Class Notes (811,227)
Canada (494,571)
Psychology (2,034)
PSYCH 261 (91)

Psych 261 Chapter 2

5 Pages
Unlock Document

University of Waterloo
Deltcho Valtchanov

STRUCTURES AND FUNCTIONS OF CELLS OF THE NERVOUS SYSTEM  Movement and behavior- primary function of the nervous system  Sensory neurons – a neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system o Information in the form of light, sound waves, odors, tastes, or contact with object is gathered from the environment by these specialized cells  Motor neuron – movements accomplished by the contraction of muscles are controlled by these neurons o Also controls the secretion of the gland  Interneuron – A neuron located entirely within the central nervous system  Local interneurons – form circuits with nearby neurons and analyze small pieces of information.  Relay interneurons – connect circuits of local interneurons in one region of the brain with those in other regions  100 billion of neurons - estimated number of neurons in the brain  CENTRAL NERVOUS SYSTEM (CNS) – consist of the parts that are encased by the bones of the skull and spinal column: the brain and the spinal cord  PERIPHERAL NERVOUS SYSTEM (PNS) - consist of the nerves and most of the sensory organs CELLS OF THE ENRVOUS SYSTEM  Neurons – nerve cell; most important cells of the nervous system; the information processing and the information- transmitting element of the nervous system. o BASIC STRUCTURE OF NEURONS  Cell body or soma – contains the nucleus and much of the machinery that provides for the life processes of the cell  Dendrites – grk: tree; Dendrites serve as an important recipient of these messages as the neurons converse to each other  the messages that pass from neuron to neuron are transmitted across the synapse – a junction between the terminal buttons of an axon and a membrane of another neuron ; the messages that pass from neuron to neuron are transmitted here  Axon - a long slender tube covered by a myelin sheath; it carries information from the cell body to the terminal buttons  Action potential – the basic message that is being carried by an axon o A brief electrical/ chemical event that starts at the end of the axon next to the cell body and travels toward the terminal buttons. *full strength action potential  Multipolar neuron - a neuron with one axon and many dendrites attached to its soma  Bipolar neuron – give rise to one axon and one dendritic tree, at opposite ends of the soma. o Bipolar neurons are sensory (i.e. the detect events occurring in the environment and communicate it to the CNS)  Unipolar neuron – one axon attached to its soma then the axon divides with one branch receiving sensory info and the other sends info to the CNS  Terminal buttons – secretes neurotransmitters (has an inhibitory or excitatory effect on another neuron) o INTERNAL STRUCTURE  Membrane – a structure consisting principally of lipid molecules that defines the outer boundaries of the cell and also constitutes many of the cell organelles, such as the Golgi apparatus  Nucleus – round in structure and is enclosed by the nuclear membrane containing the nucleolus and chromosome  Nucleolus – produces ribosomes  Ribosome – a cytoplasmic structure, made of protein, that serves as the site of production of proteins translated from mRNA  Chromosome – a strand of DNA, with associated proteins, found in the nucleus; carries genetic info  DNA (deoxyribonucleic acid) – a long complex macromolecule consisting of two interconnected helical strands; along with associated proteins, strands of DNA constitute the chromosome SUPPORTING CELLS o Glia – neuroglia or nerve glue is most important supporting cells of the CNS  Glue the CNS together  Surround neurons and control their supply of nutrients and some of the chemicals they need to exchange chemicals with the neurons  They insulate neurons to one another so that neural messages do not get scrambled  They destroy and remove the carcasses of neurons that are killed by disease  Types of Glial Cells:  Astrocytes – star cell; provides physical support to neurons and cleans up debris within the brain o They help control the chemical composition of the fluid surrounding neurons o Involved in providing nourishment to neurons o Holds neurons in place – the nerve glue o Clean debris when cells in the CNS die o Phagocytosis – the process by which cells engulf and digest other cells or debris caused by cellular degeneration  Oligodendrocytes – a type of glial cell; provide support to axons and provide the myelin sheath o Myelin sheath – a sheath that surrounds axons and insulates them , preventing messages from spreading between adjacent axons (80% lipid, 20% protein) o Node of Ranvier – a naked portion of a myelinated axon between adjacent oligodendroglia or Schwann cells.  Microglia – the smallest of glial cells; act as phagocytes and protect the brain from invading microorganisms SCHWANN CELLS - A cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath THE BLOOD BRAIN BARRIER
More Less

Related notes for PSYCH 261

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.