Biological Psychology 2.0 Teeheee

Nervous system

Is composed of two main types of cells: neurons and glia

Neurons

Cells specialized for communication using electrical and chemical signals

Glia

Cells that support neuronal signaling, provide nutrients, guide neurons in development and perform other support functions

Gene Expression

The type and functions of nervous system cells are defined by their

Neuron

A specialized cell for communication using electrical and chemical signals

Synapse

The site where communication between neurons occurs

Brain 2% and uses 25%

The human brain energy use

86 billion

Number of human neurons

Afferent

A message toward the brain; sensory neurons

Sensory Neuron

A neuron that carries sensory information toward the central nervous system

Efferent

A message away from the brain: motor neurons

Motor neuron

A neuron that carries information away from the central nervous system to muscles

Interneuron

A neuron that sends message between neurons

Dendrites

Parts of a neuron that receive information

Cell body/Soma

The main part of the neuron containing the cell’s nucleus and other cellular compenents

Axon

The part of the neuron through which the electrical signal spreads

Axon Terminals

The ends of an axon that release neurotransmitters to synaptic partners

Myelin Sheath

An insulating covering axon that prevents ion leak and helps action potentials travel rapidly

Node of Ranvier

Gaps in the myelin sheath that are densely packed with ion channels

Glia

Means “never glue.” Make up about 30-60% of total brain mass and support neuronal signaling, provide nutrients, and guide neurons in development.

Astrocytes

Glial cells involved in development, energy and metabolism, synaptic functions, and maintenance of the blood-brain barrier

Microglia

The “immune system” in the brain; they eliminate synapses and provide signaling to other cells

Oligodendrocytes

Glial cells that myelinate the central nervous system

Schwann Cells

Glial cells that myelinate the peripheral nervous system

Central Nervous System (CNS)

The brain and spinal cord

Peripheral Nervous System (PNS)

The peripheral motor and sensory nerves

Somatic Nervous System

The part of the peripheral nervous system containing sensory nerves that carry information to the CNS and motor nerves that carry information from the CNS to muscles

Sensory Nerves

Nerves that carry information to the central nervous system

Motor Nerves

Nerves that carry information from the central nervous system to the muscles

Autonomic Nervous System

The part of the peripheral nervous system involved in automatic bodily functions includes the sympathetic and parasympathetic nervous system

Sympathetic Nervous System

The division of the autonomic nervous system responsible for the fight-or-flight response

Parasympathetic Nervous System

The division of the autonomic nervous system responsible for rest and digest

12 cranial nerves

This amount of cranial nerves that enter and exit directly from the brain. They innervate the face, head, and neck, plus the vagus nerve

Neural Circuit

A group of neurons connected by synapses that process specific types of information

Patellar Reflex

A stretch of the patellar tendon causes the quadriceps muscle to stretch. Sensory nerves send a signal to the spinal cord, where sensory nerves synapse directly onto the motor neurons. Motor neurons fire, causing the quadriceps to contract and the lower leg lift

Simple Reflex Circuit

A circuit in which sensory information travels to the spinal cord and activates motor neurons to produce a rapid response

Bilateral Symmetry

The left and right hemispheres of the brain and spinal cord are nearly mirror images

Meninges

Protective layers around the brain and spinal cord

Dura Mater

The outer layer of the meninges

Arachnoid Mater

The middle layer of the meninges

Pia Mater

The inner layer of the meninges

Spinal cord

A functionally organized part of the central nervous system that carries sensory and motor information

Dorsal Horn

The part of the spinal cord containing sensory interneurons

Ventral Horn

The part of the spinal cord containing motor neurons

Dorsal Root

A bundle through which axons carrying sensory information emerge from the spinal cord

Ventral Root

A bundle through which axons carrying motor information emerge from the spinal cord

Mixed Nerve

A nerve containing both sensory and motor axons

Spinal Cord tracts

Pathways that carry sensory and motor information to and from the brain

31 spinal nerves

Amount of pairs of nerve bundles containing many axons that exit between the vertebrae

Cerebrospinal fluid (CSF)

Fluid that cushions and protect the brain, exchanges material between the blood and brain, and found in the ventricular system and subarachnoid space

Choroid Plexus

A tissue suspended in the ventricles and produces cerebrospinal fluid

Ventricular System

The system of brain ventricles through which cerebrospinal fluid flows

Subarahnoid Space

The space where cerebrospinal fluid found around the brain and spinal cord

Vascular System

The system provides nutrients and energy and carries away waste

Gray Matter

Brain and spinal cord tissue containing bodies and dendrites

White Matter

Brain and spinal cord tissue containing myelinated axons

Neuronal Communication

Both electrical and chemical

Action potential

An electrical signal that spreads through a neuron across the axon and triggers transmitter release to the neuron’s synaptic partners

Neurotransmitter

A chemical signal released by a neuron to transfer information between neurons and exicte, inhibit, or modulate the activity of neurons

7,000

Typical neuron Synaptic Partners

400

Neuronal Message Rate

Presynaptic Terminal

The axon terminal of the neuron that stores and releases neurotransmitter

Postsynaptic Terminal

The receiving part of the neuron, typically a dendrites

Synaptic Cleft

The space between the presynaptic and postsynaptic neruons where neurotransmitters are released

Vesicle

A small structure in the presynaptic terminal that stores neurotransmitters

Receptor

A protein that recognizes and binds a specific neurotransmitter

Presynaptic Neuron

The neuron that releases neurotransmitter into the synaptic cleft

Postsynaptic Neuron

The neuron that receives neurotransmitter through postsynaptic receptors

Storaged Neurotransmitter

Are stored in vesicles in the presynaptic terminal

Glutamate

A neurotransmitter that can excite neurons

GABA

A neurotransmitter that can inhibit neurons

Dopamine, serotonin, norepinephrine

A neurotransmitter that can modulate neuronal activity

Receptor binding

A neurotransmitter binds to postsynaptic receptors and produces an electrical change in the receiving neuron

Excitatory postsynaptic potential (EPSP)

A brief electrical change that excites a neuron and makes an action potential more likely

Inhibitory postsynaptic potential (IPSP)

A brief electrical change that inhibits a neuron and makes an action potential less likely/

Electrical Synapse

A synapse in which connexon physically bridges two neurons and allows both electrical signals and small molecules to pass between neurons in both directions

Connexon

A structure that physically bridges two neurons at an electrical synapse

Threshold

The membrane potential that must be reached for an action potential to be triggered

Parallel Processing

Information spreads along multiple pathways

Feedback

Neurons influence their own inputs

Rhythmicity

Repeating patterns of neuronal activity

Balance

Excitation and inhibition

Reverberatory Activity

Activity that allows neurons to stay active for longer periods of time and help maintain in working memory

Divergent Connections

Connections in which a small number of neurons broadcast a message to large number of recipients

Midbrain Dopaminergic Neurons

An example of neurons with divergent connections that broadcast messages to many recipients

Convergent Connections

Connections in which many different neurons send signals to a small number of recipients neurons

Electrochemical Force

Forces that influence the movement of ions across a cell membrane, including electrical and diffusion forces.

Electrical Potential

The separation of charge produces an electrical potential across the membrane. It is measured in volts.

Current

The flow of charge over time. It is measured in amps

Conductance

The amount of ion flow allowed through channels; the more channels open, the higher it is. It is measured in siemens.

Membrane Potential

The electrical inside of cell relative to the outside of the cell

Electrode

A device used to measure electrical potential inside cells relative to outside

-70

Resting membrane potential approximately what number

Ion

A charged particle that can generate current in neurons

Sodium (Na+), Potassium (K+), Calcium (Ca2+), Chloride (CI-)

An ion that is present at a high concentration outside a typical neuron

Extracellular fluid

The fluid outside fo a typical neuron that is high in Na+, CI-, Ca2+

Intercellular fluid

The fluid inside a typical neuron that is high in K+

Diffusive force

Produced by a difference in concentration that pushes ions from areas of high concentration toward areas of low concentrations

Electrostatic Force

A forc cause electrical charges attracts opposite charges and repels like charges

Ion Pump

A protein machine that uses energy to move ions against their concentration gradient