CNS part 2 Flashcards
Pathway of CSF flow
Lateral ventricles– 3rd ventricle – 4th ventricle – subarachnoid space – arachnoid villi of dural venous sinuses – heart and lungs
Identify the major ascending pathways and describe.
- Posterior columns
Carries fine touch, pressure, vibration, proprioception to primary sensory cortex - Spinothalamic pathways
Carries crude touch, pressure, pain, temperature to primary sensory cortex - Spinocerebellar pathways
- Carries proprioceptive information about position of skeletal muscles, tendons, joints
- Involves only 2 sensory neurons– 2nd neuron goes to cerebellum instead of thalamus
Identify the major descending pathways and describe.
- Pyramidal pathways
Neurons send impulses through the brainstem via the large pyramidal (corticospinal) tracts - Extrapyramidal pathways:
- Provide subconscious involuntary control of posture, balance, muscle tone
- Coordinate learned movement patterns
- Consist of several tracts
- Upper motor neurons originate in several parts of brain eg. basal nuclei, midbrain, cerebellum
Where are the cell bodies of the 1st, 2nd and 3rd order sensory neurons in the spinothalamic pathway located?
1st- Dorsal root ganglion
2nd- Spinal cord/ medullary nuclei
3rd- Thalamus
What are the primary components of the reflex arc and describe.
The primary components of the reflex arc are the sensory neurons (or receptors) that receive stimulation and in turn connect to other nerve cells that activate muscle cells (or effectors), which perform the reflex action.
Identify the brain areas involved in language and memory.
Wernicke’s area is a critical language area in the posterior superior temporal lobe connects to Broca’s area via a neural pathway.
The main parts of the brain involved with memory the cerebellum, and the cerebral cortex.
Define EEG and distinguish between alpha, beta, theta and delta brain waves.
EEG- Graphic record of the electrical activity of nerve cells in the brain.
Alpha- relatively regular and rhythmic, low-amplitude, synchronous waves.
Beta- are also rhythmic, but less regular than alpha waves and with a higher frequency.
Theta- are still more irregular. Though common in children, theta waves are uncommon in awake adults but may appear when concentrating.
Delta Waves- are high-amplitude waves seen during deep sleep and when the reticular activating system is suppressed, such as during anesthesia.
Describe consciousness clinically.
Clinically, consciousness is defined on a continuum that grades behavior in response to stimuli as (1) alertness, (2) drowsiness or lethargy (which proceeds to sleep), (3) stupor, and (4) coma
Compare and contrast the events and importance of slow-wave and REM sleep.
Slow-wave sleep is presumed to be restorative.
REM sleep may
(1) give the brain an opportunity to analyze the day’s events and work through emotional problems in dream imagery, or
(2) eliminate unneeded synaptic connections—in other words, we dream to forget.
Name three factors that can enhance transfer of information from STM to LTM.
Transfer of memory from STM to LTM is enhanced by (1) rehearsal, (2) association (tying “new” information to “old” information), and (3) a heightened emotional state (for example, alert, motivated, surprised, or aroused).
Which two states of consciousness are between alertness and coma?
Drowsiness (or lethargy) and stupor are stages of consciousness between alertness and coma.
What does the Na+ K+ ATPase do?
Maintains potential of concentration gradient by pumping out Na+ and pumping in K+
For an open channel, what factors determine in which direction ions will move through the channel?
The concentration gradient and the electrochemical gradient - together determine the direction in which ions flow through an open membrane channel.
For which cation is there the greatest amount of leakage across the cell membrane?
There is more leakage of K+ than any other cation.
Which part of the brain is the main integration center of the ANS?
Which part exerts the most direct influence over autonomic functions?
- Hypothalamus
2. The brain stem
