»Ever wonder how you can do everything you do?

1 Sensory receptors allow us to sense our external environment as well as sense changes internally.

2 Coordinates body activities (actions both involuntary and voluntary)

3. Assimilates experiences in order to have memory and intelligence – Thinking!

4. Helps maintain homeostasis by detecting changes either on the outside or inside and allowing your body to react appropriately.

»Central Nervous System (CNS) Central Nervous System (CNS) = brain and spinal cord

»Peripheral Nervous System (PNS) Peripheral Nervous System (PNS) = cranial and spinal nerves and are information lines (like corded telephones)

» The CNS is the control center. It houses the brain and spinal cord.

» The PNS is the message center. It connects the CNS to the rest of the body.

1.1. Neurons : Neurons : the basic cell and functional unite of the nervous system. ˃ They transmit information to the body in the

form of nerve impulses.

2.2. Nerves:Nerves: are bundles of axons. 3.3. Nervous Tissue: Nervous Tissue: Bundles of neurons or

nerve cells put together. 4.4. Neuroglial cells: Neuroglial cells: supporting cells in the

nervous tissue.

Conducts impulses to the

neuron

Conducts impulses to the

body

Neuron structure explained:» 1. Cell body: Contains the nucleus and organelles. » 2. Dendrites: The part that receives the signal from

sensory neurons or other neurons. » 3. Axon: The part that conducts the nerve impulse

(The highway it travels down)» 4. Myelin sheath: protects the axon- either covered

by a Schwann cell or Oligodendrocytes» 5. Nodes of Ranvier: The gap where there is no

sheath protecting it.» 6. Axon Terminal: The part where impulses are sent

out to another nerve.

Depending on what your body needs to do- there are different types of neurons. 1. Bipolar(interneuron) 2. Unipolar (Sensory) 3. Multipolar(motor)

1. Each neuron is either a Sensory Neuron, a Motor Neuron or an Interneuron.

1. SENSORY NEURON: Is considered Afferent or it brings information from the body into the neurons located in the brain or spinal cord (CNS). Stimulated by changes from inside or outside the body- the sense it and act on it.

2. MOTOR NEURON: Is considered Efferent or it brings messages away from the CNS and sends them to the body. It stimulates muscles to contract, or your body to “do” something either voluntarily or involuntarily.

3. INTERNEURON: Lie within the CNS and link other neurons together. They transmit impulses from one part of the brain or spinal cord to another.

1.1. FunctionFunction: : Fill in spaces, provide structural frameworks, produce myelin, carry on phagocytosis

2. 2. TypesTypes:: ˃ Microglial: scattered throughout, support

neurons, phagocytize bacterial cells and cellular debris

˃ Oligodendrocites: occur in rows, provide insulating layers of myelin around axons within the brain and spinal cord

3. Astrocytes3. Astrocytes: : found between neurons and blood vessels, provide structural support – form scar tissue that fills spaces within the CNS

4. Ependymal: 4. Ependymal: epithelial like membrane that covers specialized brain parts and forms inner linings that enclose spaces within the brain.

5. Schwann cells 5. Schwann cells – in PNS, form covering of myelin around axons

1. Use the book and your notes to create a foldable about the different types of neurons.

2. You may fold it anyway you like as long as on the outside you have three flaps (1 for each of the types of neurons)

3. The outside you will need to draw what each neuron looks like and label it.

4. The inside will answer the following info: 1. Where it is located. 2. Something about the number of axons and

dendrites. 3. If it is a sensory neuron, interneuron, or motor

neuron and what that means. 4. Is it afferent or efferent. 5. One piece of other information.

1. you are working on the following questions:

* Check your recall pp. 207, 208, 209, 212 (1 &2)* Review exercises p 249 Q1, 2, 3, 4, 6, 7

1. Composed of Gray matter and white matter.

2. Gray: Cell bodies that are non-myelinated

3. White: axons that are myelinated

CNS:

1. The brain is composed of about 100 billion neurons and even more nerve fibers to communicate.

2. Divided into three major portions: The cerebrum, cerebellum, and the brain stem

1.1. CerebrumCerebrum controls sensory and motor functions, higher mental functions – memory and reasoning (Divided into sections)

2.2. Cerebellum Cerebellum coordinates voluntary muscle activity

3.3. Brain stem Brain stem regulates activities and connects various parts of the nervous system

Cerebrum:» Divided into 2 hemispheres called Divided into 2 hemispheres called

the Left and Right Cerebral the Left and Right Cerebral Hemispheres. Hemispheres.

» The two hemispheres communicate The two hemispheres communicate by the by the corpus callosumcorpus callosum: acts like a : acts like a bridge between the two. bridge between the two.

1. The Frontal Lobe2. The Parietal Lobe3. The Occipital Lobe4. The Temporal Lobe

1. Forms the anterior portion of each hemisphere

Functions:Functions:• How we know what we are doing

within our environment (Consciousness).

• Controls our emotional response. • Controls our expressive language. • Memory for habits and motor

activities.

Observed Problems:Observed Problems:• Loss of simple movement (Paralysis). • Inability to plan a sequence of complex

movements, such as making coffee (Sequencing).• Inability to focus on task (Attending) Changes in

social behavior. Changes in personality. • Inability to express language (Broca's Aphasia).

Location: Location: Posterior to the frontal lobe, on the top part of the cerebrum.

Function: Function: •Location for visual attention. •Location for touch perception. •Goal directed voluntary movements.•Manipulation of objects.

Observed Problems:Observed Problems:• Inability to attend to more than one object

at a time.• Inability to name an object (Anomia). • Inability to locate the words for writing

(Agraphia).• Problems with reading , drawing and

math(Alexia). • Difficulties with eye and hand coordination.

Location: Location: Most posterior, at the back of the head/brain. Function: Function: •Vision control center. Observed Problems: Observed Problems: •Defects in vision (Visual Field Cuts). •Difficulty with identifying colors (Color Agnosia).•Production of hallucinations Visual illusions - inaccurately seeing objects.

Location: Location: Laterally (each side close to the ears. FunctionFunction: •Hearing ability •Memory acquisition •Categorization of objects. Observed problemsObserved problems: •Difficulty in recognizing faces. •Short-term memory loss. •Inability to categorize objects (Categorization). •Right lobe damage can cause persistent talking. •Increased aggressive behavior.

Deep in Brain, leads to spinal cord.Functions: » Breathing Heart Rate Swallowing Reflexes to seeing and

hearing (Startle Response). Controls sweating, blood pressure, digestion, temperature (Autonomic Nervous System). Affects level of alertness. Ability to sleep.

» Sense of balance (Vestibular Function). Observed Problems:» Decreased vital capacity in breathing, important for

speech. Swallowing food and water (Dysphagia). Difficulty with organization/perception of the environment. Problems with balance and movement. Dizziness and nausea (Vertigo).

» Sleeping difficulties (Insomnia, sleep apnea).

» Includes midbrain, pons, and medulla oblongata» Midbrain – several masses of gray matter that serve as

reflex centers = vision reflex and auditory reflex» Pons –Pons – relay sensory impulses from peripheral nerves to

higher brain centers» Medulla oblongataMedulla oblongata – similar to the pons, but also controls

the cardiac center, vasoconstriction and vasodilatation, and respiratory center.

Located at the base of the skull.Functions:\

» Coordination of voluntary movement Balance and equilibrium

» Some memory for reflex motor acts. Observed Problems:» Loss of ability to coordinate fine movements.

Loss of ability to walk. Inability to reach out and grab objects. Tremors. Dizziness (Vertigo). Slurred Speech (Scanning Speech).

» Inability to make rapid movements.

» Hypothalamus is important in maintaining homeostais by regulating:˃ Heart rate˃ Water and electrolyte balance˃ Hunger and body weight˃ Body temp˃ Sleep and wakefulness˃ Controls pituitary gland

» Thalamus: receivesAll sensory information

Hypothalamus and Hypothalamus and ThalamusThalamus

Spinal Cord

» connected to the brain » descends down the middle of the back and is

surrounded and protected by the bony vertebral column

» surrounded by a clear fluid called Cerebral Spinal Cerebral Spinal Fluid (CSF),Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae

» transmit electrical informationelectrical information to and from the limbs, trunk and organs of the body, back to and from the brain

The Spinal Cord

The Spinal CordThe Spinal Cord

» Cerebral Spinal Fluid:

Spinal NervesThere are four main groups of spinal nerves which exit

different levels of the spinal cord.

These are in descending order down the vertebral column:

1.1. Cervical Nerves "C"Cervical Nerves "C" : (nerves in the neck) supply movement and feeling to the arms, neck and upper trunk. (8 total)

2.2. Thoracic Nerves "T"Thoracic Nerves "T" : (nerves in the upper back) supply the trunk and abdomen. (12 total)

3. Lumbar Nerves "L" and Sacral Nerves "S"Lumbar Nerves "L" and Sacral Nerves "S" : (nerves in the lower back) supply the legs, the bladder, bowel and sexual organs. (5L and 5S)

1. Labeling and vocab worksheets. 2. Brain/Neuron packet. 3. Brain and Spines board game

1. Autonomic nervous system Autonomic nervous system – controls everything we don’t think about.. Smooth muscles, glands, breathing, etc. = involuntary movement

2. Somatic nervous system Somatic nervous system – controls the skeletal muscle = voluntary movement

Cranial NervesPair of nerves What is does

1.Olfactory smell

2. Optic vision

3. Oculomotor Raise eyelids, move the eye, controls involuntary muscles of the eye, adjusts amount of light into the eyes

4. Trochlear Carries motor impulses to the fifth voluntary muscle of the eye

5. Trigeminal Ophthalmic division = sensory fibers from the surface of the eye, tear glands, anterior scalp, forehead, upper eyelidsMaxillary division = upper teeth, upper gum, upper lipMandibular division = scalp behind ears, skin of jaw, lower teeth, lower gum, lower lip

Pair of nerves What is does

6. Abducens Moves the rest of the eye

7. Facial Taste, anterior two-thirds of tongue, facial expression

8. Vestibulocochlear Vestibular branch = maintain equilibriumCochlear branch = hearing

9. Glossopharyngeal Tongue and pharynx, tonsils, posterior third of tongue

10. Vagus Somatic= Larynx, swallowing, speechAutonomic = heart and smooth muscles

11. Accessory Cranial branch = soft palate, pharynx, larynxSpinal branch = neck muscles

12. Hypoglossal Move the tongue for speaking, chewing, swallowing

How does your brain How does your brain send out signals?send out signals?

» The surface of a cell membrane is usually electrically charged. »When the charges are not equal it

is said to be polarized and is VERY IMPORTANT in sending Nerve impulses to and from the body CNS to the PNS!

» The difference in electrical charge between the inside and outside of a cell is called the POTENTIAL DIFFERENCE. POTENTIAL DIFFERENCE.

» In a nerve cell that is “RESTING” or not sending impulses this difference in charges is called the RESTING POTENTIALRESTING POTENTIAL

» As long as the nerve cell remains undisturbed or the charges do not change it will remain in a resting potential state.

» Nerve cells are EXCITABLE: they can respond to changes in their environment.

» In order to do this their potential difference must change (The balance of Na+ and K- ions must change)

» In order for this to happen a certain “Degree” or “level” of change must occur called the Threshold.

» Once the threshold level is reached the neuron can now go from a resting potential to an ACTION ACTION POTENTIALPOTENTIAL

» Action Potential: Action Potential: 1. Electrical charges change by sodium channels

opening and allowing positive sodium into the cell. This makes it positive. And is called DEPOLARIZATION

2. Soon after potassium channels open and allow potassium in ions in again bringing the charge back to negative. This is called REPOLARIZATION

The action potential is the rapid change from The action potential is the rapid change from Depolarization to Repolarization which Depolarization to Repolarization which causes an impulse to be sent through the causes an impulse to be sent through the neuron neuron

» A wave of action potentials that move down the neuron and axon until they hit either another neuron or body cell to transmit the impulse.

» Nerve Pathways- when nerve impulses travel from neuron to neuron.

» The junction between two communicating neurons is called the synapsesynapse.

» The neurons DO NOT TOUCH- there is a gap called the synaptic cleft synaptic cleft that separates them

1. An Impulse (action potential) travels from the dendrite to the cell body and then the axon to the axon terminals (or end of the neuron).

2. There the impulse encounters a synapse separating it from another neuron.

3. At the synapse NEUROTRANSMITTERS are released from the axon terminals.

4. Neurotransmitters diffuse across the synaptic cleft to the next neuron or body cell.

» They can either inhibit the action potential (stop it- lessens the chance that a nerve impulse will continue)

» Or they can excite and trigger a nerve impulse and stimulus to occur.

» 50 different types: ˃ Acetylcholine: stimulates skeletal muscle

contractions˃ Norepinephrine: Autonomic nervous system

actions. Creates a sense of feeling good (Low levels cause depression)

˃ Endorphins: Inhibits; reduces pain.

» The simplest nerve pathways that are only a few neurons long are called REFLEXE ARCS.

» Reflexes are automatic subconscious responses to changes within or outside the body.

» Example: The Knee-Jerk reflex: Only 2 neurons. A sensory neuron communicating directly with a motor neuron.

Page 221-222 in book

Knee Jerk activity

» 1. what is an action potential in your own words

» 2. Resting potential» 3. How is an impulse sent