Neuro Flashcards
what does the nervous system consist of?
brain, spinal cord, and peripheral nerves
major sensory organs
eyes and ears
what is the nervous system divided into
cns and pns
pns consists of what
12 cranial nerves, 31 pairs of spinal nerves, and the autonomic nervous system
basic cell of the nervous system
neuron
short, branch-like extensions on the cell body that carry impulses to the cell body from other cells
dendrites
controls the function of the neuron
cell body
single, long projection that carries impulses away from the cell body
axon
white fatty substance that protects the axon
myelin sheath
nerves with a myelin sheath
myelinated (white nerve fibers)
nerves w/o myelin sheaths
unmyelinated (gray nerve fibers)
impulses move from one neuron to another across a ____
synapse
a chemical ____ such as acetylcholine either helps or stops the impulse from crossing the synapse
neurotransmitter
_____ neurons carry impulses from the skin and muscles to the CNS
sensory (afferent)
____ neurons carry impulses from the CNS to the muscles for contraction or glands for secretion
motor (efferent)
what is the control center of the nervous system
brain
what is the brain protected by
bony skull and membranes
the outer layer of the meninges
dura mater
the middle layer of the meninges
arachnoid
the inner layer of the meninges (directly attached to the brain)
pia mater
where are arterial blood vessels located
epidural space (b/t skull and dura mater)
where is csf found
Subarachnoid space (b/t arachnoid and pia mater)
4 major regions of the brain
cerebrum, diencephalon, brainstem, cerebellum
largest area of the brain that is separated into the right and left hemispheres
cerebrum
deep grooves in the cerebrum
fissures
what connects the hemispheres and allows for communication
corpus callosum
left hemi is responsible for what
speech, problem solving, reasoning, and calculations
right hemi is responsible for what
visual-spatial info, art, music, and surrounding physical environment
the ____ contains gray matter, while the rest of the cerebrum is made up of white matter
cerebral cortex
each hemi is divided into 4 lobes
frontal, parietal, temporal, occipital
____ contains the thalamus and hypothalamus
diencephalon
what does the hypothalamus regulate
temp, fluid balance, thirst, appetite, emotions, and the sleep-wake cycle
what does the brain stem consist of
midbrain, pons, medulla oblongata
___ is the center for auditory and visual reflexes
midbrain
___ controls respiration
pons
___ controls hr, bp, resp, coughing, swallowing, and vomiting
medulla oblongata
___ is connected to the brain stem and has two hemispheres, and coordinates involuntary muscle activity and fine motor movements as well as balance and posture
cerebellum
a clear, colorless liquid that protects the brain and spinal cord from trauma. It also provides a place for nutrient exchange an waste removal
csf (cerebrospinal fluid)
daily production of csf (mL)
125-150 mL
what is in csf
high glucose, few wbc, and no rbc
how much blood does the brain get per/min
750mL/min (20% od cardiac output)
what is the brain’s only source of energy
glucose (cannot store O2 or glucose, so needs constant supply)
two arterial systems that supply the brain
internal carotid (cerebrum) and vertebral arteries (cerebellum and brainstem)
the major arterial supplies of the brain are connected by smaller arteries forming a ring called ____
circle of Willis (alternative routes when artery is blocked)
cerebral veins drain venous blood into the ____
jugular veins
composed of astrocytes that are joined by tight junctions which decreases permeability so that harmful substances in the blood cannot enter the brain
blood-brain barrier
what can pass through the bbb
lipids, glucose, some amino acids, CO2, O2, and water
what cannot pass the bbb
urea, creatinine, some toxins, and most antibiotics
where does the spinal cord exit the skull
foramen magnum
what protects the spinal cord
vertebral column
vertebral column consists of what
C 7, T 12, L 5, S 5, 4 fused coccyx
the ventral horn consists of ___ neurons
motor
the dorsal horn consists of ___ neurons
sensory
the lateral horn consists of ___ neurons
sympathetic
____ matter forms ascending and descending pathways known as spinal tracts
white
these carry messages to and from the brain: ascending sensory pathways and descending motor pathways
spinal tracts
the pns is divided into ____ and ____
sensory and autonomic nervous systems
connects the skin and muscles to the cns
sensory ns
controls visceral organs and some glands
autonomic ns
31 pairs of spinal nerves
C8, T12, L5, S5
sensory fibers are in the ___ root
dorsal
motor fibers are in the ___ root
ventral
an area of skin supplied by a single spinal nerve is called
dermatome (useful for locating pain and neurologic lesions)
which cranial nerves just control sensory function
I, II, VIII
how many pairs of cranial nerves
12
a part of the PNS that is responsible for maintaining the body’s internal homeostasis
ANS
the ANS regulates what
respiration, HR, digestion, urinary excretion, body temp, and sexual function
two divisions of the ANS
sympathetic and parasympathetic
prepares for the body to handle stress “fight or flight”
sns
operates during non-stressful events to conserve the body’s energy “rest and digest”
psns
pneumonic for the cranial nerves and their function
oh oh oh to touch and feel very good vagina ah ha
some say marry money but my brother says big brains matter more
protect the eyeballs
eyelids and eyelashes
thin mucous membrane that lines the inner surface of the eyelid
conjunctiva
secretes and drains tears to cleanse and moisten the eye’s surface
lacrimal apparatus
tears are produced by what
lacrimal gland
where do tears drain
lacrimal ducts (then into nose)
when the cornea is touched the eyelids blink and tears are secreted
corneal reflex
colored part of the eye, regulates light entering the eye by controlling the size of the pupil
iris
a transparent structure behind the pupil that can change shape to focus light onto the retina
lens
vascular layer of the eyeball
choroid
the innermost lining of the eyeball and contains millions of light receptors called rods and cones
retina
light sensitive and allows us to see in dim light
rods
allow us to see color and provide a sharper image
cones
the area where light passing through the pupil and lens focuses on the retina
macula
the center of the macula that allows for detailed color vision
fovea centralis
the optic nerve enters the eye at
optic disk
the eye has two interior cavities
posterior and anterior cavity
posterior cavity behind the lens contains clear gelatinous ___
vitreous body
anterior cavity is divided further into ___ and ____
anterior (b/t cornea and iris) and posterior (b/t iris and lens) chamber
the anterior cavity is filled with ___
aqueous humor (constantly formed and drained to maintain relative pressure within the eye)
___ at the junction of the sclera and the cornea (limbus) allows aqueous humor to flow b/t the anterior and posterior chambers
canal of Schlemm
to change the point of focus from far to near, the lens changes shape, the pupil constricts, and the eyes converge
accommodation
where do the optic and the cranial nerves meet
optic chiasma
impulses generated in the retina travel to the ____ in the occipital lobe of the brain
visual cortex
the visual fields of each eye overlap considerably and each eye sees a slightly different view allowing for ___
depth perception
2 primary functions of the ear
hearing and maintaining balance
3 areas of the ear
external, middle, and inner
glands in the auditory canal secrete what
cerumen (traps debris, protecting the tympanic membrane)
