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Slide 1
Chapter 39 Endocrine System
Slide 2
A system of glands that secrete hormones into the blood that
regulate growth, development and metabolic processes.
Slide 3
Hypothalamus The hypothalamus makes hormones that control the
pituitary gland. In addition, it makes hormones that are stored in
the pituitary gland. Pituitary gland The pituitary gland produces
hormones that regulate many of the other endocrine glands.
Parathyroid glands These four glands release parathyroid hormone,
which regulate the level of calcium in the blood. Thymus During
childhood, the thymus releases thymosin, which stimulates Tcell
development. Adrenal glands The adrenal glands release epinephrine
and nonepinephrine, which help the body deal with stress. Pineal
gland The pineal gland releases melatonin, which is involved in
rhythmic activities, such as daily sleep-wake cycles. Thyroid The
thyroid produces thyroxine, which regulates metabolism. Pancreas
The pancreas produces insulin and glucagon, which regulate the
level of glucose in the blood. Ovary The ovaries produce estrogen
and progesterone. Estrogen is required for the development of
secondary sex characteristics and for the development of eggs.
Progesterone prepares the uterus for a fertilized egg. Testis The
testes produce testosterone, which is responsible for sperm
production and the development of male secondary sex
characteristics Section 39-1 The Endocrine Glands
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Hormones Hormones chemical messengers that travel to remote
target tissues. Produce slow responses of long duration. Hormones
only affect target tissues that have the correct receptor to fit
the hormone.
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Steroid Hormone Target cell membrane mRNA Cytoplasm Protein
synthesis Altered cellular function Receptor Hormone- receptor
complex Nucleus DNA Nonsteroid hormone (first messenger) Receptor
Target cell membrane cAMP (second messenger) Enzyme activities
Altered cellular function Cytoplasm Nucleus Hormone Action Section
39-1
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Negative Feedback Hormone levels in the blood are regulated by
a negative feedback mechanism. Hormones secreted into the blood
bring about a change. When the change occurs, secretion of the
hormone stops. Ex: The pancreas secretes insulin to lower blood
sugar levels and glucagon to raise blood sugar levels. Secretion of
these hormones stops when sugar levels are correct. Diabetics
cannot produce enough insulin to maintain correct sugar
levels.
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Pancreas releases insulin into the blood Body cells absorb
glucose Blood glucose level decreases Homeostasis: Normal blood
glucose level Blood glucose level decreases Pancreas releases
glucagon into blood Liver converts glycogen to glucose Blood
glucose level increases Liver converts excess glucose to glycogen
for storage Actions of Insulin and Glucagon Section 39-2
Slide 8
Chapter 39 The Reproductive System
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Reproduction A life process necessary for the survival of a
species, but not an individual
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The Male Reproductive System The testes produce the male sex
cell sperm through the process of meiosis. Sperm are haploid (23
chromosomes). The testes also produce the hormone testosterone.
Testosterone aids in sperm production and is responsible for the
development of secondary sex characteristics.
Slide 11
The Male Reproductive System Section 39-3
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The Female Reproductive System The ovaries produce the female
sex cell eggs through the process of meiosis. Eggs are haploid (23
chromosomes). The ovaries also produce the hormones estrogen and
progesterone. Estrogen aids in egg development and is responsible
for the formation of secondary sex characteristics. Progesterone
prepares the uterus for implantation by a fertilized egg.
Slide 13
The Female Reproductive System Section 39-3
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The Menstrual Cycle Beginning with puberty, the female
reproductive system begins a periodic cycle of events regulated by
hormones from the pituitary and ovaries. This is known as the
menstrual cycle. This cycle prepares the uterus each month for the
advent of pregnancy, when a fertilized egg will implant itself in
the uterine wall. If this does not occur, the uterine lining is
shed out the vagina. This is called menstruation.
Slide 15
The Menstrual Cycle Section 39-3
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Fertilization and Development Fertilization occurs in the
Fallopian tube (oviduct). A sperm unites with the egg to produce a
diploid zygote (46 chromosomes). The zygote undergoes a series of
mitotic cell divisions without growth in size (cleavage) on its way
to the uterus. Approximately 7 days later the hollow ball of cells
(blastocyst) implants itself in the uterine wall. Development
occurs in the uterus (womb).
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Implantation of blastocyst Day 7 Fertilization Day 4 Day 3 Day
2 Day 1 Day 0 Egg released by ovary Fertilization and Implantation
Section 39-4 Uterine wall Blastocyst Morula 4 cells2 cells Zygote
Ovary Fallopian tube
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Development After implantation the cells begin to
differentiate. Tissue from both the mother and embryo form the
placenta a temporary organ that will nourish the developing baby.
Throughout the next nine months the developing baby obtains
nutrients and gets rid of wastes through its connection to the
placenta, the umbilical cord. Nutrients and wastes pass between the
blood of the mother and baby by diffusion.
Slide 19
The Placenta Section 39-4
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Birth At the end of nine months hormone changes produce a
series of contractions in the uterus known as labor. The protective
membrane surrounding the baby (amnion) ruptures releasing fluid
(water breaks). Birth is imminent. Contractions stretch the cervix
to a diameter of about 10 cm and the baby is delivered head first
(usually). Contractions close off the umbilical cord near the baby.
The cord is cut, and eventually falls off leaving a scar (belly
button). Soon after, a second series of contractions force the
placenta out of the womb (after birth).