Transcript Nervous System 2015x

What is an Animal?
Characteristics of All Animals
1. Animals are Multicellular
2. Animals are Eukaryotic
3. Animals are Heterotrophs
4. Animal cells lack cell walls
Evolutionary/Developmental
Milestones in Animals
1. Cell specialization and levels of organization
2. Development of body symmetry and
segmentation
3. Development of an internal body cavity and
tissue layers
Levels of Organization
Body Segmentation
Segmentation of the body allows development of
various specialized limbs, such as antennae, pincers,
walking legs, claws, wings, etc.
Cephalization is the concentration of nervous tissues
in one location which eventually produces a head
region with sensory organs and a brain.
Tissue Layers & Body Cavity
Tissue Layer
Develops Into
Endoderm
digestion and respiration structures
Mesoderm
muscles, bones, blood, skin, reproductive organs
Ectoderm
skin, brain, nervous system
A body cavity, called a coelom, increases the
efficiency of food intake and waste removal.
ANIMAL BODY SYSTEMS
Body systems are all interrelated and work together to
perform their functions in animals. Body systems can
be organized and studies by these functions:
 REGULATION: Excretory & Nervous Systems
 NUTRIENT ABSORPTION: Respiration, Digestion, &
Circulatory Systems
 DEFENSE: Immune, Integumentary, Lymphatic,
Skeletal, & Muscular Systems
 REPRODUCTION: Reproductive & Endocrine
Systems
FACT OF THE DAY:
Messages travel along the nerves
as electrical impulses. They travel
at speeds up to 248 miles per
hour!
*
REGULATION
Nervous System
The nervous system maintains homeostasis
(an internal stable environment) by
controlling and regulating all other parts of
the body.
http://faculty.washington.edu/chudler/stm0.html
(short-term memory)
Functions of the Nervous System
1. Sensory-uses receptors to gather
information from all over the body
2. Interpretation-the brain then
processes the information into
possible responses
3. Response-sends messages back
through the system of nerve cells to
A. Control and coordinate functions throughout
the body
B. Respond to internal and external stimuli
Evolutionary Trends of the Nervous System
Complex
Simple
Animal
Taxon
Type of
Nervous
Tissue
Aquatic
Invertebrates
Flatworms &
Roundworms
Segmented
Worms &
Arthropods
Vertebrates
A simple system with
interconnected neurons
called nerve nets;
contain specialized cells
for touch and chemical
detection
Ganglia (a group of
nerve cells) and nerve
cords run along the
body; can detect
chemicals, touch, and
some have eyespots
Cephalization occurs
which is the
concentration of nerve
cells in a head region to
form a brain; intense
senses in arthropods
A well developed
brain evolved from
the spinal cord; the
size and complexity
increases from fish to
mammals
Picture of
system
planaria, flukes,
Examples
sponges, jellyfish, hydra
tapeworm,
hookworm
earthworm, ants,
grasshopper, bees
mammals, birds,
reptiles, fish,
amphibians
Structures of the Nervous System
Neurons: the functional cell that transmits signals
through the body; an individual nerve cell
Parts of a Neuron
1. cell body- the largest part of the neuron;
contains the nucleus and organelles
2. dendrites- short, branching extensions
spreading out from the cell body; receive and
carry impulses to the cell body
3. axon- long, fibrous part of neuron; conducts
nerve impulses away from cell body
dendrite
Axon
cell body
cell
body
TYPICAL MOTOR
NEURON
synapse
muscle
tissue
Because neurons never touch,
chemical signalers called
neurotransmitters must travel
through the space called synapse
between two neurons.
Neurotransmitters (pink
spheres)
Synapse (gap)
The message
is transferred
when
RECEPTORS
receive
neurotransmitters.
Neuron
Nerve Impulse- an electrical signal is sent from the dendrite, along
the axon, to the terminal. A chemical message, called a
neurotransmitter is released from the axon terminals into the
synapse, where it travels to the next cell.
How Impulses Are Carried
– Flow of Impulse:
dendrite  nucleus
 axon  jumps
synapse  next
dendrite
Types of Neurons
a. sensory neurons- carry
impulses from sense
organs to brain/spinal
cord (CNS)
b. motor neurons- carry
impulses from brain/
spinal cord (CNS) to
muscles/ organs
c. interneurons- carry
impulses between sensory
and motor neurons
(within CNS)
Reflexes
Reflexes:
• They are involuntary
• They happen very quickly
• Take place without the brain receiving the message
• They protect you by triggering an involuntary
response to stimuli (stepping on a tack)
Divisions of the Nervous
System
• Central
Nervous
System
(CNS)
• Peripheral
Nervous
System
(PNS)
Central Nervous System (CNS)
A. Brain- “control center”- receives and
analyzes information; processes and
sends back instructions
Parts of the Brain
1. Cerebrum
•
•
•
•
•
•
Controls muscles
Jobs that are
voluntary
It stores messages
Studying/thought
Language
judgment
Lobes of the cerebrum
Reasoning, logic, language,
etc.
Processes sensory
(taste/reading) impulses
from the body
Visual
images/
vision
Hearing, smell,
memories
the Cerebrum
Language and Speech – strokes, tumors, injuries
• Broca’s Area:
• Wernicke’s Area:
– The posterior part of
– Primary motor cortex in
temporal lobe
the frontal lobe that
– Damage to area means
controls muscles
you can speak but
– Damage to area means
unable to comprehend
you can understand
speech
language but are unable
• Responsible for hearing
to speak it
• Responsible for
speech generation
• Ex – stroke patients
http://www.hulu.com/#!watch/378989 (NY
Med brocas area) 28:28- d section)
speech
http://www.hulu.com/watch/33
9577/greys-anatomy-one-steptoo-far
Go to 21 min mark
Parts of the Brain
2. Cerebellum: controls involuntary
functions of muscles & maintains balance
and posture ( hand-eye coordination)
Parts of the Brain
3. Hypothalamus:
Controls homeostasis in body
* body temperature, water balance,
hunger, thirst, biological clock, flight or
fight response)
Parts of the Brain
4. Brain stem
Controls involuntary functions
Medulla Oblongata & Pons :
*breathing, heart rate,
blood pressure, swallowing, vomiting,
digestion
Peripheral Nervous System
(PNS)
A. Consists of nerves –ropelike
bundles of neurons outside
of the CNS
B. Gathers information,
delivers it to and from CNS
C. PNS divided into two
systems:
Somatic (voluntary)
Autonomic (involuntary)
Autonomic Nervous System
 Autonomic Nervous System The involuntary branch of the
nervous system
 Divided into two divisions:
1. Sympathetic division
2. Parasympathetic division
Autonomic Functioning
 Sympathetic – “Fight-or-flight”
 Response to unusual stimulus
 Takes over to increase activities
 Increases heart rate, blood pressure,
blood glucose levels, dilates the
bronchioles of the lungs, and dilates
the pupils
 Remember as the “E”
division = Exercise,
excitement, emergency,
and embarrassment
Autonomic Functioning
 Sympathetic – “Fight-or-flight”
 The effects of sympathetic nervous
system activation continue for
several minutes until its hormones
are destroyed by the liver.
 Helps explain why
we need time to
“calm down” after
an extremely
stressful situation.
Autonomic Functioning
 Parasympathetic –
Housekeeping activites
 “Resting and digesting” system
 Chiefly concerned with promoting normal
digestion and elimination of feces and urine
and with conserving body energy
 Heart rate, blood pressure, and respiratory
rates are at low normal levels; pupils are
constricted; skin is warm; digestive tract is
actively digesting food
 Remember as the “D” division - Digestion,
defecation, and diuresis (urination)
Levels of Organization
Neurons
Nerves
Brain,
spinal cord
Nervous
Interaction with other systems for Regulation
 Bones of the skeletal system protect
the spinal cord and brain.
 The brain controls heart rate, blood
pressure, and breathing via the
circulatory and respiratory systems.
 Glands in the brain control the release
of hormones of the endocrine and
reproductive systems.
 The brain controls muscles both in
digestion and movement.
Diseases / Disorders of the
Nervous System
1.
Polio- a virus that attacks the spinal cord; eventually
causes paralysis
2. Multiple Sclerosis (MS)- affects neurons; slows nerve
impulses, causing muscle weakness, possibly paralysis.
3. Alzheimer’s- brain tissue deteriorates; severe memory
loss
4. Stroke- a blockage in a blood vessel in the brain,
causing brain damage
5. Concussion- a bruise to the brain when the brain hits
the inside of the skull
Fun Facts
• A human body contains more nerve
cells than there are stars in the Milky
Way
• Neurons are the largest cell in the
body and do NOT undergo mitosis
• Nerve impulses move at 100 meters
per second or more
• Longest axon of a neuron is 15 ft! (in
the giraffe)
Reticular Formation – neurons in the
core of the brainstem (midbrain -arousal, pons
& medulla-sleep)
•Sleep & wakefulness produces patterns of
electrical activity in the brain
•Recorded as an ElectoEncephaloGram
(EEG)
•Most dreaming during REM (rapid eye
movement sleep)
Did You Know…
• Bottlenose Dolphins swim while sleeping,
rising to the surface to breathe air regularly!
– Their forebrain is divided into two halves. Since
they sleep with one eye open and one closed
they are able to sleep with one brain hemisphere
at a time.
The amygdala is
responsible for
determining what
memories are stored
and where the
memories are stored
in the brain
The hippocampus sends memories out to the appropriate part of the brain for
long-term storage and retrieves them when necessary. Damage to this area of the
brain may result in an inability to form new memories.
Lobotomy…
• Phineas Gage, 1848 – was a loving,
caring father until the accident and
then became detached, impatient & erratic
• Later in the 20th century, surgical procedures were done
to remove portions of the frontal lobe in attempt to
cure severe behavioral and psychiatric behaviors