PSY 106 Midterm 1 Study Guide PDF

1 PSY 106 Midterm 1 Study Guide EXAM 1 is on 10/23/24 at 3:30 pm, in person in CHEM 1179 Week 1 (9/30-10/4) Brain Basics, Cell Biology Basics, Neurons ➔ Define the term “biopsychology” ◆ Biopsychology is the biological approach to psychology that studies the relationshi...

1 PSY 106 Midterm 1 Study Guide EXAM 1 is on 10/23/24 at 3:30 pm, in person in CHEM 1179 Week 1 (9/30-10/4) Brain Basics, Cell Biology Basics, Neurons ➔ Define the term “biopsychology” ◆ Biopsychology is the biological approach to psychology that studies the relationship between behavior and the brain ◆ “Behavioral neuroscience” What is the physiological basis for emotions? What changes in the brain when someone learns something new? How do we recognize familiar faces? ➔ Differentiate between the central and peripheral nervous systems ◆ Central Nervous System (CNS) Consists of the brain and spinal cord. Processes and integrates sensory information; responsible for higher brain functions (e.g., thinking, emotions). Encased in the skull and vertebral column; protected by cerebrospinal fluid and the blood-brain barrier. Limited ability to regenerate after injury. ◆ Peripheral Nervous System (PNS) Includes all nerves outside the CNS, such as cranial nerves and spinal nerves. Connects the CNS to the rest of the body; responsible for transmitting sensory information to the CNS and motor commands from the CNS to muscles. Not protected by bony structures; more vulnerable to injury. Greater capacity for regeneration after injury compared to the CNS. ➔ List the main animal species used in biopsychology research ◆ Rodents (usually rats or mice)  1 ◆ Non-human primates (macaques & marmosets) ◆ Aquatic vertebrates (fish & frogs) ◆ Squid ◆ Flies ◆ Worms ➔ List the major components of a typical cell ◆ Plasma membrane: A thin outer layer that controls what enters and exits the cell; composed of a phospholipid bilayer ◆ Nucleus: The "control center" of the cell, containing most of the cell's DNA and the nucleolus. ◆ Mitochondria: responsible for generating ATP ◆ Ribosomes: Responsible for protein synthesis ➔ Describe the key properties of the plasma membrane ◆ Composed of phospholipid bilayer ◆ Has two sets of phospholipid molecules, facing in opposite directions Hydrophobic tails face inwards, hydrophilic tails face ◆ Selectively permeable Some molecules can freely pass across the bilayer (like oxygen), but many others need to use special hallways (called channels) or active transporters ➔ Explain what ATP is and why it is important for a cell ◆ ATP (Adenosine Triphosphate): Primary energy carrier in cells. Brain uses more energy than any other organ in the body ◆ Composed of adenine, ribose, and three phosphate groups. ◆ Energy is released when ATP is hydrolyzed to ADP and a phosphate group. ◆ Importance: Powers cellular processes like muscle contraction, active transport, and biochemical reactions. Essential for metabolism, protein synthesis, and DNA replication. ➔ Describe the process through which DNA results in proteins ◆ Transcription: Occurs in the nucleus. DNA is transcribed into mRNA by RNA polymerase. mRNA carries genetic information from DNA to the ribosomes. ◆ Translation: Happens at the ribosome. tRNA brings amino acids based on codons in mRNA.  1 Ribosome links amino acids into a polypeptide chain. Polypeptide folds into a functional protein. ➔ Define the terms cation, anion, monovalent, and divalent ◆ Cation: Positively charged ion (e.g., Na⁺). ◆ Anion: Negatively charged ion (e.g., Cl⁻). ◆ Monovalent: Ion with a charge of +1 or -1 (e.g., Na⁺, Cl⁻). ◆ Divalent: Ion with a charge of +2 or -2 (e.g., Ca²⁺, SO₄²⁻). ➔ Explain how we have come to learn about the brain and what it’s made out of ◆ Early observations: Nissl stain (by Franz Nissl) stains the nucleus of cells and the rough ER surrounding it- results in all cell bodies being darkened Golgi stain (by Camillo Golgi) darkens entire cells with silver, but only a small percentage of them, at random ◆ Microscopy: Led to the neuron doctrine (Ramón y Cajal). ○ The brain is made up of individual neurons that connect to one another with long projections  1 ◆ Modern techniques: Neuroimaging (e.g., MRI, fMRI, PET scans): Non-invasive brain imaging. Electrophysiology: Measures electrical activity in neurons. Molecular biology: Studies the brain at the genetic and protein level. ◆ Brain composition: Neurons, glial cells, and other structures for information processing and bodily regulation. ➔ Describe what makes a neuron different from other cell types ◆ Excitability: Can generate and propagate electrical impulses (action potentials). ◆ Synaptic transmission: Communicates via neurotransmitter release at synapses. ◆ Unique structure: Dendrites (receive signals), axon (transmit signals), soma (cell body). ◆ Polarity: Signals flow in one direction—from dendrites to axon terminal. ➔ Label the parts of a typical neuron ◆ Dendrites: Receive signals from other neurons. ◆ Cell body (soma): Contains nucleus and organelles; integrates signals. ◆ Axon: Transmits electrical impulses away from the soma. ◆ Axon hillock: Where the axon connects to the soma; action potentials initiated. ◆ Myelin sheath: Insulates axon, speeding up signal transmission. ◆ Nodes of Ranvier: Gaps in the myelin sheath where action potentials are regenerated. ◆ Axon terminal: Releases neurotransmitters to communicate with other neurons.  1 Week 2 (10/7-10/13) Glia; Membranes & Potentials; The Action Potential ➔ Compare and contrast various glia types and their functions ◆ Astrocytes Location: Central Nervous System (CNS) Functions: ○ Structural support: Astrocytes provide physical scaffolding for neurons and maintain the structural integrity of the brain. ○ Nutrient supply: They regulate the blood-brain barrier and help deliver nutrients from the bloodstream to neurons. ○ Waste removal: Astrocytes participate in clearing excess neurotransmitters and metabolic waste. ○ Ion balance: They regulate the extracellular environment by maintaining ion balance, particularly potassium (K+), around neurons. ○ Neurotransmitter recycling: Astrocytes uptake and recycle neurotransmitters like glutamate and GABA, preventing excitotoxicity. ○ Modulation of synaptic activity: They release gliotransmitters that modulate neuronal signaling. ◆ Microglia Location: CNS Functions: ○ Immune defense: Microglia act as the primary immune cells of the CNS. They respond to infection, injury, or disease by removing pathogens and dead cells through phagocytosis. ○ Synaptic pruning: During development and in response to injury, microglia help refine neural circuits by eliminating unnecessary synapses. ○ Inflammatory response: Microglia produce inflammatory cytokines and other signaling molecules to recruit immune cells when needed, but chronic activation can contribute to neuroinflammation in diseases like Alzheimer's. ◆ Oligodendrocytes Location: CNS Functions:  1 ○ Myelination: Oligodendrocytes form the myelin sheath around axons in the CNS. This sheath increases the speed of action potentials by facilitating saltatory conduction. ○ Support: They supply metabolic support to neurons, particularly to the long axons that they myelinate. ◆ Schwann Cells Location: Peripheral Nervous System (PNS) Functions: ○ Myelination: Similar to oligodendrocytes, Schwann cells produce the myelin sheath in the PNS, which helps in the rapid transmission of electrical signals along peripheral nerves. ○ Axonal regeneration: In the event of injury in the PNS, Schwann cells play an essential role in guiding axonal regrowth and repair. ➔ Describe the important ions inside and outside of the neuron and compare their concentration gradients ◆ Sodium ions (Na⁺): Outside the neuron: High concentration. Inside the neuron: Low concentration. Concentration gradient pushes Na⁺ into the neuron, but Na⁺ channels remain closed during resting potential, preventing influx. ○ STRONG inward driving force ◆ Potassium ions (K⁺): Outside the neuron: Low concentration. Inside the neuron: High concentration. Concentration gradient pushes K⁺ out of the neuron, but the selective permeability of the neuron membrane allows some K⁺ to leak out, maintaining resting potential. ○ WEAK outward driving force ◆ Chloride ions (Cl⁻): Outside the neuron: High concentration.  1 Inside the neuron: Low concentration. Cl⁻ concentration gradient pulls it into the cell, but it typically remains balanced due to electrostatic forces and chloride channels. ○ Little to no driving force ◆ Calcium ions (Ca²⁺): Outside the neuron: High concentration. Inside the neuron: Very low concentration. Ca²⁺ enters the neuron during synaptic transmission, triggering neurotransmitter release, but it is actively pumped out afterward to maintain low intracellular levels. ○ STRONG inward driving force ➔ Explain how diffusional and electrostatic forces act upon ions ◆ Diffusional (concentration) forces: Moving ions from regions of high concentration to regions of low concentration ○ A difference in concentration between regions is called a concentration gradient For example: ○ Sodium ions (Na⁺) are more concentrated outside the neuron, so diffusional forces push Na⁺ into the neuron. ○ Potassium ions (K⁺) are more concentrated inside the neuron, so diffusional forces push K⁺ out of the neuron. Diffusional forces occur due to the random movement of particles and are independent of the ions' electrical charge. ◆ Electrostatic forces: Moving ions based on electrical charge ○ Opposite charges attract (e.g., positive ions are drawn to negatively charged areas). ○ Like charges repel (e.g., two positive ions will push away from each other). A difference in charge is called electric potential, or voltage ➔ Describe how ions can cross the phospholipid bilayer ◆ Ion channels: Ion channels are proteins embedded in the phospholipid bilayer that provide a passageway for ions to move across the membrane. Channels are selective for specific ions (e.g., Na⁺, K⁺, Cl⁻) and can be either open or gated (closed until a stimulus opens them).  1 ○ Leak channels: Always open, allowing specific ions (e.g., K⁺) to move down their concentration gradient. ○ Voltage-gated channels: Open or close in response to changes in membrane potential (e.g., Na⁺ channels open during an action potential). ➔ Define resting membrane potential, threshold potential, and action potential ◆ The resting membrane potential is the electrical charge difference across the neuron's membrane when it is not actively sending a signal (i.e., at rest). Typically around -65 mV, the inside of the neuron is more negative compared to the outside. ◆ The threshold potential is the critical level of membrane depolarization that must be reached for an action potential to be triggered. Usually around -55 mV, if the neuron’s membrane potential reaches this value, voltage-gated sodium channels open, allowing Na⁺ to rush into the cell. ◆ The action potential, also called a “spike”, is a rapid and dramatic redistribution of charge across the membrane This is an essential element of communication between neurons Allows for the transmission of information across very long distances ➔ Explain the concept of an equilibrium potential for an ion ◆ The equilibrium potential for an ion is the membrane potential at which there is no net movement of that ion across the membrane. At this point, the ion’s concentration gradient (diffusion) and electrostatic forces (charge) are balanced. ◆ Each ion has its own equilibrium potential, calculated using the Nernst equation. For example: ○ Potassium (K⁺) has an equilibrium potential of about -80 mV. ○ Sodium (Na⁺) has an equilibrium potential of around +60 mV. ➔ Describe the phases of an action potential and what sodium and potassium ions are doing during them ◆ States: Resting state: ○ Membrane potential: ~65 mV. ○ Na⁺ and K⁺ channels are closed, and the sodium-potassium pump maintains the resting potential. Depolarization:  1 ○ Na⁺ channels open, and Na⁺ rushes into the neuron, making the inside more positive. Membrane potential gets closer to 0 (becomes equal to outside of cell) ○ Membrane potential rapidly rises toward +30 mV. Repolarization: ○ Na⁺ channels close, and K⁺ channels open. ○ K⁺ flows out of the neuron, restoring the negative charge inside. Hyperpolarization: ○ K⁺ channels remain open briefly, causing the membrane to become more negative than the resting potential. Membrane potential gets farther from zero. Return to resting potential: ○ K⁺ channels close, and the sodium-potassium pump restores the resting state by moving Na⁺ out and K⁺ in. ◆ Phases: Rising Phase: Voltage-gated Na⁺ channels are now able to open up, and since Na⁺ is under strong diffusional and electrostatic forces, Na⁺ ions rapidly rush into the neuron, depolarizing it further (making it less negative) Overshoot: Sodium’s equilibrium potential is very positive (around 60 mV): Na⁺ ions will enter the cell for as long as sodium channels are open Falling Phase: With Na⁺ no longer entering the cell and K⁺ now rushing out, the action potential is in the falling phase (repolarization) Undershoot: Voltage gated K⁺ channels remain open, allowing K⁺ to continue flowing outward in an attempt to reach the K⁺ equilibrium potential of -80 mV ➔ Compare the absolute and relative refractory periods and what causes them ◆ Absolute Refractory Period: No second action potential can be initiated, regardless of stimulus strength. Duration: During depolarization and most of repolarization. Cause: Inactivation of Na⁺ channels prevents reopening until the membrane potential returns to a certain level. ◆ Relative Refractory Period: A second action potential can be initiated, but only with a stronger-than-normal stimulus.  1 Duration: After the absolute refractory period, during the latter part of repolarization and undershoot. Cause: Open K⁺ channels lead to hyperpolarization, requiring a stronger stimulus to reach the threshold. ➔ Explain how the sodium-potassium pump functions to maintain potassium and sodium distributions ◆ The sodium potassium pump has to continually work to get things back to normal The pumps take 3 molecules of sodium from the inside and push them outside, and take 2 molecules of potassium from the outside and push them in ○ The process uses a lot of ATP since it is working against the concentration gradient Week 3 (10/14-10/20) Synaptic Transmission & Neurotransmitters ➔ Describe where action potentials originate and how they travel down the axon ◆ Action potentials originate at the axon hillock (trigger zone). ◆ The action potential is propagated down the axon toward the axon terminals ◆ They travel down the axon by depolarizing sections of the membrane in a wave-like manner, where sodium (Na+) ions enter and potassium (K+) ions exit. ➔ Explain what myelin is and how it results in saltatory conduction ◆ Myelin is a fatty substance that insulates axons, produced by Schwann cells (PNS) or oligodendrocytes (CNS). ◆ Myelinated axons conduct action potentials faster through saltatory conduction, where the signal jumps between Nodes of Ranvier. V-gated sodium channels are only at the nodes ◆ Saltatory conduction: leaping conduction  1 ➔ Compare and contrast electrical and chemical synapses ◆ Electrical synapses: Direct ion flow between cells via gap junctions; fast but less flexible; simpler than chemical synapses More common in invertebrates ◆ Chemical synapses: Use neurotransmitters to transfer signals across a synaptic cleft; slower but highly adaptable. Acts on specific receptors on the receiving cell’s surface ➔ Identify the proteins and ions that are required for neurotransmitter release 2+ ◆ Calcium ions (𝐶𝑎 ) trigger vesicle fusion. ◆ SNARE proteins (syntaxin, SNAP-25, synaptobrevin) are essential for vesicle docking and neurotransmitter release. Found on the membrane of the vesicles and on the neuronal membrane itself ➔ Describe the sequence of events that results in the release of neurotransmitter ◆ Action potential reaches the axon terminal. 2+ ◆ Voltage-gated 𝐶𝑎 channels open, allowing calcium to enter. ◆ Synaptic vesicles fuse with the membrane, releasing neurotransmitters. ◆ Neurotransmitters diffuse across the synapse and bind to receptors. ➔ Define “ligand” and “receptor” ◆ Ligand: A molecule that binds to a receptor (e.g., neurotransmitter). ◆ Receptor: A protein on the cell surface that ligands bind to, initiating a response ➔ Compare and contrast ionotropic and metabotropic receptors ◆ Ionotropic receptors: receptor is an ion channel, ions rapidly flow through with open (depending on driving force); can also call these “transmitter-gated ion channels Ligand-gated ion channels, fast-acting, direct effects on ion flow. ◆ Metabotropic receptors: ligand induces change in shape that leads to intracellular cascade of events Many different effects, depending on protein complex Receptor is connected to multiple pathways inside the cell G-protein-coupled receptors, slower, indirect, activate secondary messenger pathways (chain reaction from single transmitter) ➔ Explain how excitatory and inhibitory postsynaptic potentials are generated ◆ EPSPs: Generated by depolarization (e.g., Na+ influx), making action potentials more likely. ◆ IPSPs: Generated by hyperpolarization (e.g., Cl- influx), making action potentials less likely.  1 ➔ Compare and contrast spatial and temporal summation of postsynaptic potentials ◆ Spatial summation: Multiple signals from different synapses combine at the postsynaptic neuron. ◆ Temporal summation: Rapid, successive signals from the same synapse combine over time. ➔ Describe the synthesis, effects, and clearance methods of a few key neurotransmitters Neurotransmitter Where does it What does it Where does it Function in the come from? bind to? go nervous system afterwards? Glutamate Synthesized in Ionotropic Reuptake by Primary excitatory neurons from receptors: glial cells neurotransmitter in glutamine via NMDA, AMPA, (astrocytes) or the CNS, involved in the enzyme kainate glutamate learning, memory, glutaminase. receptors transporters and synaptic (excitatory). plasticity. Metabotropic receptors: mGluR (metabotropic glutamate receptors). GABA Synthesized Ionotropic Reuptake by Primary inhibitory from receptors: presynaptic neurotransmitter in glutamate by GABA-A neurons or the CNS, involved in the enzyme receptors glial cells via reducing neural glutamic acid (chloride GABA excitability, decarboxylase channels, transporters regulating muscle (GAD) in inhibitory). (GAT), then tone, and preventing neurons. degraded by overstimulation.  1 GABA transaminase. Acetylcholine (ACH) Synthesized in Ionotropic Broken down Involved in muscle neurons from receptors: in the synaptic contraction (PNS), choline and Nicotinic cleft by autonomic nervous acetyl-CoA by acetylcholine acetylcholinest system functions, the enzyme receptors erase (AChE) attention, learning, choline (nAChRs). into choline and memory (CNS). acetyltransfera Metabotropic and acetate; se (ChAT). receptors: choline is Muscarinic taken back up acetylcholine into the neuron receptors for reuse. (mAChRs). Dopamine Synthesized in Metabotropic Reuptake by Regulates reward neurons from receptors: presynaptic and motivation, tyrosine via D1-like neurons via motor control, and tyrosine (excitatory) dopamine mood. Dysregulation hydroxylase and D2-like transporters is implicated in and DOPA (inhibitory) (DAT); broken Parkinson’s disease decarboxylase. dopamine down by and schizophrenia. receptors. monoamine oxidase (MAO) and catechol-O-me thyltransferase (COMT). Serotonin Synthesized Ionotropic Reuptake by Regulates mood, from receptors: presynaptic sleep, appetite, and tryptophan by 5-HT3 neurons via pain perception. tryptophan receptors. serotonin Imbalances are hydroxylase Metabotropic transporters linked to depression and aromatic receptors: (SERT); and anxiety L-amino acid Several 5-HT degraded by disorders. decarboxylase. receptor monoamine subtypes (e.g., oxidase (MAO). 5-HT1A, 5-HT2A).  1 Week 4 (10/21-10/27) Recap and Review ➔