Transcript Regents Biology - I Love Science

AP Biology
The
Nervous
System
2003-2004
Let’s go to the Video!
AP Biology
2003-2004
Overview
 The Nervous System controls and
coordinates all the functions of the
body.
 The Nervous System consists of two
main sub-divisions:


Central Nervous System (CNS)
Peripheral Nervous System (PNS)
• The Peripheral Nervous System is
divided into two sub-divisions:


Somatic- voluntary
Autonomic- involuntary
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http://inside.salve.edu/walsh/cns_pns.jpg
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Structure and Function of the Neuron
 Neuron is the scientific name for a Nerve
Cell.
 Neurons consist of 3 basic structures:



Cyton, or cell body.
Dendrites- receive messages, impulses, and
send them to the cell body.
Axons- send messages away from the cell
body.
• Nerve impulses travel from one neuron to
another across synapses, or spaces in
between the cells.
• The “jumping across” the synapse is
facilitated (helped) by chemicals called
Neurotransmitters.
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Parts of the Neuron
 Dendrites – Branched
 A Neuron
parts of a neuron that
receive impulses from
other neurons.
 Cyton- Contains
cytoplasm and the
nucleus. Impulses pass
through here to the
axon.
 Axon- Single long fiber
that carries impulses
away from the cell body.
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Myelin Sheath
signal
direction
 Axon coated with insulation
made of myelin cells (Fatty,
protein substance)
speeds signal
 330 mph vs. 11 mph

myelin coating
Multiple Sclerosis
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 immune system (T cells) attacks myelin coating
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 loss of signal
Synapse
Junction between nerve cells


1st cell releases chemical to trigger
next cell
where drugs affect nervous system
synapse
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Types of Neurons
Neurons can also be classified by the direction
that they send information:
･Sensory (or afferent) neurons: send
information from sensory receptors (e.g., in
skin, eyes, nose, tongue, ears) TOWARD the
central nervous system.
･Motor (or efferent) neurons: send information
AWAY from the central nervous system to
muscles or glands.
･Interneurons: send information BETWEEN
sensory neurons and motor neurons. Most
interneurons are located in the central
nervous system.
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Reflexes
 Stimulus- a change


in the environment.
Response/Reactionhow the body reacts
to a stimulus.
Reflex Arc- the
pathway that an
impulse follows to
illicit a response to a
stimulus.
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Parts of the Central Nervous System
 Brain
 Spinal cord
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What Protects the CNS?
1. Skull and Vertebrae
2. 3 protective layers called meninges
3. Dura Mater (outer layer): consists of connective tissues,
blood vessels, and nerves.
4. Arachnoid Layer (middle layer): elastic and weblike
5. Pia Mater (inner layer): contains nerves and blood vessels.
6. Cerebrospinal fluid




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a clear watery liquid
separates the middle and inner layers
Acts as shock absorber
exchange of nutrients between blood and nervous system
The Brain




Coordinates body activities
Made up of approximately 100 billion neurons
Uses 20% of bodies oxygen and energy
Divided into three major parts


the Cerebrum
the Cerebellum
the Brain Stem (Medulla Oblongata, Pons)
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Cerebrum
 Largest part of the brain
 Thinking
 Memory is stored
 Movements are controlled
 Impulses from the senses are
interpreted.
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Gray Matter vs. White Matter
 Gray Matter – Absence of myelin in

masses of neurons accounts for the gray
matter of the brain – Cerebral Cortex
White Matter - Myelinated neurons gives
neurons a white appearance – inner layer
of cerebrum
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Cerebrum specialization
 Regions specialized for different functions
 Lobes

frontal
frontal
parietal
 speech,
control of emotions

temporal
 smell, hearing

occipital
 vision

parietal
 speech, taste
reading
temporal
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occipital
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Craniotomy
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Brain Tumor Surgery
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Sub-Arachnoid Cyst Removal
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Cerebral Hemhorrage
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Subdural Hematoma
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Brain Worms!
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Cerebellum
 Responsible for the
coordination of
muscles and is the
center of balance
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Medulla
 Center of heart beat,
respiration, and
other involuntary
actions
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Other Structures inside the Brain
 Thalamus – receives messages from
sensory receptors; relays information to
proper regions of cerebrum
 Hypothalamus - Regulates hunger, thirst,
fatigue, anger, etc…

Control of pituitary for endocrine function
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Section 35-3
Cerebrum
Thalamus
Pineal
gland
Hypothalamus
Cerebellum
Pituitary gland
Pons
Medulla oblongata
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Spinal cord
The Spinal Cord
 Extension of the brain stem
 Bundles of neurons that carry impulses
from all parts of the body to the brain
and from the brain to all parts of your
body
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The
Peripheral
Nervous
System
Your brain
and spinal
Somatic
cord are
and
connected
Autonomic
to the rest
Systems
of your
The
body by
peripheral
the
nervous
peripheral
system
has
nervous
two
major
system.
divisions.
The PNS
is made up
somatic
of 12 pairs
system
of nerves
controls
from your
voluntary
brain It
actions.
called
is
made up
cranial
of
the
nerves, and
cranial
and 31
spinal
pairs from
nerves
that
your
go
from
spinal
the
cord called
central
spinal
nervous
nerves. to
system
Spinal
your
nerves are
skeletal
made up of
muscles.
bundles of
The
sensory
autonomic
and motor
system
neurons
controls
bound
involuntary
together by
actionsconnective
those
not
tissue. For
under
this
conscious
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These
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system.
nerves
along
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Make
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the
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nervous
outlining
sensory
system,
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neurons,
make
medical
and
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some
advances.
contain
body's
only motor
nervous
neurons,
system.
but most
nerves
contain
both types
of neurons.
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Peripheral Nervous System
 Connects body to brain & spinal cord
 12 pairs of nerves from your brain

(cranial nerves)
31 pairs from your spinal cord (spinal
nerves)

Bundles of sensory and motor neurons
held together by connective tissue
 Two divisions
Somatic
 Autonomic

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Divisions of the PNS:
Somatic Nervous System
 Controls voluntary actions
 Made up of the cranial and spinal
nerves that go from the central nervous
system to your skeletal muscles
Autonomic Nervous System
 Controls involuntary actions-those not
under conscious control-such as your
heart rate, breathing, digestion, and
glandular functions
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http://www.christopherreeve.org/Research/Research.cfm?ID=178&c=21
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Animals rely on two systems for regulation:
Nervous System is a system of nerve cells called neurons. It
consists of a central nervous system (brain and spinal cord)
and peripheral nerves. Typical responses are fast and short
lasting.
Endocrine System is a system of ductless glands that secrete
hormone into the blood. Hormones travel to target tissues.
Typical responses are slow and long lasting.
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Progesterone
Estradiol
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Human Endocrine
Glands
Ductless glands
transport hormones in
the blood
Duct glands are
exocrine glands that
use tubes to carry the
secretion
(salivary, tears)
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Pituitary gland and Hypothalamus serve to link the nervous
system other glands and metabolic functions.
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Thyroid and Parathyroid help regulate calcium
metabolism
Feedback!
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Goiter: Iodine deficiency and feedback causes the thyroid to
enlarge
This people have a goiter, a condition
that is easily preventable with iodized
salt
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Thyroid regulates metabolism
Graves disease: hyperthyroid
feedback
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Pancreas helps regulate blood glucose
feedback
Insulin from Beta cells reduce blood sugar
Glucagon
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Biologyfrom Alpha cells increase blood sugar
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THE FIGHT OR FLIGHT MECHANISM
•Large amount of adrenaline pumped into the body to put
us in a state of increased alertness
•Blood is redirected away from the extremities to the large
muscles of the body
•The heart starts working harder to move the blood to the
large muscle groups as quickly as it can
•Increase in Respiratory Rate
•Release of red blood cells
•Release of sugar by liver
•Increase in metabolic rate
alektorophobia
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Gonads: Testes and Ovaries produce hormones that
regulate secondary sex traits
Male sex traits include
those changes that
occur during puberty
Androgens include
testosterone
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feedback
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feedback
Female sex traits
include the
menstrual cycle and
the changes seen
during puberty
LH and FSH from
the pituitary
Estrogen and
progesterone from
the ovary
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Identify the Glands
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