Chapter 12: Human Growth and
Development
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The Male Reproductive System
• Primary Organs
–
Gonads: testes
• Accessory Structures
–
Ducts that transport sperm cells & hormones
–
Exocrine glands
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The Male Reproductive System (cont’d)
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Testes
• Located outside body, midline below torso
• Suspended by spermatic cord in scrotum
• Spermatic cord: bundle of blood & lymphatic vessels &
nerves
• Oval-shaped
• Site of sperm generation
• Produce testosterone
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Structure of the Testis
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Testosterone
• Main male sex hormone
• Diffuses from testes into surrounding fluid & is absorbed
into bloodstream
• Functions:
–
Develops & maintains reproductive structures
–
Develops sperm cells
–
Develops secondary sex characteristics (deeper voice, body hair)
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Spermatozoa
• Sperm cells
• Fertilize egg cell
• >200 million in average ejaculation
• Manufactured continuously after puberty in testes
• Head: nucleus containing chromosomes, enzymes to
penetrate ovum
• Tail: propels sperm through female reproductive system
to reach ovum
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Accessory Structures
• Epididymis
–
Coiled tube on surface of testes
–
Stores sperm
• Vas deferens
–
Duct in spermatic cord
–
Carries sperm to ejaculatory duct
• Ejaculatory duct
–
Delivers sperm to urethra
• Penis: delivers sperm to vagina during intercourse
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Semen
• Mix of sperm cells & secretions from other glands
• Expelled from body in ejaculation
• Functions of secretions in semen:
–
Nourish sperm cells
–
Transport them
–
Neutralize acidity of male urethra & female vaginal tract
–
Lubricate female reproductive tract during intercourse
–
Prevent infection by using antibacterial enzymes & antibodies
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The Urethra and Penis
• Urethra
–
Tube that transports both urine & semen through pelvic cavity &
penis
–
Ejection of semen made possible by erection
• Penis
–
Made of spongy tissue that engorges with blood when erect
–
Contractions of skeletal muscles in pelvic floor expel semen
–
Penis & scrotum make up male external genitalia
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Common Diseases and Conditions of the
Male Reproductive System
• Enlarged prostate
• Prostate cancer
• Testicular cancer
• Orchitis
• Cryptorchidism
• Epididymitis
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The Female Reproductive System
• Ovaries
–
Female gonads
–
Site of egg formation
• Accessory Structures
–
Uterus
–
Various passageways
–
Bartholin glands
–
External genitalia
–
Breasts
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The Female Reproductive System (cont’d)
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The Female Reproductive System (cont’d)
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The Ovaries
• Outer layer consists of single layer of epithelium
• Ovarian follicle
–
Cluster of cells where ovum ripens
–
Secretes estrogen, beginning development of endometrium
• Ovulation
–
Follicle ruptures & discharges ripened egg
• Menstruation
–
The sloughing off of endometrium
–
Expulsion of unfertilized egg
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Accessory Structures
• Fallopian tubes
• Uterus
• Vagina
• Bartholin glands
• Vulva & perineum
• Breasts
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The Menstrual Cycle
• Process that prepares female’s body for pregnancy
• Egg ripens & is released
• Endometrium is prepared
• If no fertilization:
–
Estrogen & progesterone levels decrease
–
Bloody discharge
• Average duration: 2 to 6 days
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Common Diseases and Conditions of the
Female Reproductive System
• Cervical cancer
• Endometriosis
• Ovarian tumors
• Fibroid tumors
• Pelvic inflammatory
disease
• Menstrual disorders
• Uterine cancer
• Yeast infection
• Breast cancer
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Effects of Aging on the Reproductive
System
• Men: decrease in testosterone production
• Women: menopause—menstruation gradually ceases
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Common Diseases and Conditions of Both
the Male & Female Reproductive Systems
• Chlamydia
• Gonorrhea
• Syphilis
• Genital herpes
• Human papillomavirus (HPV)
• Pubic lice
• Infertility
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Factors Influencing Growth and
Development
• Heredity
• Prenatal factors (mother’s age/health during pregnancy)
• Caregiver factors (mental illness)
• Individual differences (vision & hearing impairments)
• Health or illness
• Environment, including culture
• Nutrition
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Stages of Growth and Development
• Embryo & fetus
• Adolescent (12-18 years)
• Neonate (birth to 1 month) • Young adult (18-40 years)
• Infant (1 month to 1 year)
• Toddler (1-3 years)
• Preschool child (3-6 years)
• Middle-aged adult (40-65
years)
• Older adult (>65 years)
• School-aged child (6-12
years)
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Stages of Grief
1. Denial
2. Anger
3. Bargaining
4. Depression
5. Acceptance
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Theories of Development
• Erik Erikson
• Robert J. Havighurst
• Sigmund Freud
• Maslow’s hierarchy of needs
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