T he brain is remarkable in what it can do. This lecture will show that the brain plays an important part in everything we think and do. Brain, Body and Behavior UNIT 3

Figure 3.1 Structure of the neuron Dendrites Soma Axon Terminal buttons

Brain Communication A NEURON is a nerve cell. It is the smallest part of the nervous system.

Brain Communication Dendrites branch off the body of the neuron and receive impulses from other neurons.

Brain Communication Axons gather impulses from dendrites and carry them to other neurons.

The synapse is the space between the axon of the sending neuron and the dendrites of the receiving neuron. Brain Communication

The Soma is the cell body.

The Neural Impulse Neural Impulse – Brief electric surge that carries the neuron’s message Ions – Charged particles that are moved across the cell membrane

The Neural Impulse: The Action Potential Stimulation causes cell membrane to open briefly Positively charged sodium ions flow in Shift in electrical charge travels along neuron – All – or – none law: Size of the action potential is unaffected by increases in the intensity of stimulation beyond the threshold level

The Neural Impulse: The Resting Potential Polarization of cellular fluid within a neuron, which provides the capacity to produce an action potential

The Refractory Period The neuron can’t fire or will fire with more intense stimulation

Neurotransmitters are messenger molecules (pain, pleasure, movement)

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Produces sensations of pleasure and reward; used by CNS neurons in voluntary movement Problems with Imbalance: Schizophrenia, Parkinson’s disease Substances that Affect: Cocaine, amphetamines, Ritalin, alcohol

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Regulates sleep and dreaming, mood, pain, aggression, appetite and sexual behavior Problems with Imbalance: Depression, certain anxiety disorders, obsessive- compulsive disorder Substances that Affect: Prozac, hallucinogenics (e.g. LSD) Neurotransmitters

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Controls heart rate, sleep, sexual responsiveness, stress, vigilance and appetite Problems with Imbalance: High blood pressure, depression Substances that Affect: Tricyclic antidepressants, beta blockers

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Primary transmitter used by neurons carrying messages from CNS; involved in some kinds of learning and memory Problems with Imbalance: Certain muscular disorders, Alzheimer’s disease Substances that Affect: Nicotine, botulism toxin, curare, atropine

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Most prevalent inhibitory neurotransmitter in neurons of CNS Problems with Imbalance: Anxiety, epilepsy Substances that Affect: Barbiturates, tranquilizers (e.g. Valium, Librium), alcohol

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Primary excitatory neurotransmitter in CNS; involved in learning and memory Problems with Imbalance: Brain damage after stroke Substances that Affect: PCP (“angel dust”)

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Pleasurable sensations and control of pain Problems with Imbalance: Lowered levels resulting from opiate addiction Substances that Affect: Opiates: opium, heroin, morphine, methadone

The Four Lobes of the Cerebral Cortex Frontal Lobe (movement and thinking) Parietal Lobe (touch sensation and spatial relationships) Occipital Lobe (contain visual cortex) Temporal Lobe (process sounds, including speech)

Cerebral Cortex The Cerebral Cortex is the outermost layer of the brain and controls very high level thought processes.

Front Right Rear Left The Corpus Callosum is a thin band of tissues inside the fissure.

Brain Diagram Cerebral cortex Hypothalamus Thalamus Cerebellum Corpus callosum Pituitary Reticular activating system Hippocampus Amygdala

The cerebral cortex covers, protects, and influences the lower brain structures. The Lower Brain Cerebral cortex Corpus callosum Pituitary Reticular activating system Hippocampus Thalamus Cerebellum Hypothalamus Amygdala

The Lower Brain The thalamus acts as a relay station to send incoming and outgoing messages to appropriate areas in the brain. Thalamus Corpus callosum Pituitary Reticular activating system Hippocampus Cerebellum Hypothalamus Amygdala Cerebral cortex

The Lower Brain The hypothalamus controls hunger, pleasure, thirst, rage, and sexual desire. Hypothalamus Corpus callosum Pituitary Reticular activating system Hippocampus Cerebellum Thalamus Amygdala Cerebral cortex

The Lower Brain The cerebellum helps you to stand upright and keeps your movements coordinated. Cerebellum Corpus callosum Pituitary Reticular activating system Hippocampus Hypothalamus Thalamus Amygdala Cerebral cortex

The Limbic System is involved with basic emotions and memory. Two important structures include The Amygdala (emotional responses and aggression) The Hippocampus (the formation of new memories) The Reticular Activating System keeps track of nerve impulse activity and helps regulate how alert or sleepy we feel. Other Lower Brain Structures

The Motor Cortex Controls the action of the body’s voluntary muscles

Motor and Somatosensory Cortex Somatosensory Cortex – Processes info about temperature, touch, body position, & pain Auditory Cortex – Receives and processes auditory information Visual Cortex – Processes visual information Association Cortex – High-level brain processes

Tasks of the Cerebral Hemispheres The brain is divided into halves. Each half, or hemisphere, controls the opposite side of the body.

Specialization of the Cerebral Hemispheres Left Hemisphere Right Hemisphere Spontaneous speaking and writing Responses to complex commands Word recognition Memory for words and numbers Sequences of movements Feelings of anxiety Positive emotion Repetitive but not spontaneous speaking Responses to simple commands Facial recognition Memory for shapes and music Spatial interpretation Emotional responsiveness Negative emotion

Hemispheric Lateralization

Central Nervous System (CNS) Peripheral Nervous System (PNS) Brain Spinal Cord Somatic Nervous System Autonomic Nervous System Sympathetic Nervous System Parasympathetic Nervous System The Nervous System

The Nervous System

The Central and Peripheral Nervous Systems

(the body’s chemical messenger system) The Endocrine System

Pituitary gland Thyroid Adrenal gland Female gonads (ovaries) Male gonads (testes)

Pituitary Gland the master gland controlled by the hypothalamus sends a message to other glands to begin working determines how tall or short a person will be (growth hormone) The Endocrine System Pituitary gland

The Gonads sex glands that produce either sperm or eggs used in reproduction The Endocrine System Female gonads (ovaries) Male gonads (testes)

The Endocrine System The Thyroid Gland controls metabolism overactive thyroid may cause restlessness and anxiety underactive thyroid may result in sadness and even depression Thyroid

The Endocrine System The Adrenal Gland secretes adrenaline into the bloodstream blood pressure goes up, muscles tense, and hands tremble Adrenal gland

Summary of Main Topics Covered Parts of the Brain Brain Communication The Nervous System The Endocrine System Left/Right Brain Functions