B2.021 Altered Mental Status in an Elderly Patient Flashcards
what characterizes the darker areas of brain matter?
cell bodies in high density
what characterizes the light areas in brain matter?
signaling pathways, axons of neurons present (no cell bodies)
what is a resting membrane potential?
the typically negative electrical charge of the cytoplasm of the cell
what is a synapse?
the interaction between neurons
how is information from sensory systems transmitted?
all information is encoded into action potentials, frequency changes in potentials represent different sets of information
what are motor neurons?
neurons that act on muscle cells
what are interneurons?
local circuitry between neurons
what are sensory neurons?
receive information from periphery
why might some neurons not have dendrites?
simplistic structure = simplistic function, transfer information quickly along axon from point A to point B
what might some neurons not have an axon?
interact exclusively with other neurons through dendrites
why do cerebellar Purkinje cells have a large network of dendrites?
receive 200000 synapses from other neurons
what are glial cells?
cells that fill space between neurons in CNS, 10x more glial cells than neurons
what are 5 functions of glial cells?
- maintain ionic balance
- modulate the rate of nerve signal propagation
- uptake of neurotransmitters
- regulate recovery of neurons from injury
- form the epithelium in the ventricles
what are 4 types of glial cells?
- astrocyte/satellite cell
- oligodendrocyte/schwann cell
- microglial cell
- ependymal cell
what is the function of myelin?
accelerates transmission of action potentials
what are neurotransmitters?
molecules used by neurons to communicate with one another
what are the two types of synapses?
chemical and electrical
what is the distance between the pre-and post-synaptic membrane in a chemical synapse?
50 nm, relatively large and causes a diffusion delay of 1-2 ms
what ion channel activates vesicle functions?
Ca2+
what enzyme is responsible for the degradation of ACh?
ACh esterase
what are two mechanisms for removal of neurotransmitters?
degradation and removal/re-uptake
what types of receptors bind ACh?
nicotinic
what are the types of postsynaptic potentials?
excitatory (EPSP) and inhibitory (IPSP)
what characterizes an EPSP?
depolarization of the membrane due to the transient increase in Na+ or Ca2+ conductance
what characterizes an IPSP?
hyperpolarization of the membrane due to the transient increase in K+ or Cl- conductance
what is spatial summation?
simultaneous inputs from two locations
what is temporal summation?
quick succession of inputs in one location
what is the distance between the pre-and post-synaptic membrane in an electrical synapse?
3.5 nm, no response delay
characterize an electrical synapse
- direct passage of molecules/ions
- no delay in transduction
- conduction in both directions
- inactivated by H+ or Ca2+
- useful in reflex pathways and during development
what are the two types of cortical areas and their respective makeup %?
primary and sensory motor areas - 25%
association cortices- 75%
what does the association cortex do?
integrate information from various brain regions, influence a broad range of behaviors/functions
what is declarative memory?
available to consciousness, can be described in words
what is procedural memory?
not available to consciousness, cannot be described in words
what are types of declarative memories?
daily episodes, words and their meanings, history
what are types of procedural memories?
motor skills, associations, priming cues, and puzzle solving skills
where is short term declarative memory storage?
hippocampus and related structures
where is long term declarative memory storage?
cortical sites: wernickes area for word meanings, temporal cortex for memories of objects and faces
where is long term procedural memory storage?
cerebellum, basal ganglia, premotor cortex, and other sites related to motor behavior
what are the two types of amnesia?
anterograde- inability to establish new memories
retrograde- inability to retrieve old memories
when does retrograde amnesia occur?
damage to cortical areas
what characterizes anterograde amnesia?
normal IQ, no difficulty in perception, abstract thinking is normal, declarative long term memory is normal, procedural memories are normal, short term declarative memory is compromised
what are two treatments for AD symptoms?
AChE inhibitors and NMDA receptor antagonists
