Physio Psych Exam #1

Physiology

The study of the functions of life and living matter

Physiological Psych

The study of the brain in relation to thoughts, feelings, and behaviors

Levels of Physio Psych

Molecular, Cellular, Organ, or the System level

Physio gives insight into how we

Think, feel, behave, understand whats wrong, create new drugs, understand stress, understand visual illusions

Central Nervous System

Brain and Spinal Cord

Peripheral Nervous System

Everything else besides brain and spinal Cord, including the nerves attached to the brain and spinal Cord

3 Types of Nuerons

Sensory (Afferent), Motor (Efferent), and Interneurons

Interneurons

Local interneurons (analyzing small bits of info) and relay interneurons (connecting local neurons across brain regions).

Soma

Cell Body, contains the nucleus, contains the cells dna, contains machinery for life processes

Dendrites

Receives information from other neurons, antennas basically receiving from synapses

Axons

Carries info from soma to terminal buttons,

Terminal Buttons

Secrete Neurotransmitters

Nerves

Bundles of thousands of neurons wrapped in touch, protective membrane

The Shape of Nuerons

Neuron shape is related to location, shape of neuron is informed by number of dendrites and number of stalks leaving the soma, foot to brain neurons are really long

Unipolar Neuron

One process splits into an axon and dendrite to carry touch and pain sensory signals.

Bipolar

Two opposing processes (one axon, one dendrite) transmit specialized vision, smell, and hearing signals.

Multipolar

Multiple dendrites and one axon integrate complex signals for brain thinking and muscle movement.

Cell Membrane

A hydrophobic lipid bi-layer provides a boundary for the cell, hydrophobic ends

Cytoplasm

Provides support to the interior of the cell and its organelles

Cytoskeleton

Provides structure, microtubules

Nucleus

Control center of cell, produces ribosomes and chromosomes, protein synthesis

Mitochondria

Responsible for energy extraction: ATP

Organelles within the cytoplasm of the soma

Nucleus and Mitochondria

Endoplasmic Reticulum

2 types: Rough (contains ribosomes) and Smooth (provides a pathway for molecules in the cell and reduces lipids), storage spot

Golgi Apparatus

Special type of smooth endoplasmic reticulum, allows for packaging products to transfer outside of the cell (exocytosis), produces lysosomes

Axoplasmic Transport

Active process by which substances are propelled along microtubules that run inside the axonM

Movement from soma to terminal buttons

Anterograde Axoplasmic transport via kinesin molecules

Movement from terminal buttons to soma

Retrograde axoplasmic transport via dynein molecules

Nuerons

Veru fast metabolism, no means of storing nutrients, must be supplied by a support nueron

Glial Cells

Support system for central nervous system

3 Types of Glial Cells

Astrocytes, Oligodendrocytes, Microglia

Astrocytes

The glue of the nervous system, consumes dead cells in CNS and can replicate to help which leaves scar tissue, can travel throughout the CNS, “Star Cell”, most abundant support cell in brain, maintain homeostasis and provides nourishment

Oligodendrocytes

Supports axon and produces myelin sheath

Microglia

Primary Function: Part of the immune response to any threat or trauma to the brain, smallest glial cells, acts as phagocytes for unwanted material (dead and dying neurons)

Schwann Cells

Located in the peripheral nervous system, forms the myelin sheath, neuronal damage can be absorbed by these cells

The Blood-Brain Barrier

Barrier between blood and the fluid surrounding the cells of the brain and spinal cord, selectively permeable which is unlike the rest of the body where blood can flow regardless, area postema controls vomiting by detecting toxic substances in the blood

Action Potential

Brief electrical impulse that provides the basis for conduction of information along the axon, intiated by Na+ movement into cell, stays the same size as it travels, gave rise to two laws: All or None Law and Rate Law

Process of Processing Something

Sent from the soma

→ down the axon

→ to the terminal buttons

→ stimulating the release of neurotransmitters

Membrane Potential

Difference in electrical charge between inside & outside of cell, Balance of diffusion and electrostatic pressure (milliVolts)

Resting potential

MP at rest = -70mV

Depolarization

Inside of axon becomes more positive than outside, more positive change inside MP, more likely to send a message

Hyperpolarization

Inside of axon becomes more negative than outside, more negative change inside MP, less likely to send a message

Action Potential

A very rapid reversal of membrane potential caused by depolarization

Threshold of Excitation

Each neuron has one, set point for depolarization to trigger the main electrical event in an axon, the action potential

Diffusion

The movement of molecules from high to low density, molecules distribute themselves evenly

Electrostatic Pressure

Attractive force between particles, + drawn to - and repelled by +

Intracellular Fluid

Negatively Charged

Extracellular Fluid

Positively Charged

Four Most Important Ions

Organic Anions (A-), Chloride Ions (Cl-), Sodium Ions (Na+), Potassium Ions (K+)

Organic Anions (A-)

Found only in intracellular fluid, cannot pass through axon membrane, negatively charged proteins that are products of the cells metabolic processes

Chloride Ions (Cl-), Sodium Ions (Na+), Potassium Ions (K+)

Found in both intra and extracellular fluid, K+ and Cl- are balanced via opposing forces

Sodium Potassium Pump

Transports Na+ out of the cell to return to resting potential, 3 NA+ in exchange for 2 K+, driven by energy via ATP from mitochondria

Sodium Potassium Transporters

Large number of protein molecules embedded in membrane

Ion Channels

Allows ions to leave or enter, two types: Ligand-gated ion channel and Voltage-dependant ion channels

Voltage-dependant ion channels

Only opens by changes in MP

Ligand-gated ion channel

Opens or closes in response to the binding of a chemical such as a nuerotransmitter

Action Potential Process

An action potential begins when a stimulus depolarizes the neuron's membrane to its threshold, triggering voltage-gated Na+ channels to rapidly open so sodium rushes into the cell and creates a positive charge. At the peak of this electrical impulse, the Na+ channels quickly inactivate to stop the inward current, while slower voltage-gated K+ channels fully open to let potassium rush out and repolarize the cell. Because these K+ channels close slowly, an overshoot occurs that temporarily hyperpolarizes the membrane below its normal resting level. Once these slow K+channels finally close completely, the neuron uses active transport pumps to return to its original resting state.

All-Or-None Law

An action potential either occurs or does not occur, once triggered it is always transmitter down axon to its end, never interupted, remains the same size

Rate Law

Variation in the intensity of the stimulus, or information, in an axon are represented by variations in the rate of firing (bright light means lots of stimulus lots of firing whereas a dim light slowly turns on means a low amount of firing), its the rate of firing not the size

Saltatory Conduction

Conduction of action potentials by myelinated axons, advantages expends less energy and more speedy

Synaptic Transmission

Transmission of messages from nueron to another synapse

Synapses

Junction between terminal buttons of an axon and membrane of another neuron, facilitates communication through release of nuerotransmitters

Postsynaptic Potentials

Produced by neurotransmitters, brief depolarization or hyperpolarizations that increase or decrease rate of firing of the axon of the postsynaptic neuron

Binding Site

Location where neurotransmitters attach on a receptor cell

Ligand

Chemical that attaches to binding site

Series of events in transmission

Terminal buttons of the presynaptic neuron receive an action potential, This causes secretion of a neurotransmitter into the synaptic cleft, The neurotransmitter acts on the postsynaptic receptors, Receptor activation acts to increase or decrease the potential of the postsynaptic membrane, If the threshold of excitation is reached, an action potential is initiated down the axon, and the sequence repeats.

NEUROTRANSMITTER RELEASE

When the action potential occurs, vesicles near the presynaptic membrane fuse with the membrane, break open and allow contents into cleft

ACTIVATION OF RECEPTORS

Neurotransmitters diffuse across the cleft and attach to binding sites of postsynaptic receptors, this causes ligan-gated ion channels to open

Two ways to open ion channels

Direct: Ionotropic receptors, Indirect: Metabotropic receptors

Excitatory Postsynaptic Potential (EPSP)

Inflow of Na+ causes depolarization, increase likelihood of firing

Inhibitory Postsynaptic Potential (IPSP)

Outflow of K+ causes hyperpolarization, Opening of Cl- channels neutralizes EPSPs, decrease liklihood of firing.

Reuptake

Reentry of the neurotransmitter back into the membrane of the presynaptic terminal button

Enzymatic Deactivation

Destruction of a neurotransmitter by an enzyme shortly after release, Breaks down peptides & neurotransmitters

Neural Integration

Process by which inhibitory and excitatory postsynaptic potentials combine and control the rate of firing of a neuron

Neuromodulators

Chemicals released by neurons that travel much further and are dispersed more widely than neurotransmitters, Regulates diverse populations of neurotransmitters

Hormones

Chemical substances released by an endocrine gland that has effects on target cells of other organs