hs 130 anatomy & physiology ii unit 9 seminar chapters 20 & 21 reproduction, growth and...
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HS 130 Anatomy & Physiology IIUnit 9 Seminar
Chapters 20 & 21Reproduction,
Growth and Development
Male Reproductive SystemMale Reproductive System
• Structural plan Reproductive organs are classified as
essential or accessory Essential organs of reproduction are the
gonads (testes in males), which produce sex cells called sperm
TestesTestes
• Testes: the gonads of men Structure and location
Testes in scrotum—lower temperature Covered by tunica albuginea, which
divides testis into lobules containing seminiferous tubules
Interstitial cells produce testosterone
What is the importance of the lower temperature of the scrotum?
Tubules of the Testis and Epididymis
the testicle is the darker sphere in the center
Spermatozoa
Spermatogenesis
What are the steps in the process of
spermatogenesis?
Female Reproductive SystemFemale Reproductive System
How does the location of the female gonads differ from the location of the male gonads?
• Microscopic structure Ovarian follicles—contain oocyte, an
immature sex cell (about 1 million at birth) Primary follicles—are covered with
granulosa cells (about 400,000 at puberty) Secondary follicles have a hollow chamber
called the antrum Corpus luteum forms after ovulation from
ruptured follicle
OvariesOvaries
OvariesOvaries
What is the role of the corpus luteum if fertilization occurs?
OvariesOvaries
Menstrual CycleMenstrual Cycle
Menstrual CycleMenstrual Cycle
• Male organs Designed to produce, store, and introduce mature sperm into the female reproductive tract
• Female organsDesigned to produce ova, receive the sperm, permit fertilization, facilitate fetal development and birth, and perform lactation
Summary of Male and Female Reproductive Systems
Summary of Male and Female Reproductive Systems
Prenatal PeriodPrenatal Period
• Prenatal period begins at conception and continues until birth
• Science of fetal growth and development is called embryology
Approximately how long does pregnancy last? Why is prenatal care so important?
Fertilization and ImplantationFertilization and Implantation•Fertilization is a specific biological event•occurs when the male and female sex cells fuse•after union between a sperm cell and the ovum has occurred, the cycle of life begins. •scanning electron micrograph shows spermatozoa attaching themselves to the surface of an ovum•only one will penetrate and fertilize the ovum.
• After three days of cell division, the zygote has developed into a solid cell mass called a morula
• Continued cell division of the morula produces a hollow ball of cells called a blastocyst
• The blastocyst implants in the uterine wall about 10 days after fertilization
• The blastocyst forms the amniotic cavity and chorion of the placenta
Implantation and Early DevelopmentImplantation and Early Development
How does the embryo receive nutrients before the placenta is functional?
Primary Germ LayersPrimary Germ Layers
The PlacentaThe Placenta
What are the functions of the placenta?
Birth DefectsBirth Defects
• Any structural or functional abnormality present at birth May be caused by genetic factors
Abnormal genes Abnormal number of chromosomes
May be caused by environmental factors Environmental factors are called
teratogens Especially harmful during the first
trimester
Postnatal PeriodPostnatal Period• Postnatal period begins at birth and lasts until
death• Divisions of postnatal period into isolated time
frames can be misleading• Life, growth, and development are continuous• Obvious changes in the physical appearance
occur between birth and maturity
InfancyInfancy• First four weeks is called neonatal period• Cardiovascular and respiratory changes
occur at birth Fetus is totally dependent on mother Newborn must immediately become
totally self-supporting
ChildhoodChildhood
• Extends from end of infancy to puberty
• Overall rate of growth remains rapid but decelerates
• Continuing development of motor and coordination skills
• Loss of deciduous or baby teeth and eruption of permanent teeth
AdolescenceAdolescence
• Average age range of adolescence varies from 13 to 19 years
• Period of rapid growth results in sexual maturity (adolescence)
• Appearance of secondary sex characteristics regulated by secretion of sex hormones
• Growth spurt typical of adolescence; begins in girls at age 10 and in boys at age 12
AdulthoodAdulthood
• Bones’ growth plates are fully closed in adult• Other structures such as the sinuses acquire
adult placement• Adulthood characterized by maintenance of
existing body tissues• Older adulthood
Every organ system of the body undergoes degenerative changes
Effects of AgingEffects of Aging• Skeletal system
Aging causes changes in the texture, calcification, and shape of bones
Bone spurs develop around joints Bones become porous and fracture easily
Effects of AgingEffects of Aging
• Integumentary system (skin) With age, skin sags and becomes
Thin Dry Wrinkled
Effects of AgingEffects of Aging
• Urinary system Nephron units decrease in number by 50%
between ages 30 and 75 Blood flow to kidney and ability to form
urine decrease
Effects of AgingEffects of Aging
• Respiratory system Calcification of costal cartilages makes it
difficult for rib cage to expand and contract normally
Wasting of respiratory muscles decreases respiratory efficiency
Respiratory membrane thickens; movement of oxygen from alveoli to blood is slowed
Effects of AgingEffects of Aging
• Cardiovascular system Degenerative heart and blood vessel
disease is among the most common and serious effects of aging
Hardening of arteries (arteriosclerosis) may result in rupture of blood vessels
Hypertension or high blood pressure is common in older adulthood
Effects of AgingEffects of Aging
• Special senses Eye lenses become hard and cannot
accommodate for near vision Decreased transmission of sound waves
caused by loss of elasticity of eardrum and fixing of the bony ear ossicles is common Some degree of hearing impairment is
universally present in the aged
Thanks for attending!
I’ll “see” everyone on the discussion boards!
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