10.2 Neuron Structure Sponge: Set up Cornell Notes on pg. 5 Topic: 10.2 Neuron Structure Essential Question: What is the major function of the axon? Text: 358-361 2.1 Atoms, Ions, and Molecules What is the major function of the axon?

Neurons and Neurotransmitters 5m35s *Add info to picture bubble map

Objective SWU: the general structure of a neuron SW: create a picture-bubble map of a neuron identifying the location and function of each part

Neuron Picture Bubble-Map 1. Draw/label a neuron on pg. 4. Make a “picture bubble map” explaining the function of each part of a neuron (p.356-361) Include: dendrites, nucleus, cell body, axon, myelin sheath, Nodes of Ranvier, Schwann cells, axon terminal, synapse, neurotransmitter 2. Explain the function of each (keep short)

(aka action potential) Myelin sheath (covering/ only in PNS) NEURON Nucleus Synapse (gap between neurons) Axon terminals Nerve Impulse (aka action potential) axon Schwann Cells (only in PNS) Myelin sheath (covering/ only in PNS) Dendrites Cell body (aka Soma) Nodes of Ranvier (only in PNS) Neurotransmitters 4 5

Neurons P.5 Neurons are nerve cells that are specialized to carry nerve impulses through an electrochemical process 

Nerve impulse aka action potential: Electrical signal that carries messages down the axon Dendrites receive “message” from nearby neuron to be sent to next neuron

Dendrites: Receive nerve impulses Provide receptive surfaces for communication Usually highly branched

Cell body aka Soma: The cells life support center that contains the cytoplasm/organelles Ex: mitochondria, lysosomes, golgi apparatus, and microtubules Neurofibrils: A network of fine threads that extends into the axon for support—make up the axon Nissl bodies: consist of rough endoplasmic reticulum (E.R.) needed for protein synthesis Nucleus which contains the DNA of a cell

Axon: Specialized to conduct nerve impulses AWAY from the cell body to other neurons, muscles, and glands Only one axon per neuron Slender and cylindrical– can be VERY long

Axon cont’: FOUND ONLY IN P.N.S.: Schwann cells: Covers the axon and forms the myelin sheath Gaps between Schwann cells are nodes of Ranvier (Ron-vee-ā) Myelin sheath- is a insulating lipid (fatty) layer surrounding the axon These work together to INCREASE THE SPEED of transmissions

Nerves: Bundles of axons

Axon terminals: the endings of a neuron Location of ‘contact’ with other nerve or effector cells takes place May have up to 10,000 connections from a single neuron Neurotransmitters

Allows information to be transmitted from neuron to neuron Neurotransmitters: Chemical signals released by axon terminal through the synaptic gap Allows information to be transmitted from neuron to neuron Neurotransmitters

Synapse or synaptic gap: Gaps between neurons

How neurons send signals:

How neurons send signals: The function of a neuron is to receive INPUT "information" from other neurons, to process that information, then to send "information" as OUTPUT to other neurons.

How neurons send signals: 1. An action potential or nerve impulse is generated near the cell body portion of the axon. 

2. This signal moves along the axon until it reaches the axon terminals.  An action potential travels along the axon quickly, moving at rates up to 150 meters (or roughly 500 feet) per second. 

2. This signal moves along the axon until it reaches the axon terminals. 

2. This signal moves along the axon until it reaches the axon terminals. 

2. This signal moves along the axon until it reaches the axon terminals. 

2. This signal moves along the axon until it reaches the axon terminals. 

2. This signal moves along the axon until it reaches the axon terminals.  Dendrites of next neuron

3. The signal ends at the axon terminals 3. The signal ends at the axon terminals. Axon terminals are where neurotransmission begins.    Synapse (gap) Axon terminal Dendrites of next neuron

3. The synaptic gap creates a physical barrier for the electrical signal carried by one neuron to be transferred to another neuron.  Synapse (gap) Axon terminal Dendrites of next neuron

3. Neurotransmitters transmit signals across the synapse, from one neuron to another "target" neuron, muscle cell, or gland cell Synapse (gap) Axon terminal Dendrites of next neuron

3. Neurotransmitters are released into the synaptic gap, where they are received by receptors on other neurons. Synapse (gap) Axon terminal Dendrites of next neuron

Sponge: Set up Cornell Notes on pg. 7 Topic: 10.2 Three Types of Neurons Essential Question: Describe the major difference between a sensory and motor neuron. Text: 363-364 10.2 Three Types of Neurons 2.1 Atoms, Ions, and Molecules Describe the major difference between a sensory and motor neuron.

A Closer Look at Neurons 4m49s Add info to picture bubble map

Neurons Neurons process ALL of the "information" that flows within, to, or out of the CNS. All of it! All of the sensory information through which we are able to see, to hear, to smell, to taste, and to touch All of the cognitive information through which we are able to reason, to think, to dream, to plan, to remember, and to do everything else that we do with our minds. All of the motor information through which we are able to move

Sensory neurons Interneurons Motor neurons

Three Neuron Functions: Some carry impulses into the brain or spinal cord Others conduct impulses from neuron to neuron within the brain and spinal cord Others carry impulses out of the brain or spinal cord

Three Types of Neurons 1m59s

1. Sensory Neurons: Located in PNS The dendrites act as sensory receptors Most are unipolar, some bipolar Function: (PNS CNS) They gather information and carry impulses TO the brain and spinal cord

2)Interneurons: Located in CNS Multipolar Function: Receive signals from sensory neurons and relay them within the brain and spinal cord Direct incoming sensory impulses to appropriate regions for processing/ interpreting/ decision making

3)Motor neurons: Located in the PNS Multipolar Function: (CNSPNS) Carry nerve impulses OUT of the brain or spinal cord to effectors (muscles and glands) to complete an action

Motor Neurons 59s

Key: Motor Neurons Effectors Receptors Sensory Neurons Interneurons 1._______________ 2. ________________ Answer on p. 7 3. ______________ 4. _____________ 5._____________

Key: Motor Neurons Effectors Receptors Sensory Neurons Interneurons 1._______________ 2. ________________ 3. ______________ 4. _____________ 5._____________

2. Sensory Neurons 3. Interneurons 4. Motor Neurons 1. Receptors 5. Effectors

Stimuli and Neurons 2m49- 4m 16s

Types of Neurons Picture Flow MAP Sensory Neurons Interneurons Motor Neurons Function Location Function Location Function Location Give a real life example (Tell a story) Draw a picture for each As short as possible As short as possible As short as possible 2. My brain interprets this information and identifies the sound as the phone ringing. I decide to answer the phone. This info is sent to my motor neurons 3. The motor neurons send nerve impulses to my muscles in my arm/hand which allows me to answer the phone. 1. The phone rings. The sensory neurons in my ear gather the sound information and send it to my CNS

10.2 Classification of Neurons and neuroglial cells Sponge: Set up Cornell Notes on pg. 9 Topic: 10.2 Classification of neurons and neuroglial cells Essential Question: None. Text: 361-367 10.2 Classification of Neurons and neuroglial cells 2.1 Atoms, Ions, and Molecules Then turn to p. 6 for signature of HW

Table Talk Share your neuron “story” with your table Pick the best one Be ready to share with class- pick reader

Structural Characteristics Classification of Neurons and Neuroglial Cells Neurons based on structure….(361-2/Table 10.1) Bipolar Neurons Unipolar Neurons Multipolar Neurons Neuroglial Cells in CNS (p.364-6/Table 10.2) 4. Astrocytes 5. Oligodendrocytes 6. Microglia 7. Ependyma Neuroglial Cells in PNS (364/Table 10.2) 8. Satellite Cells 9. Schwann Cells Title Illustration Function Location CNS/PNS Specific location? Structural Characteristics Shape # of processes Other important information

Neuron Gallery Walk We will go on a gallery walk to gather our notes 3 mins each (30 mins) Use your books to fill in any missing information

Classification of Neurons – Structural Differences 1. Bipolar neurons: Only 2 processes One is an axon/ one is a dendrite Location: Found in PNS sensory neurons Eyes, nose, ears Function: They gather information and carry impulses into the brain and spinal cord

2. Unipolar neurons: 1 process extending from its cell body Divides into two branches One branch enters the brain or spinal cord Location: Found in PNS sensory neurons Gather in specialized masses of nerve tissue called ganglia outside the brain and spinal cord Function: They gather information and carry impulses into the brain and spinal cord

3. Multipolar Neurons: Many processes One is an axon, the rest dendrites Location: Found within the CNS Function: They transmit nerve impulses between neurons within the brain and spinal cord AND conduct nerve impulses out of the brain and spinal cord to muscles or glands

Types of Neuroglial Cells Neuroglial cells: provide support to the neurons. In much the same way that the foundation, framework, walls, and roof of a house prove the structure through which run various electric, cable, and telephone lines, along with various pipes for water and waste, not only do glia provide the structural framework that allows networks of neurons to remain connected, they also attend to the brain's various house keeping functions (such as removing debris after neuronal death). It is worth noting that there are as many as 50 times more glia than neurons in our CNS!

Types of Neuroglial Cells in the PNS Schwann Cells: Location: PNS Function: Produce myelin that wrap tightly around the axons of peripheral neurons and Speed up neurotransmissions

2. Satellite Cells: Small cuboidal cells that surround clusters of neuron cell bodies called ganglia Function: Support ganglia in the PNS

Types of Neuroglial (Neu-rag-lial) Cells in the CNS Astrocytes: Star shaped Abundant (many) processes Location: Found in CNS between neurons and blood vessels Functions: Provide support & hold structures together Respond to injury of brain tissue and form scar tissue Transports substances between blood vessels and neurons Communicate with one another, and with neurons Aide in metabolism of certain substances (glucose) Regulate the concentrations of important ions (potassium)

2. Oligodendrocytes: (Ollie-go-dendro-cytes) Fewer processes than Astrocytes Occur in rows along myelated axons May provide myelin for many axons at one time Functions: Form myelin sheaths within the brain and spinal cord Produce nerve growth factors

3. Microglia: (Mycro-glea) Small Have very few processes Scattered through the CNS Functions: Support neurons Phagocytize bacterial cells and cellular debris (immune protection) Multiply whenever the brain or spinal cord is inflamed due to injury or disease

4. Ependyma: (uh-pen-dĭma) Cuboidal or columnar in shape Found in the inner lining of the ventricles of the brain and the central canal of the spinal cord Function: They form a porous layer through which substances diffuse freely between the interstitial fluid of the brain and the cerebrospinal fluid within the ventricles

Crash Course: Nervous System Part I 9m36s https://www.youtube.com/watch?v=qPix_X-9t7E