Recommended Websites:

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Life Science Mr. Galloway
Chapters 20-21 Human Biology Health Nervous,
Endocrine, Reproductive Systems
Recommended Websites www.soulcare.org www.icr.org
www.AnswersInGenesis.org
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Three Functions of Nervous System

• Receive Information
• Sensing stimuli
• Respond to Information
• Reacting to a stimuli
• Maintaining Homeostasis
• Directing the body to keep in balance

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Major Structures of the Nervous System
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A Neuron
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Key Terms Nervous System

• Nerve (Neuron) a bundle of nerve fibers, that
  carries information (impulse) through the nervous
  system.
• Axon carries impulses away from the cell body.
• Dendrite carries impulses toward the cell body
• Synapse tiny space between each axon tip and
  the next structure.
• Neurochemicals carry the impulse across the
  synapse.

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More Terms Nervous System

• Stimulus any change or signal in the
  environment that can make an organism react.
• Response what you body does in reaction to a
  stimulus.
• Three Types of Neurons
• Sensory picks up stimuli inside or outside body
  
• Interneurons carries impulses nerve to nerve
• Motorneurons sends impulses to a muscle

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Types of Neurons
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Central Nervous SystemControl Center of the Body

• Brain Controls most of the bodys functions
• Concussion bruiselike injury of the brain.
• Using a helmet on skateboards and bikes is
  important.
• Spinal Cord thick column of nerve tissue
  linking the brain to the peripheral nerve system.

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The Human Brain
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The Brain

• 100 billion neurons (all interneurons)
• Each receives from up to 10,000 other neurons
• Each sends to about 1,000 more neurons
• Cerebrum interprets input from senses and
  controls skeletal muscles, thinking, etc.
• Cerebellum coordinates muscles and balance
• Brainstem controls involuntary actions
• Automatic actions like breathing, heart beat, etc.

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Spinal Cord
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Peripheral Nervous System

• A network of nerves branching out from the
  central nervous system and connecting it to the
  rest of the body.
• It is subdivided into two branches
• Somatic controls the voluntary actions using
  your skeletal muscles (like tying your shoes).
• Autonomic controls the involuntary actions
  using your smooth muscles (stomach, blood
  vessels).

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A Voluntary Somatic Response
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Reflex Automatic response that occurs very
rapidly and without conscious control.
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Your Six Senses

• Vision cells convert light stimulus to a nerve
  signal
• Hearing cells converts sound waves to nerve
  signal
• Smell cells in nose convert chemical stimuli
• Taste cells on tongue convert chemical stimuli
• Touch cells on skin convert mechanical pressure
  to nerve signals (impulses).
• Balance Inner ears semicircular canals
  indirectly convert the effect of gravity to nerve
  signals for balance

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Structures of the Human Eye
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Vision

• Eyes convert light into nerve impulses
• Eye Structure
• Cornea clear tissue covering the front of the
  eye
• Pupil the opening through which the light
  enters
• Iris colored area around the pupil which opens
  or closes
• Lens flexible structure that focuses the light
  (bends rays)
• Retina layer of receptor cells at back of the
  eye (130 million) (Rod cells see black/white)
  (Cones see color)

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Vision Problems

• Nearsightedness
• Able to see near objects clearly, not distant
  objects
• Eyeball is too long, so focal point is before
  retina.
• Corrected by a concave lens
• Farsightedness
• Able to see far off objects clearly, not near
  objects.
• Eyeball is too short, so focal point is beyond
  retina.
• Corrected by a convex lens

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Hearing

• Ears convert sound waves into nerve impulses
• Sound waves are vibrating waves in any substance
• Hearing Structures and Processes
• Eardrum receives waves and vibrates the ear
  bones
• Cochlea receives vibrations from the stirrup
  bone
• It is filled with fluid lined with receptors
  that respond to sound.
• Sensory neurons send the receptor signals to the
  interneurons of the brain.
• Biotechnologists have now invented an artificial
  cochlea that can be surgically implanted for
  those with certain hearing problems.

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Your Brain on Alcohol Drugs Eph 515-18 Be
filled (controlled) by Gods Spirit

• Medicines used properly are helpful, but even
  they can have serious side-effects.
• Drowsiness, confusion, tremors, memory loss, etc
• Can become addictive, making you a slave of the
  chemical
• Alcohol and many drugs are chemicals that
  interfere with your ability to control your
  brain.
• Disrupts coordination, making many activities
  dangerous
• Can damage heart and brain cells.
• Can become addictive, making you a slave of the
  chemical

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Endocrine System
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The Endocrine System

• Chemically controls many body functions as well
  as long-term changes like development.
• Endocrine Glands make the chemicals (hormones)
• Hormones change the functions of other organs
  (Turn them on off, speed them up or slow down)
• Endocrine chemicals work differently from nerves
  which cause quick responses, the effect of
  endocrine hormones take longer.
• The Brains Hypothalamus area controls the
  release of hormones from various endocrine glands.

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How Hormones Work

• Hypothalamus is a tiny middle part of the brain,
  which links the nervous endocrine systems.
• It produces nerve impulses controlling sleep,
  hunger, etc.
• It produces hormones controlling other endocrine
  glands
• Both play a major role in maintaining
  homeostasis.
• Target Cells are specific cells in certain organs
  that respond ONLY to particular hormones.
• Hormones are chemicals, so they fit like a keys
  into locks, and each lock is a specific target
  cell.

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Pituitary Gland

• It lays just below the hypothalamus
• Communicates with the hypothalamus to control
  many body activities.
• It responds to both nerve signals and hormones
  from the hypothalamus.
• It then releases its hormones, which then act on
  other endocrine glands.

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Homeostasis Uses negative feedback in a way
very similar to a house thermostat.
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Negative Feedback

• Like a thermostat controlling the room temp.
• Negative feedback means the system is turned OFF
  by the condition it produces.
• When the air conditioner in the room makes the
  temperature go above the set level, it turns off.
• When the amount of a released hormone reaches a
  certain level, a feedback signal causes the body
  to turn off the release of that hormone.

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The Reproductive System

• Sex Cells Contain HALF the chromosomes of a
  normal cell (46 normal, sex cell has 23).
• Eggs female sex cell
• Sperm male sex cell
• Zygote (Fertilized Egg by Sperm) is a new baby
  formed when the sperm and egg unite into a single
  cell.

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Sperm Cell
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One Egg cell many sperm, but it only takes one
sperm
A Baby Trillions of Cells
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Male Reproductive System
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Male Reproductive System (Mostly external
structures)

• Testes Two oval structures made up of hundreds
  of tiny coiled tubes.
• Produce sperm cells
• Produce male hormones (testosterone)
• Testosterone controls development of male
  characteristics like facial hair, deeper voice,
  ability to produce sperm.

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Female Reproductive System(Mostly internal
structures)

• Ovaries two oval shaped organs
• Produces eggs
• Produces female hormones (estrogen)

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Egg Releasing
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Female Menstrual Cycle

• Menstrual Cycle monthly cycle of changes
• Stages ovulation, fertilization or menstruation
• Endocrine Control cycle is regulated by
  hormones.

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Human Life Beginning to Birth

• Zygote fertilized egg/sperm union
• Cells divide and multiply until is hollow ball
• Embryo name for growing baby (1-8 weeks)
• Amniotic Sac filled with fluid is where embryo
  lives
• Placenta a mass of blood vessels from Mom
  baby
• Their blood never mixes, but O2, nutrients,
  waste exchange.
• Umbilical Cord forms between embryo placenta
• Fetus name for baby (9 weeks to birth)
• Birth occurs about nine months after fertilization

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Psalm 13913-14 13 For You formed my inward
parts You covered me in my mother's womb. 14 I
will praise You, for I am fearfully and
wonderfully made Marvelous are Your works, And
that my soul knows very well. Psalm 13923-24 23
Search me, O God, and know my heart Try me, and
know my anxieties 24 And see if there is any
wicked way in me, And lead me in the way
everlasting.