lecture 6 and 7 The Nervous System Flashcards
3 regions of brain
- forebrain
- midbrain
- hindbrain
cerebral cortex
-how many lobes ?
4 lobes on each hemisphere
- frontal lobe
- parietal lobe
- temporal lobe
- occipital lobe
Forebrain : Cerebrum
made up of?
cerebral cortex, basal nuclei and part of limbic system
sulcus
- dips in the brain
- lateral sulcus or sylvian fissure (between frontal lobe and temporal lobe)
- central sulcus (between parietal lobe and frontal lobe)
gyrus
- bump over brain
- sulcus down, gyrus up
2 types of cells in cerebral cortex
pyramidal : form major output for cerebral cortex, sending axons
non-pyramidal : receiving input, receiving cells into cerebral cortex
frontal lobe
3 major areas
motor cortex : middle area, movements
pre frontal cortex : thinking and problem solving
Broca’s area (lateral side near temporal lobe) : small area, involved in speech
parietal lobe
includes : somatosensory cortex
function :
- processes senses
- spatial manipulation of the body and space around us
Temporal lobe
includes : Wernicke’s area
function :
- auditory processing
- language perception and comprehension
occipital lobe
includes :
-primary visual cortex
function : vision
where is
- broca’s area, prefrontal cortex and primary motor cortex
- central sulcus/lateral sulcus (sylvian fissure)
- primary somatosensory cortex
- wernicke’s area
- primary visual cortex
phineas gage
-rod went through his skull and damaged frontal lobe
-personality and behaviour changed
basal nuclei (basal ganglia)
important function in controlling movement and posture
cerrebrum + diencephalon + midbrain : the limbic system
learning, emotional experience, behaviors, visceral and endocrine functions
forebrain : diencephalon
what does it contain + function?
thalamus, hypothalamus and epithalamus
thalamus : synaptic relay station, attention focusing, relay motor and sensory signals to the cerebral cortex
hypothalamus : command centre, regulation of environment
epithalamus : controls circadian rhythm, releases melatonin (sleep)
hindbrain : cerebellum
important center for coordinating movements and controlling posture and balance
gait ataxia
inability to coordinate voluntary muscular activity of limbs, trunk and head
brainstem (hindbrain + midbrain)
3 components
medulla oblongata, pons, midbrain (reticular formation)
-also releases cranial nerves
medulla
- cardiovascular center
- dorsal and ventral respiratory groups
- vomiting, coughing, sneezing centres (basic rhythm of breathing)
pons
“bridge” latin
-pontine respiratory group (intensity + rate of breathing)
midbrain
reticular formation
essential for life, motor function, cardiovascular and respiratory control, rest/wakefulness
midbrain
red nucleus
play a role in motor coordination
midbrain
substantia nigra
lots of dopamine which plays a role in movement
parkinsons disease
degenerative, progressive disease that affects the cells in the basal nuclei and substantia nigra : cant initiate movements
symptoms : bradykinesia (slowness of movement), involuntary shaking, stiffness, imbalance
spinal cord
- has gray and white matter
- afferent neuron= dorsal side
- efferent neuron = ventral side
- ventral horns and dorsal horns
- central canal (where CSF flows)
spinal cord segments
5 sections
- cervical (8 segments)
- thoracic (12 segments)
- lumbar (5 segments)
- sacral (5 segments)
- coccygeal (1 segment)
- nerves exit above their corresponding spinal vertebrae in cervical region, at T1 corresponding nerves will exit below their given segment
conus medullaris
end of spinal cord
filum terminale
pia meter extension
cauda equina
lumbar, sacral and coccygeal nerve roots
spinal cord white matter contains
ascending (sensory) and descending (motor) tracts
PNS has how many pairs of nerves
43 pairs of nerves
12 pairs of cranial nerves
31 pairs of spinal nerves (8,12,5,5,1)
afferent vs efferent neurons
afferent : convey information from sensory receptors to CNS
efferent : carry signals from CNS to muscles, glands and other tissues
-divided into somatic nervous system and autonomic nervous system
do spinal nerves contain efferent or afferent neurons?
cranial nerves?
spina nerves : both
cranial nerves : not all contain both, some only have one or the other
somatic nervous sytem
- innervates skeletal muscle
- single neuron between CNS and skeletal muscle
- can lead only to muscle cell excitation (release ACTH)
autonomic nervous system
- innervates smooth and cardiac muscle, glands and neurons in the gastrointestinal tract and other tissues
- two neuron chain between CNS and affector organ
- can be excitatory or inhibitory
division of the autonomic nervous system
sympathetic divison : fight or fright (comes of thoracolumbar division)
parasympathetic division : rest-or-digest (comes off cranial and sacral areas)
one activated one is not very activated
most organs innervated by both division of ANS (palms just have sympathetic)
sympathetic chain/trunk
run parallel and external to vertebral column
cervical sympathetic ganglia
-superior, middle and inferior cervical ganglia project to structures in the head and neck as well as the heart
superior →face, eyes
middle→heart
inferior→heart, lungs
parasympathetic ganglia
4 pairs in the head : others situated close to target organ
cillary ganglion : located just behind the eye
submandibular ganglion : near mandible (bottom)
otic ganglion : head/neck of mandible
pterygopalatine ganglion : cheek bone
somatic nervous system sequence of neurotransmitter release
SNS
CNS→neurons release ACh →binds to nicotonic Ach receptor→ skeletal muscles
autonomic nervous system sequence of events with release of NT’s
parsympathetic division
ANS Parasympathetic divison
CNS→neuron release ACh (in ganglion) →nicotinic ACh receptor→neuron →release ACh→muscarinic ACh receptor (g proteins)→smooth or cardiac muscles, glands or other cells
autonomic nervous system sequence of events with release of NT’s
sympathetic division
sympathetic division
CNS →neuron→ releases ACh (in ganglion)→binds to nicotinic Ach receptor→neuron→releases Norepinephrine→binds to adrenergic receptors→smooth or cardiac muscles, glands or other cells (alpha-adranergic receptors)
or
CNS→neuron releases ACh (in adrenal medulla)→binds to nicotinic receptor→ACh released into bloodstream→epinephrine releases→ smooth or cardiac muscles, glands or other cells (beta-adrenergic receptors)
