1. FACT OF THE DAY:
* Messages travel along the nerves as electrical impulses. They travel at speeds up to 248 miles per hour!

2. REGULATION
Nervous System The nervous system maintains homeostasis by controlling and regulating all other parts of the body. (short-term memory)

3. Functions of the Nervous System
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
Control and coordinate functions throughout the body
Respond to internal and external stimuli

4. Evolutionary Trends of the Nervous System
Simple
Complex
Animal Taxon
Aquatic Invertebrates
Flatworms & Roundworms
Segmented Worms & Arthropods
Vertebrates
Type of Nervous Tissue
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
Examples
sponges, jellyfish, hydra
planaria, flukes, tapeworm, hookworm
earthworm, ants, grasshopper, bees
mammals, birds, reptiles, fish, amphibians

6. Structures of the Nervous System
Neurons: the functional cell that transmits signals through the body; an individual nerve cell
Parts of a Neuron
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

7. TYPICAL MOTOR NEURON dendrite muscle tissue Axon cell body synapse
Impulse
in a Neuron
muscle tissue
TYPICAL MOTOR NEURON
Axon
dendrite
synapse
cell body
cell
body

8. Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons.
Neurotransmitters
(pink
spheres)
The message is transferred when RECEPTORS receive neurotrans-mitters.
Synapse (gap)

9. 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.

10. 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)

11. 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)

12. Divisions of the Nervous System
Central Nervous System (CNS)
Peripheral Nervous System (PNS)

14. Central Nervous System (CNS)
Brain- “control center”- receives and analyzes information; processes and sends back instructions

16. Parts of the Brain 1. Cerebrum Controls muscles
Jobs that are voluntary
It stores messages
Studying/thought
Language
judgment

17. Lobes of the cerebrum Processes sensory impulses from the body
Reasoning, logic, language, etc.
Visual images
Hearing, smell, memories

18. Logic/reasoning
Speech

19. Language and Speech – strokes, tumors, injuries
Wernicke’s Area:
The posterior part of temporal lobe
Damage to area means you can speak but unable to comprehend speech
Responsible for hearing speech
Broca’s Area:
Primary motor cortex in the frontal lobe that controls muscles
Damage to area means you can understand language but are unable to speak it
Responsible for
speech generation
Ex – stroke patients
(NY Med brocas area) 28:28- d section)
Go to 21 min mark

20. Parts of the Brain 2. Cerebellum: controls involuntary
functions of muscles & maintains balance
and posture ( hand-eye coordination)

21. Parts of the Brain 3. Hypothalamus: Controls homeostasis in body
* body temperature, water balance, hunger, thirst, biological clock, flight or fight response)

22. Parts of the Brain Medulla Oblongata & Pons : 4. Brain stem
Controls involuntary functions
Medulla Oblongata & Pons :
*breathing, heart rate,
blood pressure, swallowing, vomiting, digestion

23. Peripheral Nervous System (PNS)
Consists of nerves –ropelike bundles of neurons outside of the CNS
Gathers information, delivers it to and from CNS
C. PNS divided into two systems:
Somatic (voluntary)
Autonomic (involuntary)

24. Autonomic Nervous System
Autonomic Nervous System - The involuntary branch of the nervous system
Divided into two divisions:
Sympathetic division
Parasympathetic division

25. 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

26. 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.

27. 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)

28. Levels of Organization
Nerves
Brain, spinal cord
Nervous
Neurons

29. 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.

30. Diseases / Disorders of the Nervous System
Polio- a virus that attacks the spinal cord; eventually causes paralysis
Multiple Sclerosis (MS)- affects neurons; slows nerve impulses, causing muscle weakness, possibly paralysis.
Alzheimer’s- brain tissue deteriorates; severe memory loss
Stroke- a blockage in a blood vessel in the brain, causing brain damage
Concussion- a bruise to the brain when the brain hits the inside of the skull

31. 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)

32. 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)

33. 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.

34. 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