Download Unit 2: The Human Brain and Body

Unit 2: The Human Brain and
Body
The Nervous System
• The human nervous system is
responsible for all our internal
functions.
• It is involved in dreaming, thinking,
feeling, moving.
• The nervous system is composed
of two parts:
• a. The peripheral nervous system
(PNS)
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b. The central nervous
system (CNS)
The Peripheral Nervous System
• The PNS is made up of
nerve cells that send
messages between the
CNS and other parts of
the body.
• So how do nerve cells
communicate with each
other?
• NEURONS!!!
Neurons
• Neurons are nerve cells that
run throughout our entire
bodies.
• Neurons send and receive
messages.
• Messages can relay events
such as a pin- prick.
• Neuroplasticity- the brain
has the ability to reroute
itself to make up for
disease, injury or changes in
environment.
Anatomy of a Neuron
• Each of us have more than 100
billion neurons, most of which
are found in the brain.
• Neurons have a tree-like
structure
• There are three basic
components: cell body ,
dendrites and axon.
• Cell body- produces energy for
activity.
• Dendrites- carry messages to the
cell body.
• Axon- carry messages away from
cell body.
Somatic Nervous System
• The part of the PNS
that transmits control
of voluntary muscles
and sense organs.
Automatic Nervous System
• The part of the PNS that
transmits control of the
bodies vital functions
(involuntary).
• Heart beat, breathing,
digestion are all a
transmitted by the ANS.
• The ANS is composed of
two parts:
• Sympathetic systemACTION!
• Parasympathetic systemRESTORE!
Anatomy of the Human Brain
• The brain is divided
into three main
sections:
• The hindbrain- back of
skull, vital functions.
• The midbrain- middle
of brain, vision and
hearing
• The Forebrain- front of
brain, complex
thoughts and emotions
The hindbrain
• The Medulla- is involved
in vital functions such as
heart rate, blood
pressure and breathing.
• The pons- involved in
regulating movement
and sleep, attention
• The cerebellum (little
brain) – involved in
balance and coordination
The midbrain
• The midbrain contains the
parts of the brain that are
involved in vision and hearing.
• The reticular activating system
is important for attention,
sleep, and arousal.
• Stimulation of this portion of
the brain makes us alert and
increases brain activity.
• Some drugs, such as alcohol,
reduce the activity of the RAS,
which mean the alertness and
reaction time will decrease.
The Forebrain
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Thalamus- serves as a relay station for sensory
stimulation going to other parts of the brain.
Hypothalamus- (under the thalamus).
Involved in many aspects of behavior and
physiology.
Limbic System- Involved in learning and
memory, emotion, sex, hunger, and
aggression
The Cerebrum-(Latin for brain)accounts for
about 70% of brains weight. Site for most
cognitive and intellectual activities.
The cerebral cortex is the wrinkly outer layer
of the cerebrum- memory, language, motor
skills
The cerebral cortex is divided into two sides
or hemispheres.
Each hemispheres are divided into four lobes
The structure that connects the two
hemispheres is called the corpus callosum
Scientists study the brain
• Much of our early
understanding of the
brain came from people
who had injuries.
• Lesions-Scientists can
intentionally cutting,
damaging or removing
parts.
• 3. Electrical Stimulation• 4.Electroencephalogra
m-a device that records
the electrical activity of
the brain. (EEG)
• 5. Brain Imaging- CAT
scans-x-rays, MRImagnetic fields
The Endocrine System
• This body system produces chemicals called
hormones that affect growth and
development and some behaviors.
• Hormones stimulate growth and many
reactions.
Glands
• The pituitary gland (just the size
of a pea and situated under the
hypothalamus), controls growth
hormones, hormones (Oxytocin)
that stimulate labor for pregnant
women, and “mothering
instincts”.
• The thyroid gland produces
thyroxin which affects the body’s
metabolism.
• Too little thyroxin leads to
hypothyroid disorder – and these
people can be overweight.
• Too much thyroxin leads to
hyperthyroid disorder, which can
make people lose weight,
become hyperactive, or sleepless.
Glands
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The adrenal glands are located above the kidneys and secrete cortical steroids.
Cortical steroids increase resistance to stress and promote muscle development.
The adrenal glands also release adrenaline… meant to help people in a stressful
situation.
Nonadrenaline also steps in to help calm people during the stressful situation,
whereas adrenaline prepares people for a fight. (Fight-or-Flight response)
The Testes produce testosterone and small amounts or estrogen and progesterone
in males.
It is responsible for pushing boys through puberty so that they are ready to
reproduce.
The ovaries produce estrogen and progesterone and small amounts of
testosterone in women.
Again, the ovaries prepare women for puberty – which lead to reproduction and
childbirth.
Really, sexual attraction is very chemical (or hormonal) because women have
higher libido’s when they are ovulating because there is more estrogen in their
body.
Closure Activities
• Nervous system worksheet