Lecture 4 Flashcards
The Nervous System
The Body’s electrochemical communication system
Divided into two parts: The Central Nervous System and the Peripheral Nervous System
The Central Nervous System
Made up of the brain and the spinal cord
Functions include: receiving, processing and storing incoming information; sends out messages to muscles, glands and internal organs
The central command system which controls thought and movement
The Peripheral Nervous System
Nervous system outside the brain and spinal cord which handles input and output of the CNS
Connects the brain and spinal cord to the other areas of the body—organs and muscles
Sensory and Afferent Neurons
carry information to the brain from the skin muscles organs
Motor or Efferent Neurons
Carry the brains output to carry the brains output to muscles, glands, and organs
Interneurons
neurons that connect sensory neurons, motor neurons or other interneurons
Mirror Neurons
neurons which are activated by performing an action or by seeing another perform the same action· May play a role in developing new motor skills
· Empathy and language (partly based on imitation)
· Dysfunction linked to autistic spectrum disorders
Glial Cells
hold the neurons in place, nourish and insulate neurons. Non-neuron cells which provide a supportive function for the nervous system
Dendrites
receive messages from other neurons, transmit to the cell body
Cell body/ Soma
Keep neurons alive; contains substances for growth, determines whether to fire
Axons
Transmit messages away from the cell body to other neurons, muscles or glands
The axon is insulated by fatty material called the myelin sheath which helps the nerve impulse travel faster
The axon ends in branches or terminal buttons
Synapses
the gaps (tiny spaces) between the neurons-often between the axon of one neuron and the dendrite or cell body of another neuron through which communication occurs.
Long-Term studies about brain and experiences
· Long-term studies indicate that enriched environments for rats, even later in life can lead to not only functional, but structural brain changes evident in the synapses and their connections
Brain growth and new connections have also been seen in human subjects
Resting Potential
a neuron at its stable negative charge when it is inactive
Action Potential
when a nerve is stimulated an electrical impulse occurs and moves down the axon to the end of the axon’s terminal tip
Synaptic Vessicles
release neurotransmitters which then bind with a dendrite receptor site
· Can excite or inhibit the firing of the receiving neuron
Absolute refractory period: minimum amount of time during which another action potential cannot begin
Absolute Refractory Period
minimum amount of time during which another action potential cannot begin
Neurotransmitters
chemical substances which carry information across the synaptic gap to the next neuron
Each neurotransmitter binds to a particular receptor site
Affects many behavior and functions
Excitatory PSP’s
increases the likelihood it will fire an action potential
Inhibitory PSP’s
decreases the likelihood of an action potential
Serotonin
involved in sleep and wakefulness, mood, depression, eating and aggression
Dopamine
regulates motor behavior, motivation, *pleasure and emotional arousal
High levels of dopamine associated with schizophrenia
Low levels of dopamine associated with Parkinson’s
*Recent research challenges the role of dopamine in the experience of pleasure
Acetylcholine
muscle action and control, memory and attention. Some receptors stimulated by nicotine
Norepinephrine
involved in mood, arousal: alertness and wakefulness; excite heart muscles, intestines and urogenital tract
Glutamine
excitatory transmitter widely distributed and implicated in memory formation, information transmission in the brain
GABA
(gamma amino butyric acid) Inhibitory neurotransmitter,
- Low levels linked with anxiety - Anti-anxiety drugs increase the inhibitory effects of GABA
Endorphins
The Brains natural opiates
Produce effects of reducing pain; promoting pleasure
Act within the pain pathways and emotion centers of the brain
Levels increase during stress or fear response which gives an evolutionary advantage ( during childbirth, exercise)
Hormones
Chemical messengers manufactured in the endocrine glands and released into the blood stream
Some may be classified as neurotransmitters depending on how it is “operationalized”
A few of particular interest:
Melatonin: regulates biological rhythm
Adrenal hormones: involved in emotions and stress; cortisol
The Somatic Nervous System
Sensory nerves relay information from the skin and muscles to the CNS about pain, temperature and informs muscles when to act, conscious or voluntary control over this system
The Automatic Nervous System
Fight or flight response
Works automatically/involuntary
Takes messages to and from the body’s internal organs monitoring breathing, heart rate and digestion
Sympathetic Nervous System: o Mobilizes body for action, stops digestion, increases oxygen to the blood for muscle responses, increases heart rate, dilates pupils, dry mouth, goose bumps
Parasympathetic Nervous System:o Slows actions down, conserves bodily resources
The Central Nervous System: The Brain and the Spinal Cord
Different ways to learn about the brain
1. Study the disease process
2. The lesion method: damage or remove section of brain and observe the effects
3. Electrode Method EEG: detect electrical activity of neurons; look at brain waves across events.
Newer uses of EEG being explored with improved
Technology
· 4. CT scans: Multiple X-Rays of successive slices of the brain. Looks at brain structure
· 5. PET scans: Records biochemical changes in the brain as they occur by detecting radioactive material, which has been injected or inhaled. Looks at brain function
· 6. MRI: Uses magnetic fields and radio frequencies, which produce vibrations that are picked up by receivers. Provides a structural view of the brain
· 7. fMRI: (Functional/Fast MRI): assess changes in blood oxygen flow to areas of the brain, able to look at both structure and function of the brain
· 8. Electrical Stimulation of the Brain: Newer studies look at “electrical stimulation” deep in the brain, which promotes particular sensations and emotions. Used as treatment for Parkinson’s disease, Depression and Obsessive Compulsive Disorder in Clinical Trials
