Midterm 1 Flashcards
Brain, Neuron, Perception
Neuron Structure
Input -> Dendrite -> Cell Body -> Axon Hillock -> Axon -> Output
Node of Ranvier
Inbetween myelin sheath
3 types of Synapses
Axosomatic: axon - cell body
Axodendritic: axon - dendrite (most common)
Axoaxonic: - axon - axon
The Neuron as a Battery
Uses the Difference in electical potential ( more positive ions outside the cell) (more negative ions inside the cell) to give the neuron a resting potential of -70mv
Ion Channels vs Ion Pumps
Passive transport via gradient (Na, K, Ca, Clvs Active transport (Na, K, Ca)
K+ Electrochemical Equilibrium
Electrical Gradient brings K+ into Cell
Concentration Gradient pushes K+ out of Cell
Nernst Equation
calculates potential bt inside and outside of cell when K+ ions are in balance.
Eion = Equilibrium potential for ion R = Universal gas constant F = Faraday constant T = Temperature z = Valence ln() = natural logarithm [ion]o = outside concentration of ion [ion]i = inside concentration of ion
Na+ Electrochemical Equilibrium
both push in bc more sodium outside the cell ( conc. gradient) and more -ive inside = elec. gradient
Na/K Pump
For 1 molecule of ATP
(adenosine triphosphate):
● 2 K+ in
● 3 Na+ out
Result:
Concentration gradients
● Greater Na+ outside
● Greater K+ inside
Electrical gradient
● Higher potential outside
ACTION POTENTIAL EVENTS
- At threshold, voltage-gated Na+ channels open, and positive Na+ ions flow into cell
- As depolarization continues, even more voltage-gated Na+ channels open, increasing depolarization
- Voltage-gated K+ channels open, and K+ ions flow out of cell
- Voltage-gated Na+ channels close, while voltage-gated K+ channels are still open
During hyperpolarization, another action potential cannot be generated (absolute refractory period) - Voltage-gated K+ channels close when the membrane is hyperpolarized (below resting potential), and the membrane potential returns to steady state at the resting potential (relative refractory period)
Propagation of Action Potential (long distance)
second way the action potential travels through the neuron.
long distance signal transmission
spiking of potential conducts to nearby tissue which then excites the nearby tissue = action potential goes and so on and so on.
Glutamate
Excitatory neurotransmitter
GABA
Inhibatory Neurotransmitter
Ionotropic Receptors
Short response time
Metabotropic Receptors
Long Response time
Strength of Post Synaptic Potential Depends on:
Strength of PSP at the synapse ● Timecourse of PSP at the synapse ● Distance to the synapse ● Time since the action potential`
Summation of Post Synaptic Potentials
PSPs then summate ● EPSPs add to the membrane potential ● IPSPs subtract from the membrane potential
Major Developmental Divisions of the Brain
Hind Brain: Metencephalon, Myelencephalon -Brainstem
Mid Brain: Mesencephalon - Brainstem
Forebrain: Diencephalon, Telencephalon - Cerebral Cortex
Telencephalon
Forebrain,
Cerebral Cortex,
Basal Ganglia,
Hippocampus
Diencephalon
Forebrain,
Hypothalamus + Thalamus
Mesencephalon
Midbrain,
Superior Colliculus
Inferior Colliculus
Motor nuclei
Metencephalon
Hindbrain,
Pons
Cerebellum
Myelencephalon
Medulla
Cerebellum fx
Motor control, coordination, posture, equilibrium,
etc…
Hypothalamus fx
Hormone release, body temperature, hunger, thirst,
sleep, etc
Thalamus fx
Sensory-motor hub and relay, e.g.:
● Lateral geniculate nucleus: visual relay
● Medial geniculate nucleus: auditory relay
3 Basal Ganglia (top to bottom)
Caudate Nucleus - Voluntary movement &
goal-directed action
Putamen - Motor skills &
reinforcement learning
Globus pallidus - Regulation of voluntary
movement
Cerebral Cortex Lobs
Frontal
Parietal
Temporal
Occipital
Sulcus that splits the two hemispheres
Longitudinal Fissure
Precentral Gyrus
Motor control
Cingulate Gyrus
Early Visual Processing
Comissures
= Connections between hemispheres
- Corpus Callosum
- Fornix
- Anterior Commisure
Gray + White Matter
Gray matter:
Cortical surface
Cell bodies
White matter:
Myelinated axons
Neuroglia
Ependymal Cells (CNS) - Produce CSF Astrocytes (CNS) - Support + Blood Brain Barrier Oligodendrocytes (CNS) - Wrap Axon in Myelin = reaches out and attaches) Schwann Cells (PNS) - Wrap axon in Myelin = Attached to Cell Body Micro Glia (CNS) - Commence Phagocytosis Satelite Cells (PNS) - Support + Blood Brain Barrier
Central Nervous System
Brain + Spinal Cord
Peripheral Nervous System
Everything other than the Brain and Spinal Cord
- Somatic (Voluntary)
- Autonomic (Sympathetic and parasympathetic)
How Are Autonomic Motor Neurons diff than Somatic
different from somatic bc the autonomic the signals go to sympathetic or parasympathetic ganglia then go to effector vs directly to effector
Sympathetic vs Parasympatheric
Sympathetic: ● “Fight or flight” and quick response ● Increases blood flow to skeletal muscles ● Increases heart rate ● Inhibits digestion ● Dilates pupils for far vision
Parasympathetic ●Rest and digest”, “feed and breed”, and calmness ● Increases blood flow to gut ● Facilitates digestion ● Constricts pupils for near vision
Meninges
Dura Mater
Arachnoid Mater Thin fibrous membrane with trabeculae extending through the subarachnoid space to the pia mater
Sub Arachnoid Space
filled with CSF
Pia Mater
Ventricles of Brain
Right Ventricle Left Ventricle Choroid Plexus - produces CSF Third Ventricle Fourth Ventricle
