Language of Medicine - Chapter 10 Flashcards
Nervous System
describe nerves
collections of nerve cells which carry electrical messages all over the bodyd
define acetylcholine
internal chemical that activates the cell membranes of nerve cells
define nervous impulses
electrical discharge, transverse the length of associated nerves
define receptors
receive impulses and may in turn transmit impulses to complex network of nerve cells in brain + spinal cord
what are the two divisions of the nervous system?
central nervous system (CNS)
peripheral nervous system (PNS)
what does the CNS consist of?
brain + spinal cord
what does the PNS consist of?
cranial nerves, spinal nerves, plexuses, and peripheral nerves throughout the body
what does the Vegus nerve do?
carries messages to and from the neck, chest and abdomen
define a plexus
large network of nerves in PNS
define sense receptors
include receptors for sight (eye), hearing + balance (ear), smell (olfactory), and touch (skin sensation)
afferent VS efferent nerves
sensory (afferent) nerves that carry messages related to changes in environment TOWARD spinal cord + brain
motor (efferent) nerves travel FROM the spinal cord + brain to muscles of the body - telling them how to respond
define autonomic nervous system (ANS)
system of nerves that carries impulses to glands, heart, blood vessels, involuntary muscles found in the walls of tubes like intestines + hollow organs like stomach + urinary bladder
what are the two types of automatic nerves?
- sympathetic nerves
- parasympathetic nerves
define sympathetic nerves
stimulate the body in times of stress and crisis, increase HR + forcefulness, dilate (relax) airways so more oxygen can enter, increase BP, also stimulate adrenal glands + secrete epinephrine (adrenaline)
define parasympathetic nerves
act as a balance for sympathetic nerves, slows HR, lowers BP, stimulates intestinal contractions to clear the rectum
define neuron
individual nerve cell
define stimulus
begins an impulse in branching fibres of a neuron
define dendrites
branching fibres of the neuron
define cell body
impulses reaches cell body and contains the cell nucleus
define ganglia
small collections of nerve cell bodies outside the brain + spinal cord
define myeline sheath (white matter)
insulate the axon + speed transmission of electrical impulse, has a white appearance
define terminal end fibers
nerve impulses pass through the axon and leave the cell via terminal end fibres
define synapse
the space where nerve impulses jump from one neuron to another
define neurotransmitter
transfer of impulse across the synapse depends on the release of the chemical substance the neurotransmitter
what are some examples of neurotransmitters?
acetylcholine, norepinephrine, epinephrine (adrenaline), dopamine, serotonin, and endorphines
define stroma
connective + supportive tissue of the organ
define glial (neuroglial) cells
make up the supportive framework + help ward off infection
list the 4 type of supporting glial cells
- astrocytes (astroglial cells) - star like appearance + transport water + salts between capillaries + neurons
- microglial cells - small cells with many branching processes (dendrites) + are phagocytes so they protect neurons in response to inflammation
- oligodendroglial cells (oligodendrocytes) - have few dendrites, form the myelin sheath in CNS
- ependymal cells - lines membranes within the brain + spinal cord where CSF is produced and circulates
what is the blood brain barrier (BBB)
protective barrier between the blood + brain cells
define cerebrum
largest part of the brain, acts as the “thinking” area
- thinking, personality, sensations, movements, and memory
define the cerebral cortex
on the surface of the cerebrum, nerve cells lie in sheets which make up cerebral cortex
define gyri
arranged folds in the brain
define sulci
grooves in the brain
define cerebral hemisphere
brain is divided into right and left hemispheres these are known as cerebral hemispheres
define ventricles
contain watery fluid that flows throughout the brain + around spinal cord
define cerebrospinal fluid (CSF)
protects brain + spinal cord from shock by acting like a cushion.
typically clear, colourless, and contains lymphocytes, sugar, + proteins
define thalamus
acts like a triage centre, it decides what is important and what is not, selectively processing + relaying sensory information to cerebral cortex + maintains awareness + consciousness
define hypothalamus
contains neuron’s that control body temperature, sleep, appetite, sexual desire, + emotions like fear + pleasure + also regulates release of hormones from pituitary gland at the base of brain + integrates activities of sympathetic + parasympathetic nervous systems
what structures lie in the back + below the cerebrum + connect the cerebrum with spinal cord?
cerebellum, midbrain, pons, and medulla oblongata
what are the parts of the brainstem?
midbrain, pons, medulla oblongata
define cerebellum
functions to coordinate voluntary movements + to maintain balance + posture
define midbrain
uppermost portion of brainstem, contains pathways connecting the cerebrum with lower portions of the brain + structures involved with seeing + hearing
define pons
part of brainstem (means bridge), contains nerve fiber tracts that that connect the cerebellum and cerebrum with the rest of the brain, nerves affecting the face + eye movement are located here
define medulla oblongata
in brainstem, connects the spinal cord with the rest of the brain, nerve tracts cross from right to left and left to right of the medulla oblongata
ex. left side of brain controls right side of body and vice versa
what are the 3 parts of medulla oblongata?
- respiratory center
- cardiac center
- vasomotor center
define respiratory center
controls muscles of respiration in response to chemicals or other stimuli
define cardiac center
slows heart rate when the heart is beating too rapidly
define vasomotor center
affects (constrict or dilate) the muscles in the walls of blood vessels, thus influencing blood pressure
define spinal cord
column of nervous tissue extending from medulla oblongata to the second lumbar vertebra within the vertebral column
define cauda equina
looks like a horse tail - fan of nerve fibers
define grey matter
contains cell bodies + dendrites, inner region
define white matter
contains nerve fiber tracts with myeline shealths, outer region, conducts impulses to + from the brain
define meninges
3 layers of CT membranes that surround the brain + spinal cord
layers: dura mater, arachnoid membrane, pia mater
define dura mater
outermost layer of the membrane of the meninges, thick, tough membrane contains channels (dural sinuses) that contain blood
define subdural space
below dural membrane
define arachnoid membrane
second layer surrounding brain, spider like membrane is loosely attached to other meninges by web like fibres
define subarachnoid space
space for fluid between the web like fibres and 3rd membrane is the subarachnoid space + contains CSF
define pia mater
3rd layer of meninges, closest to the brain, contains a delicate CT with rich supply of blood vessels
cerebell/o
cerebellum
cerebr/o
cerebrum
dur/o
dura mater
encephal/o
brain
gli/o
glial cells
lept/o
thin, slender
mening/o
meningi/o
membranes, meninges
my/o
muscle
myel/o
spinal cord
neur/o
nerve
pont/o
pons
radicul/o
nerve root (of spinal nerve)
thalam/o
thalamus
thec/o
sheath (refers to meninges)
vag/o
vagus nerve (10th cranial nerve)
alges/o
–algesia
sensitivity to pain
–algia
pain
caus/o
burning
comat/o
deep sleep (coma)
esthesi/o
–esthesia
feeling, nervous sensation
kines/o, kinesi/o
–kinesia, –kinesis, –kinetic
movement
–lepsy
seizure
lex/o
word, phrase
–paresis
weakness
–phasia
speech
–plegia
paralysis (loss or impairment of ability to move parts of the body)
–praxia
action
–sthenia
strength
syncop/o
to cut off, cut short
tax/o
order, coordination
