Flashcards in A & P Exam 3 Deck (314):
Microscopic nerve cells or nerve fibers are also called
Where are neurons found?
Brain, spinal cord, peripheral nerves
What is the basic functional unit of the nervous system?
Neurons have a high requirement for what?
What do neurons use for energy?
Neurons cannot reproduce but can regenerate cell processed if the cell ____ remains intact
These cells structurally and functionally support and protect the neurons.
Neuroglia or glial cells
There are __X as many glial cells as there are neurons.
Are glial cells directly involved in the transmission of information or impulses through the nervous system?
The central cell body of a neuron is also called (2 names)
soma or perikaryon
This nerve cell process receives stimuli from other neurons and conducts the stimuli to the cell body. Short, numerous, multi-branched projections extending from the cell body.
This nerve cell process conducts nerve impulses away from the cell body toward another neuron or an effector cell. They are single, long processes.
These nerve cell processes may be modified into sensory receptors that receive stimuli such as heat, cold, touch, pressure, stretch, or other physical changes from inside or outside the body.
A cell that does something when stimulated such as a muscle or gland cell.
Axons may be covered with a fatty substance that appears white.
Nervous tissue containing many myelinated axons is called
Nervous tissue made up largely of neuron cell bodies appears as
Do myelinated axons conduct impulses faster or slower than unmyelinated ones?
Cell membrane of glial cells tightly wrapped around the axon is called a
Glial cells located in the brain and spinal cord are called
Glial cells in the nerves outside the brain and spinal cord are called
Gaps between adjacent glial cells on a myelin sheath are called
Nodes of Ranvier
A group of axons outside the CNS
A group of axons inside the CNS
A collection of cell bodies located outside the CNS
A cell body that is outside the CNS in a ganglion
A cell body entirely within the CNS
A cell body in the spinal cord, and axon outside the CNS is called
Cell bodies are located in the ____ (sensory) or in the _____ (motor).
Does a nerve contain cell bodies?
Within a nerve, each fiber (axon) is surrounded by a connective tissue sheath called an ______, which insulates it from the other neurons adjacent to it.
Groups of fibers are bound by a coarser connective tissue, called the
Finally, all fascicles are bound together by a tough, fibrous connective tissue sheath called the
Blood vessels and lymphatic vessels serving the fibers also travel within the
The brain and spinal cord make up the
Central Nervous System (CNS)
This nervous system consists of nerves that link the CNS with the rest of the body
Peripheral nervous system (PNS)
Cranial nerves originate directly from the
Spinal nerves emerge from the
The PNS is separated into what?
Somatic nervous system and Autonomic nervous system
Voluntary nervous system with input from sense organs and output to skeletal muscles is called the
Somatic nervous system
Involuntary nervous system with input from internal receptors and output to smooth muscles and glands is called
Autonomic nervous system
The autonomic nervous system is divided into
Sympathetic and Parasympathetic motor systems
Autonomic motor system that initiates "fight or flight" responses. Involves neurotransmitter noradrenaline, so also called Adrenergic System.
Sympathetic Motor System
Autonomic motor system in charge of relaxing responses. Involves neurotransmitter acetylcholine, so also called Cholinergic System.
Parasympathetic Motor system
The sympathetic motor system is also known as
The parasympathetic motor system is also known as
Somatic motor nerves send impulses to
This nervous system is in charge of functions that determine the relationship of the animal to the outside world.
This nervous system is in charge of functions that relate to the internal environment of the animal.
Autonomic motor nerves send impulses to (3)
smooth muscle, cardiac muscle, and glands
An animal turning its head in response to its name being called is an example of autonomic or somatic?
Slowing of the heart rate in response to an increased blood pressure is an example of autonomic or somatic?
These nerves, also called sensory nerves, conduct impulses toward the CNS. They conduct sensations from sensory receptors in the skin and other locations in the body to the CNS.
These nerves, also called motor nerves, conduct impulses away from CNS towards muscles and other organs.
This type of nerve causes muscle contraction and movement among other things. They also cause glands to excrete a substance.
Cranial and spinal nerves in the PNS and nerve tracts (bundles of axons) in the CNS may carry which type of nerve fibers?
Sensory and motor
Afferent nerves are also called
Efferent nerves are also called
Perception of pain from an injection of antibiotics is controlled by
Conscious movement of a forelimb is controlled by
Perception of the amount of acidity present in the duodenum is controlled by
Slowing of heart rate in response to an increased blood pressure is controlled by
Autonomic, sensory: sensing the increased blood pressure
Autonomic, motor: slowing the heart rate
Constriction of blood vessels in the skin in response to cold temps is controlled by
Somatic, sensory: sensing cold temps
Autonomic, motor: constricting the vessels
What are the 4 different areas of the brain?
cerebrum, cerebellum, diencephalon, brain stem
Largest part of the brain in domestic animals. Area responsible for higher-order behaviors (learning, intelligence, awareness). Contains corpus callosum, gray and white matter.
Ear shaped area in the cerebrum is called the
Cerebral cortex; outer layer of the brain made up mainly of neuron cell bodies
Made up mainly of myelinated axons; fibers beneath the cortex and corpus callosum (fibers that connect the 2 halves of the cerebral cortex).
Folds or hills in the cerebral hemispheres.
Shallow grooves separating the gyri. Divides the cerebral hemispheres into lobes.
Deep grooves separating the gyri are called
Prominent fissure that divides the cerebrum into right and left cerebral hemispheres.
The 2nd largest component of the brain. Located just caudal to the cerebrum. Area of the brain responsible for coordinated movement, balance, posture, and complex reflexes.
Feline panleukopenia due to viral infection of the dam during pregnancy can cause a undergrowth of the cerebellum called
congenital cerebellar hypoplasia
Passageway between brain stem and cerebrum. Contains the thalamus, hypothalamus and pineal body(*different from what book says).
Located in the diencephalon. Acts as a relay station for regulating sensory inputs to the cerebrum
Located in the diencephalon. Interface between the nervous system and the endocrine system.
Located in the diencephalon. Produces serotonin derivative melatonin, a hormone that affects the modulation of wake/sleep patterns and seasonal fuctions.
This structure is associated with the diencephalon. It is the endocrine "master gland" that regulates hormone production and release.
The connection between the rest of the brain and the spinal cord. Composed of the medulla oblongata, pons, and midbrain. Area responsible for basic support functions (heart, respiration, swallowing, vomitting). Many of the cranial nerves originate from this area of the brain.
A set of connective tissue layers that surround the brain and spinal cord. Contains blood vessels, fluid, and fat. Supply nutrients and O2 to the superficial tissues of the brain and spinal cord. Provides some cushioning and distribution of nutrients of the CNS.
What are the 3 tissue layers of the meninges?
Dura mater, arachnoid, pia mater
The tough, fibrous outer tissue layer of the meninges, just deep to the skull bone.
The delicate, spiderweb-like tissue layer of the meninges, deep to the subdural space.
The very thin tissue layer of the meninges that lies directly on the surface of the brain and spinal cord. Deep to the subarachnoid space.
Fluid between layers of the meninges (subarachnoid space) and in ventricles (inside the brain) and the central canal (of spinal cord). Provides cushioning fuctions, regulation of autonomic functions such as respiration and vomiting, diagnostic tool.
Cerebrospinal fluid (CSF)
Where is CSF located (3)?
Subarachnoid space, ventricles (brain), and central canal (spinal cord)
What is the procedure called when collecting CSF from subarachnoid space between the atlanto-occipital joint or L5-L6?
Contrast injected into the subarachnoid space at L5-L6 is called
A local anesthetic injected in the epidural space is called
Space between the dura mater and surrounding bone is called
There is no epidural space in the skull because the dura mater is fused with the
The restriction of large molecules to the vascular space is the result of tight junctions between neighboring capillary endothelial cells in the brain. This is called the
This prevents many drugs, proteins, ions, and other large molecules from readily passing from the blood into the brain.
This type of junction, located in the capillaries of the blood-brain barrier are not found in capillaries elsewhere in the body.
In addition to tight junctions, the blood-brain barrier also contains processes of ____ cells that surround the outside of capillary endothelial cells.
A protein found on endothelial cells impedes transport of various drugs from the capillaries to the brain. Approximately 35% of collies have a genetic mutation creating a non-functional protein here. This allows for ivermectin doses that would normally be blocked from the CNS to gain access to it. What is this condition called?
How many cranial nerve pairs originate directly from the brain stem?
12 (numbered in Roman numerals)
What are the 2 cranial nerves that do not originate from the brain stem?
Olfactory and optic
Each cranial nerve may contain axons of motor neurons, axons of sensory neurons, or
combinations of both
The outer portion of the spinal cord that consists of white matter and surrounds the gray matter.
The central part of the spinal cord composed of gray matter.
This structure of the spinal cord contains the residual embryonic neural tube.
The dorsal nerve roots contain ____ fibers.
The ventral nerve roots contain ___ fibers.
The dorsal and ventral nerve roots emerge from the spinal cord between each pair of adjacent
Neurons in gray matter of the spinal cord that forward sensory nerve impulses to brain or other parts of the spinal cord.
Neurons in gray matter of the spinal cord that forward motor (efferent) nerve impulses to the spinal nerves
When a neuron is not being stimulated, it is in a
Difference in electrical charge across a neuronal membrane. The inside of the neuron is more negatively charged than the outside.
Resting membrane potential
Neuron receives external stimulus. Sodium channel opens on neuron cell membrane. Sodium ions flow into cell by passive diffusion. These are steps associated with
Sodium channels close; K+ channels open; K+ diffuses out of the cell; the net negative charge in the cell is restored; K+ channels close. These are steps associated with
The Na+ & K+ ions are now on opposite sides from where they began. Sodium-potassium pumps moves sodium & potassium ions back to their original sides. Resting state restored. These are steps associated with
Specialized molecule that helps maintain cell resting state. It is an antiport since it pumps ions in different directions.
The Na+-K+ pump pumps how many Na+ ions from inside the neuron to the outside?
The Na+-K+ pump pumps how many K+ ions from outside the neuron to the inside?
The stimulus must be sufficient to make the neuron respond and cause complete depolarization. This is known as the
The neuron depolarizes to its maximum strength or not at all. This principle is known as the
all or nothing principle
The initial stimulus causes a spreading wave of opening sodium channels to travel along the cell membrane of the entire neuron. This is called the wave of depolarization, conduction of action potential, or
Time period during which a neuron is insensitive to additional stimuli is called the
What are the 2 refractory periods?
Absolute and relative
The refractory period during sodium influx and early potassium outflow. Cell is still in depolarization/early repolarization. The cell cannot respond to stimuli.
Absolute refractory period
The refractory period during end of the repolarization period. It may be possible to stimulate another depolarization if stimulus is very large.
Relative refractory period
Myelin sheath prevents Na+ ions from flowing across the neuronal cell membrane. Depolarization wave in myelinated axons skips from 1 node of Ranvier to the next. Rapid means of conducting an action potential. This is called the
Immune system destroys the myelin covering axons resulting in delayed transmission nerve impulses known as
What happens when the depolarization wave has been successfully conducted to the end of the axon?
Neuron must release neurotransmitters to stimulate the next neuron or cell.
The perpetuation of nerve impulse from one neuron to the next cell is called
The junction between 2 neurons or a neuron and a target cell is called a
The gap between 2 adjacent neurons
The neuron bringing the depolarization wave to the synapse and releasing the neurotransmitter is called the
The neuron that contains receptors for the neurotransmitter being released is called the
The branched structure on the presynaptic neuron that contain vesicles and have a terminal button.
The slightly enlarged bulb on the end of each telodendron. Also called the synaptic end bulb or synaptic knob.
The neurotransmitter is contained in _____ in the knob of the presynaptic neuron.
When _______ _____ reaches the synaptic knob, vesicles fuse with the knob's cellular membrane and dump neurotransmitter into the synaptic cleft.
______ on the postsynaptic membrane bind to the neurotransmitter. They are very specific about which neurotransmitters they will bind.
What are the 2 types of neurotransmitters?
Inhibitory and excitatory
This type of neurotransmitter usually causes an influx of sodium so that the postsynaptic membrane moves toward the threshold.
This type of neurotransmitter may cause Cl- channels or K+ channels to open up on the postsynaptic membrane. They will make the charge within the postsynaptic cell even more negative which moves it farther away from the threshold.
This neurotransmitter can be either excitatory or inhibitory depending on its location in the body. It is excitatory to skeletal muscle cells and has an inhibitory effect on the heart rate.
Acetylcholine binds to what receptors?
Muscarinic and nicotinic are types of ____ receptors.
Norepinephrine, epinephrine, and dopamine are what type of neurotransmitter?
Norepinephrine is associated with the _____ nervous system.
Epinephrine plays a role in the "fight or flight" reactions of the ____ nervous system. It is primarily released from the adrenal medulla.
Dopamine is involved with ____ functions and muscle control. It is mostly inhibitory.
Vassopressor is a type of _____ that constricts blood vessels causing increased blood pressure.
Catecholamines bind to what receptors?
What are the 3 types of adrenergic receptors?
Alpha 1, beta 1, beta 2
A type of inhibitory neurotransmitter found in the brain. It cannot be manipulated by drugs.
GABA (gamma-aminobutyric acid)
A type of inhibitory neurotransmitter found in the spinal cord. It cannot be manipulated by drugs.
What would happen if the neurotransmitter were allowed to remain in the synapse or on the postsynaptic receptor?
The postsynaptic neuron would continue to be excited or inhibited.
The enzyme found on the postsynaptic membrane that breaks down acetylcholine.
Organophosphates in ____. Parasympathetic nervous system is overstimulated. SLUDD
Monoamine oxidase (MAO) & catechol-o-methyl transferase (COMT) break down which neurotransmitter?
MAOI's act as ______. Allows norepi to prolong its excitatory effect on the brain.
This nervous system controls automatic functions at the subconscious level. It differentiates into sympathetic and parasympathetic.
For the sympathetic nervous system, nerves emerge from which parts of the CNS?
thoracic and lumbar vertebral regions (thoracolumbar system)
For the parasympathetic nervous system, nerves emerge from which parts of the CNS?
brain and sacral vertebral regions (cranial-sacral)
Efferent motor nerves of sym & parasym nervous systems are composed of a sequence of at least ___ neurons to conduct an impulse from the spinal cord or brain to a muscle or gland.
What are the 2 neurons of the efferent motor nerves called?
This efferent neuron has its cell body in the brain or spinal cord and the axon extends out from the CNS to an autonomic ganglion.
A cluster of neuronal cell bodies outside the CNS
A series of autonomic ganglia outside the thoracolumbar area of the spinal cord.
sympathetic ganglion chain
Sympathetic ______ neuron synapses w/either a neuron in the ganglion chain or a neuron beyond the sympathetic ganglion chain.
Which preganglionic neuron travels directly from the brain and sacral region of the spinal cord to its target organ?
Which system has a long preganglionic neuron and a short postganglionic neuron?
Which system has a short preganglionic neuron and a long postganglionic neuron?
What is the primary neurotransmitter of the sympathetic nervous system?
Neurons that release norepinephrine are what kind of neurons?
Alpha 1, and adrenergic receptor, cause vasoconstriction of what?
Skin, GI tract, & kidneys
Beta 1, and adrenergic receptor, increases what?
heart rate & force of contraction
Beta 2, and adrenergic receptor, causes what?
Beta blockers are used for
high blood pressure
The primary neurotransmitter of the parasympathetic nervous system is
Neurons that release Ach are
Anticholinergic drugs, such as ____, bind to cholinergic receptors blocking Ach from binding.
Both sympathetic and parasympathetic preganglionic neurons release
This type of Ach receptor is found on postganglionic neurons of sympathetic & parasympathetic systems & between motor neurons and muscles.
This type of Ach receptor is found on target organs and tissues supplied by the postganglionic neuron of the parasympathetic nervous system.
Disease in which autoantibodies specific for Ach receptors block and/or damage receptors. Csx: generalized muscle weakness, megaesophagus. Diagnosis: reversal of signs following test dose of anticholinesterase drugs.
Anticholinesterase drugs prevent the breakdown of
Which nervous system does this describe?
preganglionic neuron> ach> nicotinic receptor on postganglionic neuron> norepi> adrenergic receptor (a1, b1, b2) on tissue
Which nervous system does this describe?
preganglionic neuron> ach> nicotinic receptor on postganglionic neuron> ach> muscarinic receptor on tissue
Rapid, automatic responses to stimuli in the internal or external environment designed to protect body and maintain homeostasis.
Reflex happens ____ and an impulse will be sent to the brain as long as there isn't a lesion interrupting it on the way to the brain.
All reflexes have the same basic structure call the
This receptor receives a stimulus, reaches threshold, and sends the nerve impulse along the sensory neuron to the gray matter of the spinal cord or brain stem.
Where does the sensory neuron travel to get to the spinal cord and what part of the spinal cord does it go to for the reflex arc.
dorsal nerve root, dorsal horn
These neurons serve to integrate incoming sensory impulse with other impulses from other sensory neurons. They are located in the CNS.
This neuron sends an impulse to the target organ (muscle or gland).
What part of the spinal cord is the motor neuron located in and where does it leave the spinal cord for the reflex arc.
ventral horn, ventral nerve root
This type of reflex involves contraction of skeletal muscles.
This type of reflex regulates smooth muscle, cardiac muscle and endocrine glands.
This type of reflex starts on one side of the body and travels to the opposite side.
This type of reflex, the stimulus and response are on the same side of the body.
This type of reflex arc is the simplest. It involves a sensory neuron & a motor neuron with only 1 synapse between them without any interneurons.
Monosynaptic reflex arc
This type of reflex is also known as the flexor reflex. It involves several interneuron synapses and results in contraction or flexing of muscles.
This type of reflex is a contralateral reflex. If withdrawal reflex is initiated, afferent sensory neuron synapse with interneurons and causes contraction of opposite extensor muscles.
Crossed extensor reflex
With injury, intact reflex arcs caudal to the spinal cord trauma become
Trauma where reflex arc enters or leaves the spinal cord, or damage to the sensory nerve or motor nerve of the reflex, results in either _____ or absent reflex arcs.
Light tap on the medial canthus of the eye produces a blink of the eyelids.
Normal response to shining light in the eye of an animal is for the iris in both eyes to constrict.
Pupillary light reflex (PLR)
Touch, hearing and balance are what types of stimuli?
Hot and cold are what types of stimuli?
Vision is what type of stimuli
Taste & smell are what type of stimuli?
How many senses are there?
This type of sense if distributed generally throughout the body. It includes visceral, touch, temperature, pain, proprioception.
This type of sense if organized into specific, often complex sensory organs & structures all located in the head. It includes taste, smell, hearing, equilibrium, vision.
Hunger, thirst, hollow-organ fullness are part of what sense? Also includes stretch receptors in GI tract & urinary bladder. If wall of organ is stretched, it is very painful with the exception of the urinary bladder. Organs can be handled, cut or crushed without any apparent pain.
Body position and movement are part of what sense?
Pain involves what type(s) of stimulus?
Mechanical, chemical or thermal
Visceral sensations involve what type(s) of stimulus?
chemical and mechanical
Sensation of something being in contact with the surface of the body. Also known as tactile sense.
Sensation of something pressing on the body surface.
Temperature receptors in the skin; detect upward and downward changes in skin temperature.
Superficial temperature receptors
Temperature receptors in the hypothalamus; monitor the temperature of the blood
Central temperature receptors
Pain receptors are called
The process of experiencing pain
Pain receptors are widely distributed inside & on the surface of the body but are not present in one organ.
What are the 4 processes of nociception?
transduction, transmission, modulation, perception
The conversion of stimulus into nerve impulse. Part of nociception.
The conduction of nerve impulse to the spinal cord. Part of nociception.
Changing of the sensory nerve impulses can occur in the spinal cord & significantly influence the information the brain receives. Can amplify or suppress sensory impulses.
Awareness of painful stimuli. Conscious perception occurs in the cerebral cortex as well as other areas of the brain.
Prevention of modulation during surger?
Give pre-analgesics & local anesthetics
Stretch receptors for this sense are located in skeletal muscles, tendons, ligaments & joint capsules. Receptors keep the CNS informed about the movements of limbs, positions of joints, the state of contraction of muscles, and the amount of tension being exerted on tendons & ligaments.
Taste is also known as
What is the stimulus for the gustatory sense?
Chemical receptors for taste are located in taste buds on the sides of ____. They are also found in the lining of the mouth and _____.
Taste buds are tiny, round structures made up of ____ cells.
Tiny openings on the surface of each taste bud that allow dissolved substances to enter the taste buds & contact the sensory receptors.
What is the stimulus of olfactory sense?
What cranial nerves are involved in taste?
CN VII: facial, both sensory & motor
CN IX: glossopharyngeal, both sensory & motor
Where is the olfactory region located?
High in nasal passages
Olfactory epithelium is made up of what 2 types of cells?
Sensory (olfactory) cells and supporting cells
What projects up from the olfactory cells into the icons layer that covers the epithelium?
Hairlike processes (modified dendrites)
Odor molecules dissolve in the ....... And contact the sensory processes.
What cranial nerve is involved in the olfactory sense?
CN I: olfactory, sensory
Hearing is also know as what?
What type of stimulus is involved in hearing?
Hearing converts ...... Of air molecules into nerve impulses.
What cranial nerve is involved in hearing?
CN VIII: vestibulocochlear, sensory
This part of the ear acts as a funnel to collect sound wave vibrations and direct them to the eardrum.
This part of the ear amplifies and transmits the vibrations from the eardrum to the inner ear
This part of the ear contains the sensory receptors that convert the mechanical vibrations to nerve impulses, along with receptors for the equilibrium sense.
This structure of the external ear is made of elastic cartilage and skin.
This structure of the external ear is usually an L shaped membrane lined tube. It includes a vertical and horizontal section.
External ear (auditory) canal
This structure, also known as the eardrum, is in the external ear.
Sound wave vibrations strike the tympanic membrane and cause it to
The middle ear is located in what part of the skull?
The middle ear is filled with air and contains the ossicles and the opening of the
These 3 small bones in the middle ear link the tympanic membrane with the cochlea of the inner ear. They act as a system of levers that transmit sound wave vibrations from the tympanic membrane to the cochlea. What is the name for all 3 bones?
The outermost ossicle, attached to the tympanic membrane. Also called the hammer.
The middle ossicle, also called the anvil.
The medial most ossicle, attached to the membrane that covers the oval window of the cochlea. Also called the stirrup.
This connects the middle ear cavity with the pharynx. It equalized air reassure on the two sides of the tympanic membrane. Swallowing or yawning causes the slit like opening of this to stretch open allowing are to enter or leave to equalize pressure.
The procedure that allows access to the middle ear. Fluid can then be removed from the middle ear.
What structures are in the inner ear?
Cochlea, vestibule, semicircular canals
The hearing portion of the ear is located in the
A snail shell-shaped spiral cavity in the inner ear
The receptor organ of hearing is the
Organ of corti
The long tube in the cochlea that contains the organ of corti and is filled with endolymph.
The cochlear duct is filled with fluid called
A U-shaped tube containing another fluid, ......., lies on either side of the cochlear duct.
These windows are membrane-covered openings at the ends of the U-shaped tube in the inner ear.
Round window and oval window
The Organ of Corti consists of these hearing receptors, supporting cells, and tectorial membrane.
What are the receptor cells of hearing? They have tiny, hairlike projections (modified dendrites) on their surfaces.
The gelatin-like tectorial membrane lies ..... Of the hair cells. (Above or below)
Sound wave vibrations cause the ....... ...... and ossicles in the middle ear to vibrate
As the stapes vibrates back and forth, it pushes and pulls the membrane covering the
The vibration of the oval window causes the ...... around the cochlear duct to vibrate.
The membrane of the ..... ........ acts as a pressure relief.
Fluid vibration causes the cochlear duct to move which causes the tectorial membrane and the hair cells of the ...... ... ...... To rub against each other. This generates nerve impulses that travel to the brain and are interpreted as sound.
Organ of Corti
Equilibrium has what type of stimulus?
This sense helps maintain balance by keeping track of the position and movements of the head
Equilibrium involves receptors and info from the ..... And ......
Eyes and proprioceptors
Receptors for equilibrium are located where in the inner ear?
Vestibule and semicircular canals
This structure of the inner ear is located between the cochlea and semicircular canals. It is composed of 2 saclike spaces that are continuous with the cochlear duct and filled with the same endolymph and surrounded by perilymph.
What are the 2 saclike spaces in the vestibule?
Utricle and saccule
In each utricle and saccule is a patch of sensory epithelium called the
In the macula are crystals of calcium carbonate called
What causes otoliths and the gelatinous matrix to put pressure on the hairs in the vestibule?
The movement of the head bends the sensory hairs. This generates nerve impulses that give the brain information about the ______ of the head.
This structure related to equilibrium is located opposite the vestibule from the cochlea.
Three semicircular canals oriented in different planes at ___ angles to each other.
Endolymph-filled membranous tubes of the semicircular canals are surrounded by
The enlarged area near the utricle end of each semicircular canal is called an
The receptor within the ampulla of the semicircular canals. Similar to the macula of the vestibule. Supporting cells and hair cells with modified dendrites sticking up into the cupula.
The gelatinous structure that functions as a float that moves with the endolymph in the semicircular canals.
When the head moves, endolymph movement in the semicircular canals lags behind the movement of the canal itself. This generates impulses that give the brain information about ____ of the head.
Photoreceptors that detect the image and generate visual nerve impulses are in a single layer of cells in the
What cranial nerves are involved in vision?
CN II: optic, sensory
CN III: oculomotor, motor
What are the 3 layers of the eyeball?
outer fibrous layer
middle vascular layer
inner nervous layer
This part of the eye is transparent and admits light to the interior of the eye. It is richly supplied with pain receptors. Arrangement of collagen fibers, no blood vessels.
Corneal edema or corneal dehydration causes the cornea to become
This is the "white" of the eye made of dense fibrous connective tissue.
The junction of the cornea and the sclera
This area of the eye, also called the middle vascular layer, contains the choroid, iris & ciliary body.
This area of the eye is between the sclera and retina. It contains pigment and the blood vessels that supply the retina. In most animals, (except people & swine) it forms the tapetum lucidum.
The highly reflective area in the rear of the eye. It acts as an amplifier to aid low-light vision.
After light has passed through the photoreceptors, it reflects off the _____ and passes back through the photoreceptors again, stimulating them a second time.
This part of the middle vascular layer of the eye is the pigmented muscular diaphragm. It controls the amount of light that enters the posterior part of the eyeball.
The opening at center of iris
The muscle fibers of the iris that are arranged ____ (radially or circularly) enlarge the pupil when the contract.
The muscle fibers of the iris that are arranged ____ (radially or circularly) constrict the pupil when the contract.
The condition when the pupils of an animal are different sizes.
The ring-shaped structure behind the iris. Contains tiny muscles that adjust shape of the lens to allow near & far vision.
The muscles contained within the ciliary processes attached to the lens by the
This structure of the inner nervous layer of the eye lines the back of the eye and contains the sensory receptors for vision, the rods & cones
This compartment of the eye is in front of the lens. It contains a clear watery fluid. It is subdivided into anterior & posterior chambers.
The clear, watery fluid in the aqueous compartment