PBSI 235 FINAL EXAM Alwood TAMU

Neuron

Basic information-processing cell of the nervous system

Glial Cells

Support cells that assist neurons

Nucleus

Contains DNA and controls cell activity

Ribosomes

Translate mRNA into proteins r

Mitochondria

Produce ATP (energy)

Transcription

DNA is copied into RNA

Translation

RNA is used to create proteins

Dendrites

Receive input from other neurons

Soma

Integrates incoming signals and contains nucleus

Axon

Sends signals away from the soma

Axon Terminals

Release neurotransmitters

Synapse

Connection between neurons

Presynaptic Membrane

Releases neurotransmitters pre

Postsynaptic Membrane

Receives neurotransmitters

Synaptic Cleft

Gap between neurons

Neuron Doctrine

Brain is made of individual neurons

Reticulum Theory

Incorrect idea that brain is one continuous network

Astrocytes

Maintain environment and blood-brain barrier

Oligodendrocytes

Myelinate CNS axons

Schwann Cells

Myelinate PNS axons

Microglia

Immune defense cells

Ependymal Cells

Help circulate cerebrospinal fluid

Resting Potential

Baseline electrical charge (~ -70 mV)

Ion Channels

Proteins that allow ions to cross membrane

Diffusion

Movement from high to low concentration

Electrostatic Force

Attraction/repulsion of charged ions

Na+/K+ Pump

Moves 3 Na+ out and 2 K+ in using ATP

Hyperpolarization

Inside becomes more negative

Depolarization

Inside becomes more positive

Action Potential

All-or-none electrical signal

Ionotropic Receptors

Open ion channels when NT binds

EPSP

Excitatory depolarization

IPSP

Inhibitory hyperpolarization

Spatial Summation

PSPs combine across space

Temporal Summation

PSPs combine over time

Neurotransmitter

Chemical messenger between neurons

Synaptic Vesicles

Store neurotransmitters

Ionotropic Receptors

Fast ion channel response

Metabotropic Receptors

Slow G-protein response

Reuptake

NTs reabsorbed into presynaptic neuron

Enzymatic Degradation

NTs broken down by enzymes

Agonist

Mimics neurotransmitter

Antagonist

Blocks neurotransmitter

ED50

Effective dose for 50%

LD50

Lethal dose for 50%

Therapeutic Index

Safety margin of a drug

Tolerance

Reduced drug effect over time

Sensitization

Increased drug effect over time

Dependence

Withdrawal when drug removed

Glutamate

Main excitatory neurotransmitter

GABA

Main inhibitory neurotransmitter

Skeletal Muscle

Produces movement by contracting

Motor Neuron

Sends signals from CNS to muscles

Motor Unit

One neuron and its muscle fibers

Neuromuscular Junction

Synapse between neuron and muscle

Primary Motor Cortex

Executes voluntary movement

Premotor Cortex

Plans movement

Supplementary Motor Area

Prepares movement sequences

Basal Ganglia

Initiates or stops movement

Cerebellum

Coordinates precision and balance

Nigrostriatal Pathway

Dopamine pathway for movement

Parkinson's Disease

Loss of dopamine causing motor deficits

Sensory Transduction

Converts stimuli into neural signals

Sound

Air pressure waves

Amplitude

Loudness

Frequency

Pitch

Cochlea

Converts sound into neural signals

Organ of Corti

Contains sound receptors

Hair Cells

Transduce sound vibrations

Basilar Membrane

Encodes frequency

Superior Olivary Nucleus

Sound localization

Primary Auditory Cortex

Processes sound

Gustation

Taste

Olfaction

Smell

Papillae

Structures containing taste buds

Taste Buds

Contain taste receptor cells

Sweet

Sugar detection via G-proteins

Sour

H+ ion detection

Salty

Na+ ion detection

Bitter

T2R receptor activation

Umami

Glutamate detection

Retina

Converts light into neural signals

Cornea

Bends light

Lens

Focuses light

Rods

Low light, no color vision

Cones

Color and detail vision

Photoreceptors

Detect light

Bipolar Cells

Relay signals

Ganglion Cells

Send signals to brain

Fovea

Area of highest acuity

Blind Spot

Area without photoreceptors

Homeostasis

Maintains stable internal environment

Set Point

Ideal physiological level

Negative Feedback

Reverses deviations

Thermoregulation

Temperature control

Hypothalamus

Regulates body balance

Osmotic Thirst

Triggered by high salt

Hypovolemic Thirst

Triggered by low fluid

Insulin

Lowers blood glucose

Glucagon

Raises blood glucose