitary produces 2 gonadotropic hormones: 1.FSH 2.LH Inhibin is produced by seminiferous tubules. All these hormones are involved in a negative feedback relationship that maintains the fairly constant production of sperm and testosterone.

Hormonal Control of Testes

Functions of Testosterone: Is the main sex hormone in males. Is essential for: 1. The normal development and functioning of the sexual organs. 2. Maturation of sperm. 3. Brings about and maintains the male secondary sex characteristics that develop at the time of puberty.

Female Reproductive System: (Fig.41.8 &Table 41.2 page 777) The ovaries Produce the female sex hormones and a secondary oocyte each month. The oviducts Also called uterine or fallopian tubes. Have fingerlike projections called fimbriae that sweep over the ovaries. Are the location of fertilization.

The uterus It is a thick-walled muscular organ. Its narrow end is called the cervix. The uterine lining is called the endometrium. A small opening at the cervix leads to the vaginal canal.

The vagina Its mucosal lining lies in folds and can distend. It serves as birth canal. It facilitate intercourse. The residence of several different types of bacteria.

Female Reproductive System

The vulva Is the external genital organs. Composed of: The mons pubis and 2 folds of skin called labia minora and labia majora are on either side of the urethral and vaginal openings. Beneath the labia majora, pea-sized greater vestibular gland (Bartholin glands) open on either side of the vagina. Bartholin glands keep the vulva moist and lubricated during intercouse. At the juncture of the labia minora is the clitoris which has many sensory receptors that allow it to function as a sexually sensitive organ.

They alternate in producing one oocyte (ovum or egg) each month. The ovaries They alternate in producing one oocyte (ovum or egg) each month. They also produce the female sex hormones during the ovarian cycle. The ovarian cycle (Fig.41.9 Page778, Fig.41.11 page 779 &Table 41.3 page 780) Oogenesis and Ovulation

Phases of the Ovarian cycle The ovarian cycle has 3 phases: 1.Follicular phase: Days 1-13. 2.Ovulation: Day 14. 3.Luteal phase: Days 15-28

Ovarian Cycle

Hormonal Control of Ovaries

The Uterine cycle (Table 41.3 page 780 & Fig.41.11 page 779) Estrogen and progesterone affect the endometrium of the uterus, causing the cyclical series of events known as the uterine cycle. The 28-day cycle is divided into 3 phases as follows: 1. Menstruation: Days 1-5. 2.Proliferative phase: Days 6-13. Ovulation usually occurs on the 14th day of the 28-day cycle. 3.Secretory phase: Days 15-28.

Female Hormone Levels During the Ovarian and Uterine Cycles

Menstruation: 7-10 days before the start of menstruation, some women suffer from premenstrual syndrome (PMS). Degenerating endometrium, mucus, and blood descend from the uterus, through the vagina, creating menstrual flow. The first menstrual period is called menarche occurs between the ages of 11 and 12. If it does not occur by age 16, or normal uterine cycles are interrupted for 6 months or more, amenorrhea exists. Types of amenorrhea: 1.Primary amenorrhea 2.Secondary amenorrhea

Menopause Usually occurs between ages 45 and 55. It is the time in a woman's life when menstruation ceases because the ovaries are no longer functioning. Fertilization and Pregnancy: The placenta originates from both maternal and embryonic tissues. No menstruation occurs during pregnancy.

Estrogen and Progesterone: 1. Estrogen is essential for the normal development and functioning of the female reproductive organs. 2. Estrogen is largely responsible for the secondary sex characteristics.

The female breast: (Fig.41.12 page 781) Contains 15-24 lobules, each with its own mammary duct. A duct begins at the nipple and divides into numerous other ducts, which end in blind sacs called alveoli. After skin cancer, breast cancer is the most common type of cancer in females. Women should regularly check their breasts for lumps and other irregularities and have mammograms. Although breast cancer genes have been described, most forms of breast cancer are nonhereditary.

Breast cancer treatments includes: Traditional Surgery Radiation Chemotherapy Hormonal Therapy Targeted Therapy

Anatomy of the Breast

Control of Human Reproduction Several means are available to dampen or enhance the human reproductive potential. Birth Control Methods (Fig.41.13 page 782) Less Common Birth Control Methods: 1.Morning-after pill (emergency contraception) 2.Contraceptive vaccine

Various Birth Control Methods 1. Abstinence. 2. Intrauterine devices (mechanically prevent implantation and can contain progesterone to prevent ovulation). 3. Vasectomy in males / Tubal ligation in females. 4. Hormone Skin Patch. 5. Female and Male Condom. 6. Diaphragm and Spermicidal Jelly. 7. Depo-Provera (a progesterone injection) 8. Oral Contraception (Birth Control Pills).

Reproductive Technologies Infertility is the inability of a couple to achieve pregnancy after one year of regular, unprotected intercourse. Causes of infertility in males 1. Low sperm count &/or 2. Large proportion of abnormal sperm. Causes of infertility in females 1. Body weight 2. Blocked oviducts

Assisted Reproductive Technologies Consist of techniques used to increase the chances of pregnancy. 1. Artificial Insemination by Donor (AID) 2. Intrauterine Insemination (IUI) 3. In Vitro Fertilization (IVF) 4. Gamete Intrafallopian Transfer (GIFT) 5. Surrogate Mothers 6. Intracytoplasmic Sperm Injection (ICSI)

If all assisted reproductive technologies discussed were employed simultaneously, it would be possible for a baby to have 5 parents!! 1. Sperm donor, 2. Egg donor, 3. Surrogate mother, 4. Contracting mother, 5. Contracting father.

Sexually Transmitted Diseases (STDs) Cause of the Disease Name of the Disease HIV(Human Immunodeficiency Virus) AIDS (Acquired Immune Deficiency Syndrome) HPV (Human Papilloma Virus) Genital Warts HSV-2 (Herpes Simplex Type 2) Genital Herpes Hepatitis A,B.Viruses. Hepatitis Tiny Bacteria; Chlamydia trachomatis Chlamydia Bacteria; Nisseria gonorrheae Gonorrhea Bacteria; Treponema pallidum Syphilis Bacteria; Gardnerella vaginalis Bacterial vaginosis Protozoan; Trichomonas vaginalis OR Yeast; Candida albicans Vaginitis