Nervous System Correct your endocrine glands diagram The nervous system makes you: Aware of your surroundings Happy about your surroundings React to your surroundings Nervous about your surroundings True or False…. If its false make it true Unlike the endocrine system, the nervous system is a communication system for your body. The neuron is the longest cell in the human body.

Neurons Basic cell of the nervous system “nerve cell”

What Do Neurons Do? Receive, integrate, and transmit information Operate through electrical impulses Communicate with other neurons through chemical signals

Neuron Packaging Grouped in bundles called nerves.

How many neurons do you have? Figure 2.1: Estimated numbers of neurons in humans. Because of the small size of many neurons and the variation in cell density from one spot to another, obtaining an accurate count is difficult. (Source: R. W. Williams & Herrup, 1988)

Parts of The Neuron Direction of impulse Figure 2.6 from: Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall. Source: Nerve impulse: the way nerve cells (neurons) communicate with one another. It moves from the dendrites to the axon terminal, then it jumps to another neuron.

Parts of the neuron Dendrites: receive signals from neighboring neurons and carry signals back to the cell body Cell body: contains the nucleus. Passes impulse to the axon

The Parts of a Neuron Axon: A thin, long structure that transmits electrical signals from the cell body to the axon terminal. Myelin sheath: covers the axon, helps insulate and speed up transmission of an impulse Axon Terminal: receives the impulse from the axon; last step in transmission of information

Neurotransmitters & Synapses Neurotransmitter: chemical signal that is present in the axon terminal; transmits impulse across the synapse. Synapse: the area in-between two neurons that a signal must cross.

Label the parts of the neuron and draw the direction of the impulse.

Q: What is the function of the nervous system Q: What is the function of the nervous system? A: Controls and coordinates functions throughout the body and responds to internal and external stimuli

Let’s conduct some neurological tests……how does your brain process information?

How many black dots can you count?

Are the lines straight or bent?

peripheral nervous system (PNS) your nervous system is divided into the central nervous system (CNS) which is the brain and spinal cord Medical Art Service, Munich /, Wellcome Images and the peripheral nervous system (PNS) Credit Medical Art Service, Munich /, Wellcome Images which connects everything to the brain and spinal cord

Classification of Neurons Sensory Neurons –have specialized receptor ends that sense stimuli and then carry impulses from peripheral body parts (PNS) to brain or spinal cord (CNS). Motor Neurons – carry impulses (“messages”) out of the brain or spinal cord (CNS) to muscles and glands in the PNS.

Draw an image showing a motor neuron and a sense neuron passing and receiving messages.

The Peripheral Nervous System Describe – sensory neuron receives pain signal. Sends pain signal to brain. Brain sends out message “impulse” as to what action limb should do through the motor neuron

The Peripheral Nervous System Nerves that are connected to the brain and spinal cord on one end and other parts of the body on the other end. Divided into the sensory division and the motor division. Sensory division Motor division

Sensory Division and Motor Division Similar to motor and sense neurons The sensory division transmits impulses from the sense organs, skin, muscles, organs to the central nervous system (CNS). The motor division transmits impulses from the central nervous system (CNS) to the muscles, glands, or organs. Motor division is divided into Somatic NS and Autonomic NS

The Motor Division is further divided into the somatic nervous system and the autonomic nervous system.

Somatic Nervous System Controls all voluntary muscular systems within the body Example: Controls the process of involuntary reflex arcs Reacts to outside stimuli affecting the body such as in touch, cuts, heat and cold sensations.

Voluntary movement In order to lift a cup of water to drink, you must: You see the water stimulating a sensory neuron, Sensory neuron sends the message to the brain to process Brain sends a signal to a motor neuron to lift your arm.

Reflex Arc (Involuntary) The Withdrawal Reflex If you touch something hot Sensory receptors stimulate a sensory neuron Sensory neurons send a signal to the spinal cord Spinal cord sends a signal to a motor neuron to move your hand. Figure 2.5B from: Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.

Compare Voluntary Movement to Reflex Arc Involves the Spinal Cord and Brain Involuntary Involves only the Spinal Cord

Autonomic Nervous System Autonomic Nerves – nerves that you can not control. (involuntary) Regulates the functions of our internal organs such as the heart, stomach and intestines. 2 types of autonomic nerves: sympathetic – fight or flight parasympathetic – rest and digest

Sympathetic Nervous System Speeds up the body and prepares it for “fight or flight” These nerves lead to all vital organs (liver, pancreas, stomach, intestines, heart, blood supply, sweat and salivary glands) They prepare your body for action! Let’s look at some examples

Parasympathetic Nervous System Slows the body down, acts as a brake Allows your body to “rest and digest”

Which picture is show the parasympathetic nervous system and which one activates the sympathetic nervous system?

Let’s look at an example of your nervous system at work…