neuro lab stuff Flashcards
Sensory input
Monitors internal and external environments & changes
Monitored by approximately 1 million sensors
Integrates sensory information
Processes info; decides what should be done
Some processesing is uncontious and some is contious
Motor output
Coordinates voluntary and involuntary responses by activating effectors (muscles & glands)
CNS
Central nervous system
Brain and spinal cord
Very fragile and surrounded by membranes
PNS
Peripheral nervous system
All the nervous tissue outside of CNS
12 pairs cranial nerves
31 pairs spinal nerves and branches
(not all the nerves in the body)
Afferent Division
AKA Sensory division
Going towards the CNS
is apart of PNS
Efferent division
AKA motor division
Going away from CNS
is apart of PNS
Somatic sensory division
Stimuli from muscles, bones, joints, skin & special senses
Is apart of Afferent division
Sending information towards CNS
somatic = coming in from the body
Visceral sensory division
Stimuli from viceral (internal) organs
Is apart of Afferent division
Sends information towards CNS
Somatic motor division
Voluntary
Controls skeletal muscles
From CNS
is apart of Efferent division
Autonomic nervous system (ANS)
Controls smooth and cardiac muscle & glands
All involuntary
From CNS
is apart of Efferent division
Sympathetic division
Mobilizes body systems during activity
Involved in response during perceived threat (fight or flight response)
is apart of autonomic nervous system
Parasympathetic division
Conserves energy
Involved in house keeping ductions during rest (rest & digest system)
restores body to state of calm
is apart of autonomic nervous system
Glial cells
Makes up about half the nervous tissue
Supports the neurons
4 types in CNS
2 types in PNS
Astrocytes
Glial cells in CNS
Star shaped; largest & most common
Projections wrap around capillaries which anchors neurons and capillaries in place (internal background scaffolding)
Helps transport nutrients and gases from blood vessels to neurons
Able to divide and repair damaged brain tissue
Maintains blood brain barrier
Maintaining blood brain barrier
Astrocytes
Isolates CNS from general blood circulation
Surround and induce capillary cells to form tight junctions which hormones, amino acids and ions cannot pass through. This prevents them interfering with neuron function
EX: some hormones & amino acids are neurotransmitters
EX: helps keep bacteria and viruses out on neurons
Oligodendrocytes
Glial cell in CNS
Form sheet of myelin to insulate CNS axons which helps increase speed of action potentials
Lipid (fat) rich substance
Each cell wraps segments of several axons
White matter
Are myelinated axons
Axons surrounded by Oligodendrocytes or Schwann cells
Gray matter
Gray/brown color
Unmyelinated cell bodies, dendrites, axons, cell bodies (short axons are usually unmyelinated)
Not surrounded by any glial cells
Microglial
Glial cell in CNS
Smallest and rarest of CNS glial cells
Phagocytosis cells - engulfs invaders in CNS and cellular waste
Moves through nervous tissue
Ependymal cells
Glial cells in CNS
Simple cuboidal epithelium
Lines cavities in CNS filled with CSF — over capillaries of the choroid plexus
Secretes CSF in some areas
Circulates CST in CNS with cilia in other areas
Satellite cells
Glial cells in PNS
Surround and support neuron cell bodies in PNS
Processes link them with other parts of neuron, other satellite cells, nearby Schwann cells
Function not entirely understood — may regulate extracellular environment similar to Astrocytes in CNS
Schwann cells
Glial cells in PNS
Cover axons in PNS with myelin sheath (similar to Oligodendrocytes)
Neurilemma = outer surface of Schwann cell myelinating an axon
Does not fully wrap around axon. Thick of a hot dog bun.
In some cases Schwann cells sandwich several axons but do not wrap fully around them
Membrane potential
Difference in electrical charge between the extracellular fluid and cytoplasm near the plasma membrane
Resting membrane potential
Membrane potential of undisturbed cell - haven’t done anything to the cell yet
Resting potential of a neuron = -70 mV
Na
Sodium.
When Na + its positively charged
K
Potassium
When K+ means positively charged
Cl
Chloride
When Cl- means negatively charged
Leak channels
Always open
Allows for only certain ions to travel through certain channels
Ions move through the leak channels at the natural pull and push of the charges or chemical gradient
Gated channels
Open or close under specific conditions
Listed on next flash cards
Ligand gated ion channels
EX: acetylcholine receptors (muscle fibers)
Only opens when neurotransmitter attaches to gated channel
Voltage gated ion channels
EX: voltage gated Na+ channels
Depolarization opens channels which can cause further depolarization
Passive ion movement
Happens through leak channels
Influenced by chemical and electrical gradients
Na+ attracted into cell by the negative charge
K+ moved out of cell due to chemical gradient
K+ diffuses out faster than Na+ enters
Gradients
Physical difference in a property of 2 connected regions of space
Polarized
Difference in electrical charge on one side vs the other side
Sodium potassium pump exchange
3 Na+ out of the cell for every 2 K+ in the cell
Na+ and K+ leak back across the membrane but K+ moves out faster than sodium enters
The sodium potassium pump moved the ions against their natural movement through leak channels
Na+ leak channel
Always open
Only allowed sodium to pass through.
Sodium leaks into the cell to get to the negative charge
(Na(h) fam, come on in!)
K+ leak channel
Always open
Only allows potassium to pass through
Potassium leaks out of the cell due to the chemical gradient.
(K(icking) out potassium from the cell)
Polarized neuron
Cell is at -70mV
it is “polished” and ready to go
Depolarized neuron
Cell voltage is shifting towards zero, moving towards the threshold of -55mV
Hyperpolarized neuron
Cell voltage is shifting further negative
EPSP
Excitatory postsynaptic potential
Voltage moves towards zero and threshold
(You are excited. Your adrenaline is going is going up)
IPSP
Inhibitory postsynaptic potential
Moves voltage more negative.
Is the reset button when we get a small increase in voltage in the cell
Ependymal cell
Simple cuboidal with cilia
Circulates cerebrospinal fluid with the cilia
Wernicke’s area
Integrative speech area
Integrates sensory info to understand language
Damaging this part of the brain affects ability to interpret what is read or heard
Broca’s area
Speech center
Regulates motor functions needed to produce speech
Damaging this part of the brain affects ability to form words
Association fibers
Connect areas of cerebral cortex within SAME cerebral hemisphere (side of brain)
Commissural fibers
Connect one hemisphere to the other
Form cerebral commissures (e.g. corpus callosum)
Projection fibers
Connect cerebrum to spinal cord
Most (sensory and motor) cross over to the other side.
EX: right hemisphere controls left side of the body
Limbic system
AKA emotional brain
Participates in: Memory, learning, behavior, emotion
: reaction of feeling nervous (butterflies in stomach) & being scared
: Ability to read emotions in someone else
Fornix
Primary white matter output tract for the limbic system
Limbic lobe
Made up of Cingulate gyri and Parahippocampal gyrus
Gray matter cortex involved in memory formation and retrieval, emotion and learning
Hippocampus
Nucleus involved in learning and memory
Amygdala
Nucleus involved in behavioral expression of emotion, particularly fear
