Nervous System VII Flashcards
What is the anatomy of CNS and what is it separated into?
Brain and spinal cord
Gray and white matter
What does gray matter consist of?
Unmyelinated somas, dendrites, and axons
- butterfly shape inside spinal cord, outer of brain
What does white matter consist of?
Mainly myelinated axons
- outer of spinal cord, inner of brain
Why is brain and spinal cord different colours?
Different portions of neurons
- more or less myelin
What are meninges and where are they located?
Pia mater(attached to brain spinal cord), arachnoid membrane (subarachnoid space), dura mater(most outer layer)
- 3 layers create protection around brain and spinal cord
Where is cerebrospinal fluid?
In subarachnoid space between pia and dura
What is the spinal cord?
Major pathways for info flowing back and forth between brain and skin, joints, organs, and muscles of the body
- brain to periphery, periphery to brain
What are 5 regions further subdivided into 31 segments?
Cervical (8), thoracic (12), lumbar (5), sacral (5), coccygeal (1)
What does each segment have?
Has bilateral pair of spinal nerves, each nerve splits into ventral and dorsal roots
What kind of sensory info does dorsal root carry?
Afferent to CNS
What type of info does ventral root carry?
Carries efferent info muscles and glands
What does
What is difference between nuclei and ganglia?
Nuclei: clusters of cell bodies in CNS
Ganglia: clusters of cell bodies in PNS
What does gray matter in spinal cord consist of?
Sensory and motor nuclei
What does white matter of spinal cord consist of?
Tracts of axons carrying info to and from brain
What are ascending tracts?
Sensory tracts that carry sensory info to brain
- dorsal and external lateral
What are descending tracts?
Efferent tracts that that carry commands to motor neurons
- ventral and interior lateral
- down regions of spinal cord
What is a spinal reflex?
Spinal cord can act as integrating center to initiate response to a stimulus without receiving input from the brain
- rapid reflex
- sensory input comes into spinal cord and immediate output is sent
What is the main difference between humans and lower organisms?
- cerebral cortex of humans has many folding in and out, increase surface area, increase neurons
How many neurons in brain?
85 billion, containing thousands of synapses
What are 6 major divisions of brain?
Cerebrum, cerebellum, diencephalon, midbrain, pons, medulla
- last 3 are brainstem
What is the brainstem
Oldest and most primitive region of the brain
What are 4 major regions of brainstem?
- midbrain, pons, medulla oblongata, reticular formation
What does brainstem contain?
- ascending and descending tracts run through
- 11 of 12 cranial nerves (not olfactory)
- many nuclei
What basic processes is brainstem involved in?
Arousal and sleep, muscle tone and stretch reflexes, coordination of breathing, blood pressure regulation and modulation of pain
What does medulla contain?
White matter contain all ascending somatosensory tracts and descending corticospinal tracts
Nuclei
Why does left side of brain control right side of body?
90% of corticospinal tracts crossover at pyramids of medulla
What involuntary functions does nuclei of medulla control?
- cardiovascular center and respiratory center
- vomiting center
- swallowing center
- coughing, sneezing and hiccuping
What does pons contain and do?
Contains nuclei and tracts
- relays info between cerebellum and cerebrum
- assists medulla in coordination of breathing
What is the midbrain (mesencephalon)?
Junction between lower brainstem and diencephalon (nuclei and tracts)
- contains substantia Nigra
What are functions of midbrain?
-primary is controlling eye movement
- relays auditory and visual reflexes (movement of body in response to stimuli)
