Basics Quiz 1 Flashcards
Coronal section
vertical slice
Horizontal Section
You guessed it.
Sagittal Section
Anterior to posterior slice
Describe direction of these terms (point of reference = face):
- Dorsal
- Medial
- Lateral
- Anterior
- Posterior
- Ventra
- Dorsal (up; topside)
- Medial (toward the midline)
- Lateral (away from the midline)
- Anterior (front end)
- Posterior (hind end)
- Ventral (bottom side)
Describe direction of these terms (point of reference = body):
- Rostral
- Dorsal (superior)
- Ventral (inferior)
- Caudal
- Rostral: head end
- Dorsal (superior): back or top side
- Ventral (inferior): belly or bottom side
- Caudal: tail end
Define:
- Ipsilateral
- Contralateral
- Bilateral
- Ipsilateral (structures that lie on the same sides)
- Contralateral (structures that lie on opposite sides)
- Bilateral (if one lies in each hemisphere)
Define stroke
interruption of blood flow to brain that kills brain cells & suddenly causes neurological symptoms
hemorrhagic: burst vessel bleeding into the brain (more severe)
Tissue plasminogen activator
Tissue plasminogen activator (t-PA):
breaks up clots and allows normal blood flow to return to the affected region
afferent vs. efferent
afferent (any movement toward a brain structure) vs.
efferent (any movement away from a brain structure)
autonomic (automatic) nervous system (ANS)
acts via ganglia either to activate (sympathetic nerves; arousing, “fight and flee”) or to inhibit (parasympathetic nerves; calming, “rest and digest”) the body’s internal organs
Name the Anatomical Nervous System Divisions
Nervous Systems
- Central Nervous System (CNS)
- Brain
- Spinal cord
- Peripheral Nervous System (PNS)
- Somatic nervous system
- Autonomic nervous system
Functional Nervous System Divisions
Nervous system:
- Central nervous system (mediates behavior)
- Brain
- Spinal cord
- Somatic nervous system (transmitts sensation, produces movement)
- Cranial nerves
- Spinal nerves
- Autonomic nervous systems (ANS; balances internal functions)
- Sympathetic division (arousing)
- Parasympathetic division (calming)
parasympathetic nerves
i.e., calming nerves
“rest and digest”
sympathetic nerves
i.e., arousing nerves
“flight or flight”
Cerebral Security
- Skull
- Meninges
- Dura mater
- Arachnoid membrane
- Pia mater
- Subarachnoid space (filled w/ CSF)
hydrocephalus
literally, “water brain;” severe intellectual impairments and even death can result from the built-up cerebrospinal fluid (CSF) pressure.
Blood-brain barrier
Protects brain and spinal cord by limiting movement of chemicals from the rest of the body into the CNS and by protecting it from toxic substances and infection.
Sulci and gyri of neocortex
Brain Lobes
- Frontal
- Parietal
- Occipital
- Temporal
Cingulate gyrus
part of the limbic system located just above the corpus callosum, spans the inner surface of all four neocortical lobes
Sulci and gyri of neocortex
Brain lobe functions
- Frontal
- Parietal
- Occipital
- Temporal
- Frontal (motor functions)
- Parietal (body senses)
- Occipital (vision)
- Temporal (audition)
Choroid plexus
- Produces CSF
- (location wise) moves downward toward the fourth ventricle
cerebrospinal fluid (CSF)
- cushions brain and spinal cord from shock and sudden pressure changes
- circulates through brain’s four ventricles, the spinal column, and within the subarachnoid space in the brain’s meninges
- CSF continually made and drained off into the circulatory system through connecting channels among the ventricles.
ependymal cells
line the brain’s ventricles and make CSF
arachnoid villi
re-absorbs CSF into the blood stream
Ventricles
Cavity of the brain that contains cerebrospinal fluid.
tract
Large collection of axons coursing together within the central nervous system; also fiber pathway
nerve
collection of nerve fibers (axons) in the peripheral nervous system
Brainstem
mediates regulatory functions such as eating, drinking, and moving
Parts:
- hindbrain
- midbrain
- diencephalon
forebrain functional regions
- basal ganglia (motor coordination)
- limbic system (emotion, motivation, & memory)
- neocortex (sensory, motor, & cognitive functions)
Hindbrain
Hindbrain: controls movement and balance
Contains:
- Pons
- Retricular formation
- Medulla
pons
pons: means bridge in latin “bridge”
- connect the cerebrum and the cerebellum
- bridges sensory information between the left and right hemispheres of the brain.
reticular formation
part of the hindbrain
plays a role in states of consciousness (e.g., alertness, arousal, sleep)
medulla
medulla: regulate breathing and the functioning of the cardiovascular system
midbrain
midbrain:
Parts:
- tectum
- tegmentum
Function:
- Vision & hearing (particularly movements of the eye)
- motor functions
diencephalon
relays sensory information between brain regions and controls many autonomic functions of the peripheral nervous system
- part of the brainstem
- the caudal (posterior) part of the forebrain, contains:
- epithalamus,
- thalamus
- hypothalamus
- and ventral thalamus
- and the third ventricle
Limbic system
Limbic system
plays a role in self-regulatory behaviors including emotion, personal memories, spatial behavior, and social behavior
Limbic system Mnemonic
- Hippocampus means mythical sea monster that resembles a sea horse.
- Imagine 2 Sea horses sleeping under the light bulb under the sea (“C”).
- The sea “C” is flipped horizontally and there are 2 big “C”s surrounding 2 seahorses:
- Inner smaller “C” representing Corpus callosum.
- Outer larger “C” representing Cingulate gyrus and it’s Continuations.
- Inner smaller “C” representing Corpus callosum.
- The sea horses are sleeping under the the light bulb:
- The light bulb is the olfactory bulb.
- The illumination of light bulb around the head of the seahorses form several structures:
- Illumination field: Anterior perforated substance
- Superior lateral border: Lateral olfactory tract
- Superior medial border: Medial olfactory tract
- Inferior medial border: Diagonal band of Broca
- Medial to the Medial olfactory tract and just below the limbic gyrus lies Septal nucleus.
- Now the 2 sleeping sea horses:
- Outer sea horse:
- Body = Hippocampus
- Tail = Fornix
- Tail fin = Mammillary body
- Inner sea horse:
- Body and tail = Stria terminalis
- Tail fin = Hypothalamus
- Outer sea horse:
- Head of both sea horses = Amygdala
-
Thalamus lies above hypothalamus.
- Dorsomedial nucleus: Connected to amygdala
- Anterior nucleus: Connected to mammillary bodies
principle structures: limbic system
- amygdala (“almond”) - emotion
- hippocampus“seahorse”: personal memory, spatial navigation
- cingulate “girdle” cortex: sexual behavior, among other social interactions
cytoarchitectonic maps / Brodmann
regional density of cells
parcels cortex into many subregions
basal ganglia
Associated w/ movement and learning
Parts:
- Caudate nucleus
- Putamen
- Globus pallidus
Bell–Magendie law
dorsal / posterior spinal cord roots = sensory
ventral / anterior spinal cord roots = motor
Functions and parts of the neuron
- Dendrites (information flows through to terminal button)
- Dendritic spines
- Cell body (soma); fuels cell, houses nucleus
- Axon
- Axon hillock: may branch into axon collaterals (usually emerge at it from right angles)
- Axon collateral: may divide into a number of smaller branches called teleodendria (“end branches”) before contacting the dendrites of another neuron.
- Terminal button (end foot); releases chemical message
Synapse
the “almost connection” between surface of the axon’s end foot & corresponding surface of the neighboring dendritic spine (plus the space between the two)
- Some synapses are
- inhibitory (decrease neuron’s ability to pass info along to other neurons)
- excitatory (increase neuron’s ability to pass info along to other neurons)
Wilder Penfield and Early Clues to the Electrical Nature of the Brain
- Stimulated the somatosensory cortex in epileptic patients and topographically mapped S1
How Ions Travel: Diffusion, Concentration Gradients, Voltage Gradients
- Diffusion: diffuses away from synaptic cleft; molecules spontaneously spread out from where they are more concentrated to where they are less concentrated
- Concentration Gradients: describes relative differences in amounts at different locations in a container (when a substance is not evenly dispersed).
- Voltage Gradients: difference in charge between two regions that allows a flow of current if the two regions are connected
Graded Potentials (p. 102)
Slight decreases or increases in an axon’s membrane voltage
(highly localized and restricted to the vicinity on the axon where they are produced)
decrease: depolarization
increase: hyperpolarization
Threshold Potential
Voltage level of a neural membrane at which an action potential is triggered by the opening of sodium and potassium voltage-sensitive channels; about –50 mV
action potential
brief, but extremely large reversal in the polarity of axon’s membrane (lasting about 1 ms)
Saltatory Conduction
Myelinated stretches of axon are interrupted by nodes of Ranvier, rich in voltage-sensitive channels. In saltatory conduction, the action potential jumps from node to node, carrying the action potential rapidly along.
Excitatory Postsynaptic Potentials (ESPSs)
EPSPs increase the probability that an action potential will result
Inhibitory Postsynaptic Potentials
decrease the probability that an action potential will result
Temporal and Spatial Summation
Spatial: two EPSPs occurring close together in time and also located close together, form a larger EPSP
Temporal summation
Temporal: two excitatory postsynaptic potentials (EPSPs) occurring close together or even at the same time
4 steps of neurotransmission
- synthesis and storage
- release
- activation of receptors
- deactivation
Structure of synapse
Although neurons transmit information via electrical signals, synapses transmit information rapidly via chemicals - these are called neurotransmitters.
When an action potential reaches the end of a neuron (called the pre-synaptic neuron) - called the axon terminus - the change in potential across the cell’s plasma membrane stimulates the opening of voltage-gated calcium (Ca2+) channels - causing calcium to rush into the axon terminus.
This in turn triggers the fusion of synaptic vesicles, which carry the molecules of neurotransmitter, with the plasma cell membrane - this releases the neurotransmitter into the gap (called the synaptic cleft) via exocytosis (the fancy word for transporting ‘stuff’ such as proteins out of a cell).
The neurotransmitter molecules with then travel across the gap and bind to receptors on the plasma membrane of the post-synaptic cell. This binding then triggers the influx of ions - normally sodium (Na+) into the post-synaptic cell. If this amount of sodium reaches the threshold potential of the neuron, an action potential will be set up in this cell.
Rules for neurotransmitter classification
- Chemical must be synthesized or present in neuron
- When released chemical must produce response in target cell
- Same receptor action must be obtained when chemical is experimentally placed on target
- There must be a mechanism for removal after chemical’s work is done.
Common neurotransmitters & their functions
- dopamine (DA): coordinating movement, in attention and learning, and in behaviors that are reinforcing
- glutamate (Glu): Excitatory
- GABA: Inhibitory
- Acetylcholine (ACh): Inhibitory
- norepinephrine (NE): Excitatory
- Glycine: Inhibitory
- Epinephrine (EP): Excitatory
- Serotonin (5-HT): Regulates mood, aggression, appetite, arousal, pain, and respiration
- Histamine (H): Causes constriction of smooth muscles
Ionotropic receptors
- Have direct effects
- Binding sites for neurotransmitter
- Allow the movement of ions across the membrane
- Rapid changes in voltage
- Do not last long
- Mostly excitatory
Metabotropic Receptors
- Indirect effects
- Usually inhibitory
- Slower
- Last longer
- G-Protein has 3 subunits
- Alpha, Beta, Gamma
- Second messenger chemical
- Carries message to other structures in the cell
Habituation
a response to a stimulus weakens with repeated presentations
Neuroplasticity
potential for physical or chemical change that enhances its adaptability to environmental change and its ability to compensate for injury
Sensitization
sensitization, increased responsiveness to equal doses of a drug, is much more likely to develop with occasional use
Long-term potentiation
High-frequency electrical stimulation applied briefly to the hippocampus resulted in a long-term change in the efficiency of synapses activated by the stimulation, a phenomenon called long-term potentiation
Individual differences in drug responses
- Tolerance
- Metabolic
- Cellular
- Learned
- Sensitization
- Disinhibitory theory (alcohol, selective depressant effect on the cortex, the brain region that controls judgment).
- Alcohol myopia
Blood-Brain Barrier Exceptions
Several areas of the brain lack the tight junctions
- Pituitary Gland
- Allows exchange of hypothalamic chemicals, which influences hormone secretion
- Area Postrema
- Allows entry of toxic substances to trigger vomiting
- Pineal Gland
- Allows entry of hormones that regulate day–night cycles
Cross tolerance
results when the tolerance developed for one drug is carried over to a different member of the drug group
Agonist vs. Antagonist (examples and mechanisms) (see page 145).
- Agonists: Drugs that increase the effectiveness of neurotransmission
- Antagonists: Drugs that decrease the effectiveness of neurotransmission
Action of Anti-anxiety agents
- antianxiety agents: aka minor tranquilizers, are the benzodiazepines such as diazepam; marketed in the widely prescribed drugs Valium, Xanax, and Klonopin.
- Used by people having trouble coping with a major life stress as an aid to sleep, and as pre-surgical relaxation agents
- inhibitory effect of GABA is to decrease a neuron’s firing rate.
Schizophrenia symptoms (positive and negative)
- positive (i.e. hallucinations, delusions, racing thoughts)
- negative (i.e. apathy, lack of emotion, poor or nonexistant social functioning),
- and cognitive (disorganized thoughts, difficulty concentrating and/or following instructions, difficulty completing tasks, memory problems).
Dopamine hypothesis of schizophrenia
- Some of the main schizophrenic symptoms are related to dopamine excess
- Chronic users of amphetamines—a dopamine agonist—show schizophrenia-like symptoms
Depression symptoms
- prolonged feelings of worthlessness and guilt
- disruption of normal eating habits
- sleep disturbances
- a general slowing of behavior
- frequent thoughts of suicide.
Depression medications
- begin their effects very quickly, but their antidepressant actions take weeks to develop.
-
SSRI fluoxetine (Prozac) increases the production of new neurons in hippocampus.
- Hippocampus is vulnerable to stress-induced damage
- Significant portion of patients do not respond to antidepressant drugs.
- Ketamine very rapidly alleviates depressive symptoms
- Researchers trying to find ketamine-like drugs without the hallucinogenic effects
- Cognitive & intrapersonal therapies as effective as drug therapies
Stimulants
Increase motor behavior and elevate mood and alertness
- Cocaine
- Blocks dopamine reuptake
- Is a refined powder that is snorted or injected
- Crack: potent and highly concentrated cocaine
- Amphetamine
- Stimulates the release of dopamine and blocks dopamine reuptake
- Still used today to help troops and pilots stay alert, increase confidence and aggression, and boost morale and productivity
- Amphetamine-based drugs are prescribed for ADD, ADHD
- Methamphetamine: a derivative of amphetamine
- Street names: ice, crystal, glass, crystal meth.
- Can be inhaled or smoked.
- Easy to manufacture but potent
Wanting and Liking theory of addiction and associated neurotransmitters
- Incentive-sensitization theory also called wanting and liking theory
- Wanting = craving for drug
- Neural basis: mesolimbic dopamine pathway
- dopamine neurons in midbrain the frontal cortex and limbic system
- Neural basis: mesolimbic dopamine pathway
- Wanting = craving for drug
- Liking = pleasure produced by taking the drug
- Neural basis: activity of opioid neurons
- Decreases in addiction
- Endorphins: associated with pleasure in early use
meninges
meninges
Triple-layered set of membranes:
- Dura mater: tough double layer of tissue enclosing the brain in a kind of loose sack
- arachnoid membrane: very thin sheet of delicate tissue that follows the brain’s contours
- pia mater: moderately tough tissue that clings to the brain’s surface
