NeuronsNeurons

• Neurons are basic nerves cells– Dendrites branching extensions of neurons that

receive chemical messages – Axon an extension from the cell body through which

messages pass to other neurons– Myelin sheath a layer of fatty tissue that enables

faster transmission speed of neural impulses– Action potential the electrical charge that travels

down the axon causing the neuron to “fire”

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Neural StructureNeural Structure

Dendritic SpinesDendritic Spines

Golgi type II(cortex)

Basket cell (Cerebellum)

Neural ActivityNeural Activity

• Inside the neuron has a negative ionic charge• (negative inside/positive outside) = resting

potential• Neurons are selectively permeable (usually

blocking POSITIVELY charged sodium ions until given the signal to fire

• Depolarization occurs when neurons allow sodium ions inside causing neurological firing

Neural ActivityNeural Activity

• All or nothing response neurons either fire or they don’t…There is no in between

• The gaps between neurons are called synapse or the synaptic gap or cleft

• Neurotransmitters are chemical messengers that travel between the synaptic gap; binding to receptors determining whether the neuron will generate an impulse and allowing depolarization to occur

Neural StructureNeural Structure

AXON HILLOCK

NeurotransmittersNeurotransmitters

This Info can be This Info can be excitatoryexcitatory or or inhibitoryinhibitory to a neighboring neuronto a neighboring neuron

Neurotransmitters Neurotransmitters

• Acetylcholine

• Dopamine linked

• Seratonin

• Endorphins

• Norepinephrine

• Excessive amounts of neurotransmitters are reabsorbed by the neurons in a process called reuptake

NeurotransmittersNeurotransmitters

Neurotransmitters Neurotransmitters

• Agonists excite; blocking reuptake and cause neurons to fire rapidly– Black widow venom causing convulsions,

muscular contractions (++ACl)

• Antagonists inhibit the neurotransmitters release– Botox paralyzing muscular function

Nervous SystemNervous System

• The body’s electrochemical network that consists of all the nerve cells of the:– Central Nervous system (CNS) – Peripheral Nervous system

Nervous SystemNervous System

• Central Nervous System– Brain – Spinal cord

• Peripheral Nervous System (everything else)

– Sensory neurons– Motor neurons– Sensory neurons and motor neurons connect

the CNS to the rest of the body

Peripheral Nervous SystemPeripheral Nervous System

• Consists of 3 types of neurons– Sensory neurons send info from the body’s

tissues and organs to the CNS– Motor neurons send info from the CNS back

to the body’s tissues– Interneurons process and interpret info from

sensory and motor neurons

Sensory NeuronSensory Neuron

Bipolar --------(vision)

--- Unipolar(Pain & Touch)

Peripheral Nervous systemPeripheral Nervous system

• Somatic nervous system– Skeletal muscles

• Autonomic Nervous system– Internal organs– Glands

Autonomic Nervous systemAutonomic Nervous system

• Sympathetic nervous system– Arouses and alerts

• Parasympathetic nervous system– Calms and conserves energy

Central Nervous SystemCentral Nervous System

• Consists of the brain and spinal cord• Reflexes are automatic responses to stimuli

– Single sensory neuron and a motor neuron• Knee jerk reflex

– Pain reflexes often work in the same way• Stepping on a nail but jumping away before realizing what

you stepped on

• Neural networks – Clusters of neurons that strengthen connections– Learning builds and stimulates neural networks

Endocrine SystemEndocrine System

• Endocrine system refers to the body’s other chemical messengers HORMONES

• Neurotransmitters quickly send messages and communicate; hormones slowly send messages but have long lasting effects

• The endocrine system effects– Growth– Reproduction– Metabolism– Mood

• The pituitary gland is the master gland which is controlled by the hypothalamus

• Medulla– Involuntary functioning, heart rate, breathing, blood

pressure

• Reticular formation– arousal

• Thalamus– Central processing unit, routes your senses except

smell

• Cerebellum– Balance, motor functioning, coordination

Brain structureBrain structure

• Limbic system – the C shaped structure that is the hub of the brain’s older

structures and the cerebral hemispheres• Hippocampus

– Processes memory• Hypothalamus

– Hunger, thirst, sex drive– Controls the pituitary gland– Reward centers of the brain

• Amygdala– Pea shaped structures linked to fear and aggression

• Pons– Sleep regulation

• Corpus callosum– The bundle of nerves that separates the

hemispheres of the brain

• Cerebrum– Consciousness, memory, problem solving

Lobes of the BrainLobes of the Brain

• The cerebral hemispheres are divided into 4 lobes • Each lobe has a function but many functions require the

interplay of several lobes• Frontal lobe

– Personality, attention span, emotional control, coordination of hands, feet, arms and legs

• Parietal lobe– Sense of touch, awareness of your body, depth perception

• Occipital lobe– Interprets signals sent from your eyes creates the mental images

you see• Temporal lobe

– Sense of hearing and smell

Brain structuresBrain structures

• Motor cortex– Rear of the frontal lobe controls voluntary movement

• Somatosensory cortex– Rear of the frontal lobe; in front of the parietal lobe receives info

from senses– Provides processing for your sense of touch

• Association areas– Specialized areas of the brain that are involved in higher mental

functioning• Broca’s area language expression (speak your own words)• Wernickes area controls language reception (speak meaningfully)• Angular gyrus visual cues into auditory• Visual cortex constructs our moving mental picture to the occipital

lobe• Auditory cortex helps interpret sounds

HeadacheHeadache

• The brain is not sensitive to pain because it lacks pain-sensitive nerve fibers.

• Types of “headaches”– Vascular- migraines headaches which are

neurological in nature– Muscular/myogenic- tensing or tightening of the

facial and neck muscles– Cervicogenic- disorders of the neck precipitated by

awkward neck positioning or neck movement– Traction and inflammatory- stems from other

disorders ranging from a stroke to sinus infection

Brain injuryBrain injury

• Temporal lobe– Sound recognition, voice recognition

• Occipital lobe– blindness

• Parietal lobe– Defects in touch, self perception

• Frontal lobe– Concentration, abstract thinking, gross and fine motor ability

• Thalamus– Altered states of arousal, memory defects, speech defects

• Hypothalamus– Uncontrollable eating/drinking, hyposexuality

• Cerebellum– Motor control issues/coordination

Sensory and Motor defectsSensory and Motor defects

• Brain lesions are the most common causes of sensory and motor defects

• Lesions are tissue that has been altered by:– Chemical imbalance in the brain– Physical injury– Infection

• Plasticity– The brains ability to modify itself after damage

Sensory and Motor defectsSensory and Motor defects

• Amnesia – Memory loss

• Anomia– Inability to find words to things

• Alexia– Inability to read

• Aphasia– Impaired speech or writing ability

• Anopia – Inability to see

Brain ImageryBrain Imagery

• EEG (electroencephalogram)– Records an amplified reading of the brain’ss electrical

activity or waves• PET (positron emissions tomography) scan

– Visual scan of glucose activity in areas of the brain when stimulation is present

• MRI (magnetic resonance imaging)– Uses magnetic fields and radio waves to create a

computer generated image of the brain– Allows doctors to see brain structures

• fMRI (functional magnetic resonance imaging)– Allows doctors to see blood flow and brain activity

Figure 2.12 An electroencephalograph providing amplified tracings of waves of electrical activity in the brainMyers: Psychology, Eighth EditionCopyright © 2007 by Worth Publishers

Figure 2.13 The PET scanMyers: Psychology, Eighth EditionCopyright © 2007 by Worth Publishers

Figure 2.14 MRI scan of a healthy individual (left) and a person with schizophrenia (right)Myers: Psychology, Eighth EditionCopyright © 2007 by Worth Publishers

Figure 2.15 Brain readingMyers: Psychology, Eighth EditionCopyright © 2007 by Worth Publishers