Lectures For Test 2 Flashcards
Neural networks
Complex organizations of neurons that 1. Receive information and interpret and 2. Produce and output response from network Itself.
- can adapt and change
- more connections between neural network than neurons itself
Glial cells
Doesn’t transit or receive information but is a neuron.
- dispose cellular waste
- insulate the axons to increase speed
- form blood/brain barrier
- form white matter of brain
Dendrites receive
- Excitatory messages- neuron should fire action potential
2. Inhibitory messages- neuron should not fire action potential.
Cell body (Soma)
When will neuron fire
Integrates all excitatory/ inhibitory information
-if the difference in excitatory and inhibitory messages reach a threshold, neuron will fire
Axon states
- Resting potential
- neuron has stored up electrical chemical energy (polarized)
- has capacity to create an action potential. -70 millivolts - Action potential
-release of the stored up electrical energy (depolarization)
-neuron fires
+40 millivolts - Refractory period (reset chemical polarization
- absolute (not possible for axon to fire action potential)
- relative (possible to fire again, but cel body needs to exceed threshold by greater amount)
All or none law
Size of action potential is not influenced by increases in intensity of stimulation beyond the threshold. Ap only travels away from the cell body down to axon.
More frequent fires=
Greater i transit of stimulation
Biochemical basis of AP
Outside membrane is positively charged, inside is negatively charged. Positive floods in during AP. During refractory period, sodium pump removes sodium back to outside.
Nodes of ranvier
Gaps in muskets sheath what allow electrical impulses to jump to speed up transmission
Myelin sheath related diseases
MULTIPLE SCLEROSIS- hardening if fatty tissues in neurons
Gillian-Barńe syndrome- disruption in immune system where myelin sheath is seen as a pathogen
Alzeihmers?
Synapse
Electrical impulses (action potentials) travel from one neuron to another across a tiny junction known as a synapse
Reuptake
Neurotransmitters in the synapse are reabsorbed into the sending neuron through the process of reuptake.
Ex: cocaine blocks reuptake of dopamine= more euphoria
If not reuptaken, what happens to neurotransmitters
Special enzymes in the synapse destroy them into basic waste
Neurotransmitters
Have specific effects on behaviour, and operate in specific neural pathways
Neurotransmitters to note
- Acetylcholine (ACH): enables muscle action, leaning and memory (under supply=Alzheimer’s
- dopamine: affect movement, learning, attention and emotion
- serotonin: affects mood, hunger, sleep and arousal (under supply= depression)
- norepinephrine: helps control alertness and arousal
- GABA: inhibits it neurotransmitter
- Glutamate- excitatory neurotransmitter involved in memory
- endorphins: natural pain killers
Key lock analogy
Neurotransmitter molecule ha a molecular structure that precisely fits the receptor site on the receiving neuron, much as a key fits a lock
Agonists
Antagonists
Similar enough in its structure to be neurotransmitter molecule that it mimics its effects on the receiving neuron. Morphine mimics endorphins
Inhibits! Structure similar enough to the neurotransmitter to occupy its receptor site and blocks its action, but not similar enough to produce effect.
Brian’s structures
Forebrain= cerebral cortex and limbric system= thalamus, hypothalamus, hippocampus and amygdala
Midbrain- reticular formation
Hindbrain= cerebellum, medulla and pons
Oldest part of the brain
Hindbrain, automatic functions
Fissures
Gyri
Creases in brain (central and lateral)
Hills that lies between segmentation of brain. Higher areas between fissures.
Frontal lobe
- executive functioning: ability to plan, make decisions, judgments, and inhibit inappropriate behaviour (GABA)
- important in working memory
- language Center (brocade area): expressive language
- primary motor cortex: voluntary motor movements
Alcohol works as a ___ antagonist
GABA
GABA inhibits inappropriate behaviour so alcohol causes it
Temporal lobe
- sound
- primary auditory area: ability to process sounds/speech
- wernicks area: receptive language (collect/understand language)
Parietal lobe
- Integrating sensory information
- somatosensory area (body sense): ability to sense anything in skin and collect information from sense organs