Brain Sciences 1 Flashcards
How is the the nervous system divided?
- Central nervous system: brain and spinal chord
- Peripheral system: in charge of all involuntary functions in the body e.g. heart rate, and muscles, glands.
a. Parasympathetic: controls homeostasis and all rest and digest functions.
b. Sympathetic: controls reactions perceived threat and the “fight vs flight” functions.
What are the main parts of the midbrain/hindbrain and what are their functions?
- Brain stem: cardiac and respiratory function, sleep cycles, regulation of CNS, bridge for all neuron connections.
- Cerebellum: contains 90% of neurons, responsible for control of fine movement.
How is the deeper brain divided?
- Basal ganglia: control of movement, multiple dopamine pathways, close connections to the cortex.
- Hippocampus: related to memory. and learning.
- Amygdala: responsible for fear responses.
- Thalamus: gateway for all sensory input except olfatory, that muss pass through before reaching the primary sensory cortex area.
- Hypothalamus: in charge autonomic nervous system and endocrine system (hormones in charge growth, metabolism, sexuality, etc).
What are the main characteristics/functions of the forebrain and its division?
- Forebrain contains the cortex, which is the outer layer of the brain.
- Divided into right and left hemisphere; each controls the opposite side of the body, separated by the corpus callus.
- Cortex consists of grey matter (neurons arranged in layers forming a sheet of tissue) and white matter (axons and glial cells forming tracts interconnecting the brain).
- It has ventricles which have cerebrospinal fluid to offset the brain’s own weight.
- Cortex divided into parietal (motor and somatosensory cortex), frontal (motor and executive function), temporal (auditory processes) and occipital lobe (visual processes). Lobes are separated by fissures
- Folding to make signals travel faster in a shorter distance.
- Note: prefrontal cortex in charge of the executive function and visual cortex is in the occippital lobe.
How do you navigate the brain?
Dorsal (up), ventral (down), anterior (front), posterior (back), lateral (towards the outside), medial (towards the inside).
Planes: Longitudinal, frontal, horizontal and cross section.
What are the parts of the neuron?
Nucleus, dendrites, axon, synaptic cleft
How does the neuron maintain its resting potential?
Neuron is negatively charged because it has more electrons than neutrons. This creates an electric field in which Na+ and K+ comes into the neuron by attraction and Cl- comes out of the neuron by repelling.
There is a -70 mv potential (separation of charge) that results from from the electric field.
There is also chemical diffussion where Na+ come in and K+ out of the neuron as they move down their concentration gradient
Finally, there are pumps which put 3 Na+ out for each 2 K+ pumped in.
Describe all the stages of the action potential?
First, there is a resting potential of -70mv.
When the neuron receives input from a synapse from previous neuron, in the form of EPSP or IPSP (either increases or decreases the potential), if it reaches -55 mv, then the action potential occurs (all or none event) and it travels down the axon in only on direction.
There is depolarization due to Na+ into the cell and then repolarization due K+ going out of the cell. Then hyperpolarization where slowly the Na+ and K+ pump restore the potential back to -70 mv.
At resting potential, all gates are closed.
What are the synapses and what kind of communication occurs between neurons?
Synases: are connections between the presynaptic and postsynaptic neuron (adjacent neurons).
a) Electrical transmission: action potentials from presynaptic neuron opens voltage-gated channels of of postsynaptic neuron causing the an AP in the postsynatic neuron.
b) Chemical transmission: when the AP from axon terminal of presynatic neuron reaches dendrite of postsynaptic neuron, at the synapse, neurotransmitters are released into the postsynaptic neurons where they are received by the receptors.
What are the types of neurotransmitters and give examples?
Examples: glutamate, serotonin, dopamine.
Receptors take in the neurotrasmitters and can open chemically gated channels:
1. excitatory: Na+ into the neuron
2. Inhibitory: Cl- into neuron and K+ out of the neuron.
What is the cleaning procedure after neurotransmitter and use Pharmacology to explain how it can help patients with depression, Schizophrenia and parkison’s?
Cleaning procedure either by reuptake of the neurotransmitter into the presynaptic neuron or destruction by an enzyme released from the postsynaptic neuron. The reuptake mechanism is mediated by active transporters, which are transmembrane proteins that pump the neurotransmitter back across the presynaptic membrane
Depression (SSRI): SSRI blocks reabsorption of serotonin back into the presynatic neuron.
Schizophrenia: there is increased dopamine in mesolimbic (halluzinations) and decreased in (cognitive/motivational deficits), normal in nigrostratial and tuberoinfundibular. Decreasing dopamine therefore increases positive symptons like hallucinations but decreases even cognitive deficits and causes motor disfunctions similar to parkisons and more prolactin activity assocaited with loss of libido and infertility.
