Chapter 8: Nervous system Flashcards
Axon
long cell process that moves the signal away from the cell body
neuron
receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs
myelin sheath
fatty covering that protects and speeds up the signal in the axon
nodes of ranvier
gaps in the myelin sheaths where the signal from the axon skips
saltatory conduction
when the signal in the axon jumps through the nodes of ranvier, skipping parts of the axon
unipolar/pseudo unipolar
has a single process extending from the cell body
bipolar neurons
has one dendrite and one axon extending from the cell body
multipolar neurons
have many dendriites, and a single axon
astrocyte
the major supporting tissue in the CNS; also forms the blood-brain barrier between the blood and the CNS
ependymal cells
line the fluid-filled cavities within the CNS. some produce CSF while others move CSF.
microglia
act as the immune cells of the CNS. they remove bacteria and debris
oligodendrocytes
provide myelin sheaths in the CNS. covers many cells
schwann cells
provides myelin sheaths to individual cells in the PNS
differences between CNS and PNS
CNS : uses oligodendrocytes, a collection of axons is called a nerve tract, and cells of cell bodies are called nuclei
PNS : uses schwann cells, a collection of axons are called peripheral nerves, and cells of cell bodies are called ganglion
neurotransmitters
chemical substances that send messages to other parts of the body
aceytlcholine
a neurotransmitter found usually in the neuromuscular junction
norepinephrine
excitatory; cocaine and amphetamines increase the release of norepinephrine and blocks the reuptake of them, causing overstimulation
serotonin
generally inhibitory, involved with mood, anxiety, and sleep. drugs such as prozac block serotonin transporters, treating anxiety and depression
dopamine
excitatory or inhibitory; parkinsons comes as a result of destruction of dopamine secreting neurons
Gamma-aminobutyric acid (GABA)
inhibitory; drugs that increase GABA function have been used to treat epilepsy, which is an excessive release of neurons
glycine
inhibitory; can lead to tetanus of repiratory muscles if strychnine is involved
endorphins
inhibitory; makes you feel good
converging neural pathway
two or more neurons go to one neuron
diverging neural pathway
one neuron divides to 2 neurons
meningitis
infections of meninges ( wrapping arpund brain and spinal cord)
subarachnoid space
under the arachnoid mater and the pia mater that contains CSF and has blood vessels
lateral ventricles
found in each cerebral hemisphere containing CSF
third ventricle
found in the midline in the center of the diencephalon between the 2 halves of the thalamus
fourth ventricle
located at the base of the cerebellum, and contains CSF
brainstem
connects the spinal cord to the remainder of the brain. It consists of the medulla oblongata, the pons, and the midbrain.
medulla oblongata
the most inferior portion of the brainstem; continuous with the spinal cord; contains nuclei that control things like heart rate, blood vessel diameter, breathing, balance. also contains pyramids which have descending nerve tracts to motor neurons
pons
superior to the medulla oblongata, also helps control breathing, swallowing, and balance
midbrain
superior to the pons, it is the smallest part of the brainstem, contains colliculus, the inferior ones are mainly for auditory nerves, the superior ones control visual reflexes
reticular formation
scattered throughout the brainstem, these control functions like respiration, walking, and chewing.
frontal lobe
controls voluntary motor functions, aggression, moods, smell
parietal lobe
evaluates sensory input such as touch, pain, pressure, temp., taste
occipital lobe
used for vision
primary somatic sensory cortex
located in the parietal lobe posterior to the central sulcus contains general sensations
primary motor cortex
found in the frontal lobe, it controls voluntary motor movement
alpha waves
waves that are active when a person is AWAKE
Beta waves
waves that are active during intense thinking
delta waves
are active in DEEP SLEEP
Theta waves
waves found typically in children
conus medullaris
the end of the spinal cord. looks like a cone
cauda equina
nerves at the end of the spinal cord. looks like a horses tail
grey matter
material in the center of the spinal cord that looks like a butterfly
anterior horns
contains somatic neurons
posterior horns
contain axons which synapse with interneurons
lateral horns
contains autonomic neurons
spinothalamic tract
transmits action potentials dealing with pain an temperature to the thalamus and on to the cerebral cortex; ascending tract
dorsal column
transmits action potentials dealing with touch, positioon, and pressure; ascending tract.
I. Olfactory nerve
responsible for the sense of smell. sensory only.
II. optic nerve
responsible for the sense of vision. sensory only.
III. Oculomotor
motor to four of six extrinsic eye muscles and upper eyelid; parasympathetic: constricts pupil, thickens lens
IV. trochlear
motor only to one extrinsic eye muscle
V. Trigeminal
sensory to face and teeth; motor to muscles of mastication
VI. Abducens
Motor to one extrinsic eye muscle
VII. Facial
sensory: taste; motor to muscles of facial expression; parasympathetic to salivary and tear glands
VIII. vestibulocochlear
sensory for hearing and balance
IX. glossopharyngeal
sensory: taste and touch to back of tonlgue; motor to pharyngeal muscles;parasympathetic to salivary glands
X. Vagus
Sensory to pharynx, larynx, and viscera; motor to palate, pharynx, and larynx; parasympathetic to salivary glands
XI. accessory
motor to two neck and upper back muscles
XII. hypoglossal
Motor to tongue muscles
