Biology and BehaviorBiology and Behavior

Chapter 3Chapter 3

The Nervous SystemThe Nervous System

•Central Nervous System – Central Nervous System – consists of the brain and consists of the brain and spinal cord.spinal cord.

•Peripheral Nervous System – Peripheral Nervous System – made up of nerve cells that made up of nerve cells that send messages between the send messages between the central nervous system and central nervous system and all the parts of the body.all the parts of the body.

•Neurons – nerve cells that Neurons – nerve cells that communicate with each communicate with each other throughout our body.other throughout our body.–Everyone has more than Everyone has more than 100 billion of them. Most 100 billion of them. Most in your brain.in your brain.

–Cell body: produces Cell body: produces energy that fuels the energy that fuels the activity of the cellactivity of the cell

–Dendrites: fibers that Dendrites: fibers that receive information from receive information from other neuronsother neurons

–Axon: carries messages Axon: carries messages away from the cell to away from the cell to other neurons.other neurons.

–Myelin: insulates the Myelin: insulates the axonaxon

–Synapse: junction between Synapse: junction between the axon terminals and the axon terminals and dendrites.dendrites.

–Neurotransmitters: Neurotransmitters: chemicals that are released chemicals that are released from the axon. Sends a from the axon. Sends a message.message.

•There are many types of There are many types of neurotransmitters. They neurotransmitters. They are involved in a variety of are involved in a variety of behaviors from yawning to behaviors from yawning to exercising.exercising.

•Central Nervous SystemCentral Nervous System– Spinal Cord: extends from the Spinal Cord: extends from the

brain down the back. It is a brain down the back. It is a column of nerves protected by column of nerves protected by bones. If you touch a hot bones. If you touch a hot surface, a message goes surface, a message goes immediately to your spinal cord immediately to your spinal cord telling your muscles to remove telling your muscles to remove your hand.your hand.

•Peripheral Nervous SystemPeripheral Nervous System–Somatic – transmits Somatic – transmits sensory messages to the sensory messages to the central nervous system. central nervous system. Touch, pain, change in Touch, pain, change in temperature.temperature.

–Automatic: regulates Automatic: regulates body’s vital functions. body’s vital functions. Heartbeat, breathing, Heartbeat, breathing, digestion and blood digestion and blood pressure.pressure.

•Sympathetic – activated Sympathetic – activated when a person is going into when a person is going into action. Prepares the body action. Prepares the body to confront the situation or to confront the situation or to run away. “Fight or to run away. “Fight or Flight”. Suppresses Flight”. Suppresses digestion, increase in heart digestion, increase in heart rate etc.rate etc.

•Parasympathetic – Parasympathetic – restores the body’s restores the body’s energy. Normalized energy. Normalized heart rate and blood heart rate and blood pressurepressure

The BrainThe Brain

•Divided into 3 Parts:Divided into 3 Parts:– Hindbrain:Hindbrain:

•Medulla – vital functions such Medulla – vital functions such as heart rate, blood pressure as heart rate, blood pressure and breathingand breathing

•Pons – regulates body Pons – regulates body movement, attention, sleep movement, attention, sleep and alertnessand alertness

•Cerebellum – Latin for Cerebellum – Latin for “little brain”. Balance “little brain”. Balance and coordinationand coordination

–Midbrain:Midbrain:•Vision, learning, andVision, learning, and attentionattention

–Forebrain: Complex thinking Forebrain: Complex thinking processes.processes.•Thalamus – relay station Thalamus – relay station for sensory stimulation for sensory stimulation (ex: pain) Relays input (ex: pain) Relays input from eyes and ears to from eyes and ears to different parts of the brain.different parts of the brain.

•Hypothalamus – Hypothalamus – regulates body regulates body temperature, storage of temperature, storage of nutrients, motivation nutrients, motivation and emotion. Hunger, and emotion. Hunger, thirst, aggression etc. thirst, aggression etc.

•Limbic System – memory, Limbic System – memory, emotion etc.emotion etc.

•Cerebrum – 70% of the Cerebrum – 70% of the weight of the brain. The weight of the brain. The ridges and wrinkles are ridges and wrinkles are called the cerebral cortex called the cerebral cortex – outer layer of the brain. – outer layer of the brain. The part that thinks.The part that thinks.

•Cerebral Cortex: two sides Cerebral Cortex: two sides (left hemisphere and right (left hemisphere and right hemisphere)hemisphere)

•Corpus Callosum – connects Corpus Callosum – connects the right and left sides of the right and left sides of the brain (Right Side – the brain (Right Side – Creativity, Left – Logical)Creativity, Left – Logical)

•Hemispheres are divided into Hemispheres are divided into four lobes:four lobes:–Frontal: Motor, Decisions, Frontal: Motor, Decisions, SpeakingSpeaking

–Parietal: Skin SensesParietal: Skin Senses–Temporal: Hearing, Temporal: Hearing, Understanding LanguageUnderstanding Language

–Occipital: VisualOccipital: Visual

Studying the BrainStudying the Brain

•Researchers study accidents and Researchers study accidents and brain damage to understand brain damage to understand how the brain functions and is how the brain functions and is related to psychological related to psychological functions.functions.

•Some researchers have used Some researchers have used electrical stimulation to observe electrical stimulation to observe behaviors associated with a behaviors associated with a particular part of the brain.particular part of the brain.

•EEG – Electroencephalogram – a EEG – Electroencephalogram – a device that records the electrical device that records the electrical activity of the brain.activity of the brain.

•Scans – Use computer images to Scans – Use computer images to study the brain.study the brain.– CAT Scan – X-ray beams help CAT Scan – X-ray beams help

piece together a 3D view of the piece together a 3D view of the brain.brain.

–MRI – uses radio waves and MRI – uses radio waves and magnetic fields. More detail magnetic fields. More detail than a CAT Scanthan a CAT Scan

–PET – Positron Emission PET – Positron Emission Tomography – show brain Tomography – show brain activity rather than a activity rather than a snapshotsnapshot