Textbook Notes (368,214)
Canada (161,710)
Psychology (3,337)
PSYC 2410 (149)
Chapter 3

PSYC 2410 DE S12 Textbook Notes Chapter 3

11 Pages
145 Views
Unlock Document

Department
Psychology
Course
PSYC 2410
Professor
Elena Choleris
Semester
Summer

Description
Chapter 3:Anatomy of the Nervous System 3.1: General Layout of the Nervous System Divisions of the Nervous System The vertebrate nervous system is composed of two divisions: o Central Nervous System: Division of the nervous system that is located within the skull and spine. Composed of two parts: the brain (protected by the skull) and the spinal cord (protected by the spine) o Peripheral Nervous System: Division of the nervous system that is located outside of the skull and spine. Composed of two parts: the somatic nervous system and the autonomic nervous system. Somatic Nervous System: the portion of the peripheral nervous system which interacts with the environment. Afferent Nerves: Nerves within the somatic nervous sysem which carry sensory signals to the central nervous system. Efferent Nerves: Nerves within the somatic nervous system which carry motor signals from the central nervous system to the skeletal muscles. Autonomic Nervous System: Portion of the peripheral nervous system which regulates the body's internal environment. Afferent Nerves: Nerves within the autonomic nervous system which carry sensory information from the body's internal organs to the central nervous system. Efferent Nerves: Nerves within the autonomic nervous system which carry motor signals from the central nervous system to the internal organs. o Sympathetic Nerves: Class of efferent nerve within the autonomic nervous system which project from the central nervous system in the lumbar (back) and thoracic (chest) regions of the spinal cord. Sympathetic neurons synapse onto secondary neurons at a significant distance from the target organ o Parasympathetic Nerves: Class of efferent nerve within the autonomic nervous system which project from the brain and sacral (lower back) regions of the spinal cord. o All sympathetic and parasympathetic nerves are two stage neural pathways. The sympathetic and parasympathetic nerves project from the central nervous system, but do not reach the internal organs of interest. Parasympathetic nerves synapse with secondary nerves near to the target organ. o Sympathetic nerves stimulate, organize and mobilize energy resources in threatening situations. Parasympathetic nerves do the opposite, conserving and calming energy usage. o Each autonomic target receives opposite input from sympathetic and parasympathetic systems. The result is controlled by the relative input of both systems. o Sympathetic changes are associated with arousal and parasympathetic changes are associated with relaxation. o These are general rules, however each as special cases and exceptions. All neurons within the parasympathetic system except 12 cranial nerves extend from the spinal cord. The cranial nerves are numbered from 1 to 12 from front to back. Some cranial nerves are prely sensory such as the olfactory nerve and the optic nerve, but most contain both motor and sensory neurons. Longest cranial nerves are the vagus fibres which contain sensory and motor nerves for the gut. The autonomic motor fibres of the cranial nerves are parasympathetic. Meninges, Ventricles, and Cerebrospinal Fluid The brain and spinal cord are the most well protected areas of the body Both are encased in bone and 3 protective membranes Meninges: Group of three protective membranes which surround the brain and spinal cord. o Dura Mater: Tough outer mininx protecting the brain and spinal cord. Means 'Tough Mother o Arachnoid Membrane: Membrane located between the dura mater and the subarachnoid space. Name means spiderweb-like membrane, and is named so because of its appearance like a spider web. o Subarachnoid Space: Space directly below the arachnoid membrane and above the pia matter. Contains many large blood vessels Carries spinal fluid o Pia Mater: Soft, delicate innermost meninx protecting the brain and spinal cord.Attaches directly to the brain and spinal cord. Means 'Pious Mother'. Cerebrospinal Fluid: Fluid which fills the subarachnoid space, the central canal of the spinal cord and the cerebral ventricles of the brain. Central Canal: Small channel which runs the length of the spinal cord. Contains cerebrospinal fluid. Cerebral Ventricles: Four large internal chambers within the brain. o Lateral Ventricles: Largest ventricles of the brain. Located symetrically on both sides within the the cerebrum. o Third Ventricle: Ventricle located in the center of the brain. o Fourth Ventricle: Small lower ventricle located near the top of the cerebellum. The subarachnoid space, central canal and cerebral ventricles are interconnected by a series of openings and thus form a single resevoire. Cerebrospinal fluid supports the brain. Patients who have small amounts of cerebrospinal fluid removed often experience raging headaches and sharp pain every time they turn their head. Choroid Plexuses: Networks of capillaries that protrude into the ventricles from the pia mater. Responsible for the production of cerebrospinal fluid. Excess spinal fluid is drained into blood-filled spaces, or dural sinuses, which run through the dura mater and drain into the large jugular veins of the neck. Blood-Brain Barrier: The blood-brain barrier impedes many toxic substances from reaching the central nervous system and disrupting its balance. Cells that compose the walls of central nervous system blood vessels are tightly packed together and do not allow very many molecules to pass through them. In contrast, the cells that make up the walls of most other blood vessels are loosely packed together and allow many different molecules to pass through. The degree to which therapeutic and recreational drugs are able to have an effect is often due to its ability to cross the bloodbrain barrier. Large molecules that are critical to the brain's survival are actively transported through the barrier walls. Certain areas of the bloodbrain barrier allow certain large molecules to pass through unimpeded. 3.2: Cells of the Nervous System Most cells in the nervous system are of one of two types, neurons and glial cells Anatomy of Neurons Neuron: cells in the body specialized in reception, conduction, and transmission of electro- chemical signals o Neurons come in a wide variety of shapes and sizes. ExternalAnatomy of Neurons Cell Membrane: Semi-permeable membrane that encloses the neuron Dendrites: The short processes emanating from the cell body, which receive most of the synaptic connections from other neurons Axon: Long, narrow process that projects from the cell body. Axon Hillock: Cone-shaped region at the junction between the axon and the cell body. Cell Body: The metabolic centre of the neuron; also called the soma. Myelin: Fatty insulation around many axons. Nodes of Ranvier: Gaps between sections of myelin. Synapses: The gaps between adjacent neurons across which chemical signals ar
More Less

Related notes for PSYC 2410

Log In


OR

Join OneClass

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

Sign up

Join to view


OR

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.


Submit