Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
68 Cards in this Set
- Front
- Back
|
To what do the terms, central nervous system (CNS) and peripheral nervous system (PNS) refer? |
-CNS is the brain & spinal cord -PNS is the cranial nerves (12 pairs) and spinal nerves (31 pairs) and the associated ganglia. |
|
|
The PNS is divided into two main divisions, what are they? |
-Afferent (bringing info to brain) & Efferent (bringing signals away from brain & spinal cord)
|
|
|
How is a neuron different from a nerve? |
A nerve is a bundle of neurons (single nerve cells). |
|
|
What type of neuron synapses with skeletal muscle cells? |
-An efferent somatic motor neuron (also known as lower motor neurons/ alpha motor neurons) |
|
|
What two types of neurons synapse with smooth muscle, cardiac muscle or glandular cells? |
-Sympathetic & parasympathetic neurons |
|
|
Where is a muscle spindle apparatus found? |
-Amongst the regular muscle fibers (extrafusal fibers) usually near the tendon. |
|
|
What's the function of a muscle spindle apparatus? |
-monitors the length of the muscle fibers (particularly, sudden changes in length) |
|
|
Where is the Golgi Tendon Organ found? |
-in the tendon of the muscle |
|
|
How the Golgi Tendon Organ's function different from the muscle spindle apparatus? |
-It monitors the tension of the muscle fibers (tension is the amount of contraction w/o shortening of the muscle) |
|
|
What is a reflex (arc)? |
The direct interaction of a sensory neuron & a motor neuron at the spinal cord. |
|
|
Does the number of neurons involved vary from one reflex to another? |
Yes |
|
|
What is the simplest reflex? |
-Monosynaptic Stretch Reflex Arc |
|
|
How many synapses are involved in the simplest reflex? |
-one (mono) |
|
|
In reciprocal innervation (in flexor –extensor muscle pairs) when one of the pair is stimulated to contract, what neural activity prevents the other muscle from contracting so that they will not work against each other? |
-The activation of an inhibitory interneuron |
|
|
What are the functions of interneurons in a reflex pathway? |
In general, they are inhibitory. |
|
|
Do all interneurons stimulate (depolarize) other neurons? |
-No. |
|
|
What are spinal nerves? |
-The bundles of sensory & motor neurons that are bringing info to the CNS & activating skeletal/other types of muscles. |
|
|
How many spinal nerves does the human body have? |
-31 pairs 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal |
|
|
By which pathway do sensory fibers enter the spinal cord? |
-The Dorsal Root |
|
|
Which pathway do the motor fibers use to exit the spinal cord? |
-The ventral root |
|
|
What is the dorsal root ganglion? |
-The part where the majority of the sensory neuron cell bodies reside. |
|
|
What is the function of a sensory receptor? |
-Sensory receptors sample bot he external & internal environments. -Internally, they help to monitor homeostasis -Externally, they are sampling the external environment for changes that may affect the body as a whole, & aid in the body to interact w/the external environment. |
|
|
Do receptors respond to a variety of different stimuli? |
-No, this property is referred to as the Law of Specific Nerve Energies |
|
|
What part of a nerve makes up the receptor region? |
-the cell body/dendritic area of the neuron |
|
|
What types of stimulus are transduced to the CNS? |
Each receptor is specific for only 1 type of stimulus, i.e. changes in pressure. If the stimulus is encountered, the receptor "transduces" (converts) the stimulus to APs that are sent to the CNS. |
|
|
What are tonic receptors? |
-Receptors whose frequency is always directly proportional to the magnitude of the stimulus. |
|
|
What are phasic receptors? |
-Receptors that act to "alert" the brain. -When they are stimulated, they exhibit a burst of action potentials which quickly subside to a low level frequency of action potentials (adaptation) |
|
|
What is a generator potential? |
The equivalent of an EPSP which occurs on the receptor membrane. |
|
|
To what modality do the receptors in our eyes respond to? |
-light |
|
|
What are rods and cones and what are the differences between them? |
Both detect different aspects of light entering the eye. -The cones (which have 3 subtypes) respond to different colors. -The rods help to distinguish different levels of low light. |
|
|
How does the body control the amount of light that is allowed to interact with our rods and cones? |
By dilation (contraction of the radial muscle) of the iris, or constriction (contraction of the circular muscle) of the iris. |
|
|
What is the fovea centralis? |
-A portion of the retina that contains a high concentration of cones. |
|
|
What is the function of the fovea centralis? |
-It is responsible for sharp (focused) vision. |
|
|
What is the optic disk? What is its function? |
"blind spot" -Where no vision occurs; it is where all neurons and blood vessels (arteries & veins) converge & exit thru the retina. -Completely devoid of rods & cones |
|
|
What is accommodation? |
- the ability to focus an object, either far away or close up, directly on the fovea centralis |
|
|
How is accommodation controlled with respect to vision? |
-The ciliary muscles of the eye relax or contract to flatten or curve the lens of the eye, so that the image stays focused on the fovea centralis. |
|
|
Decussate |
-the term for neurons crossing-over in a spinal tract |
|
|
Pyramidal/corticospinal |
-The corticospinal tract is included in the pyramidal tract. -It is an aggregation of the upper motor neuron nerve fibers that travel from the cerebral cortex and terminate in the spinal cord. -Involved in our motor functions of the body. |
|
|
Reticulospinal |
- an extrapyramidal motor tract that descends from the reticular formation in two tracts to act on the motor neurons supplying the trunk and proximal limb muscles. It is involved mainly in locomotion and postural control |
|
|
Cranial nerve X = Vagus |
-interfaces with parasympathetic control of the heart and digestive tract |
|
|
Transduce |
-To change environmental info into APs --the common language of the NS
|
|
|
Modality |
-a particular form of energy (sound, light, pressure) that neurons respond to. |
|
|
Acuity |
-The capacity of the eye to see fine detail |
|
|
Receptive Field |
-Each somesthetic sensory neuron responds to stimulus information only within a circumscribed region of the skin surface surrounding it |
|
|
Cutaneous receptors |
-a type of sensory receptor found in the dermis or epidermis |
|
|
Adequate stimulus |
-Each type of receptor is specialized to respond to one type of stimulus |
|
|
Tonic receptors |
-those whose frequency is proportional to that of the magnitude of the stimulus |
|
|
Phasic receptors |
-Those who act to "alert" the brain. -They exhibit a burst of APs when stimulated, which quickly subside to a low level frequency of APs (adaptation) |
|
|
Generator potentials |
-The equivalent of an EPSP which occurs on the RECEPTOR membrane. |
|
|
Rods/Cones |
-Rods help to distinguish the different levels of low light. -Cones have 3 subtypes that respond to different colors for varying wavelengths. |
|
|
Reflex arc |
-a simple sensory input, motor output circuit involving only peripheral nerves & the spinal cord. |
|
|
Accommodation |
-The ability to focus an object (far/close up) directly on the fovea centralis. |
|
|
Golgi tendon organ |
-Monitors tension in muscle fibers |
|
|
Muscle spindle apparatus |
-Monitors the length of muscle fibers (particularly sudden changes in length) |
|
|
Intrafusal fiber |
- lie within spindle-shaped connective tissue capsules. - has a noncontractile central portion, with the contractile elements being limited to both ends |
|
|
Extrafusal fiber |
-the "ordinary" muscle fibers |
|
|
Nuclear bag fiber |
- responds to a certain type of stretch ( a sudden stretch of a muscle |
|
|
Nuclear chain fibers |
- respond to sustained stretch of a muscle |
|
|
Alpha motor neurons |
-Activates the extrafusal fibers -coactivated w/the gamma-motor neuron |
|
|
Gamma motor neurons |
-shortens the muscle spindle apparatus proportionally -coactivated w/the alpha-motor neuron |
|
|
Coactivation |
-(simultaneous stimulation) of the gammamotor-neuron system along with the alpha-motor-neuron system during refl ex and voluntary contractions |
|
|
Monosynaptic-stretch reflex |
-The simplest reflex arc |
|
|
Reciprocal innervation |
1. Muscle stretch activates spindle apparatus 2. Agonist muscle contracts in stretch reflex 3. Antagonist muscle relaxes |
|
|
Crossed-extensor reflex |
1. Flexor contracts & extensor relaxes to withdraw leg 2. Extensor contracts & flexor relaxes in contralateral leg to support weight |
|
|
What type of neuron is attached to or associated with a sensory receptor? |
An afferent neuron |
|
|
mechanoreceptors |
respond to deformation of their cell membrane |
|
|
Extrapyramidal |
part of the motor system that causes involuntary reflexes and movement, and modulation of movement (i.e. coordination) |
|
|
Macular Degeneration |
This condition is characterized by loss of photoreceptors in the macula lutea in association with advancing age. |
