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97 terms

Chapter 10 Nervous system

Nervous tissue and Brain
Action Potential
Sequence of changes in the membrane potential that occurs wehn a cell is stimulated to threshold. It includes Depolarization an repolarization; also called the nerve impulse anth cardiac impulse.
Brain stem
lower part of the brain that connects the brain with the spinal cord; consits of the midbrain, pons and medulla oblongata
Part of the brain located under the cerebrum; it coordinates skeletal muscle activity.
Cerebrospinal Fluid (CF)
Cushioning fluid that circulates within the subarachnoid space around the brain and spinal cord.
larges and uppermost part of the brain divided intow cerebral hemispheres. Ther are four lobes- frontal, parietal, temporal and occipital
Change in the membrane potential across the cell membrane with the inside of the cell becoming less negative or less polarized
Frontal lobe
Anterior portion of the cerebrum that controls voluntary skeletal activity and plays and importatn role in emotions critical thinking and ethical decision making.
limbic system
the emotional pain
Medulla oblongata
Part of the brain stem that controls vital functions such as respiratory and cardiovascularfunction
membranes that cover the brain and spinal cord; include the dura mater, arachnoid mater, and pia mater
White fatty material that covers some nerve fibers
Nerve cell that conduct the action potential (nerve impulse)
Chemical made within the axon terminal responsible for transmission of the signal across the synapse or junction.
occipital lobe
Cerebral lobe located in the back of the head; concerned primarily with vision.
parietal lobe
Lobe of the cerebrum concerned primarily with somatosensory function
return of the membrane potential to its restin state after the nerve impulse
reticular formation
Complex network of nerve fibers that arises within the brain stem and projects into the lower cerebrum; causes arousal of the cerebrum so that the person does not slip into a coma.
Interaction between tow nerves where cemical transmission of the electrical signal occurs
Temporal lobe
Lobe of the cerebrum responsible for hearing smelling speech and memory
Central Nervous systme (CNS)
includes the brain and the spinal cord . located in the dorsal cavity spinal cord is enclosed in the spinal cavity
Peripheral nervous system (PNS)
located outside the CNS and consists of the nerves that connect the CNS with rest of the body
Neuroglia or glial cells
are the most abundant of the Nerve cells; most are located in the CNS; they support protect insulate nourish and care for the neurons.some participate in phaygocytosis; assist in the secretion of CFS; DO NOT conduct nerve impulses
Type of Glial cell; star shaped; most abundat of the glial cells; most diverse function; support the neurons structurally cover the entire surface of the brain and help form a protective barrier, called blood-barrier around the nurons of the CNS. barrier helps prevent toxic substance in the blood from entering the nervous tissue of the brain and spinal cord; secrete nerve growth factor that promot neuron growth and enhance synaptic development
ependymal cells
GLIAL CELL; lines the inside cavity of the brain and assit in the formation fo CFS
most important in the transmission of the electrical signals ;enables the nervous system to act as a vast sommunication network. Have many shapes and sizes some are short or extremely long up to 4 ft; NONmitotic do not give rise to primary malignant tumors
treelike structure that receive signals from other neurons and the transmit the signal toward the cell body
cell body
contains the nucleus and is essential for the lif of the cell
is th long etension that transmists signals away from the cell body
axon terminals
End of the AXON extenstive to form many ; within these chemical neurostransmitters are stored.
protects and insulates the axon.
Glial cell; protective role; phagocytosis of pathogens and damaged tissue
schwann cells
glial cell; produc mylein sheath for neurons in the PNS assist in regeneration of damage fibers;lie outsdie the myelin sheath and are called the neurilemma. which are important in the regeneration fo a severed nerve
GLIAL cell; produce mylein sheath of neurons in the CNS no neurilemma no schwann cells
Nodes of Ranvier
axonal areas not covered by myelin appear at regualr intervals along the myelinated axon.
Sensory neuron/ affeerent neurons
carries information from the periphery towards the CNS
found in both the CNS and PNS
motor neuron/ efferent neurons
carries information from the CNS towards the periphery
found in both the CNS and PNS
type of neuron; only found in the CNS; form connections between sensory and motor neurons. plays a role in thinking learning and memory
clusters of cell bodies located in the CNS
ganglia (singular: ganglion)
small clusters of cell bodies in the PNS
basal nuclei
patches of gray located in the brain but located in the CNS; help regulate body movement and facial expression. neurotransmitter dopamine is largely responsible for the activity.
Nerve impulse
is an electrical signal that conveys information along a neuron.
Resting membrane potential
refers to the electrical charge difference across the memnbrane of the resting neuron. inside the resting neuron is more negative than the outside (+) . cell is quiet. no impulse being transmitted
means that the height of each nerve impulse is the same. important because it ensures that the nerve impulse does not weaken as it travels the length of the long axon.
fast conduction nerve fibers; axons of moste nerves fibers are wrapped in myelin a fatty material. the nodes of Ranvier the axonal membrane is bare or unmyelinated . the nerve impulse arrives at the axon but cannot develp on any part of the membran covered with myelin. the nerve impulse can delvelp at teh nodes of Ranvier the bare axonal membran. the myelinated fiber the nerve impulse jumps from node to node.
Saltatory conduction
The nerve impulse jumping from node to node ; this increases the speed with wich the nerve impulse travels along the nerve fiber.
synaptic cleft
is a space . the space exists because the axon terminal of neuron A )presynaptic neuron) does not phyicall touch the dendrite of the neuron B (postsynaptic neroun)
receptor sites
Dendrites of nuron B cotnains these; places on the membran to which the neurotransmitters bind (acetylcholine binds to the receptor on dendrite B. each one has specific shape and accepts only those neurotransmitters that "fit" its shape
Right and Left cerebral hemispheres
the divsions of the cerebrum.
corpus callosum
where the cerebral hemisphers are joined together by bands of white matter that form a large fiber tract.
cerebral cortex
a thin layer of gray matter forms teh outer most portion fo the cerebrum
convolutions or gyri (singular; gyrus)
the surface of the cerebrum is folded into elevations that resemble speed bumps on a road.
sulci (singular sulcus)
grooves that separate Gyri ; deep one is called a FISSURE
Central sulcus
seperates the frontal lobe from the partial lobe. important landmark speparting the precentral and postcentral gyri.
Precentral gyrus
locate in the frontal lobe directly infront of the central sulcus.
postcentral gyrus
located in the parietal lobe directly behind the central sulcus.
lateral fissure
separates teh temporal lobe from the frontal and the parietal lobes
longitudinal fissure
seprates teh left and right cerbral hemispheres
primary motor area cortex
frontal lobe contains this; nerve impulses that orginate in teh motor area control the vuntary muscle movement.
function of the precentral gyrus of the frontal lobe (means little man ) represents the amount of brain tissue that corresponds to a function of a particualr body part. two important points; each part of the body is controlled by specific area of the cerbral cortex of the precentral gyrus and the complicate nature of certain movemnts requrires large amounts of brain tissue.
broca's area
the part of the frontal lobe concerned with motor speech. in the left hemisphere
frontal eye field
area above broca's area; it controls voluntary movemnts of the eyes and eye lids
Primary somatosensory area (cortex)
it recevies senstaions from teh body also called the parietal lobe. primarly receives info from teh skin and muscles and allows you to experience th sensation of temperature pain light touch and proprioception. also concerned with reading speech and taste.
primary auditory cortex
contained in the temporal lobe; area that allows you to hear.
olfactory area
located in the temporal lobe controls smell
taste buds
sensory information in the tounge is interpreted in both the temporal and parietal lobes
Wenicke's area
broad region that is locate in the parietal and temporal lobes;concerned with the translation of thought into words.
visual cortex
located in the occipital lobe; sensory fibers from the eye send infromation to this where it is interpreted as sight.
speech area
located in an area that includes the temporal parietal and occipital lobes. most people it is located in the left hemisphere.
association areas
large areas of the cerebral cortes; concerened primarily with analyzing interpreting and intergrating information.
a deficiency of doampine withing hte basal nuclei is called Parkinsons'. it is a movement disorder. characterized by teh follwoing ;a shuffling gait and uncoordinate gait rigity slowness of speech drooling and masklike facial espressions
shaking plasy
Parkinson's is sometimes called this due to the shaking (tremors)
second main area of the brain. located beneath the cerebrum and avoe the brain stem. includes th thalamus and hypothalamus
located in the diencephalon serves as a relay station for most of the sensory fibers traveling from the lower brain and spinal cord region to the sensory areas of the cerebrum. sorts out the sensory infomration gives us a hint of the snsation we are to experience and directs the information to the specific cerebral areas for a more precise interpretation.
is the second structure in the diencephalon; it is situated directly below the thalamus and helps regulate many body process including body temprature (thermostat) water balance and metabolism. since it helps regulate the function of the autonomic nerves it exterts an effect on the heart rate blood pressure and respiration; (Part of the diencephalon that regulates the pituitary gland, autonomic nervous system water balance appetite, temperature and emotions
extends from the lower diencephalon to the pons ;relays sensory and motor information ; contains nuclei that function as reflex centers for vison and hearing
bridge extends from the midbrain to the medulla oblongata ; composed primarily of tracts that act as a bridge from information traveling to and from several brain structures; important role in the regulation of breathing rate and rhythm.
vital center
also call medulla oblongata because its importance with regard to vital functions.
emetic center
located in the medulla oblongata vomiting center; can be activated directly or indirectly. Direct activation includes stimuli from the cerebral cortex stimuli from sensory organs and signals from the equilibrium apparatus of th inner ear.
chemoreceptor trigger zone CTZ
Indirect stimulation of the vomiting center comes from here; located in the floor of the fourth ventricle can be stimulated by emetogenic compounds such as anticancer drugs and opioids. signals from the digestive tract especially the stomach trave via the vagus nerve to here. this inturn activates the vomiting center.
cerebella peduncles
the cerebellum is connected to brain stem by three pairs. these stalks or connection allow the cerebellum to receive intergrate and deliver infromation to many parts of the brain and spinal cord.
reticular formation
extending through the entire brain stem with numerous connections to the cerebral cortex is a special mass of gray matter called ----; it is concerned with the sleep wake cycle and consciousness. signal passing up to the cerebral cortex from 'HERE" stimulate us keeping us awake and tuned in.
gaze center
other nuclei witing the reticualr formation include the (allows the eyes to track and object) and special group of cells that rhythmicall send signals to the muscles that control breathing and swallowing.
Reticualr formation is also concerend with this ; the process whereby the brain learns to ignore repetitive background information.
state of wakefulness. depends on the reticular activation system (RAS) continously samples sensory information from all over the body and then slects and presents essential unusual and threatenting infomraiton to the higher structures in the cerebral cortex. different levels ; attentivenss alertness, relaxation and inattentiveness. Sleep occurs whenthe RAS is inhibited or slowed.
is a hyporesponsive state with several stages from ranging from light to deep. lightest stages some reflexes are intact may respond to light sound touch and painful stimuli. deepening the reflexes are gradually lost and become unresponisve to all stimuli.
non rapid eymovement (NREM)
type of sleep cylce; four stages from light to deep in typical 8 hour sleep period a person regularly cycles through the various stage sof sleep decednig from light to deep and the ascending from deeper to lighter. then to stage to to REM sleep.
rapid eye movement (REM)
stage after NREM totals 90 to 120 mins per night. characterized by fluctuation blood pressure respiratory rate and rhythm and pulse rate. most common is the rapid eye movments. most dreams occur during this stage.
is the ability to recall thoughts and images. three catagories; immediate -last for a few seconds; short term last for short period of time seconds to a few hours.; and long term.-years decades or lifetime.
Dura mater
outermost layer of connective tissue (meninges) dural membranes split inside the skull to form the dural sinuses they are filled with blood. beneath this small space called the subdural space.
arachnoid mater
spider like- middle layer of the meninges .connective tissue
pia mater
innermost layer and literally means soft or gentle mother. ver thin membrane contains many blood vessels and lies delicatly ove the brain and spinal cord. supplies the brain with much of its blood.
subarachnoid space
lies between the arachnoid layer and pia mater . CSF circulates within thsi space and forms a cushion around the brain and spinal cord.
arachnoid villi
specialized projections of the arachnoid membrane ; protrude up into the blood filled dural sinues and are involved in the drainage of CSF.
choroid plexus
where CSF is formed within the ventricles of the brain . Four ventricles are to lateral and a third an foruth ventricle. this is like a grapelike collection of blood vessels and ependymal cells suspended from the roof of each ventricle. water and dissolved substance are trasnported from thh blood across the walls of the """ into the ventricles.
central canal
SOme of the CSF flows through a hole in the center of the spinal cord.. this eventually drains inot he subarachnoid space at the base of the spinal cord. the rest of the CSF flow from the fourth ventricle laterally through tiny holes or foramina into the subarachnoid space that encircles the brain
blood brain barrier
arrangement of cells particualry the glia astrocytes and the selectively permeable capillary cells that act as a barrie to movemnt of potentially harmful chemical into the CNS. the astroocytes and the capillary cells select the substance allowd to enter the CNS from the blood.
pituitary gland
directly or indrirectly affects almost every hormone in the body. the hypothalamus controls the function wides srpead effects are obovious.