Transcript Endocrine System

Endocrine System
Endocrine System
 Help regulate activities
 Produces chemicals that control many of the body’s
daily activities
 Regulates long-term changes such as growth and
development
 Made up of glands: an organ that produces or
releases chemicals
 Endocrine glands: produce and release their
chemicals directly into the bloodstream
Hormones
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Chemical product of an endocrine gland
Like a chemical messenger
Regulate activities in tissues and organs
Production: nerve impulses from brain signal for
endocrine glands to produce hormones
 Action: hormones cause a slower, but longer lasting
response than the nerve impulses
 Target cells: the cells the hormones interact with,
they recognize the hormone’s structure
Functions of Endocrine Glands
 Each gland releases different hormones
 Endocrine glands:
 Hypothalamus:
 links nervous and endocrine systems
 Pituitary:
 regulates growth, blood pressure, and water balance
 Thyroid:
 controls release of energy from food molecules
 Parathyroid:
 regulate amount of calcium in blood
More endocrine glands…
 Adrenal
 Adrenaline triggers response to emergencies
 Salt and water balance in kidneys
 Sugar in the blood
 Thymus
 Immune system development
 Pancreas
 Insulin and glucagon control glucose level in blood
 Ovaries (in females)
 Estrogen controls changes in female body
 Trigger egg development
 Testes (in males)
 Testosterone controls changes in male’s body
 Regulates sperm production
Hypothalamus
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Tiny part of the brain near the middle of your head
Link between nervous system and endocrine system
Sends out never messages and produces hormones
Controls pituitary gland
Pituitary Gland
 Just below hypothalamus
 Size of a pea
 Communicates with the hypothalamus to control
body activities
 Responds to hypothalamus by releasing hormones
 Some hormones trigger other glands to produce
hormones
Negative Feedback
 Process in which a system is turned off by the
condition it produces
 When the amount of a particular hormone in the
blood reaches a certain level, the endocrine system
send signals that stop the release of that hormone.
The Reproductive System
Asexual Reproduction
 Reproduction where offspring arise from a
single parent
 Inherit the genes of that parent only
 Offspring will be exact genetic copies of
parent
 Reproduction for single cell organisms
 Bacteria
 Protists
 Many fungi
Sexual Reproduction
 Involves the production of eggs by the
female and sperm by the male
 Egg is the female sex cell
 Sperm in the male sex cell
 Fertilization: process by which male and
female living things produce offspring
 Zygote: a fertilized egg
Chromosomes
 Carry information that controls inherited
characteristics
 Cells have 46 chromosomes
 Except sex cells only have 23 chromosomes
 23 chromosomes of sperm join the 23 of the egg
 Zygote then contains the 46 need to produced
offspring
Male Reproductive System
 Specialized to produce sperm and
testosterone
 Testes
 Organ that produces sperm and testosterone
 Located in the scrotum
 External pouch of skin
 Keeps testes about 2C to 3C below body temp
 Sperm need slightly cooler condition for
development
Sperm
 Composed of a head containing
chromosomes and long tail
 Path:
 Sperm mix with fluids produced by glands
 Mixture is called semen
 Contains about 5-10 million sperms per drop
 Fluid allows for sperm to swim
 Contains nutrients that sperm use as energy
 Leaves body through penis
 Tube is call urethra (same tube urine travels through)
Female Reproductive System
 Specialized to produce eggs and nourish a
developing baby
 Ovaries
 Produce eggs and estrogen
 Egg released about once a month
 Fallopian tubes (or oviducts)
 Passageway for eggs to travel from ovary to
uterus
 Fertilization usually occurs in fallopian tube
Female Reproductive System
 Uterus
 Hollow muscular organ
 Fertilized egg attaches to wall
 Egg not fertilized breaks down and leaves
uterus through opening called cervix
 Vagina (birth canal)
 Muscular passageway leading to the outside
of the body
 Baby leaves mother’s body
Menstrual Cycle
 Monthly cycle of changes in female reproductive
system
 Egg develops in ovary while uterus prepares for
arrival of an embryo
 Stages of cycle:
 Egg matures, uterus walls thicken
 Mature egg is released (ovulation)
 Unfertilized egg enters uterus to breakdown
 Thickened walls break down
 Extra blood and tissue of thickened walls leave through
vagina (menstruation)
 Last 4-6 days
 New egg starts to mature