module 2 Flashcards
what are the 3 major parts of the brain
cerebrum
cerebellum
brainstem
cerebrum
two hemispheres divided by the longitudinal fissure
cerebral cortex
the outermost surface layer of the cerebrum (grey matter)
contains the cell bodies of the brain neurons
frontal lobe
executive functions:
- reasoning, planning, problem-solving
- inhibitory control
- working memory
motor functions:
- premotor cortex - motor planning
- primary motor cortex - execution
speech production (Broca’ area)
parietal lobe
primary somatosensory cortex:
- perception of touch
sense of space and locations
spatial attention:
- directing attention and eye-movements to explore visual world
linking vision to action:
- represents spatial location of objects around us for guiding actions
occipital lobe
Posterior part of the brain, inferior to parietal lobe
primary visual cortex (V1):
- all visual perception
Higher visual area:
- different regions process shape, colour, orientation, motion
temporal lobe
primary auditory cortex:
- perception of sound
Language comprehension:
- (Wernicke’s area)
medial temporal lobe:
- limbic system
(amygdala and hippocampus)
limbic system medial temporal lobe
amygdala:
- fear and arousal
- responds to threat/danger (snakes. spiders, angry/fearful faces)
- fear
Hippocampus
- learning and memory
- forming new episodic memories
- damage causes anterograde amnesia
corpus callosum
- neuron connections between the left and right hemispheres
- allows brain communication between hemispheres
- split brain patients - left and right hemispheres disconnected. The two hemispheres cannot communicate with each other
Phineas gage
- railway worker, Phineas Gage, accident in 1848
- iron rod, about 1. length, went through his head
- remained conscious during and after accident
- damaged frontal lobes
- died 12 years later and his skull was examined
Broca’s area - speech production
in 1861, Paul Broca described a patient who was unable to speak after damage to the left frontal lobe (Broca’s area)
- speech is slow and non-fluent
- difficulty finding appropriate words (anomia)
- speech still carries meaning
- comprehension is (mostly unaffected)
Wernicke’s area - language comprehension
in 2874, Carl Wernicke suggested that lesions to the left posterior temporal lobe led to deficits in language comprehension
- unable to understand language - deficit in comprehension
- speech is fluent with normal prosody
- speech has no meaning, nonsense, speech
Wilder Penfield
- stimulated the brain with electrical probes while the patients were conscious, during surgery for epilepsy
- in 1951, published maps of motor and sensory cortices of the human brain
homunculus
- primary sensory cortex and primary motor cortex
- brain function “mapped” by electrical stimulation
- brain stimulation leads to sensation or movement (muscle twitch)
size of area on cortex determines sensitivity or fine motor control
central nervous system
brain and spinal cord
peripheral nervous system
somatic nervous system (voluntary, motor and sensory)
autonomic
(involuntary, heart rate, respiration, sweating, stress, arousal, “fight or flight”)
Autonomic nervous system’s two divisions
sympathetic and parasympathetic
sympathetic nervous system
- emotional arousal, stress, fear
- fight or flight response
- increases heart-rate, respiration. perspiration. pupils dilate
parasympathetic nervous system
- rest and digest
- lowers heart-rate, respiration
- increases stomach, intestine activity (digestion)
- opposes the sympathetic nervous
brainstem
medulla
- autonomic nervous system functions
- controls heart rate, respiration, regulation of blood pressure, body temperature
- reflex centres for coughing, sneezing, swallowing, vomiting
disorders of consciousness
- severe damage to upper brain (hemispheres and cortex)
- of brainstem is not damaged, autonomic nervous system functions can remain
- sometimes normal respiration, control of heart rate, some face and eye movement remain
locked in syndrome
- amyotrophic lateral sclerosis (ALS) or motor neurons disease
- loss of motor neurons to spinal or brain injury
- intact cerebrum and brainstem, but disconnected from spinal cord
- normal cognitive function, vision, and hearing, but patients cannot move
- patients may be fully conscious and aware, but totally unresponsive
medulla
- Autonomic nervous system
- Controls heart-rate, respiration, regulation of blood pressure, body temperature
Reflect centres for coughing, sneezing, swallowing, vomiting
- Controls heart-rate, respiration, regulation of blood pressure, body temperature
persistent vegetative state
- sever damage to upper brain
- if brainstem is not damaged, autonomic nervous system functions can remain
- sometimes normal respiration, control of heart rate, some fave and eye movements remain
cerebellum
- hind brain
- sense of balance and co-ordination
- motor learning
dendrite
- unique to neurons
- received signals
axon
- sends signals
- wrapped in myelin for efficient transmission of signals along the axon