Download Ch 35 Nervous System

Ch 35 Nervous System
35-1 Human Body systems
35-2 The Nervous System
35-3 Divisions of The Nervous System
35-4 The Senses
35-5 Drugs and the Nervous System
35-1 Human Body Systems
 The levels of organization in a
multicellular organism
includes
 Cells
 Tissues
 Organs
 Organ systems
 Organism
 Specialized cells are uniquely
suited to perform a particular
function
35-1 Human Body Systems
 Four Basic types of Tissues
 Epithelial Tissue Glands and
tissues that cover exterior and
interior body surfaces
 Connective Tissue provides
support for the body and
connects its parts
 Nervous Tissue transmits
nerve impulses throughout the
body
 Muscle Tissue enable the
body to move
35-1 Human Body Systems
 Homeostasis is the process by which organisms keep
internal conditions relatively constant despite changes
in external environments
 Maintained by feedback loops
35-1 Human Body Systems
 Feedback inhibition or negative feedback is the
process in which a stimulus produces a response that
opposes the original stimulus
 Pg 896 (1-5)
 Arts and Crafts Tomorrow
35-2 The Nervous System
 The nervous system controls and coordinates functions
throughout the body and responds to internal and
external stimuli
 Cells that transmit impulses are called Neurons
 The largest part of a typical neuron is the Cell Body
35-2 The Nervous System
 From the cell body are short, branched extensions
called Dentrites
 The long fiber that carries impulses away from the cell
body is called the Axon
 In some neurons, the axon is surrounded by an
insulating membrane known as the Myelin Sheath
35-2 The Nervous System
 The electrical charge across the cell membrane of a
neuron in its resting state is known as the Resting
Potential
35-2 The Nervous System
 An impulse begins when a neuron is stimulated by
another neuron or by the environment
 The reversal of charges, from negative to positive, is
called a nerve impulse or an Action potential
 The minimum level of a stimulus that is required to
activate a neuron is called the Threshold
35-2 The Nervous System
 The location at which a neuron can transfer an impulse
to another cell is called a Synapse
 Neurotransmitters are chemicals used by a neuron to
transmit an impulse across a synapse to another
Neuron
 Pg 900 (1-5)
 Coloring due tomorrow Follow Directions
35-3 Divisions of the Nervous
System
 The Central Nervous System (CNS) relays messages,
processes information, and analyzes information
 The connective tissue around the brain and spinal cord is
known as Meninges
 The fluid between
the meninges and
the CNS is called
Cerebrospinal Fluid
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35-3 Divisions of the Nervous
System
 Parts of the Brain
 Cerebrum-largest, responsible for voluntary, or conscious
activity, intelligence
 Cerebellum- Coordinates commands to the muscles and
balance
 Brain Stem- Connects brain to spinal cord, includes pons and
medulla oblongata which controls important functions- Blood
Pressure, heart rate, breathing, and swallowing
 Thalamus- Receives messages from sensory receptors and
relays the information to the cerebrum
 Hypothalamus- control center for hunger, thirst, fatigue, anger
and body control
35-3 Divisions of the Nervous
System
 A Reflex is a quick, automatic response to stimulus
35-3 Divisions of the Nervous
System
 The sensory division of the peripheral nervous system
(PNS) transmits impulses from the sense organs to the
(CNS)
 The motor division transmits impulses from the central
nervous system to the muscles or glands
35-3 Divisions of the Nervous
System
 Reflex Arc
 Pg 905 (1-5)
35-4 The Senses
 Sensory Receptors, React to a specific stimulus such
as light or sound by sending impulses to other neurons,
and eventually to the CNS
 Five categories of sensory receptors





Pain Receptors-Pain
Thermoreceptors-Heat
Mechanoreceptors-Touch
Chemoreceptors-Chemicals
Photoreceptors-Light
 Vision
35-4 The Senses
 Pupil- Opening to the Iris
 Lens- Attached to muscles
that allow light to be focused
to see near or distance
objects
 Retina- Photoreceptors
arranged to collect light here
 Rods-sensitive to light but
don’t distinguish color
 Cones- respond to different
colors
35-4 The Senses
 Vibrations in the air create pressure waves in the fluidfilled cochlea of the inner ear
 Three tiny canals at right angles from each other in the
inner ear that help you with coordination and
equilibrium are the Semicircular canals
35-4 The Senses
 Pg 909 ( 1-5 )
35-5 Drugs and the Nervous
System
 A Drug is any substance, other than food, that changes
the structure or function of the body
 Stimulants increase heart rate, blood pressure, and
breathing rate
 In addition they also release neurotransmitters at some
synapse in the brain
 Depressants slow down heart rate and breathing rate,
lower blood pressure, relax muscles, and relieve
tension
35-5 Drugs and the Nervous
System
 Cocaine causes the sudden release in the brain of a
neurotransmitter called dopamine
 Mimics feeling for pleasure and satisfaction
 Opiates mimic natural chemicals in the brain known as
endorphins, which normally help to overcome
sensations of pain
 Pain killers
35-5 Drugs and the Nervous
System
 Alcohol is a depressant that slows down the rate in
which the central nervous system functions
 Slows down reflexes
 Disrupts coordination
 Impairs judgement
 Fetal Alcohol Syndrome (FAS) is a group
of birth defects caused by the effects
alcohol on the fetus
 50,000 babies a year
of
35-5 Drugs and the Nervous
System
 Drug abuse can be defined as the intentional misuse of
any drug for nonmedical use
 An uncontrollable dependence on a drug is known as a
drug Addiction
 Pg 914 (1-5)