Psych Chapter 2

Central Nervous System

Central Nervous System

Composed of brain and spinal cord

Receives sensory information, makes decisions, and commands muscles, organs and glands to take action.  

Peripheral Nervous System

Parts of the nervous system outside the brain and spinal cord.

Spinal Cord

Column of nerves that transmits information between the brain and the peripheral nervous system.

Relays brains commands to move the muscles. 

Relays sensations from skin and muscles to the brain.  

Controls automatic/unconscious reflexes.  

Spinal Nerves

Major nerves that carry sensory and motor messages in and out of the spinal cord.

Neuron

A cell in the nervous system that transmits information.

Nerve

A bundle of neuron axons.

Cranial Nerves

Leave the brain without passing through the spinal cord.

Somatic Nervous System

A network linking the spinal cord with the body and sense organs.

Allows control of voluntary muscles 

Nerves that carry sensory info from skin, muscles, and joints to CNS.  

Autonomic Nervous System

A collection of axons that carry information to and from internal organs and glands.

Controls involuntary bodily functions through organs and glands. 

Ex. Blood flow, heartbeat, etc.  

Sympathetic Nervous System

A division of the autonomic nervous system that coordinates arousal.

Arouses body to prepare for challenging situations 

Ex. Increased energy and abilities, Fight or flight response, emotional arousal.

Parasympathetic Nervous System

A division of autonomic nervous system that quiets the body and conserves energy.

Reduces arousal after emergency is over 

Reverses physical causes of sympathetic branches 

Responsible for rest and digest functions 

Dendrites

Neuron fibres that receive incoming messages.

Cell Body

The part of the neuron that contains the nucleus of the cell.

Axons

Fibers that carries information away from the cell body of a neuron.

Axon Terminals

Bulb-shaped structures at the ends of axons that form synapses with the dendrites and cell bodies of other neurons.

Resting Potential

The electrical charge of an inactive neuron.

About -70millivolts inside axon

Threshold

The point at which nerve impulse is triggered in neurons.

Action potential

A brief change in neuron's electrical charge.

Increase voltage to +40 millivolts inside the axon.

Sodium ion channels open up    

Myelin Sheath

AN insulating material that covers some axons.

Ion Channels

Tiny openings through the axon membrane.

“Gates” in the axon membrane.

Barriers to some Ions

Synapse

A microscopic space over which messages pass between two neurons.

Synaptic Transmission

Chemical process that carries information from one neuron to another.

Neurotransmitter

A chemical that moves information from one nervous-system cell to another.

Bind to receptor sites 

Fit into specific receptors like lock and key.  

Decide if a neuron will fire or not.

Receptor Site

An area on the surface of neurons and other cells that is sensitive to neurotransmitters or hormones

Neuropeptides

Brain chemicals that regulate the activity of neurons.

Neuroplasticity

The capacity of the brain to change in response to experience.

Neurogenesis

The production of new brain cells.

CT Scan

Computer-enhanced x-ray image of brain or body

MRI

3D image of the brain or body, based on its response to a magnetic field.

Localization of function

Linking specific structures in the brain to specific psychological or behavioural functions.

Electrical stimulation of the Brain (ESB)

Direct electrical stimulation and activation of brain tissue.

Electrode

Any device used to stimulate or destroy nerve tissue electrically or to record its activity.

Ex. wire, needle, metal plates.

Ablation

Surgical removal of tissue from the surface of the brain.

Deep lesioning

Removal of tissue within the brain by the use of an electrode.

Electroencephalograph (EEG)

A device that records electrical activity in the brain.

Positron Emission Tomography (PET)

A high-resolution imaging technique that captures brain activity by attaching radioactive particles to glucose molecules.

Functional MRI (fMRI)

An MRI technique that records activity levels In various areas of the brain.

Cerebral Cortex

The thin, wrinkled outer covering of the brain.

High-level processes take place here.

Corticalization

An increase in the relative size of the cerebral cortex.

Cerebral Hemispheres

The left and right sides of the cerebral cortex.

They are interconnected by the corpus callosum.

Lateralization

Differences between the two sides of the body.

Especially in the differences in abilities of the brain hemispheres.

Split-brain Operation

Surgical procedure that involves cutting the corpus callosum.

Handedness

A preference for the right or left hand in most activities. (being left or right handed)

Dominant Hemisphere

Usually applied to the side of a person’s brain that produces language.

Lobes of the Cerebral Cortex

Areas on the left and right cortex bordered by major fissures or defined by their functions.

Skills of the Left brain Hemisphere

• Language

• speech

• writing

• calculation

• time sense

• rhythm

• ordering complex movements

Skills of the right brain hemisphere

• Nonverbal

• Perceptual skills

• Visualization

• Recognition of patterns, faces, melodies, etc.

• recognition and expression of emotions

• spatial skills

• simple language comprehension

Frontal Lobes

Areas of cortex associated with movement, the sense of self, and higher mental functions.

Prefrontal Area/Cortex

The very front of the frontal lobes.

Involved in the sense of self, executive functions, and planning.

Executive Functions

Higher-level mental processes.

Allow us to regulate and coordinate our own thought process.

Association Areas/Cortex

All areas of the cerebral cortex that are not primarily sensory or motor in function.

Aphasia

A speech disturbance resulting from brain damage.

Broca’s Area

A language area related to grammar and pronunciation.

Primary motor areartex

A brain area associated with the control of movement.

Mirror Neurons

Neurons that become active when a motor action is carried out and when another organism is observed performing the same action.

Motor Neuron

A cell in the nervous system that transmits commands from the brain to the muscles.

Autism Spectrum Disorder

A lifetime disorder whose primary features are impaired communication and social interaction.

Parietal Lobes

Areas of the cortex in which body sensations register.

Primary somatosensory area/cortex

A receiving area for body sensations.

Temporal Lobes

Areas of the cortex that include the sites where hearing registers.

Primary auditory area/cortex

The part of the temporal lobe that first receives input from the ears.

Wernicke’s area

A temporal lobe brain area related to language comprehension.

Occipital lobes

Cortical areas at the back of the brain that play a role in visual processing.

Primary Visual area/cortex

The part of the occipital lobe that first receives input from the eyes.

Visual Agnosia

An inability to identify seen objects.

Facial agnosia

AN inability to perceive familiar faces.

Subcortex

A term referring to all brain structures below the cerebral cortex.

Hindbrain

A primitive part of the brain that comprises the medulla, pons, and cerebellum.

Medulla

Connects the brain with the spinal cord.

Controls vital life functions.

Pons

Area of the hindbrain that acts as a bridge between the medulla and other structures.

Reticular Formation

A collection of cells and fibres in the medulla and pons involved in arousal and attention.

Cerebellum

Structure in the hindbrain involved in controlling coordination and balance.

Midbrain

Connects the hindbrain with the forebrain.

Forebrain

A brain structure including the limbic system, thalamus, hypothalamus, and cortex.

Governs higher-order mental processes.

Thalamus

Relays sensory information to the cerebral cortex.

Hypothalamus

Small area of the brain that regulates emotional behaviours and basic biological needs.

Limbic System

A set of brain structures that play important roles in regulating emotion and memory.

Amygdala

Part of the limbic system.

Associated with the rapid processing of emotions, especially fear.

Hippocampus

Part of the limbic system

Associated with storing memories.

Endocrine system

A network of glands that release hormones into the bloodstream.

Second communication system

 

Hormones

A chemical released by the endocrine system.

Affect biological functions and motives.  

Slower communication compared to nervous system  

Pituitary glannd

The master gland of the endocrine system.

Controls the actions of all other glands.

Growth hormone

A hormone secreted by the pituitary gland that promotes body growth.

Oxytocin

A hormone released by the pituitary gland.

Plays a broad role in regulating pregnancy, parenthood, sexual activity, social bonding, trust, and reducing stress reactions.

Affects breast feeding, orgasms, relationships/bonds. 

Influences social behaviour by increasing empathy, sociability, warmth, openness, emotional sharing, etc.  

May even influence commitment to romantic relationships.  

Pineal gland

A gland in the brain that helps regulate body rhythms and sleep cycles.

Melatonin

A hormone released by the pineal gland in response to daily cycles of light and dark.

Thyroid Gland

An endocrine gland that helps regulate the rate of metabolism.

Adrenal glands

Endocrine glands that arouse the body.

Regulate salt balance, adjust the body to stress, and affect sexual functioning.

Epinephrine

An adrenal hormone that tends to arouse the body.

Associated with fear.

Norepinephrine

Both a brain neurotransmitter and an adrenal hormone.

Tends to arouse the body.

Associated with anger.

Self-regulation

The ability to consciously exert self-control.

Neurons

Cells specialized to receive, process, and transmit information with electrical and chemical signals.  

Major Parts of a Neuron

Soma, dendrites, axon, axon terminals.

Glial Cells

Provide support for neurons by supplying nutrition and energy, removing dead or damaged cells, and releasing cerebral spinal fluid.  

May affect memory formation and the activity of neurons.  

Axon Charges

Negatively charged inside axon

Positive charge outside axon

Due to different concentrations of ions inside and outside the cell.

Sodium Potassium Pumps

Maintain a negative charge inside the axon at resting potential 

Pumps three sodium ions outside of the cell for every two potassium ions that are pumped into the cell.  

Results in three positively charged ions out and two in.

End up with more positive outside than in, therefore inside remains negatively charged.

How do Ion Channels open?

Ion channels are voltage-gated therefore a certain voltage or charge must be reached for them to be opened.

Voltage is stimulated by other ions.  

Threshold of excitation= -50 millivolts (voltage at which sodium ion channels open.)

Propagation of action potential

Action potential is propagated/must travel down axon, to axon terminals.  

Ex. like falling dominos or a wave of fans at sports events 

What happens during the Negative after-potential?

Sodium ion channels close, sodium can no longer enter axon. 

Potassium ion channels open, allowing positively charged potassium ions to flow out of axon.  

Inside of axon returns to negative charge, and outside returns to positive charge.  

Electrical charge is temporarily more negative than resting potential

Negative after-potential

A drop in electrical charge below the resting potential.