Questions of the Day “ WHAT MAKES YOU WHO YOU ARE ? ” Why are you different from Everyone Else” What makes you so similar?

your NERVOUS SYSTEM

Nervous System

Functions of The Nervous System Maintains body homeostasis: by receiving and sending out electrical signals Provides sensation: touch, sight, hearing, taste, smell Higher mental functioning: solving problems, making decisions Emotional response: angry, sad, happy Activates muscle and glands: stimulate movement or specific organ function (effectors)

The Nervous System Sub-Divisions Central Nervous System(CNS) – Brain – Spinal cord Peripheral Nervous System (PNS) – Sensory nerves – Motor nerves

Function of the CNS Brain and Spinal Cord Integrating and the command center 1. Interpret incoming sensory information from the sensory nerves of the PNS 2. Send instructions to the motor nerves of the PNS to cause a response based on past experiences and current body conditions

Function of the PNS 1. Sensory Nerves: carry's electrical impulses to the spinal cord and/or Brain 2. Motor Nerves: carry impulses from the brain and/or spinal cord to a muscles, organs or glands Function: nerves are communication lines that link all parts of the body by carrying impulses to the CNS and away from the CNS to effector muscles and glands.

Sensory and Motor Nerves

1. Sensory Division Consists of nerves that convey impulses TO the CNS from sensory receptors located in various parts of the body. Locations of Sensory receptors: - Somatic Sensory: skin, muscles, joints - Visceral: organs Function: Together they keep the CNS constantly informed of events going on both inside and outside the body.

2.Motor Division Consists of nerves that convey impulses AWAY from the CNS to – Organs – Muscles – Glands Function: These nerves cause a motor response to occur (action). The motor division has 2 further subdivisions a. Somatic Nervous System b. Autonomic Nervous System

Motor Division of the Peripheral NS 1.Somatic Nervous System Voluntary Movements Skeletal Muscle 2.Autonomic Nervous System (2 subdivisions) Involuntary movements (automatic) Smooth Muscle (digestive system) Cardiac Muscle (heart) Glands (hormone release)

2 subdivisions : Autonomic Nervous System 1.Sympathetic Fight or flight response 2.Parasympathetic Rest and digest

All Together

How does the Central and Peripheral Nervous Systems Accomplish all those functions?

“Sense Think Do”

SENSE: Uses sensory receptors (organs and nerves) to monitor changes (stimuli) inside and outside the body. The information gathered is called sensory input. THINK: Processes and interprets the sensory input and makes decisions about what should be done at each moment. This is called integration. DO: Creates a response by activating muscles and glands (effectors). The response is called motor output.

Lets Break the Process into 5 Steps

Step 1: Stimulus and Receptors “Seeing” A stimulus causes a change (glass of water) Sensory receptors called sensory nerves are located throughout the body to monitor changes caused by a stimulus that are occurring inside and outside the body. Locations: – Skin (pressure, temp) – Sensory Organs

Step 2: Receptor Sends a Message When sensory nerves are stimulated they send a message to the brain (feel cold, hunger, etc…) This message is in the form of an electrical impulse that passes from one nerve to another until it reaches the brain This message is called sensory input.

Step 3: Control Center “Thinking” The brain receives the message from the sensory nerves and interneurons in the brain and spinal cord interprets and processes the sensory input (control center). Then makes a decision about what should be done about this message (compare set point to actual condition). This action by the brain is called integration.

Step 4: Control Center Sends a Message The brain sends a message out by motor neurons to the body structure needed to perform a function (effectors).

Step 5: Effectors “Do” The message from the brain targets the body structure that is needed to bring about an action. This could be a muscle, an organ or a gland. The body organ is stimulated by a motor nerve. The action is called motor output.

Label and Color Your Diagram with the Following: Stimulus Sensory Organ Sensory Input Sensory Nerve Interneuron Integration Brain Motor Output Motor Nerve Effector Net Effect: drink water

2 TYPES OF MOTOR RESPONSES 1.Voluntary actions: occur because of a conscious choice. 2. Involuntary: occurs without the conscious choice of an organism. Involuntary actions may or may not occur with the awareness of the organism performing it. Common involuntary actions are heartbeat, hiccups, digestion, coughing and sneezing. Breathing can also be considered both involuntary and voluntary Reflex’s

Reflex: Integration is done by the Spinal Cord and NOT the Brain Blue: sensory nerves Green: Interneuron Red: motor nerves

Lets Try an Example When you are driving and see a red light ahead sensory input. – Sensory receptor (eye) is stimulated and sends an electrical impulse to the brain Your nervous system integrates this information (red light means stop) The brain sends an electrical impulse by motor nerves to the leg and foot muscles The motor neurons activate your leg muscles and your foot goes for the brake pedal to stop car. This is called motor output. Now Try the bike scenario.

Activity Directions You and a partner discuss and create at least 3 examples the following sensory input: what is the stimuli coming into the bike riders brain Integration: what are your decisions for actions motor output: what parts of the body react Try voluntary and involuntary responses