Upgrade to remove ads
A + P Final Exam
Terms in this set (244)
What does the central nervous system consist of?
Brain and spinal cord
What does the peripheral nervous system consist of?
Nervous tissue outside CNS
What is the afferent division?
What is the efferent division?
What is the sensory element of the nervous system?
Monitoring internal and external environment through the presence of receptors
What is the integration element of the nervous system?
Interpretation of sensory information (information processing); complex (high order) functions
What is the motor element of the nervous system?
Stimulation of effectors
What are the 2 types of cells of the nervous system?
Neurons and neuroglia
What is the function of neurons?
Transferring and processing of information
What is the function of neuroglia?
Supporting neurons and maintaining the intercellular environment
What are the structures that protect and support the brain?
Bones of the skull, cranial meninges, and cerebrospinal fluid
How many layers does the dura mater have?
The outermost layer and the inner layer
Outermost layer of dura?
The endosteal layer fused to the periosteum of bones
Inner layer of dura?
The meningeal layer
What is between these 2 dura layers?
The dural sinuses
Larger veins and vessels that collect CSF from the brain and bring it back to the heart; not in the entire brain; not as thick anywhere else
What are dural folds?
Where the dura comes down (like between the left and right hemisphere) to protect the brain
What is the arachnoid mater?
A delicate membrane
What is within the arachnoid mater?
The subarachnoid space
What does the subarachnoid space consist of and what does it help with?
Filled with CSF, a meshwork of collagen and elastic fibers (thinner and projecting). And anchoring large blood vessels
What are arachnoid granulations and purpose?
Projections penetrating dura and sinuses
and CSF flows through these to enter into blood circulation; this is important so that pressure does not build up and CSF keeps moving
What are the characteristics of the pia mater?
Delicate, thin, layer
Where is the pia mater attached and what does this attachment help with?
Attached to the surface of the brain, following the sulci and gyri. And anchoring the larger blood vessels of the cerebellum
So what are all of the meninges layers together?
Skin-bone-dura mater-arachnoid mater-pia mater-brain tissue
Why are the ventricles of the brain filled with cerebrospinal fluid?
Fluid transports nutrients, vitamins, and ions to the CNS and transports waste away from the CNS; also provides protection and support for the brain
What are the ventricles lined with?
Ependymal cells; neuroglial cells that support the nervous system
How many ventricles?
What produces CSF?
By the choroid plexus, consisting of ependymal cells and highly permeable capillaries
What is CSF?
A clear, colorless fluid formed by filtration of blood plasma
Flow of CSF?
2 lateral ventricles (with a choroid plexus in each one that produces CSF) → Interventricular foramen →
Third ventricle (with a choroid plexus that produces CSF) → Aqueduct of the midbrain →
Fourth ventricle (with a choroid plexus that produces CSF) → Lateral/medial aperture central canal
"Release valves" (spinal cord) → Subarachnoid space
→ Arachnoid granulations → Dural sinus → Circulatory system → Blood filtered by choroid plexus and ependymal cells to create CSF and enter lateral ventricles
What are the functions of the cerebrum?
Conscious thought processes and intellect; processing of somatic sensory and motor information
What is the frontal lobe responsible for?
Conscious control of skeletal muscles
What is the temporal lobe responsible for?
Conscious perception of auditory and olfactory stimuli
What is the parietal lobe responsible for?
Conscious perception of touch, pressure, vibration, pain, temperature, and taste
What is the occipital lobe responsible for?
Perception of visual stimuli
What is the insula responsible for?
Why is grey matter grey?
All the cell bodies of the neurons appear grey
Why is white matter white?
Coming out of all these cell bodies are axons covered in myelin, which is a protective insulated barrier that appears white; so white consists of neuronal axons
What is the function of association fibers?
Connect gyri in the same hemisphere
What is the function of commissural fibers?
Connect gyri in opposite hemispheres; corpus callosum
What is the function of projection fibers?
Connect cerebrum with other parts of brain and spinal cord
What do the grey and white matter show?
The connections between different gyri, as white crosses over, demonstrating that the right and left hemisphere are communicating
What does the cerebellum contain?
2 hemispheres with 2 lobes each
What are the function of the cerebellum?
Adjust postural muscles of the body; motor coordination: program and fine tune voluntary and involuntary movements
What does the diencephalon consist of?
Epithalamus, thalamus, hypothalamus
What does the epithalamus form and what does it contain.
The roof of the third ventricle. And the Pineal Gland
What does the pineal gland do?
Produce the hormone melatonin; regulate our day/night cycles
What does the thalamus form?
Walls of third ventricle
What kind of nuclei make up the thalamus?
What is the main function of the thalamus?
Relay station; projects sensory info to cortex
What are the functions of the hypothalamus?
1. Autonomic: heart rate, blood pressure, respiration, and digestive functions
2. Link between the nervous and endocrine systems (hormone production)
3. Emotional and behavioral drives and thirst drives
What is the mammillary body?
Reflex centers associated with eating
What are the 3 parts of the brain stem?
The mesencephalon, pons, and medulla
What are the corpora quadrigemina and what are they responsible for?
Two pairs of nuclei. And processing auditory (inferior colliculi) and visual (superior colliculi) stimuli
What are the nuclei of the reticular formation?
Interconnected nuclei involved in maintaining alertness
What do cerebral peduncles have?
Ascending fibers that synapse in the thalamus and descending fibers of the corticospinal pathway
What are the pons nuclei involved with?
1. Somatic and visceral motor control
2. Sensory and motor nuclei for cranial nerves V-VIII
3. Nuclei for involuntary breathing
4. Nuclei to process and relay cerebellar commands
What do the medulla nuclei serve as and what are they associated with?
Relay stations for sensory or motor pathways. And cranial nerves VIII-XII and the autonomic control of visceral organs
What centers do Medulla nuclei have?
Cardiovascular centers for cardiac and vasomotor; respiratory center for rhythmic breathing
Where is the limbic system located?
Between the cerebrum and the diencephalon just superior to the corpus callosum
What are the functions of the limbic system?
1. Establishing emotional states
2. Linking the conscious functions with the unconscious autonomic functions
3. Facilitates memory storage and retrieval
What are the cerebral components of the limbic system?
Cortical areas, nuclei, and tracts
What are the cortical areas?
The limbic lobe, consisting of the cingulate gyrus, parahippocampal gyrus, dentate gyrus, and hippocampus
What are the nuclei of the limbic system?
Hippocampus, amygdaloid body
What is the function of the amygdaloid body?
Acts as interference between the limbic system, the cerebrum, and various sensory systems
What are the tracts of the limbic system?
Function of the fornix?
Connects hippocampus with the hypothalamus, tract of white matter
What are the diencephalic components of the limbic system?
Thalamus and hypothalamus
What are the other components of the limbic system?
The reticular formation, a network of interconnected nuclei throughout the brain stem
What is the olfactory nerve?
Sensory nerves of smell
What is the optic nerve?
Sensory nerve of vision
What is the oculomotor nerve?
Innervates extrinsic eye muscles
What is the trochlear nerve?
Innervates the superior oblique muscle
What is the trigeminal nerve?
Provides sensory innervation to the face, motor innervation to chewing muscles
What is the abducens nerve?
Abducts the eyeball, innervates lateral rectus muscle
What is the facial nerve?
Innervates muscles of facial expression
What is the vestibulocochlear nerve?
Sensory nerve of hearing and balance
What is the glossopharyngeal nerve?
Innervates structures of the tongue and pharynx
What is the vagus nerve?
A mixed sensory and motor nerve; parasympathetic innervation of organs
What is the accessory nerve?
An accessory part of the vagus nerve; innervates the trapezius muscle
What is the hypoglossal nerve?
Runs inferior to the tongue; innervates the tongue muscles
What are the 3 types of synapses?
Synapses with another neuron (neuron-neuron), neuromuscular synapses (neuron-skeletal muscle cell), and neuroglandular synapses (neuron-gland cell)
What determines the structural classification of neurons?
The number of processes from the soma
Have more than 2 processes, but axons cannot be distinguished from dendrites; found in the CNS, poorly understood
Two processes separated by cell body; one dendrite and one axon; rare: only found in eye, ear, and nose
Singular process with cell body at side; dendrites at one end and axon making up the rest of the process; sensory neurons of PNS
Multiple dendrites and a single axon; most common type (motor neurons controlling skeletal muscles
What are the functional classifications of neurons?
Sensory, motor, and interneurons neurons
In the somatic nervous system?
Innervate skeletal muscles
In the autonomic nervous system?
Visceral motor neurons
Located in the brain and spinal cord; analyze sensory inputs and coordinate muscle outputs
Which neuroglia are found in the central nervous system?
Oligodendrocytes, astrocytes, microglia, and ependymal cells
What are astrocytes?
Large, abundantly found cells that maintain the blood brain barrier, monitor and regulate fluid surrounding neurons, provide structural support, repair damaged neural tissue, stimulate the formation of scar tissue after injury, and guides neuronal development
What are oligodendrocytes?
Smaller cell body, fewer processes; create myelin sheath (composed of phospholipids) around axons of neurons in the CNS
What are microglia?
Smallest of glial cells; slender processes with fine branches; removes cell debris, wastes and pathogens by phagocytosis
What are ependymal cells?
Line ventricles of brain and spinal cord; assist in producing, monitoring, and circulating CSF; slender processes branch and contact glial cells in surrounding tissue
Which neuroglia are found in the PNS?
Satellite cells and schwann cells
Surround neuron cell bodies in ganglia, or a clustered mass of cell bodies in the PNS; regulate oxygen, carbon dioxide, nutrient and neurotransmitter levels surrounding neurons
What are schwann cells?
Surround all axons in PNS creating a neurolemma around them; responsible for myelination of peripheral axons, participates in the repair process after injury (although there is limited ability to recover after an injury in the PNS)
What is a neurolemma?
Superficial cytoplasmic covering
How do schwann cells differ from oligodendrocytes?
1. Schwann cells = PNS, oligodendrocytes = CNS
2. Schwann cells can only myelinate one segment (1mm) of a single axon OR can encircle several unmyelinated axons
3. Oligodendrocytes can myelinate several axons
What is myelin?
A multilayered membrane sheath comprised mainly of phospholipids; insulates axons, speeds electrical impulse
What are Nodes of Ranvier?
Describe the steps of neural regeneration
1. Fragmentation of axon and myelin occurs in the distal stump
2. Schwann cells form cord, grow into cut, and unite stumps - Macrophages engulf degenerating axon and myelin
3. Axon sends buds into network of schwann cells and then starts growing along cord of schwann cells
4. Axon continues to grow into distal stump and is enfolded by Schwann cells
What happens if the entire peripheral nerve is damaged?
Only some axons may reestablish normal contacts and there will be permanent impairment
What happens when the CNS experiences damage?
More axons are involved and astrocytes produce scar tissue and inhibit regrowth
Resting potential - Step 1
Transmembrane potential of resting cell
Graded Potential - Step 2
Temporary, localized change in resting potential and caused by stimulus, decreases with distance
Action Potential - Step 3
An electrical impulse initiated by graded potential and propagates along the surface of axon to synapse without degradation
Synaptic Activity - Step 4
Releases neurotransmitters at presynaptic membrane and produces graded potentials in postsynaptic membrane
Information Processing - Step 5
Response (integration of stimuli) of postsynaptic cell
What is an electrochemical gradient?
Form of potential energy
What is the equilibrium potential?
The transmembrane potential at which there is no net movement of a particular ion across the cell membrane
What is an active force across the membrane?
Sodium-potassium ATPase; carries 3 Na+ out and 2 K+ in to create a resting potential of -70mV
What are graded potentials?
Any stimulus that opens a gated channel produces a graded potential; changes in transmembrane potential that cannot spread far from the site of stimulation
What is depolarization?
A shift in transmembrane potential toward 0 mV
What is repolarization?
When the stimulus is removed, transmembrane potential returns to normal
What is hyperpolarization?
Increasing the negativity of the resting potential due to the opening of potassium channels
What are the 4 steps in the generation of action potentials?
1. Depolarization to threshold
2. Activation of voltage-gated Na+ channels
3. Inactivation of voltage-gated Na+ channels and activation of voltage gated K+ channels
4. Closing of voltage-gated K+ channels and return to normal permeability
The time period from beginning of action potential to return to resting state; membrane does not respond normally to additional stimuli
What is the absolute refractory period?
Sodium channels open or inactivated; no action potential possible; ensures that the action potential cannot bounce back the other way and moves in one direction
What is the relative refractory period?
Membrane potential almost normal; very large stimulus can initiate action potential
What are the steps of continuous propagation of an action potential along an unmyelinated axon?
1. As an action potential develops at the initial segment, the transmembrane potential at this ste depolarizes to +30mV
2. As the sodium ions entering at the initial segment spread away from open voltage-gated channels, a graded depolarization quickly brings the membrane in segment the next to threshold
3. An action potential now occurs in the next segment while the initial segment begins repolarization
4. As the sodium ions entering at that next segment spread laterally, a graded depolarization quickly brings the membrane in a segment after that to threshold, and the cycle is repeated
Why is propagation along a myelinated axon occur faster?
Because there does not have to be the opening of as many sodium channels, jumping from Node of Ranvier to Node of Ranvier via saltatory conduction
What are the steps of synaptic transmission?
1. Action potential reaches the presynaptic axon terminal (depolarization)
2. Voltage-gated Ca2+ channels open, causing influx of Ca2+ into axon terminal
3. Ca2+ causes membranes of synaptic vesicles to fuse with the presynaptic membrane and neurotransmitters are released into the synaptic cleft (exocytosis)
4. Neurotransmitters bind to receptors on postsynaptic membrane
5. Ion channels open or close, changing membrane permeability and therefore membrane potential of postsynaptic neuron
6. If membrane potential of postsynaptic neuron reaches threshold then an action potential will be initiated
The time from the arrival of an action potential at the synaptic terminal and the effect on postsynaptic membrane; from the calcium influx to the neurotransmitter release; .2 to .5 msec
What causes a faster response in synapses?
Fewer sequential synapses
When neurotransmitter cannot recycle fast enough to meet the demands of intense stimuli, the synapse is inactive until the neurotransmitter is replenished
What are the two classes of neurotransmitters?
Excitatory neurotransmitters and inhibitory neurotransmitters
What are excitatory neurotransmitters?
Promote action potentials, causes depolarization of postsynaptic membranes
What are inhibitory neurotransmitters?
Suppress action potential, causes hyperpolarization of postsynaptic membranes
What information processing happens at the level of individual neurons?
- Dendrites receive neurotransmitter messages simultaneously
- Some excitatory, some inhibitory
- Net effect on axon hillock determines if action potential is produced
What is a postsynaptic potential?
Graded potentials developed in a postsynaptic cell in response to neurotransmitter
What are the two types of postsynaptic potentials?
EPSP (graded depolarization) and IPSP (graded hyperpolarization)
What is summation?
To trigger an action potential, EPSPs (or IPSPs) combine through summation
Multiple times; rapid, repeated stimuli at one synapse
Multiple locations; many stimuli, arrive at multiple synapses
What is divergence?
A mechanism for spreading a stimulation to multiple neurons or neuronal pools in the CNS; distribution of input
What is convergence?
A mechanism providing input to a single neuron from multiple sources; allows for variable control of motor neurons
What is serial processing?
Neurons or pools work in a sequential manner
What is parallel processing?
Individual neurons or neuronal pools process information simultaneously
What is the cauda equina?
Spinal nerves still coming down after the spinal cord ends at the conus medullaris
Why are the enlargements large?
Need lots of nerves for legs and head
Why does the spinal cord stop at L1 or L2?
Because the vertebral column grew faster, but the nerves still elongated and stayed their course
Connective tissues that surround, stabilize and protect the brain and spinal cord; shock absorption
What are spinal meninges continuous with?
Continuous with the cranial (cerebral) meninges
Dura mater - spinal meninge?
Outermost layer; tough, fibrous; dense irregular connective tissue covered by squamous epithelium
Arachnoid mater - spinal meninge?
Simple squamous epithelium
Subarachnoid space of spinal cord?
Filled with CSF; meshwork of collagen and elastic fibers
Extensions to pia mater
Pia mater - spinal meninge?
Delicate, thin inner layer; bound to neural tissue; blood vessels found here
Extension from tip of cord to coccyx to anchor cord in place
Anchor cord laterally; keep from moving too much side to side
Fat and connective tissue
How many spinal nerves are there?
31 in total!
Cervical - 8
Thoracic - 12
Lumbar - 5
Sacral - 5
Coccygeal - 1
What does the dorsal ramus innervate?
Neck and back
What does the ventral ramus innervate?
Limbs and body wall
What do the rami communicantes (white ramus and grey ramus) innervate?
Smooth muscles, glands, and organs
What are visceral fibers associated with?
The autonomic nervous system
Which nerves have both white and gray communicantes?
T1 - L2
Function of semicircular canals?
Detecting rotational acceleration
Function of utricle and saccule?
Detecting linear acceleration/ static equilibrium
What are nerve plexuses?
Ventral rami of adjacent spinal nerves blend fibers to produce compound nerve trunks
Where do specific peripheral nerves emerge from?
From each plexus and contain fibers from multiple spinal cord levels
What is a dermatome?
The area of the skin that is mainly supplied by branches of a single spinal sensory nerve root
What is a reflex?
Immediate involuntary motor response to specific stimulus
Steps of a reflex
1. Arrival of stimulus and activation of receptor
2. Activation of a sensory neuron
3. Information processing in CNS
4. Activation of a motor neuron
What does a monosynaptic reflex circuit involve?
A peripheral sensory neuron and a central motor neuron
- Stimulating the receptor causes a reflexive contraction in a skeletal muscle
What does a polysynaptic reflex involve?
A sensory neuron, interneurons, and motor neurons
- Stimulating the receptor leads to coordinated contractions of two different skeletal muscles
What are the ascending sensory and motor tracts?
Spinocerebellar tracts, posterior/dorsal column pathways, and spinothalamic tracts
What are the descending sensory and motor tracts?
Somatic motor tracts and autonomic nervous system
Conscious control over eye, jaw, and face muscles; through cranial nerves
Lateral corticospinal tracts?
Conscious control over skeletal muscles; fibers cross in medulla oblongata
Anterior corticospinal tracts?
Conscious control over skeletal muscles; fibers cross at spinal cord level in anterior commissure
What are the 3 somatic motor tracts?
Corticobulbar tracts, lateral corticospinal tracts, and anterior corticospinal tracts
What are the subdivisions of the ANS?
Sympathetic (fight or flight) and parasympathetic (rest and digest)
What are the effects of the sympathetic nervous system?
- Dilation of pupils, to react to more
- Reduction of circulation to skin, more circulation to things that'll help you respond... Skeletal muscles, brain, heart, lungs
- Stimulates more energy production by skeletal muscles
- Releases stored adipose
Increased cardiovascular and respiratory activity
What are the effects of the parasympathetic nervous system?
- Pupil constriction
- Secretion of digestive enzymes from digestive glands
- Increased smooth muscle activity of the digestive system
- Nutrient uptake and energy storage
- Decreased cardiovascular and respiratory activity
- Sexual arousal
Where are the cell bodies of short preganglionic neurons?
The lateral gray horns of spinal cord (T1-L2)
Where do the preganglionic neurons extend from the spinal cord to?
Sympathetic chain ganglion, collateral ganglion, and adrenal medulla
What do preganglionic neurons release?
Where do the long postganglionic neurons extend to?
Sympathetic chain ganglia to...
Visceral effectors in thoracic cavity, head, body wall, and limbs
Collateral ganglia to...
Visceral effectors in abdominopelvic cavity
Adrenal medullae to...
Organs and systems throughout the body (epinephrine also released) (released into circulation, no postganglionic)
What postganglionic neurons release?
Are postganglionic neurons usually excitatory or inhibitory?
Usually excitatory, depends on alpha or beta receptor
Where are the cell bodies of long preganglionic neurons and what do they release? Do they diverge as much as the sympathetic division? Where do they travel?
In the brain stem and sacral segments and ACh. No, more localized. To terminal ganglion close to the effector or intramural ganglion (within wall of target organ).
Where are the postganglionic neurons? What do they release?
What do their effects depend on?
Near (terminal) the target organ or within (intramural) the target organ. ACh. The specific receptor present; nicotinic or muscarinic
Why does your nose run when you cry?
Some of the tears drain out of your eyes through lacrimal glands that run between your eye and nose; some of the tears exit and come out of your nose
What is the fibrous tunic of the eye?
Outer layer; makes up the sclera and cornea, provides some degree of protection, provides attachment sites for extraocular muscles
What is the vascular tunic?
- Middle layer; consists of blood vessels, lymphatics, and intrinsic eye muscles
- Regulates the amount of light entering the eye
- Secretes and reabsorbs aqueous fluid (aqueous humor)
- Controls the shape of the lens
If the iris is a muscle, where is it getting its coloration from?
If you look to the posterior surface of the iris, see melanocytes, present on back and front of iris, density and distribution varies, type more brown, type more yellow/redish
What is another factor in eye color?
Differing numbers of collagen present
Where is your pigment if you have blue eyes?
Have pigment on the back of the iris and that's it
Why is it important to have some pigment?
So light doesn't go through muscle & only through the pupil; bad if all light went to the back of the retina
What is the neural tunic?
The retina; inner layer
What are the two layers of the neural tunic?
Pigmented layer (outer) and neural layer (inner)
What else composes the retina?
Rods (night vision) and cones (color vision, different wavelengths of light)
Where are the rods and cones located?
Right in front of the melanocytes, they are stimulated when light hits them; they fire action potentials
What do rods and cones synapse with?
What do bipolar cells synapse with?
Retinal ganglion cells, which have axons that extend to the optic disk and optic nerve
What are horizontal cells?
Modulate activity between rods/cones and bipolar cells
What are amacrine cells?
Amacrine cells modulate activity between bipolar and ganglion cells; release neurotransmitters and create graded potentials
Why does the cow eye retina differ from the human eye retina?
It is reflective in cows but dark in humans as it is absorbing all the light
Why do we have a blindspot?
There is a lack of receptors where the optic nerve leaves the eye
What are the features of the rod system?
- Used in low illumination
- 120 million rods
- High degree of convergence on ganglion cells
1. Convergence makes rod system sensitive to low illumination
2. As long as one rod is firing, signal will converge and get to bipolar cells
- Greater concentration of rhodopsin = higher sensitivity
What is rhodopsin? How does it work?
A detector that detects light. When light shines on it, it converts to opsin and retinal, starts a signaling cascade that sends action potentials to the back of the brain to say hey there's light - opsin and retinal will reform back with ATP and an enzyme so there is more rhodopsin
What happens when you walk into a dark room from a sunny outside?
You don't have much rhodopsin left to be stimulated as it converted to opsin and retinal when light was just shining on it, takes a few minutes, then you can see better as you have more rhodopsin, works for stargazing too
Why does it hurt when you go from a dark room to the bright outside?
When sitting in a dark room you have lots of rhodopsin, ready to detect light, when you get into light they are all stimulate and your brain is saying wow that's a lot of light
- again if you wait a few minutes, you can see quite well because its adjusted and regenerates at a nice rate
What are the features of the cone system?
- Used in bright light/daytime
3 types of cone cells
1. Blue cones - short wavelength
2. Green cones - medium wavelength
3. Red cones - long wavelength
What is the perception of color dependent on?
The firing ratio of the 3 cone cells
Where is the highest concentration of cones? What does this mean?
At the fovea centralis. The sharpest acuity is here when looking straight at something because you're stimulating the highest number of cells
What are the anterior and posterior chamber?
Components of the anterior cavity, contains aqueous humor
What does the posterior cavity contain?
What is the function of the vitreous humor?
It pushes retina up against posterior wall
What if the vitreous humor shrank?
Retina would fall off, causes green flashes; if you wait too long and retina detaches
What is glaucoma?
If you had too much fluid in your eye, creating so much pressure in the eye, pressure on optic nerve, creates blurred vision
How do you focus an image?
Using the lens and the cornea
Why does the lens bend light?
If looking at object close to you, the light from that object comes in at a wider angle, to get that light at a focal point at the back of your retina, light has to bend, to get a really big bend, need the lens to be very round
When would the lens not need to be bent as much?
If from far away, not as much bending of light needed, so lens flatter
How does the lens change shape?
Parasympathetic stimulation via the ciliary ligaments connected to the lens
To flatten the lens?
Ciliary muscle relaxed, ciliary ligaments tight, make lens flat, see far things
To bend the lens?
Ciliary muscle contracts, ciliary fibers slack, lens more rounded, can see things closer
What happens if light is not put at a focal point?
Problems with vision, not seeing things clearly
What is a result of the eyeball being too deep, the curve of the lens too great? What is a result?
Myopia (nearsightedness); light focuses in front of the retina, difficulty seeing objects from a distance but no difficulty from up close
What is a result of the eyeball being too shallow, the lens too flat?
Hyperopia (farsightedness); light focuses at the back of the retina, difficulty seeing near objects but no problem seeing far ones
What are cataracts?
Lens is cloudy, typically proteins not in crystalline lattice work, happens around 50
Trace the visual pathway
- Bipolar cells
- Retinal ganglion cells
- Horizontal and amacrine cells
- Optic nerve
- Optic chiasm
- Optic tract
- LGN → visual cortex
- Superior colliculi → visual reflexes; eyes tract and follow moving objects
- Visual cortex (occipital lobe)
What do the dorsal and ventral root make up?
The spinal cord; peripheral nerve similar to muscle, dura continues around nerve, tough covering
What is a fascicle?
A bundle of nerves within the individual neurons
Endoneurium, loose CT, covers myelination
Where does motor travel?
Down from the brain
Where does sensory travel?
To the brain
Where does motor come out of?
Where does sensory come out of?
What is within the posterior grey horn?
Somatic and visceral sensory (sensory information about the body and viscera coming in
What is within the lateral grey horn?
Visceral motor (cell bodies send info out)
What is within the anterior grey horn?
Somatic motor (control/move body, mostly muscles)
What are the steps involved in hearing?
1. Sound waves vibrate the tympanic membrane
2. Ossicles vibrate, causing oval window to vibrate, causing waves in perilymph of the cochlea
3. Fluid waves distort the basilar membrane, causing hair cells to vibrate against the tectorial membrane; generates action potentials
4. Action potentials sent back to the CNS via vestibulocochlear nerve
What is pitch?
Our sensory response to frequency; location of vibration - Higher frequency early on in the cochlear, lower frequency toward the tip
What is amplitude?
Intensity of sound waves; number of hair cells stimulated; reported in decibels
What is the overall function of the semicircular canals?
Each activated by different movement/motion of the body; detect linear acceleration/static equilibrium
OTHER SETS BY THIS CREATOR
Microbiology Lecture Exam #1
Microbiology Lab Quiz #2
Child Development Final Exam
Developmental Psychology Exam #2
OTHER QUIZLET SETS
"Outliers" Test Study Guide
MGMT 320 Exam Two-Ch. 5&6
Growth of Democracy