The Nervous System: Brain, NTs, etc. Flashcards
afferent neurons
carry sensory info INTO the CNS (A for Approach)
efferent neurons
motor neurons, carry info away from CNS to the muscles and glands (E for Exit)
parts of the CNS
brain and spinal cord
3 main divisions of the the brain
brain stem, cerebrum, cerebellum
peripheral nervous system
nerves that go to/from the brain and spinal cord; broken into somatic and autonomic NS
somatic nervous system
part of peripheral NS; sends/receives sensory messages that control voluntary movement of skeletal muscles
autonomic nervous system
part of peripheral NS;
controls automatic involuntary bodily fxs (e.g., heart rate, digestion, breathing); broken into sympathetic NS and parasympathetic NS
sympathetic NS
part of autonomic NS; body’s mobilizing system, “fight or flight;”
when activated, hormones release into blood stream increasing HR, BP, breathing and slowing digestion/elimination; dominant in times of stress
parasympathetic NS
part of autonomic NS; energy conserving system, “rest and digest,” basic body maintenance (lower HR, BP, breathing; increase in digestion); dominant when relaxed
parts of spinal cord
- Cervical (neck) region
- Thoracic (chest) region
- Lumbar (back) region
- Sacral region
cerebellum
controls auto adjustments of posture and muscle tone responsible for BALANCE; @ base of brain behind brain stem; coordination of motor activity
ataxia
cerebellar disease; lack of coordination of muscles, voluntary movements
brain stem (parts)
primitive brain, below subcortical regions and in front of cerebellum;
1) pons
2) medulla
3) reticular formation (incl. RAS)
pons + medulla
parts of brain stem; involved in sleep, breathing, movement, cardiovascular activity; damage can lead to failure of bodily fxs/death
reticular formation
part of brain stem; set of interconnected nuclei; involved in awareness, attention, sleep
includes the Reticular Activating Sytem (RAS), which is responsible for sleep-wake cycle, projects to the thalamus
cerebrum
outer layer is the cerebral cortex + subcortical areas beneath; responsible for complex thought, perception, action
left cerebral hemisphere
Left = Language + Logic;
controls R side of body;
dominant in 97% of people;
verbal memory; rational, analytic, logical, and abstract thinking
right cerebral hemisphere
perceptual, artistic, intuitive, emotional, visuospatial, musical;
maintenance of body image;
comprehension/expression of visual, facial, and verbal emotion;
controls L side of body
Broca’s aphasia
damage to L FRONTAL lobe;
problem with speech production/articulation; expressive/motor aphasia; broken speech, slow w/ pauses; comprehension mostly intact; AWARE of their difficulties
Wernicke’s aphasia
damage to L TEMPORAL lobe; speech comprehension problems; person speaks fluently but nonsensical; cannot follow verbal commands or repeat phases; NOT aware of the problem (anosognosia)
aphasia
speech disorder
agraphia
inability to write
anomia
can’t recall names of things
apraxia
inability to carry out purposeful movements despite desire/physical ability
damage to L hemisphere can lead to…
aphasia (Broca’s or Wernicke’s), agraphia, anomia, apraxia, difficulties w/ R side of body
damage to R hemisphere can lead to…
L side hemi-neglect, prosopagnosia, visual/perceptual disturbances, affective abnormalities
agnosia
inability to interpret/recognize sensations or sensory stimuli (e.g., objects, ppl, shapes, sounds, smells), incl. prosopagnosia
frontal lobes
largest portion of the brain;
1) PFC - planning, initiative, personality, emotionality, inhibition, judgment, abstract thinking
2) premotor area - planning movement
3) motor area - instigates voluntary muscle movement
Broca’s area
in the L frontal lobe; controls muscles that produce speech (expressive)
Wernicke’s area
in the L temporal lobe; language comprehension
damage to frontal lobes can lead to…
loss of movement of various body parts, change in personality, lability, inattention, issues w/ problem-solving, expressive language issues (Broca’s aphasia)
parietal lobes
behind frontal lobes, house the somatosensory cortex; process sensory info, incl. touch, heat, pain, proprioception
damage to the parietal lobes can lead to…
alexia, agraphia, anomnia, acalculia, issues distinguishing L+R, lack of awareness of certain body parts, poor hand-eye coordination
alexia
acquired inability to read
temporal lobes
on outsides of each hemisphere (by the temples); primary auditory cortex (hearing); connected to limbic system (incl. hypothalamus, hippocampus, amygdala), involved in emotional bx and memory
R: visual memory
L: verbal mem, language comp (Wernicke’s area)
damage to temporal lobes can lead to…
aggressive bx (temporal ~ temper), change in interest in sexual bx, interference w/ memory, probs understanding speech (Wernicke’s aphasia), sleep issues
occipital lobes
@ back of brain; primary visual cortex; sight, reading, visual images
damage can lead to… difficulty recognizing drawn objects, ID-ing colors; hallucinations/illusions; word blindness
limbic system
set of subcortical structures, our “primitive brain;” involved in survival/basic drives, emotions, learning, memory
influences our endocrine system and autonomic NS
thalamus, hypothalamus, hippocampus, amygdala, septum
thalamus
sensory relay center (all senses except smell), pain perception
abnormalities linked to schizophrenia
hypothalamus
homeostasis; regulates temp, hunger/thirst, sex, hormone secretion, aggression, sleep/wake cycle
connected to ANS and endocrine system
contains the suprachiasmatic nucleus (SCN): the body’s circadian clock
amygdala
fear, startle, aggression, emotional memories
linked to PTSD, fear memories
activating it leads to aggression
Kluver-Bucy Syndrome
w/o amygdala –> apathy, placid, hypersexual, excessive eating, agnosias
septum
part of limbic system, moderates/decreases aggression (S for septum/”simmer down”)
basal ganglia (fx, parts)
subcortical areas regulating coordination of movement, esp. posture; inhibitory (put the brakes on movement, allowing us to be still)
send info to the premotor and motor cortices
main parts: caudate nucleus, putamen, substantia nigra, globus pallagus, subthalamic nucleus
Huntington’s
dysfx in basal ganglia, extraneous unwanted movements (thrusting of face and limbs)
Parkinson’s
loss of Da neurons in the substantia nigra (basal ganglia), difficulty w/ intended movement, tremor, rigidity, bradykinesia (slowed movement)
excitatory neurons
increase the likelihood of an AP
Ach, NE, glutamate
inhibitory neurons
decrease the likelihood of an AP
GABA, endorphins
acetylcholine (Ach)
movement + memory (prevalent in the hippocampus)
deficiency seen in Alzheimer’s
dopamine (Da)
thought, movement, emotion;
linked to brain’s reward system
excess Da in schizophrenia (antipsychotics are Da antagonists)
insufficient Da in Parkinson’s
norepinephrine (NE)
AKA noradrenalin; involved in mood (deficiency: depression; excess: mania), pain perception, sleep
also released into bloodstream as a hormone
catecholamines
Da and NE; synthesize from dietary tyrosine and phenylaline
serotonin (5-HT)
mood, sleep, appetite, aggression, sex, pain
deficient in mood disorders (similar to NE) –> hence SSRIs
dysregulation of 5-HT assoc. w/ SI, impulsivity
GABA
major inhibitory NT (along w/ glycine), calming
deficient in anxiety disorders, epilepsy (hence: benzos are GABA agonists)
glutamate
most common NT, excitatory
abnormalities suspected in schizophrenia, OCD, ASD, depression
peptide NTs
long chains of amino acids, regulate stress and pain, enkephalins and endorphins
pituitary gland
master gland, regulated by the hypothalamus
hyperthyroidism
too much thyroxin, mimics anxiety
weight loss despite increased appetite, sweating, diarrhea, palpitations, fatigue, agitated depression, insomnia, impaired memory/judgment
e.g., Grave’s Disease
hypothyroidism
too little thyroxin, mimics depression
unexplained weight gain, sluggish, fatigue, impaired memory/intellectual fx, sensitivity to cold
diabetes
Type 1: not producing insulin
Type 2: resistance to insulin
insulin regulates blood sugar levels;
hallmark of diabetes is hyperglycemia (excess blood sugar levels) but meds risk lowering it too much (hypoglycemia)
hyperglycemia
high blood sugar; increased thirst, appetite, urination
hypoglycemia
low blood sugar; nervous, irritable, cold sweats, fatigue, rapid HR, headache, confusion
Addison’s Disease
under-secretion of corticosteroids
apathy, weak, irritable, depressed, GI issues
Cushing’s Disease
excess secretion of corticosteroids
lability, agitated, depressed, irritable, memory/concentration issues
hyper/hypo-pituitarism
issues w/ secretion of growth hormone
too much –> gigantism, acromegaly
too little –> dwarfism, delayed puberty, gonadal failure
conduction aphasia
lesion in pathway b/w expressive and receptive speech areas; speak fluently w/ intact language comp BUT nonsensical and unable to repeat verbal phrases; can execute verbal commands b/c comprehension intact
anosognosia
a type of agnosia; lack of awareness of disability or problem (e.g., in Wernicke’s aphasia)
Grave’s Disease
a type of hyperthyroidism
Gerstmann’s Syndrome
-results from lesion of the L/dominant parietal lobe
-sxs: agraphia, acalculia, L-R confusion, finger agnosia
