Nervous System Flashcards
Communication and integration of activities in the body are controlled by two systems ____ and _____
The nervous and endocrine system
Nerve cells that are able to conduct nerve impulses
Neurons
These kinds of neurons conduct impulses from receptors to the central nervous system
Sensory (Afferent)
Receptors sensors sensitive to light
Electromagnetic (Photo)
Receptors that respond to chemical stimulation
Chemoreceptors
Receptors that respond to temperature changes
Thermoreceptors
Receptors that respond to touch, pressure, or stretch
Mechanoreceptors
Receptors that respond only to painful stimuli
Pain receptors
Neurons that transmit impulses from the CNS to effectors
Motor Neurons
Efferent Neurons are another name for ______ neurons
Motor Neurons
Skeletal muscles are controlled by _____ neurons
Somatic Neurons
Neurons of the voluntary system
Autonomic Neurons
Neurons that are found between sensory and motor neurons
Interneurons
When a stimulus elicits an immediate response
Reflex
This is the most primitive level of nervous system control
The spinal cord level
This is a step up from the spinal cord level of nervous system control
The brain stem and Cerebellum
This is the highest level of nervous system control
The cerebral cortex of the cerebrum
The most common type of nervous system synapse, uses small molecule rapid acting chemical transmitter substances
Chemical Synapse
An example of a small molecule rapid acting transmitter is ______
Acetylcholine
Depolarization of the axons causes ______ ____ to pass into the axon tip from the interstitial fluid
Calcium Ions
To generate an ACTION POTENTIAL, the membrane must allow Positive charges to enter causing it to ________.
Depolarize (reverse its polarity)
Excitatory chemical transmitters generate action potentials by binding to receptors on _______ ______ sodium channels, allowing sodium ions to diffuse freely into the cell
Ligand gated
When the inside of a cell becomes more negative than normal, the cell is said to become ______
Hyperpolarized
This is when a minimum of 100 or so different excitatory neurons have to fire simultaneously to excite the cell.
Spatial Summation
This is when some excitatory cells may fire at high frequency, making them more effective in exciting a cell
Temporal summation
Inhibitory presynaptic cells may be stimulated and, exhibiting spatial or temporal summation, ______ the effect of the excitatory cells
Oppose
Normal membrane resting potential is about ____mv for CNS neurons
-65
These are membrane potential changes that make the inside less negative. e.g. -65 to -55
Excitatory Postsynaptic Potentials
(EPSP’s)
These are membrane potential changes that make the potential more negative e.g. -65mv to -70mv
Inhibitory Postsynaptic Potentials
(IPSP’s)
Inhibition using IPSP’s, occurs rapidly and for short duration
Postsynaptic Inhibition
Inhibition, where inhibitory neurons act by decreasing the amount of excitatory transmitter released by the presynaptic neuron
Presynaptic Inhibition
The outer portion of the eye is composed of three tissue layers, the outer _____, the middle _____ and the inner _____
Sclera, Choroid, and Retina
The outer protective layer of the eye, is made of white fibrous _______
Sclera
Anteriorly the sclera becomes the translucent _____
Cornea
The middle layer of the eye, black in color because it absorbs light of all visible wavelengths
Choroid
Anteriorly the choroid forms the ____ and _____
Iris, and Ciliary body (structures that surround the lens of the eye)
The iris and ciliary body are the _____ eye muscles
Internal
The ciliary body is attached to the edges of the lens of the lens by _______ _________
Suspensory Ligaments
The hole in the center of the iris that allows for light to enter the eye
Pupil
The inner tissue layer of the eye
Retina
The retinal layer of the eye contains tow types of photoreceptor cells ____ and_____
rods and cones
As these kinds of rays of light from distant sources pass through the biconvex lens of the eye, they are refracted or bent such that the rays will converge with their focal point falling on the retina
Parallel rays
The process used to correct the problem of blurred images hitting the retina is called
Accommodation
The ability to accommodate correctly
Emmetropia
Another name for far sightedness
Hyperopia
Hyperopia
the eyeball is too short and the refractive power has to be increased by the ciliary muscles to accommodate a retina that is now closer to the lens
Another name for near sightedness
Myopia
Myopia
the eyeball is too elongated and the focal point for distant object falls in front of the lens
Losing the ability to accommodate is referred to as ______
Presbyopia
A condition of the lens that often occurs as part of the aging process.
Cataracts
One of the intrinsic eye muscles associated with the choroid layer is the _____
Iris (Goo Goo dolls)
The anterior cavity of the eye, in front of the lens, is filled with ______ ______
aqueous humor
If aqueous humor is produced faster than it is reabsorbed, it accumulates in the anterior cavity, increasing the intraocular pressure, it causes this condition
Glaucoma
Increase in pressure is reflected into the posterior cavity behind the lens filled with a more gelatinous substance called ______
Vitreous Humor
In rods, the visual pigment is ______ combined with a protein called ______
Retinal and Scotopsin
The combination of Retinal and Scotopsin is called ________, and whenn the _____ molecules are stimulated but light they undergo a step-wise degradation back to retinal and scotopsin
Rhodopsin
Some cones respond to shorter wavelength ____ light, some to intermediate wavelength _____ light, and some to longer wavelength _____ light.
Blue, Green, Red
Rods are able to do this _____, to different light intensities by converting between the active pigment retinal and the inactive form called retinol (aka vitamin A)
Adapt
Retinol (inactive pigment) is also known as
Vitamin A
To prevent over stimulation of rods and receptors from bright flashes of light, significant amounts of retinal are inactivated by conversion to retinol.
This process is called
Light adaptation
When entering a dark space from a previously bright environment, eyes undergo this process, where stored retinol is converted back to retinal that reacts with scotopsin, and rhodopsin is formed
Dark adaptation
A pure cone region near the center of the retina is called the _______ ______, less than a square millimeter it is the focal point of the retina
Fovea Centralis
The focal point of the retina , the fovea centralis is marked anatomically with a yellow spot called the ____ _____
Macula Lutea
An age related condition, an impairment of this most sensitive part of the retina
Associated with blurred vision and gradual loss of vision beginning centrally
Macular Degeneration
Due to injury or irregularity of protein fibers attaching the retina to the pigment layer below, can survive for up to several days
A detached retina
At the point where the optic nerve is attached, there is no overlying rods or cones. This location on the retina is called the ____ _____
Optic disk
Optic Disk also known as
Blind Spot
At the base of the brain, optic nerve fibers innervating the medial half of each retina crossover, this is called the ______ _____
optic chiasma
From the optic chiasma, optic ____ lead to the visual cortex of the brain, located in the posterior part of the cerebral cortex
Optic tracts
Eye movements within the orbits are provided by ________ skeletal muscles, six for each eye that move the eyeball within its socket
external
How we judge distance, three ways ____ _____ and ____
Size of image on retina, moving parallax, and stereopsis-binocular vision
If a close object moves slightly, it will still sweep a large portion of the retina, if a distant object moved the same amount the image will hardly move at all, by evaluating the perceived movement we judge distance via _____ _____ ( the second method)
Moving Parallax
Since the eyes are located roughly two inches apart we aren’t seeing the same image in both eyes, the closer the object the more different the image becomes, interpretation of the magnitude of difference enables us to interpret distance via _____ _____ _____(the last method)
Stereopsis-binocular vision ( works best for near objects)
The conduction pathway for sound waves transmitted in air is the _______ ear
external ear
the chamber on the inner side of the tympanic membrane is the ______ ear
Middle ear
The three small bones in each ear called ______, conduct sound waves through the middle ear
ossicles
The handle of the first ossicle, the ______, is connected to the tympanic membrane
malleus
The opposite side of the malleus is connected to the second ossicle, the ____, which in turn connects to the last ossicle, the ____
Incus, and Stapes
The inner ear structure containing the receptors for hearing is called the _____
Cochlea
The cochlea is essentially three parallel tubular passages coiled up like a snail, what are the three chambers ____ _____ and _____
Scala vestibuli, Scala media, and Scala tympani
The oval window opens into the upper chamber, the _____
Scala vestibuli
A thin membrane, the ______ separates the Scala vestibuli from the middle chamber
Reissner’s Membrane
The middle chamber of the cochlea also known as the cochlear duct is the ________
Scala Media
A thick membrane, the _____, separates the Scala Media from the lower chamber
Basilar Membrane
The lower chamber of the cochlea also known as the ______
Scala Tympani
The scala tympani and the scala vestibuli are filled with a fluid called _______, a fluid derived from tympani
Perilymph
The scala media contains _____, which is produced by the scala media itself, it contains high concentrations of potassium ions
Endolymph
The receptors for hearing are found on the basilar membrane in the scala media, these receptors are called the _____ of _____
Organ of Corti
The organ of corti is a mechanoreceptor consisting of an array of _____ cells below a membrane called the tectorial membrane
hair cells
What are the two types of deafness, ____ and ____ deafness
Nerve and Conduction Deafness
In this type of deafness, neither vibrations transmitted through the external and middle ear, nor the vibrations conducted directly through the bones of the skull are perceived
Nerve Deafness
In this type of deafness, transmission of sound vibrations from the external ear to the inner ear is impeded, usually caused by damage to the tympanic membrane, fusion of the ossicles, accumulation of ear wax, plugged Eustachian tubes or other blockages
Conduction Deafness
Taste receptors called ____ ____ consist of groups of about 40 cells each embedded in the epithelial tissue of the tongue
taste buds
Taste buds are an example of _____ receptors, due to molecules of substances entering the mouth binding to proteins in the membranes of the microvilli causing them to stimulate sensory neurons located below them
Chemoreceptors
Taste buds receptors can be categorized into five categories : _____ _____ _____ _____ and ______
Salty, Sweet, Bitter, Savory, and Umami
The spinal cord is separated into two halves right and left, by an ____ and _____
anterior fissure and a posterior sulcus
A narrow band of grey matter called the ______ _____, forms a communication link between the two halves
gray commissure
A ____ _____ continuous with the ventricles of the brain is found in the gray commissure
central canal
