midterm. Flashcards
Dualism
notion that mental activity can occur outside the body (soul)
allowed study of the mind to continue to be compatible with theology
What is an animal?
any live vertebrate animal used or intended to be used for research purposes, research training, experimentation, or biological testing or for related purposes
The 3 R’s:
Replace
reduce
refine
IACUC Institutional animal care and Use committee
reviews proposals for animal research
conducts semi-annual reviews of animal housing and surgical facilities
conducts annual post-approval monitoring meetings with investigators
Protection of human research subjects regulations based on principles in the
Belmont Report
Elements of informed consent:
information
comprehension
voluntariness
What cell staining technique did Santiago Ramón y Cajal use
Used Golgi staining techniques to carefully study sections of tissue
How did Santiago Ramón y Cajal record finer details among cells using Golgi staining?
Refined Golgi’s technique using small amounts of silver impregnation repeatedly to get more subtle stains
Dendrites
receive input from many other neurons
carry those signals to the cell body
Soma
cell body of a neuron
Axon
sends signals
conducts electrical impulses (action potentials) away from the nerve cell body
Axon hillock
nerve impulses are generated
neuron decides whether to send an action potential
Axon Terminal
end of an axon that transmits electrical impulses to other cells
dendrite spines
form synaptic connections with other neurons
Nucleus
contains DNA, genetic material, RNA
Endoplasmic reticulum
folding and transport of proteins
Ribosome
synthesizes proteins
Golgi apparatus
sorting, packing (into vesicles), and distribution
Lysosome
digestive processes in cell (degrade material taken in / obsolete intracellular components)
microtubules
provide active axonal transport
Efferent neuron
motor
Afferent neuron
sensory
Interneurons
connect sensory and motor neurons in the brain and spinal cord
Glial cells in general
Any cell that holds nerve cells in place and help them work the way they should
Oligodendrocytes
Myelin sheathing
Schwann Cells
astrocytes
facilitate BBB formation
Injury response
Termination of neurotransmission
Microglia
Remove normal cellular waste
Ependymocytes
distributes cerebrospinal fluid
blood-brain barrier
Prevents blood from contacting neurons and glial cells
to pass BBB:
Passive diffusion
–> small molecule
–> uncharged
–> fat soluble
Active transport
EPSP: Excitatory postsynaptic potential
depolarizes a local potential
IPSP: inhibitory postsynaptic potential
hyperpolarizes a local potential
What constitutes a nerve impulse?
A series of local potential changes occurring from the axon hillock to axon terminal
–> comprised of changes from resting potentials to action potentials
What role does the sodium-potassium pump play in maintaining a resting potential?
Helps maintain negative charge in the cell
–> Sodium ions are more concentrated outside the neuron; potassium ions are more concentrated inside.
Depolarization
A cell’s electrical charge distribution shifts - making the cell less negatively charged compared to its environment
Action potential
a rapid change in the voltage across a cell membrane
What are receptors
Special proteins on cell membrane
activated by neurotransmitters
result in altered intracellular events
most prevalent in synapse
Where are postsynaptic receptors located?
Postsynaptic terminal
Ionotropic receptors
receptor-channel complex
fast transmission
Metabotropic receptors
receptors and channels are physically separate
slow transmission
What are the most common amino acid neurotransmitters?
glutamate and aspartate
GABA and glycine
excitotoxicity
neuron death caused by too much glutamate stimulation
key receptors for GABA
Ionotropic receptors:
GABAa
both allow Cl- into the cell, causing inhibition
Metabotropic receptors
GABAb
Catecholamines
Dopamine, norepinephrine, epinephrine
Indoleamine
serotonin and melatonin
Mesolimbic pathways
cell bodies: ventral tegmental area
terminates: nucleus accumbens, hippocampus
Mesolimbic pathway function
reward / desire
Nigrostriatal pathway
cell bodies: substantia nigra
Terminates: basal ganglia
Nigrostriatal pathway function
cognition, reward, addiction
How are dopamine, norepinephrine, and serotonin inactivated?
Reuptake into presynaptic neuron
or broken down by enzymes:
–>MAO (monoamine oxidase)
–>COMT (catechol-o-methyltransferase)
for catecholamines
What are neurotrophins?
Family of neurotrophic factors that promote survival and plasticity of neurons during development and adulthood
What receptors do neurotrophins activate?
TrkA - activated by NGF
TrkB - activated by BDNF and NT-4
TrkC - activated by NT-3
Role of hypothalamus in hormone regulation
directly controls pituitary gland
neurons release two hormones:
–> oxytocin
–> vasopressin - suppressed by alcohol
Controls pineal gland - releases melatonin
Role of pituitary gland in hormone regulation
Anterior pituitary: glandular tissue, synthesizes several hormones
Posterior pituitary: neural tissue, considered an extension of the hypothalamus
Makes many hormones
What are the main regions of the CNS?
Spinal cord
brain
gray matter
composed of primarily neuron cell bodies and dendrites
Processes information locally
White matter
made up of bundles of myelinated axons
Transmits signals from the spinal cord to other parts of the body
Bell-Magendie law
Dorsal root carries sensory information to the brain
ventral root carries motor signals from the brain
Dorsal root ganglion
cell bodies of sensory neurons
Hindbrain
brainstem
most cranial nerves
important structures:
–> medulla
–> pons
–> cerebellum
reticular formation
Midbrain
small area between hindbrain and forebrain
surface structures include:
superior colliculus
inferior colliculus
other structures ( some of these overlap with hindbrain ):
ventral tegmental area
substantia nigra
locus coeruleus
Forebrain
Most prominent part of brain
Areas for motivation (like hypothalamus)
Sensory processing (like thalamus)
Emotion
amygdala, nucleus accumbens, prefrontal cortex
Memory:
hippocampus
basal ganglia
prefrontal cortex
Motor and sensory cortex
Medulla
Manages heart, circulation, and breathing
Pons
links brain to spinal cord
unconscious movements and processes
sleeping & breathing
Cerebellum
coordination of movement
maintaining posture and balance
muscle tone
motor learning
The limbic system
work together with other brain regions by processing your memory, thoughts & motivations, then tell your body how to respond
Occipital
visual
Temporal
auditory
Parietal
sensory
frontal
planning of movements, recent memory, some aspects of emotions
What functions does the motor cortex regulate in relation to body movement?
each location regulates movement of a different body part
primary functions of Brodmann’s areas 44 and 45 (Broca’s area)
production of speech
complex muscle movements required for articulation
command center for speech production
Function of Brodmann’s area 4 (primary motor cortex)
controls voluntary movements
movement, coordination, breathing, blinking
CT Scan
X-Ray used to determine structural changes
MRI
clear images of brain structures
PET
Brain activity
fMRI
MRI with activity
How does cerebral blood flow change in response to brain activity
blood increases in areas of greater activity
two major arteries involved in cerebral blood flow change
carotid artery
vertebral artery
What is cerebrospinal fluid
clear fluid surrounding brain cells
primary function of cerebrospinal fluid
medium for nutrients, glucose, hormones, and other chemicals
Where is cerebrospinal fluid found in the brain, and what are the names of the ventricles that contain it?
spaces filled in the brain
ventricles (4th, 3rd, lateral)
cerebral aqueduct
surrounded by periaqueductal gray
meninges
tissue surrounding brain - CSF found in subarachnoid space
Germinal
conception to ~ 2 weeks
Zygote - cell formed by two gametes (sperm & egg)
rapid cell division develops into blastocyst (~ day 5)
Blastocyst travels down fallopian tube to uterus and implants into uterine wall
Embryonic
formation of germ layers
Fetal stage
8 weeks to birth
Neural tube formation, brain cell growth, brain wave production, connectome development, nervous system development
What are the three germ layers formed during the embryonic stage, and what systems do they develop into?
ectoderm: develops into skin and nervous system
mesoderm: develops into muscles, bones, and cardiovascular system
endoderm: develops into digestive and respiratory systems
During the embryonic stage, what develops from the neural plate?
Neural plate: precursor of central and peripheral nervous system
During the embryonic stage, what develops from the neural tube?
neural tube: formed from neural plate
rostral portion - develops into brain
caudal portion - develops into spinal cord
What develops from the prosencephalon, mesencephalon, and rhombencephalon during early brain development?
Prosencephalon: the forebrain - develops into the cerebral hemispheres
Mesencephalon: midbrain
Rhombencephalon: hindbrain
Describe the significance of the ventricular zone during brain development.
Ventricular zone: area lining ventricles containing neural stem cells
primary source for neurogenesis
Neurogenesis
non-repressed ectoderm cells develop as nervous system cells
otherwise become epidermal cells (skin cells for ex.)
Neural migration
neurons migrate from ventricular zone, along radial glial cells
Differentiation & maturation
cells differentiate based on pre-spinal cord, hindbrain, midbrain, & forebrain
proteins lead to identity of neurons
development of dendrites
synaptogenesis
formation of synapses
myelination
pathfinding
–> cell adhesion
–> molecules (CAMs)
synaptic pruning and cell death
synaptic pruning: removes unnecessary synapses and strengthens the ones needed
apoptosis: programmed cell death
Why are radial glial cells referred to as neural progenitors?
develop into most, if not all neurons in the brain
How does brain structure change as people age, particularly around the age of 40 and 60?
brain begins to shrink overall ~ age 40
rate of shrinkage increases ~ age 60
Greater reductions found in PFC, cerebellum, & hippocampus
thinning of cerebral cortex, especially in frontal & temporal lobe
Neurons shrink and retract dendrites
–> fatty myelin that wraps around axons deteriorates
–> number of connections (synapses) between brain cells drops
–>affect learning and memory
What are the key symptoms and features of Autism Spectrum Disorder (ASD)?
problems with social communication, interaction, restricted/repetitive behaviors/interests
problems with eye contact
average age of diagnosis is 5 years old
show symptoms at ages 12-18 months
What are the main symptoms of inattention in ADHD?
Inattention:
Often fails to give close attention to details or make careless mistakes in school work/ work
Difficulty sustaining attention in tasks
Often does not seem to listen when spoken to directly
Often does not follow through on instructions and fails to finish schoolwork
Distracted by certain stimuli
Forgetful in daily activities.
What are the main symptoms of Hyperactive/impulsivity in ADHD?
Hyperactive/impulsivity:
Fidget or moves often
Often on the go
Talking excessively
Blurting out before someone finishes what they are saying
Difficulty waiting turn
What are the psychotic and cognitive symptoms associated with schizophrenia?
Psychotic symptoms: Hallucinations, delusions, and disorganized thinking and behavior
Cognitive impairments: Difficulty with memory (working memory & declarative memory), executive function, and mental processing speed
What are the harmful effects of lead exposure on brain development, particularly in children?
Children who are exposed to lead may develop problems with learning, reading, delayed growth and hearing loss.
Define circadian rhythms and explain their significance in regulating sleep-wake cycles.
Circadian rhythms: physical, mental, behavioral changes an organism experiences over a 24 hour cycle
What external factors influence circadian rhythms?
Light and dark
food intake
stress
physical activity
social environment
temperature
Where is the SCN located, and how does it receive input from the retina?
small nucleus in the anterior hypothalamus located just above the optic chiasm
light detected by retinohypothalamic tract, photosensitive neurons running from retina to SCN
photopigment cell melanopsin in retina
What is the role of the suprachiasmatic nucleus (SCN) in controlling circadian rhythms?
considered the central circadian clock (master clock)
exogenous cue: light (a Zeitgeber)
especially blue light (446-477 nm - peak at 460 nm)
What genes are involved in the regulation of circadian rhythms?
CLOCK (circadian locomotor output cycles kaput)
BMAL1 encode proteins that activate genes Per and Cry
Per and Cry encode proteins that switch off proteins encoded by CLOCK and BMAL1
How does core body temperature fluctuate in accordance with circadian rhythms? What is the average range of body temperature variation over a 24-hour period?
core body temperature fluctuates according to a 24 hour period
set point = 37C (98.6F)
deviates within 1C over 24 hours
SCN to hypothalamus
Describe the role of the reticular activating system (RAS) in promoting alertness.
RAS neurons release acetylcholine & glutamate in basal forebrain, hypothalamus, and thalamus (excitatory effects)
What role does adenosine play in promoting sleep, and how does caffeine affect this process?
Adenosine: inhibits basal forebrain acetylcholine receptors (inhibits alertness)
Produced extracellularly from adenosine triphosphate (ATP) released from neurons and astrocytes
Also released directly as adenosine from neurons and astrocytes
Adenosine receptors inhibit neuronal activity; appears to act on SCN to promote night phase of circadian rhythm
Caffeine blocks adenosine receptors
How do prostaglandins contribute to sleep regulation?
hormones that promote sleep - build up during the day
stimulates adenosine release
What are the key features of the different stages of Non-REM (NREM) sleep (N1, N2, and N3)?
75% of sleep is spent in Non-Rapid Eye Movement (NREM) sleep
Typical night has four to five sleep cycles in this pattern: N1, N2, N3, N2, REM every 90 to 110 minutes
Older systems had a stage 3 and 4, but this has been combined into N3
EEG of NREM1 - theta waves (lower amplitude), fewer alpha waves
Sleep spindles
12 to 14 Hz waves during a burst that lasts at least half a second
brief, powerful bursts of neuronal firing in superior temporal gyri, anterior cingulate, insular cortices, thalamus
calcium influx into cortical pyramidal cells
functions thought essential for memory consolidation - esp. procedural and declarative memory
K-complexes
long delta waves lasting ~ 1 second
Maintain sleep and memory consolidation
What is the brain’s “rinse cycle?”
N3 - slow sleep wave sleep (SWS)
rinse cycle for brain
wave of blood flow followed by wave of CSF - repeated ~ every 20 seconds
slow EEG waves
What are the characteristics of REM sleep?
increased brain activity
rapid eye movement (phasic and tonic)
breathing and heart rate increase
paralyzed muscles (might twitch)
What are some of the adverse effects of using benzodiazepines and other sedative-hypnotic medications in elderly patients?
increased risk of falls and fractures, cognitive impairment, confusion, impaired motor coordination, drowsiness, lethargy, dizziness, worsening of existing dementia, dependence, and an increased risk of motor vehicle accidents due to impaired driving abilities
How do dual orexin receptor antagonists differ from traditional sleep medications?
DORAs block only orexin receptors and thus can reduce arousal to induce sleep onset without changing the proportion of sleep phases and preventing next-day residual effects
