Chapter 3 Flashcards
cerebrum
-largest part of brain
-composed of right and left hemisphere
-performs higher functions: interpreting touch, vision, hearing, speech, reasoning, emotions, learning, fine control of movement
cerebellum
-under the cerebrum
-coordinate muscle movements, maintain posture, and balance
brainstem
-relay center connecting cerebrum and cerebellum to spinal cord
-performs many automatic functions such as breathing, HR, body temp, wake and sleep cycles, digestion, sneezing, coughing, vomiting, swallowing
-midbrain, pons, medulla
-CONTROL
frontal lobe
-personality, behavior, emotions
-judgement, planning, problem solving
-speech- speaking and writing (Broca’s area)
-body movement- motor strip
-intelligence, concentration, self awareness
-Broca’s area on left side
-damage to this area -> difficulty speaking and writing but still understands and read -> aphasia
parietal lobe
-interprets language, words
-sense of touch, pain, temperature (sensory strip)
-interprets vision, hearing, sensory, and memory
-spatial and visual perception
occipital lobe
-interprets vision (color, light, movement)
temporal lobe
-understanding language (Wernicke’s area)
-memory
-hearing
-sequencing and organization
-Wernicke’s on left side -> damage causes aphasia
-may speak in long sentences that have no meaning/create new words
-difficulty understanding speech and dont know their own mistakes
hypothalamus
-master control of ANS
-controls behaviors like hunger, thirst, sleep, sexual response
-regulates body temperature, blood pressure, emotions, secretion of hormones
pituitary gland
-connected to hypothalamus by pituitary stalk
-master gland
-controls other endocrine glands in body
-secretes hormones that control sexual development
-promote bones and muscle growth
-responds to stress
pineal gland
-regulates bodys internal clock
-circadian rhythms
-secreting melatonin
-role in sexual development
thalamus
-early station for almost all information that comes and goes to cortex
-plays role in pain sensation, attention, alertness, memory
basal ganglia
-caudate, putamen, globus pallidus
-nuclei work with cerebellum
-coordinate fine motions -> fingertip movements
-afferent and cognitive function
-start, stop, and modulate motor movement
limbic system
-center of emotions
-learning, memory
-include: cingulate gyri, hypothalamus, amygdala (emotional reactions) and hippocampus (memory)
cranial nerves
-olfactory- smell
-optic- sight
-oculomotor- moves eye, pupil
-trochlear- moves eye
-trigeminal- face sensation
-abducens- moves eye
-facial- moves face, salivate
-(auditory) vestibulocochlear- hearing and balance
-glossopharyngeal- taste, swallow
-vagus- heart rate, digestion
-accessory- moves head
-hypoglossal- moves tongue
midbrain
-control eye movements
-relays from auditory and visual systems
pons
-balance
-posture
-breathing
medulla
-breathing
-BP
-swallowing
-coughing
-vomiting
diencephalon
-thalamus and hypothalamus
-homeostasis
glial cells
-astrocytes- support neurons
-oligodendrocytes- myelin in CNS
-microglial- neuronal injury- clean up crew
synaptic relays
-relay nuclei move signals to where they need to go
-a lot in the thalamus
decussations
-sensory and motor pathways are usually symmetric
-information is relayed to contralateral side almost always
-crossings -> decussations
-dorsal column- medulla before thalamus
-anterolateral- spinal cord
conduction velocty
-large myelinated- fastest
-small unmyelinated- slowest
relay nuclei
-first order neurons (primary sensory afferent neurons) synapse on second order neurons in relay nuclei in spinal cord of brain stem
-interneurons are in the relay nuclei and are either inhibitory or excitable
-second order neurons crosses (decussation) and synapses on third order neuron in relay nuclei in thalamus
-many third order neurons can synapses on fourth order which is located in its appropriate sensory area
sensory receptors
-mechanoreceptor- somatosensory
-thermoreceptor- somatosensory
-photoreceptor
-chemoreceptor- auditory/taste
-nociceptor- somatosensory
-modality- receptors only signal for their specific function
-tell us duration as well
-usually has its cell body in dorsal root or spinal cord ganglion -> exceptions: auditory, olfactory, visual
hyperpolarized
-more negative
-inhibits
-outward current
depolarized
-inward current
-stimulantory
receptor fields
area of the body that will stimulate a specific type of receptor
-each neurons has its own field that can detect signaling
-lateral inhibition- provides precise localization of the stimulus -> contrast between inhibitory and excitable areas
-fields can be excitable or inhibitory
-stimulus location is encoded by the receptive field
mechanoreceptors
-touch- pacinian corpuscle- skin
-audition- hair cell- organ of corti
-vestibular- hair cell- macula, semicircular canal
photoreceptors
-vision- rods and cones- retina
chemoreceptors
-olfaction- olfactory receptor- olfactory mucosa
-OLFACTORY DOESNT SYNAPSE IN THALAMUS- straight to cerebral cortex -> memories, emotions
-taste- taste buds
-arterial PO2- carotid and aortic arch
-pH of CSF- ventrolateral medulla
thermoreceptors
-temperature- cold/warm receptors- skin
nociceptors
-extremes of pain and temperature- thermal and polymodal nociceptors- skin
-noxious stimuli
stimulus intensity
-encoded by:
-number of receptors activated -> large stimulus activates more receptors
-differences in firing rates of sensory neurons -> greater rate -> greater intensity
-activating different types of receptors -> more different types-> more intensity
phasic receptors
-adapt rapidly to stimulus
-ex. pacinian corpuscles
-sense when stimulus starts and end (onset, offset)
-receptor potentials change fast
-vibrations
tonic receptors
-adapt slowly
-steady pressure
-give us more information about intensity and duration of stimulus
-ex. merkel cells
-slowly adapting -> slightly reduction in potential
somatotopic map
-formed by array of neurons that receive information from and send information to specific locations on body
-preserved at each level of nervous system
-sensory homunculus in cerebral cortex
-in visual system- retinotopic
-auditory- tonotopic
dorsal column
-fine touch, pressure, two point discrimination, vibration, proprioception
-second order neurons decussate in brain stem before thalamus
-first order neurons has group 1 and 2 nerve fibers -> faster
anterolateral system
-sensations
-changes in environment
-pain, temperature, light touch
-nociceptors and thermoreceptors
-first order neurons decussate in spinal cord
-first order neurons are group 3 and 4 -> slower
types of mechanoreceptors
-pacinian corpuscle (encapsulated)- subcutaneous, IM -> very rapid -> vibration*, tapping
-meissner corpuscle (encapsulated)- nonhairy skin -> rapid -> point discrimination (small receptor field), tapping, flutter
-hair follicles - hair skin - rapidly - velocity, direction of movement
-ruffini corpuscle- hair skin - slowly- stretch, joint rotation (large receptor field)
-merkel receptor- non hairy- slowly- vertical indentation of skin
-tactile discs- hair skin- slowly- vertical indentation of skin
thermoreceptors mechanism
-slow detecting
-cold and warm
-extreme temperatures are detected by nociceptors -> pain
-warm signals open transient receptor potential (TRP) channels -> TRPV
-cold signals open a different transient receptor potential channel -> TRPM8
nociceptors mechanism
-respond to noxious stimuli that produces tissue damage
-2 types:
-thermal/mechanical -> myelinated-> sharp
-polymodal -> unmyelinated -> blunt chronic pain
-hyperalgesia- axons release substances to sensitize nociceptors to recognize stimuli that wasnt previously noxious as noxious -> having a new cut
dermatomal rule
-referred pain sites on skin
-innervated by nerves arising from same spinal cord segments as those innervating the visceral organs
tranduction
-senses are transduced from one type of energy to another
-light transduced into electrical signal
A 63-year-old man is brought to his primary care PA because of concern on the part of his family that he is acting differently. He has been having a worsening tremor at rest and difficulty walking. His family states that when he walks, he often has difficulty stopping. He has no personal or family medical history. On examination, he has a mask-like facial expression with little blinking. He is noted to have a fine tremor at rest in a “pill-rolling” manner. He has muscular rigidity and a stooped posture. On walking, the patient is noted to have rapid propulsion forward with an inability to stop. He shows no signs of dementia or depression. He subsequently is diagnosed with Parkinson disease
-direct pathway inhibitory reaction tells muscles to remain still normally- parkinsons lack this pathway
-basal ganglia located near thalamus in the diencephalon
-basal ganglia receive synaptic input from motor cortex (as well as from sensory association and prefrontal cortex) -> send output to thalamus -> feeds back to the cortex
-connections from and back to motor cortical areas -> basal ganglia provide motor loop that contributes to the planning and
programming of voluntary movement
-basal ganglia important for some cognitive
processes-> organization of behavioral responses and verbal problem solving
-4 nuclei of the basal ganglia-
striatum, globus pallidus, substantia nigra, and subthalamic nucleus.
-the motor loop comprises 2 parallel pathways that travel from the cortex through the basal ganglia -> to thalamus
-> back to cortex.
-In direct pathway, excitatory input to basal ganglia excites thalamic neurons by inhibiting inhibitory output neurons in
internal segment of the globus pallidus.
-indirect pathway- excitatory input to basal ganglia further inhibits thalamic neurons by disinhibiting the inhibitory output neurons in the internal segment of the globus pallidus.
parkinsons traits
stooped posture, back rigidty, masked face, flexed elbows and wrists, tremors in the legs, forward tilt of trunk, reduced arm swing, hand tremor, slightly flexed hip and knees, shuffling, short, stepped gait
