bpsych exam 1

central nervous system

the body’s processing center which contains the brain and spinal cord

peripheral nervous system

the structure that connects the central nervous system to the rest of the body and contains nerves, ganglions and glia

somatic nervous system

part of the PNS that interacts with external environment by processing sensory information and controlling voluntary movement

autonomic nervous system

part of the PNS that regulates the body’s internal environment and controls involuntary bodily functions

blood brain barrier

a protective border of tightly packed endothelial cells that controls what moves between the CNS and the blood

what is an advantage and disadvantage of the blood brain barrier?

advantage: keeps out harmful immune cells (and other toxins) that could cause widespread cell death

disadvantage: keeps out nutrients and large/electrically charged molecules thus requiring channels and different transportation methods

neurons

cells that receive, conduct and transmit electrochemical signals to other cells

identify all the structures on the reduced cell structure

dendrites: receives information from other cells

soma: the cell body

nucleus: contains all genetic information

axon: the point of trigger for an action potential

axon hillock: where the action potential originates

pre-synaptic (axon) terminals: the point where the axon releases the action potential

nodes of ranvier: interruptions of the myelin sheath cot taking voltage gets ion channels that the action potential jumps over

myelin sheath: fatty lining of the axon that speeds up transmission

synapse: the gap between the pre-synaptic and post-synaptic terminals where electrochemical signals cross

identities all the structures of the enlarged neuron

cell membrane: structure that separates the inside of the cell from the external environment

nucleus: contains genetic information

mitochondrion: performs metabolic activity

endoplasmic reticulum: network of tubes that transports synthesized proteins

ribosomes: site of cell synthesis of protein molecules

what are the aspects of neuronal variability?

neurons vary across shape, size, function, cell body projection and dendritic branching

what is the difference between afferent and efferent neurons?

afferent neurons are neurons that carries sensory signals from the body to the CNS while efferent neurons carry motor commands away from the CNS

neural anatomy: unipolar neurons

neurons where the cell body are separate from the axon to allow quick relay of somatosensory signals to the CNS

neural anatomy: bipolar neuron

neurons where the cell body is in the middle of the axon to preserve information and prevents interference from other signals

sensory neuron

neurons that receive input information from the external environment and sends output information to the CNS

neural anatomy: multipolar neuron

neurons where the cell body is before the axon to allow information to be gathered simultaneously

motor neuron

receives input from the CNS and sends output information to the muscles

interneuron

specialized nerve cells that connect motor and sensory neurons that receive sensory messages and responds instantly without waiting for the brain’s command

glia

cells that provide a variety of support and a intense functions for the nervous system

oligodendrocytes

produces multiple myelin sheath segments in the CNS

schwann cells

produces one myelin sheath segment in the PNS and guides regrowth for attached axon

microglia

functions as part of the immune system by triggering inflammatory response, removing waste and proliferating in areas of brain damage

radial glia

guides neuronal growth of axons and dendrites during embryonic development

astrocytes

• synchronizes activity of axon by wrapping around pre synaptic terminal and taking up chemicals released by axon

• provides nourishment by dilating blood vessels

• anchors neurons

• digest cell debris

• creates scar tissue

what function do microglia and astrocytes have together?

they prune ineffective synapses and adjust the effectiveness of others

what’s the difference between cations and anions?

cations have a positive charge and anions have a negative charge

voltage potential

a difference in electrical charge

resting membrane potential

the difference in charge between the inside and outside of the cell when neurons are at rest; typically -70 mv

what is the ionic basis for membrane potential?

sodium enters the cell due to attraction to negative proteins and attraction to lower concentration of sodium which leads to an influx of sodium; potassium enters the cell due to attraction to negative proteins and exits the cell due to attraction to lower concentration which leads to an almost balanced force where potassium leaks out at rest

passive selective membrane permeability

provides a barrier that allows uncharged chemicals to enter the cell but prevents positive ions from entering to depolarize the cell

active sodium potassium pump

protein complex that transports 3 sodium out of the cell and 2 potassium into the cell which is required for the body’s restoration

post synaptic potentials

changes of electrical charge that occurs in a post synaptic neuron’s membrane after neurotransmitters bind to receptors on the post synaptic cells’ membrane

depolarization

when the resting membrane potential decreases by moving towards zero mv

hyperpolarization

when the resting membrane potential increases by moving away from zero mv

graded potentials

membrane potentials that varies in magnitude in relation to the intensity of the stimulus

excitatory post synaptic potentials

a graded post synaptic depolarizations that increase the likelihood of the neuron firing

inhibitory post synaptic potentials

a graded post synaptic hyperpolarization that decreases the likelihood of the neuron firing

explain the net effect of post synaptic potentials

post synaptic potentials at one single synapse have little effect, so neuronal firing is dependent on the balance between EPSP and IPSP

spatial summation

multiple post synaptic potentials that occur at the same time at different spots of the neuron and combine at the trigger zone

temporal summation

multiple post synaptic potentials that occur successively that combine at the trigger zone

action potential

the rapid depolarization and reversal of the resting membrane potential that allows the cell to send signals

explain the basis of an action potential

1. sodium channels open and sodium rushes in, causing the interior to become increasingly positive and moves towards 0mv

2. potassium starts flooding out of the cell because the polarity of the cell membrane is reversed

3. voltage gated sodium channels shut due to the increased positive charge of the interior cell

4. the potassium channels close slowly causing potassium to leak out of the cell (aka hyperpolarization); when channels close, the original polarity is reached so the sodium potassium pump works to return the ions to original concentrations

absolute refractory period

the point in time when a neuron cannot produce an action potential

relative refractory period

the point in time when the neuron can produce an action potential but requires more stimulation that usual

all or nothing principle

the idea that for a neuron the strength and speed of an action potential are independent of the stimulus that initiated it

explain the propogation of the action potential

1. action potential begins at the axon hillock

2. as the action potential rises, sodium ions enter the axon

3. positive ions move towards the patch of neighboring axon with negative charge

4. voltage gated sodium channels open on the patch of membrane

5. a new action potential is generated

6. process is repeated down the axon unchanged in magnitude

saltatory conduction

the action potential jumps from node to node which requires less energy and allows faster propagation of the action potential

explain the process of saltatory conduction

saltatory conduction works where sodium enters through channels at each node of ranvier, passively diffuses to the next node, depolarizes the membrane and regenerates the action potential

multiple sclerosis

a neurodegenerative disease where the myelin sheath is broken down and sodium channels are destroyed making it impossible for the action potential to communicate; symptoms include tremors, loss of coordination, vision problems and cognitive impairment

neurotransmitters

chemical messengers in nervous system used to carry signals between neurons or to target cells

sequence of chemical transmission

1. neuron synthesizes neurotransmitters

2. action potential travels down the axon and opens calcium channels

3. calcium floods in and releases neurotransmitters into synaptic cleft

4. neurotransmitters bind to receptors on post synaptic membrane

5. neurotransmitters separate from receptors and are either inactivated or are taken up into the pre synaptic cell

ligand gated

ion channels that that open or close when specific chemical messengers bind to them

post synaptic receptors

ligand gated protein channels embedded in the membrane with neurotransmitter binding sites

ionotropic receptors

ligand gated ion channels that cause fast/short term effects by inducing post synaptic potentials (EPSP: sodium moves into post synaptic cell and IPSP: potassium moves out/chlorine moves into)

metabotropic receptors

neurotransmitter binds causing a sequence of metabolic events (a G protein is released and activates a messenger that open/close ion channels or DNA binding/expression) of slow/long lasting effects

inactivation

when neurotransmitters are broken apart in synapse by enzymes and the inactive elements are recycled to recreate neurotransmitter

reuptake

when neurotransmitters remain active but detach from receptors and are brought back into the pre synaptic cell where they’re reused

auto-receptors

a component of negative feedback that are located in the presynaptic terminal and keep track of whether the neurotransmitter has been released by binding and stopping neurotransmitter release

retrograde transmission

a component of negative feedback where some post synaptic cells respond to stimulation by releasing chemicals in the pre synaptic cells where the neurotransmitter release is inhibited

electrical transmission

when the membranes of two cells directly touch since the gap junction channels are always open/aligned causing quick transmission of signals

(note: found in neural systems requiring fast responses like defense reflexes)

amino acid: glutamate

the principle excitatory and depolarizing neurotransmitter that comes from glutamic acid; involved in learning/memory and excess amount causes seizures

amino acid: GABA

the principles inhibitory and hyper-polarizing neurotransmitter that regulates neuronal excitability with its calming effect; an excess amount can lead to coma

(note: can be synthesized from glutamate)

monoamines: catecholamines: dopamine

neurotransmitters that