WARM UP 3/8WARM UP 3/8

1.1. Use Na+, receptors, Ach, action potential, Use Na+, receptors, Ach, action potential, neuromuscular junction in a sentence.neuromuscular junction in a sentence.

2.2. List 5 things you learned on the internet List 5 things you learned on the internet assignment.assignment.

3.3. What is the function of the nervous What is the function of the nervous system?system?

NOTES Ch 10 3/8NOTES Ch 10 3/8

The nervous system introThe nervous system intro

NERVOUS SYSTEM NERVOUS SYSTEM FUNCTION:FUNCTION:

1.1. CommunicationCommunication2.2. Integration – (making body systems work Integration – (making body systems work

together)together)

PARTSPARTS

Brain, spinal cord, nerves Brain, spinal cord, nerves

2 MAIN TYPES OF CELLS2 MAIN TYPES OF CELLS

1.1. Neurons – nerve cellsNeurons – nerve cells

2. Neuroglia (glia) – special connective 2. Neuroglia (glia) – special connective tissue cellstissue cells

4 MAIN TYPES OF GLIA4 MAIN TYPES OF GLIA

1.1. ASTROCYTES ASTROCYTES * helps maintain K+ balance* helps maintain K+ balance

2.2. MICROGLIA MICROGLIA * destroy microbes* destroy microbes

3.3. OLIGODENDROGLIAOLIGODENDROGLIA * hold nerve fibers together* hold nerve fibers together * produce myelin sheath* produce myelin sheath

4.4. SCHWANN CELLSSCHWANN CELLS * form covering on some nerves* form covering on some nerves

3 MAIN TYPES OF NEURONS3 MAIN TYPES OF NEURONS

1.1. AFFERENT sensory neurons – take impulses to AFFERENT sensory neurons – take impulses to spinal cord or brain (pick up info through spinal cord or brain (pick up info through receptors)receptors)

2.2. EFFERENT motor neurons– take impulses EFFERENT motor neurons– take impulses away from spinal cord or brain to effectors away from spinal cord or brain to effectors (muscles and glands)(muscles and glands)

3.3. INTERNEURONS – carry information between INTERNEURONS – carry information between afferent and efferent neuronsafferent and efferent neurons

STRUCTURE OF A NEURONSTRUCTURE OF A NEURON

1. CELL BODY (SOMA) – main part of 1. CELL BODY (SOMA) – main part of neuron; contains nucleus neuron; contains nucleus

2.2. AXON – end that sends messages away AXON – end that sends messages away from the neuronfrom the neuron

* ends – synaptic knobs* ends – synaptic knobs

3. DENDRITES – ends that receive messages3. DENDRITES – ends that receive messages * ends receptors* ends receptors

http://www.shodor.org/Hodgkin/cell.gif

4.4. MYELIN SHEATH – wraps around the MYELIN SHEATH – wraps around the axon in some neurons for insulation; axon in some neurons for insulation; makes impulse travel fastermakes impulse travel faster

Unmyelinated – no sheathUnmyelinated – no sheath Myelinated – has sheathMyelinated – has sheath

http://www.diseaseworld.com/ms.gif

5. NODE OF RANVIER – spaces between 5. NODE OF RANVIER – spaces between each Schwann celleach Schwann cell

PURPOSE: impulses can jump from one PURPOSE: impulses can jump from one node to the next; makes impulse fasternode to the next; makes impulse faster

SALTATORY CONDUCTION – when SALTATORY CONDUCTION – when impulse leaps from one node to anotherimpulse leaps from one node to another

6. SCHWANN CELL – each unit on the axon 6. SCHWANN CELL – each unit on the axon that is wrappedthat is wrapped

IMPULSES CAN IMPULSES CAN TRAVEL UP TO TRAVEL UP TO 280 MPH!280 MPH!

DRAWING A NEURONDRAWING A NEURON

Draw a picture of a neuron and labelDraw a picture of a neuron and label