CNS

Question 1

afferent div vs efferent div

Answer 1

both part of PNS

afferent senses signals & sends to CNS
* sensory stimuli
* visceral stimuli

efferent transmits signals from CNS to effector organs
* somatic muscle system: fibers of motor neurons that supply skeletal muscles
* autonomic nervous system: fibers that innervate smooth muscle, cardiac muscle, & glands
* sympathetic: fight or flight
* parasympathetic: rest & digest
* enteric nervous system (ENS): nerve network of GI

Question 2

protection for the brain

Answer 2

1. bones: cranium & vertebral columns
2. brain floats in CSF
   
   • surrounds & cushions brain
   • between pia mater & arachnoid mater
   • hydrocephalus: build up of CSF in brain (zika virus)
3. meningeal membranes wrap, protect, & nourish CNS
   
   1. dura mater
   2. arachnoid mater
   3. pia mater
4. BBB: regulates exchanges between blood & brain
   
   • highly selective
   • shields from harmful changes (ex: blood-borne illnesses )

Question 3

brain is made of:

Answer 3

1. forebrain: cerebrum & diencephalon
2. cerebellum
3. brain stem

Question 4

cerebrum made of:

Answer 4

1. cerebral cortex
2. basal nuclei

Question 5

cerebral cortex

Answer 5

• higher level processing
• frontal lobe = precentral gyrus ➔ primary motor cortex
• parietal lobe = postcentral gyrus ➔ somatosensory cortex
• occipital lobe = primary visual cortex
• temporal lobe = primary auditory cortex
• divided into R & L hemispheres connected through corpus callosum
• outer shell of gray matter covering an inner core of white matter
  
  • gray matter: contains cell bodies
  • white matter: contains axons

Question 6

basal nuclei (basal ganglia)

Answer 6

large nuclei in center of brain interconnected w/ cerebral cortex & thalamus

• gray matter
• involved in motor planning & initiating motor sequences
• parkinson’s disease: destroys dopaminergic neurons in basal ganglia
  
  • difficulty initiating movements
  • resting tremors: when muscle is relaxed

Question 7

diencephalon

Answer 7

hypothalamus: regulates homeostatic fxs

• collection of specific nuclei & associated fibers that lie beneath the thalamus
• integrating center for many important homeostatic fxs
• circadian rhythms, thermoregulation, blood pressure, hormone levels, BTR: body temperature rhythm

thalamus: sensory relay station important for motor control & preliminary processing of sensory input

• everything goes through thalamus

Question 8

cerebellum

Answer 8

• control of motor coordination
• compares planned movement w/ actual movement & makes corrective adjustments
• cerebellar cortex: outer, highly folded surface of cerebellum
• deep nuclei: nuclear structures that lie below the cortex deep in cerebellum (analogous to basal ganglia in cerebrum)
• multiple sclerosis: autoimmune disease causes demyelination of neurons in cerebellum
  
  • difficulty making precise movements
  • essential tremors (aka action tremors)

Question 9

brain stem

Answer 9

brain, midbrain, & pons

• cranial nerves arise
• centers that control cardiovascular, respiratory, & digestive fx
• regulates equilibrium & postural reflexes
• controls overall degree of cortical alertness
• along with hypothalamus: houses centers that govern sleep