Central Nervous System Flashcards
The nervous system consists of what ?
A sensory part (sensory input)
A central part (integrative portion )
Motor part (motor output )
The nervous system is subdivided into what ?
Central nervous system
Peripheral nervous system
What is the CNS consisting of ?
Brain protected by the skull
Spinal cord enclosed by the vertebral column
The peripheral nervous system consists of what ?
12 pairs of cranial nerves
31 pairs of spinal nerves
What is the structural unit of nervous system ?
Neuron
What are the type of neuroglial cells?
Microglia
Macroglia - oligodendroglia, Schwann cells, astrocytes
What are astrocytes important for ?
Blood-brain barrier
What is a synapse ?
The site of contact between two neurons
What are the two methods by which synaptic transmission occurs ?
Chemical synapse
Electrical synapse
What are the excitatory chemical transmitters ?
Acetyl choline
Noradrenaline
Dopamine
Serotonin
What is spatial summation ?
Many synaptic knobs discharge at the same time
What is temporal summation ?
Rapid, repeated discharge from single knob
What are the inhibitory chemical transmitters ?
GABA
Glycine
What are the properties of synaptic transmissions ?
Law of forward direction
Synaptic delay
Synaptic fatigue
Summation of post synaptic potential
How long is the synaptic delay ?
O.5 msec
What is the synaptic delay needed for ?
For release of neurotransmitters from the synaptic knobs
What are type of somatic sensations ?
Superficial
Deep sensations
Combined sensation
Superficial sensations include what ?
Pain
Temperature
Touch
What are the two types of touch ?
Crude (light) touch
Fine touch
What does fine touch include ?
Tactile localization
Tactile discrimination
What is tactile localization ?
The ability of the person with closed eyes to localize the stimulated area of the skin
What is tactile discrimination ?
The ability of the person with closed eyes to differentiate between 2 touch stimuli
What is deep sensation ?
From muscles, tendons, ligaments and joints
Deep sensations includes what?
Proprioceptive sensation
Deep pressure sense
Sense of muscle tension
Muscle sense
What does proprioceptive sensation include ?
Sense of position
Sense of movements
What is graphesthesia ?
Related to writing
What is stereognosis ?
The ability of the person with closed eyes to recognize the nature of a familiar object placed in his hands
Special senses include what ?
Vision
Hearing
Smell
Taste
What is withdrawal reflex ?
A protective mechanism
What are the types of pain ?
Fast (sharp) pain
Slow (delayed) pain
Referred pain
Fast pain is conducted by what ?
A delta nerve fibers
Slow pain is conducted by what ?
Unmyelinated C nerve fibers
What is referred pain ?
Pain going somewhere else
What are the examples of referred pain ?
What does the reflex arc consist of ?
Receptor
Afferent fiber
Center
Efferent fiber
Effecter organ
Sensory neurons is which fiber ?
Afferent fiber
Motor neuron is which fiber ?
Efferent fiber
What are the types of reflex arc ?
Monosynaptic
Polysynaptic
What is monosynaptic reflex arc ?
No interneurons as the afferent synapses directly with the efferent fibers
Example of monosynaptic reflex arc
Stretch reflex
What is polysynaptic reflex arc ?
Interneurons are present between the afferent and efferent fibers
Example of polysynaptic reflex arc
Most of the body reflexes
What are the types of central reflexes ?
Conditioned reflexes
Unconditioned reflexes
What are conditioned reflexes ?
Acquired after birth, needs education and training and integrated in the cerebral cortex
What are unconditioned reflexes ?
Inborn reflexes
What are types of superficial reflexes ?
Corneal reflex
Plantar reflex abdominal reflex
Withdrawal reflex
What is corneal reflex ?
What is plantar reflex ?
What is muscle tone ?
A state of partial continuous contraction of skeletal muscle at rest
Muscle tone is present where ?
Antigravity muscles
What is the function of muscle tone ?
Keeping the erect posture of the body by contraction of the antigravity muscles
What are the properties of reflex action ?
Law of forward direction
Central delay
Central fatigue
What is central delay in reflex action ?
The total reflex time is the time between the stimulus application and the appearance of the response
What does the central delay in reflex action include ?
Time of the conduction along the afferent
Latent period of the muscle
What is central fatigue ?
What is the function of microglia?
Macrophages of CNS that phagocytose tissue debris and help in tissue repair
What is the function of oligodendroglia ?
Forms and maintains the myelin sheath around axons in the CNS
What is the function of Schwann cells?
Forms and maintains the myelin sheath around axons in the PNS
What is the difference between chemical and electrical synapse ?
Electrical is faster and the impulse transmission occurs in both directions
What does combined sensation include ?
Vibration sense
Stereognosis
Texture of materials
Graphesthesia
What is corticospinal tract ?
The pyramidal tract is associated with which part?
Distal part
What are the functions of pyramidal tract ?
Initiates fine movement
Facilitatory to muscle tone
Inhibits the primitive withdrawal reflex
Where does the extra pyramidal tract originate?
Originates from the premotor areas then descends to basal ganglia, reticular formation, vestibular nuclei, red nuclei
Which part is the extra pyramidal tract associated with ?
Proximal part
What are the functions of extra pyramidal tracts ?
Control gross movement
Provide postural background
Responsible for subconscious associated movements
Regulation of muscle tone
What are he two neurons the motor pathways include?
In which motor neuron are the reflexes exaggerated ?
Upper motor neuron
In which motor neuron are the reflexes low?
Lower motor neuron
What are the cerebellum functions ?
Control of equilibrium and postural movements
Control of voluntary movements
What is included in control voluntary movement function if the cerebellum ?
Servo-comparator function - comparing plan with performance
Damping (stopping) of movements - cerebellum acts as a brake to stop the movement precisely at the intended point
Control of ballistic movements - very rapid movement
Planning of sequential movements - smooth transition from one sequence of movement to the next
Cerebellum functions can be tested by what?
What is the function of the brain in communication ?
Sensory part (language input) - involves ears and eyes
Motor aspect (language output) - involves vocalization
What is associated learning ?
Developed by repeatedly pairing of a stimulus with another one
What are the two main forms of memory ?
Implicit memory
Explicit memory
What is implicit memory ?
It is totally at the subconscious level
What is explicit memory ?
It is the conscious recall of information
What are types of explicit memory ?
Episodic memory - memory of events
Semantic memory - memory of words, rules and language
What are type of memory ?
Primary memory - short term
Secondary memory - long term