Exam 4 Flashcards
Olfactory Nerve (give #, function, and type)
I, smell, sensory
optic nerve (give #, function, and type)
II, vision, sensory
Oculomotor nerve (give #, function, and type)
- III
- moves eyeball/eyelid, adjusts lens for near vision, constricts pupil
- motor
Trochlear nerve (give #, function, and type)
IV, moves the eyeballs, motor
Trigeminal nerve (give #, function, and type)
- V
- largest cranial nerve, splits into 3 divisions. Control facials muscles involved in chewing and convey sensations of touch, pain, and temperature from front of head and mouth
- mixed
abducens nerve (give #, function, and type)
- VI
- moves the eyeballs outwards
- motor
facial nerve (give #, function, and type)
- VII
- sensory fibers detect taste, motor fibers control tear and saliva secretions and facial expressions
- mixed
Vestibulocochlear nerve (give #, function, and type)
- VIII
- branches into vestibular nerve (balance) and cochlear nerve (hearing)
- sensory
glossopharyngeal nerve (give #, function, and type)
- IX
- monitors bp, pulse ox, senses taste, touch, and pain from posterior 1/3 of tongue and soft palate
- mixed
Vagus nerve (give #, function, and type)
- X
- Motor:
- Under conscious control
Stimulates voluntary muscles that effect swallowing,
coughing and speech. - Under unconscious control
o Stimulates the contraction and relaxation of smooth
muscle in GI tract
o Can trigger reduction (slowing) of heart-rate
o Stimulates secretion of digestive fluids
Sensory: - Monitors blood pressure
- Monitors levels of oxygen and carbon dioxide in blood
- Sensations of touch, pain and temperature from throat area
- Sensations from visceral organs in thorax and abdomen
accessory nerve (give #, function, and type)
- XI
- controls swallowing movements and movement of head and shoulders
- motor
hypoglossal nerve (give #, function, and type)
- XII
- involved in speech and swallowing
- motor
What are the four regions of the brain?
- cerebrum
- diencephalon
- brainstem
- cerabellum
What is the difference between gyri and sulci?
gyri are the ridges of the outer surface of the brain while sulci are the depressions between ridges
What is gray matter made of?
neuron cell bodies, dendrites, and unmyelinated axons
What is the gray matter surface of the cerebrum called?
cerebral cortex
what are cerebral nuclei?
regions of gray matter found deep in the cerebrum
what does white matter consist of?
myelinated axons
What are cranial meninges?
three connective tissue layers that separate and support soft tissue of brain
what are some major functions of cranial meninges?
- enclose and protect blood vessels supplying the brain
- help contain and circulate cerebrospinal fluid
List the cranial meninges from deep to superficial
- pia mater
- arachnoid matter
- dura mater
What is pia mater?
innermost of the meninges that adheres to brain surface and is composed of a thin layer of areolar CT
What is arachnoid mater?
made of a web of collagen and elastic fibers
- arachnoid trabeculae extend to pia matter through subarachnoid space
- subarachnoid space contain cerebrospinal fluid
What is dura mater?
- tough outer membrane
- made of 2 layers of dense irregular CT
what are the function of dural venous sinuses?
separated sections of dura that drain blood from brain
What are the two layers of the dura mater?
- meningeal layer (deeper layer of dura)
- periosteal layer (more superficial layer of dura)
What are cranial dural septa?
- sheets of dura mater the extend into cranial cavity
- form partitions between brain areas and provide support
What are brain ventricles?
cavities within brain lined with ependymal cells and contain CSF
where are the two lateral ventricles?
large cavities in cerebrum separated by medial partition called septum pellucidum
Where is the third ventricle?
narrow space in middle of diencephalon connected to each lateral ventricle by an interventricular foramen
Where is the fourth ventircle?
sickle shaped space between pons and cerebellum
What is cerebrospinal fluid
- clear, colorless liquid surrounding CNS
- circulates in ventricles and subarachnoid space
What are the functions of CSF?
- provides buoyancy
- protects CNS by providing a liquid cushion
- keeps CNS environment stable
- helps transport nutrients/wastes
What forms CSF
specialized tissue in each ventricle called choroid plexus
How is CSF formed?
- blood plasma is filtered through capillary and modified by ependymal cells
- also composed of interstitial fluid from subarachnoid space
How does CSF circulate the CNS?
1.) CSF formation begins in choroid plexus of ventricles
2.) CSF flows from lateral ventricles into third ventricle
3.) From third ventricle into fourth ventricle
4.) After passing through apertures, it flows in subarachnoid space and down into central canal of spinal cord
5.) Excess CSF flows into arachnoid villi and drains into dural venous sinuses
What are the functions of the blood-brain barrier?
- regulates which substances enter brain’s interstitial fluid
- help prevent neuron exposure to harmful substances
What is the blood-brain barrier composed of?
specialized capillaries
- endothelial cells connected by many tight junctions
- wrapped by perivascular feet
True or false, the BBB is reduced in certain areas for functional reasons
True.
The choroid plexus needs to produce CSF and the hypothalamus and pineal gland need to secrete hormones
Where is the origin of all complex intellectual functions?
the cerebrum
What is the cerebrum responsible for
center of:
- intelligence and reasoning
- thought, memory, judgement
- voluntary motor, visual, and auditory activities
Where is the primary motor cortex located?
within the frontal lobe in the precentral gyrus
What is the primary motor cortex responsible for?
controls skeletal muscle area on opposite side of body
What area of the cerebrum controls motor speech
brocas area
What is the function of the frontal eye field
regulates eye movements needed for reading and binocular vision
what is the function of the premotor cortex?
coordinates learned, skill activities
what is the function of the primary somatosensory cortex?
receives somatic sensory information
What is the function of the prefrontal cortex?
complex thought, judgement, personality, planning and deciding
What part of the brain is responsible for language comprehension?
wernicke area
What is white brain matter composed of?
myelinated axons grouped into tracts
What kind of tract connects regions of cerebral cortex within the same hemisphere
Association tracts
What are two type of association tracts?
arcuate fibers and longitudinal fasciuli
What kind of tract connects regions in different hemispheres
commissural tracts
What kind of tract is the corpus callosum?
commissural tracts
What are cerebral nuclei?
gray matter deep in cerebrum that help regulate motor output
How many pairs of spinal nerves are there?
31 pairs
How are spinal nerves formed?
formed from merger of anterior root and posterior root
How is each spinal nerve named?
each nerve is named for part of spinal cord it comes from and a number
what is the smaller branch of a spinal nerve called?
posterior ramus
what is the larger branch of a spinal nerve called?
anterior ramus
what are rami communicantes?
small branches of autonomic fibers that extend between spinal nerve and sympathetic trunk ganglion
What are dermatomes?
segment of skin supplied by a single nerve (involved in referred pain)
what is a nerve plexus
network of interweaving anterior rami of spinal nerves
What are the 4 main plexuses?
cervical, brachial, lumbar, and sacral
What is a ramus?
a branch of a spinal nerve; contains both motor and sensory fibers
What important nerve is in the cervical plexus?
phrenic nerve
what areas does the cervical plexus innervate?
diaphragm, shoulder, and neck
What important nerves are in the brachial plexus?
axillary, radial, median, musculocutaneous, ulnar
What areas does the brachial plexus innervate?
shoulder, arm, forearm, and hand
What important nerves are in the lumbar plexus?
femoral and obturator
what areas does the lumbar plexus innervate?
lower abdomen and anterior and medial thighs
What important nerves are in the sacral plexus
sciatic, tibial, and fibular
what areas does the sacral plexus innervate?
lower trunk and posterior thigh, lateral and posterior leg and foot, gluteal muscles of hip area
What are some characteristics of reflexes
- requires a stimulus
- rapid response
- preprogrammed/always the same
- involuntary
What ways can a reflex be classified?
spinal or cranial: is spinal cord or brain the integration center
somatic or visceral; is effector a skeletal muscle?
monosynaptic or polysynaptic: do sensory neurons synapse motor neurons w/ or w/out interneurons
ipsilateral or contralateral: are receptor and effector on the same side of the body
innate or acquired: are you born with it?
What is a stretch reflex?
a reflex that occurs when a muscle contracts after it is stretched
What detects the stretch in a stretch reflex?
a muscle spindle receptor
What is the golgi tendon reflex?
prevents muscles from contracting excessively
What are golgi tendon organs and what do they do
proprioceptors with sensory ending at muscle tendon junction that detect excessive tension
what is the withdrawal reflex?
pulls a body part away from a painful stimulus
How does a withdrawal reflex occur?
stimulus excites nociceptor sensory neuron that transmits signal to spinal cord
What is the crossed extensor reflex
occurs in conjunction with withdrawal reflex, allows the opposite side limb to support body while the hurt limb withdraws
What does the somatic nervous system control?
consciously perceived or controlled processes
What does the autonomic nervous system control?
processes regulated below conscious level, functions to maintain homeostasis
What are the subdivisions of the ANS
sympathetic and parasympathetic
What are the neurons used by the ANS to reach the effector?
preganglionic neuron and ganglionic (post ganglionic) neuron
What is a preganglionic neuron?
cell body within brainstem that releases ACh from synaptic knob to excite second motor neuron
What is a ganglionic neuron?
cell body with autonomic ganglion, releases ACh or norepinephrine from synaptic knob to excite/inhibit effectors
What are the advantages of a 2 neuron system?
- neuronal convergence: multiple preganglionic neurons synapsing on one ganglionic neuron
- neuronal divergence: branches of axon from one preganglionic neuron synapsing with numerous ganglionic neurons
What part of the brain controls both divisions of the ANS
hypothalamus
what part of the brain controls major ANS reflex centers
brainstem
what part of CNS controls some ANS reflexes?
spinal cord
What is the parasympathetic division of the ANS responsible for?
“rest and digest” conserves energy and replenishes nutrients
What is the sympathetic division of the ANS responsible for?
“fight or flight” for exercise, excitement, and emergency
How do the anatomy of the parasympathetic and sympathetic division compare?
In parasympathetic division. preganglionic axons are long and postganglionic axons are short. Preganglionic axons also have few branches
Sympathetic division has preganglionic axons that are short and postganglionic axons are long. Preganglionic axons have many branches
How do the divisions of the ANS differ in degree of response
- parasympathetic activity is fairly localized
- sympathetic activity often facilitates mass activation
Where are ganglia located in the parasympathetic division
terminal: closer to effector
intramural: located within wall of target organ
What cranial nerves are part of the parasympathetic division?
oculomotor, facial, glossopharyngeal, and vagus nerve
where are ganglia located in the sympathetic division?
close to CNS, but anatomical pathways are complex
What are the 4 types of sympathetic pathways
- spinal nerve pathway
- postganglionic sympathetic pathway
- splanchnic nerve pathway
- adrenal medulla pathway
What neurotransmitters are used by the ANS
acetylcholine (ACh) and norepinephrine (NE)
what are cholinergic neurons?
cells that release ACh
What are examples of cholinergic neurons?
all ANS preganglionic neurons, all parasympathetic gangilionic neurons and some sympathetic ganglionic neurons
What are adrenergic neurons?
cells that release norepinephrine
most sympathetic ganglionic neurons are______(adrenergic or cholinergic)
adrenergic
What are the two main types of cholinergic receptors?
nicotinic and muscarinic
where are nicotinic receptors found?
found in all ganglionic neurons and adrenal medulla cells
What happens when ACh binds to a nicotinic receptor?
it opens cation channel, cell depolarizes and EPSP produced
Where are muscarinic receptors found?
found on all target organs of parasympathetic division and a few of sympathetic division
True or false, all muscarinic receptors use second messengers
true, but different subtypes of receptor have different effects
What are the two main types of adrenergic receptors?
alpha and beta receptors
what is the difference between alpha and beta receptors?
cells with alpha receptors are typically stimulated by NE, cells with beta receptors may be stimulated or inhibited by NE
where are a1 receptors found?
most smooth muscle cells
where are b1 receptors found?
heart and kidney
where are b2 receptors found?
smooth muscle of heart, liver, and skeletal muscle
where are b3 receptors found?
adipose
What is an autonomic tone?
when both divisions of ANS continuously release neurotransmitter to same effector
what is dual innervation?
organ receives input from both the sympathetic and parasympathetic divisions
What are autonomic reflexes?
pre programmed response to a stimulus generated by a reflex arc
what are the components of a reflex arc?
1.) receptor
2.) sensory relay to CNS
3.) CNS integration center
4.) motor neuron
5.) effector
What is the cardiovascular reflex?
stretch receptors in vessel walls respond to pressure elevation by sending signals to cardiac center in medulla –> heart rate slowed, bp decreases
What is the gastrointestinal reflex
sensory receptors respond to rectum stretch by fecal matter and spinal cord relaxes internal anal sphincter
what is the micturition reflex?
stretch receptors detect full bladder and once toilet trained, signals through pons allow for voluntary control of urethral sphincter
What are the accessory structures of the eye?
eyelids, eyelashes, conjunctiva, lacrimal apparatus, and extrinsic eye muscles
What is the function of the conjuctiva
membrane that secretes mucus to lubricate the eye
What is the function of the lacrimal apparatus?
protects, moistens, and lubricates the eye
What are the three layers of the eye?
Fibrous layer: outside layer
Vascular layer: middle layer
Sensory layer: inside layer
What structures are found in the fibrous layer?
sclera and cornea
what is the function of the sclera?
white connective tissue layer of the eye
What is the function of the cornea?
transparent portion that allows for light to pass through
What are the structures of the vascular layer?
choroid, ciliary body, iris, and pupil
what is the function of the choroid
blood rich nutritice layer that has pigment to prevent light from scattering
what is the function of the iris
regulates amount of light entering eye
what is the function of the pupil
rounded opening in iris
what is the function of the ciliary body
smooth muscle that controls lens
What are the structures of the sensory layer
retina and optic disc
What are the two layers of the retina
- Outer pigmented layer absorbs light and prevents it from
scattering - Inner neural layer contains rods and cones
What type of vision do rods percieve?
allow vision in dim light and peripheral vision, all perceptions are in gray tones
What type of vision do cones percieve
allow for detailed color vision
what is the fovea centralis?
area of retina with only cones where sharpest vision is from
What causes colorblindness?
lack of one cone type (3 different types)
How does cataracts occur?
occurs when lens becomes hard and opaque
What chamber contains aqueous humor?
anterior segment
what chamber contains vitreous humor?
posterior cavity
What is the function of the aqueous humor?
watery fluid that helps maintain intraocular pressure and provides nutrients to lens and cornea
What is the function of the vitreous humor?
gel like structure that prevents eye from collapsing
At what point do the optic nerves cross?
optic chiasm
What is the path of nerve impulses from the retina to the brain?
1.Optic nerve
2.Optic chiasm
3.Optic tract
4.Thalamus
5.Optic radiation
6.Visual cortex in occipital lobe of brain
What are two types of eye reflexes
photopupillary reflex and accommodation pupillary reflex
What causes night blindness?
inhibited rod function that hinders the ability to see at night
What is glaucoma?
can cause blindness due to increasing pressure within the eye
What is hemianopia?
loss of the same side of the visual field of both eyes
What are the three regions of the ear?
1.External (outer) ear
2.Middle ear (tympanic cavity)
3.Inner ear (bony labyrinth)
What are the structures of the external ear?
auricle (pinna) and external acoustic meatus (auditory canal)
What is the function of the middle ear?
air filled cavity within the temporal bone that is involved only with hearing
What are the three bones of the middle ear
1.Malleus (hammer)
2.Incus (anvil)
3.Stapes (stirrup)
What are the structures of the inner ear?
cochlea, vestibule, semicircular canals
What are the two components of the vestibular apparatus
static equilibrium and dynamic equilibrium
What are the receptors found in the static equilibrium and what are their function?
maculae
- report on position of head via vestibular nerve
How does static equilibrium work?
hair cells embedded in otolithic membrane and tiny stones float in gel around hairs
what is the inner ear filled with
perilymph
How does dynamic equilibrium work?
The movement of the cupula stimulates the hair cells during angular head movements
Describe the process of hearing
- Vibrations from sound waves move tectorial membrane
- Hair cells are bent by the membrane
- An action potential starts in the cochlear nerve
How are high pitched sounds interpreted compared to low pitched sounds
high pitched sounds disturb short stiff fibers while low pitched cells disturb long floppy fibers
How does conduction deafness happen?
results when transmission of sound vibrations through external/middle ear is hindered
How does sensorineural deafness happen?
results from damage to the nervous
system structures involved in hearing
