Textbook Notes (368,330)
Canada (161,803)
York University (12,829)
Psychology (3,584)
PSYC 3530 (13)
Guy Proulx (13)

3. Organization of the Nervous System.pdf

12 Pages
Unlock Document

PSYC 3530
Guy Proulx

3. Organization of the Nervous System Tuesday, September 10, 2013:27 PM Neuroanatomy: Finding Your Way Around the Brain • Stroke - an interruption of blood to the brain that kills brain cells and causes the sudden appearance of neurological symptoms ○ Worldwide, stroke is the second leading cause of death • Ischemia - a deficiency of blood flow to the brain due to functional constriction or to the actual obstruction of a blood vessel, such as by a clot • Unlike the more severe hemorrhagic stroke that results from a burst vessel bleeding into the brain, ischemic stroke can be treated with a drug called tissue plasminogen activator (t-PA) that breaks up clots and allows the return of normal blood flow to the affected region ○ An anticlotting drug decreases tissue death in ischemic stroke but aggravates cell death in hemorrhagic stroke • The neurons in the brain are organized in layers as well as in groups callednuclei, groups of cells forming clusters that can be visualized with special stains to identify a functional grouping • • Structures that lie on the same side are ipsilateral; if they lie on opposite sides, they are contralateral to each other • If one of them lies in each hemisphere, the structures are bilateral • Structures that are close to one another are proximal; those far from one another are distal • Any movement toward a brain structure is afferent, whereas movement away from it is efferent • Dorsal and ventral in quadrupeds are anterior and posterior in upright humans An Overview of Nervous System Structure and Function Textbook Notes Page 1 • • The brain and spinal cord are supported and protected from injury and infection in four ways: ○ 1) The CNS is encased in bone; the PNS is not but can renew after injury ○ 2) Within the bony case enclosing the CNS is a triple-layered set of membranes, the meninges ○ 3) The brain and spinal cord are cushioned from shock and sudden changes of pressure by the cerebrospinal fluid (CSF)  If the outflow is blocked, as occurs in a congenital condition called hydrocephalus (literally, water brain), severe mental retardation and even death can result ○ 4) The brain and spinal cord are protected from many chemical substances circulating in the rest of the body by the blood–brain barrier ○ • Textbook Notes Page 2 • • Textbook Notes Page 3 • • Gray matter acquires its characteristic gray-brown color from the capillary blood vessels and neuronal cell bodies that predominate there • White matter consists largely of axons that extend from these cell bodies to form connections with neurons in other brain areas • Reticular matter contains a mixture of cell bodies and axons from which it acquires its mottled gray and white, or netlike, appearance • • A large collection of axons projecting to or away from a nucleus or layer in the CNS is called atract • Fibers and fiber pathways that enter and leave the CNS are callednerves, such as the auditory nerve or the vagus nerve; but, after they have entered the central nervous system, they, too, are called tracts The Origin and Development of the Central Nervous System Textbook Notes Page 4 The Origin and Development of the Central Nervous System • • The prosencephalon (“front brain”) is responsible for olfaction, the mesencephalon (“middle brain”) is the seat of vision and hearing, and the rhombencephalon (hindbrain) controls movement and balance • The Spinal Cord Textbook Notes Page 5 The Spinal Cord • • Dorsal root-- nerve, composed of fibers carrying sensory information, that enters each segment of the dorsal (posterior in humans) part ofthe spinal cord • Ventral root-- tract of fibers leaving the spinal cord; on the ventral part of an animal’s spinal cord and on the anterior part of a human’sspinal cord • • The principle that the dorsal part of the spinal cord is sensory and the ventral part is motor is called theBell–Magendie law • Movements dependent only on spinal-cord function are referred to as reflexes, specific movements elicited by specific forms of sensory stimulation Textbook Notes Page 6 stimulation • The stimulation of pain and temperature receptors in a limb usually producesflexion movements that bring the limb inward, toward the body and away from injury • The stimulation of fine touch and muscle receptors in a limb usually producesextension movements, which extend the limb outward, away from the body • Textbook Notes Page 7 • • The spinal cord is connected to a chain of autonomic control centers, collections of neural cells calledsympathetic ganglia. These ganglia, collections of nerve cells that function somewhat like a primitive brain, control the internal organs • Pain in the internal organs is perceived as coming from the outer parts of the dermatome and so is calledreferred pain The Brainstem • The brainstem begins where the spinal cord enters the skull and extends upward to the lower areas of the forebrain • 3 main regions: 1) The diencephalon  "Between brain"-- some anatomists place it in the brainstem, others in the forebrain  3 main structures: 1) The hypoth
More Less

Related notes for PSYC 3530

Log In


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.