Test 1 Studying Flashcards
4 types of glial cells
Oligodendrocytes, Schwann cells, Astrocytes, and microglial cells.
Oligodendrocytes
Forms myelin in the CNS
Schwann Cells
Forms myelin in the PNS
Astrocytes
Numerous processes including forming tough outer membranes of the brain.
Microglial Cells
Primary job is contain and cleaning up sites of injury. Remove cellular debris.
Multipolar neurons
Most common. Many dendrites –> a single axon
Bipolar neurons
Common in sensory systems. Single dendrite –> single axon
Unipolar neurons
Single branch(axon) that leaves cell body then extends in two directions. One is input zone(dendrites) and the other end is output zone(terminals).
Differentiate between grey and white matter
Grey matter: mostly receives and processes info
White matter: mostly transmits info
Brainstem parts
Midbrain, pons, medulla
Midbrain parts
Tectum: Superior colliculi
Inferior colliculi
Motor: Substantia Nigra
Other: Reticular formation
Periaqueductal gray
Cervical
Neck (8 segments)
Thoracic
Trunk (12 segments)
Lumbar
Lower back (5 segments)
Sacral
Pelvic (5 segments)
Coccygeal
Bottom (1 segment)
Different levels of analysis
Social>Organ>Neural Systems> Brain Region>Circuit>Cellular>Synaptic>Molecular
Resting potential
(-70mV) Cells interior is more negative
Depolarization
(-55mV) Positive Na ions enter the cell through Na channels to make it more positive up to +30mV
Repolarization
Potassium channels open slowly allowing potassium to flow out bringing the voltage back to zero.
Why does myelin speed up conduction?
Saltatory conduction lets action potentials jump between myelin because it resists the flow of ions
Influences on action potential conduction velocity
Larger axon diameter=spread faster
Excitatory postsynaptic potentials (EPSP)
Increase the probability that a postsynaptic neuron will fire an action potential
Inhibitory postsynaptic potentials (IPSP)
Decreases the probability that a postsynaptic neuron will fire an action potential
Spatial summation
Summing of all potentials that reach the axon hillock, if the sum reaches the threshold we get an action potential
Temporal summation
Summing of all potential but based on time of arrival. The closer together the greater their impact and chance of making an action potential
Sequence of chemical transmission between two neurons
- Action potential arrives at presynaptic neuron
- Voltage gated Ca channels in the terminal open and Ca enters
- Ca causes synaptic vesicles to fuse and dump neurotransmitters into synaptic cleft
- Transmitters bind to postsynaptic receptor molecules causing ion channels to open and leading to an EPSP or IPSP
- EPSP or IPSP spreads toward postsynaptic axon hillock, if threshold is reached then we get action potential
- Synaptic transmission is rapidly stopped
- Transmitter may activate presynaptic receipts that decrease transmitter release
Tonic-clonic seizures
Abnormal EEG activity all over
Simple partial seizures
(absence attacks) Spike and wave EEG activity
Complex partial seizures
Do not involve entire brain
Basal Ganglia
(motor control) Labels
Limbic system
(emotion and learning) Labels
Major parts of the neuron
Labels
Acetylcholine
(Quaternary Amine family) Plays a major role in neurotransmission in the forebrain, widespread loss can lead to Alzheimers
Dopamine
(Monoamine family) Associated with motor control and reward system
Serotonin
(Monoamine family) Associated with mood, vision, sex, anxiety, sleep and many others.
Norepinephrine
(Monoamine family) Controls behaviours like mood
GABA
(Amino acid family) A common inhibitor in all mammals
Glutamate
(Amino acid family) A transmitter that is very common in excitatory transmission
Agonists
Mimics the action of a transmitter or makes it more effective
Antagonists
Blocks the action of a transmitter or makes it less effective
Dose-response curve
A formal graph of dose given (x) vs drug effect (y)
Affinity
The desire of molecules of a drug to bind to receptors
Benzodiazepines vs SSRI’s
Benzos: Enhance inhibitory effects of GABA
SSRI’s: block reuptake of serotonin
Sometimes Benz is prescribed with SSRI to reduce anxiety
Cannabis
Delta-9-tetrahydrocannabinol(THC), works off cannabinoid receptors
Moral model
Abuser lacks self control
Disease model
Abuser requires medical treatments
Physical dependence model
Abuser uses to avoid withdrawal symptoms
Positive reward model
Abuser is controlled by positive rewards from drugs
Social brain hypothesis
The neocortex evolved to accommodate social interactions
Ecological intelligence hypothesis
Larger brain could have been advantageous for adapting to different environments and solving complex ecological challenges
Cultural brain hypothesis
The transmission of knowledge, skills and cultural practices among people may have placed pressure on cognitive abilities
Cognitive buffer hypothesis
A larger brain provided a cognitive buffer against environmental uncertainty
Dietary brain hypothesis
Shift to a diet that was more energy rich played a role in brain expansion
Evolutionary eye development
Photosensitive patch>cup eye>pinhole camera> lens camera
Six stages of brain development
- Neurogenesis
- Cell migration
- Cell differentiation
- Synaptogenesis
- Cell death
- Synapse rearrangement
- Neurogenesis
Mitosis produces neurons from non-neuronal cells forming ventricular zone
- Cell migration
Cells move out of the ventricular zone toward their destination, where they express particular genes
- Cell differentiation
Cells become distinctive types of neurons or glial cells
- Synaptogenesis
Establishment of synaptic connections
- Cell death
Selective death of many neurons we don’t need
- Synapse rearrangement
Loss or development of synapses, fine-tuning
Human embryonic development stages
3 layers develop in the embryo; endoderm, mesoderm and ectoderm.
Crests of the neural groove join forming the neural tube
Anterior part of the neural tube has 3 subdivisions, the forebrain, midbrain and hindbrain.
Ectoderm
The outer layer of the embryo that becomes the nervous system
Visual deprivation experiments
Eyelids were sutured shut or animal suited with frosted contacts in order to see the effect of early disuse of visual system
Binocular deprivation
Covering of both eyes. If done for long enough during sensitive period, will blind a person. Light enters eyes and a visual signal is sent but the brain ignores it
Monocular deprivation
Covering of one eye. Can permanently impair vision in the deprived eye
Genotype
All genetic information one inherits
Phenotype
The expression of genes, ones physical characteristics
Epigenetics
The study of factors that affect gene expression without making any changes to the nucleotide sequence
Alzheimers
Brain exhibits cortical atrophy and reduced metabolism. Patches of amyloid plaques formed by beta-amyloid buildup, neurofibrillary tangles, loss of neurons that make acetylcholine in the forebrain.
