Psych 454 Exam 1

Identify the two main cell types in the nervous system.

• Neurons

• Glial Cells

Neurons

The primary signaling cells responsible for transmitting information

Describe any main subtypes or categories of neurons

• Sensory neurons: Transmit sensory information

• motor neurons: Control muscle actions

• interneurons: Connect neurons within the central nervous system

Glial Cells

Support neurons in various ways

Describe any main subtypes or categories of Glial cells

• Astrocytes: nutritional support

• Oligodendrocytes/Schwann cells: Myelination

• Microglia: immune defense

• Ependymal cells: produce cerebrospinal fluid

Adenosine Triphosphate (ATP)

The source of energy for use and storage at the cellular level

Identify the main organelles of the neuron that are involved in energy or protein production.

• Mitochondria

• Ribosomes

• Golgi apparatus

Mitochondria

Provide energy (ATP) for neuronal functions

Ribosomes

Synthesize proteins

Golgi apparatus

Modifies and packages proteins

What are the parts of the neuron

• Soma (Cell Body)

• Dendrites

• Axon

• Axon Hillock

• Axon Terminals

Soma (Cell Body)

Contains the nucleus and organelles

Dendrites

Receive incoming signals from other neurons

Axon

Transmits signals to other cells

Axon Hillock

Where action potentials are initiated

Axon Terminals

Release neurotransmitters into the synapse.

Synapse

The points where neurons connect and communicate with each other

What are the parts of the synapse

• Presynaptic Terminal

• Synaptic Cleft

• Postsynaptic Membrane

Presynaptic Terminal

Contains synaptic vesicles filled with neurotransmitters

Synaptic Cleft

The gap between the presynaptic and postsynaptic cells

Postsynaptic Membrane

Contains receptors that bind neurotransmitters

Amino acids

Molecules that combine to form proteins

Define axoplasmic transport and describe why it is important

The process of moving materials (proteins, organelles) along the axon. It is essential for the neuron’s health and function, as it delivers necessary materials from the cell body to the axon terminal.

Identify the two most important ions for neural function and describe the forces that act upon them, including their net effect on the direction of ion flow.

• Sodium (Na+)

• Potassium (K+)

Sodium (Na+)

Driven by both concentration gradient and electrochemical forces to flow inward

Potassium (K+)

Concentration gradient drives it out of the cell, but electrochemical forces attract it inward

Define the resting membrane potential

The electrical potential difference across the neuron's membrane when it is not actively sending a signal, typically around -70mV.

Explain what the sodium-potassium pump is and how it helps establish ionic concentration gradients across the neuronal membrane.

A membrane protein that actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell, helping to maintain the resting membrane potential and establish ionic gradients.

Action Potential

A rapid change in voltage across a cell membrane, which is caused by the opening and closing of ion channels

Describe the phases of the action potential in terms of depolarization, repolarization, hyperpolarization, and the ion flow that is involved

• Depolarization: Na+ channels open, and Na+ flows in, making the inside more positive.

• Repolarization: K+ channels open, and K+ flows out, restoring negative potential.

• Hyperpolarization: Excess K+ flows out, making the inside briefly more negative than resting potential.

Explain why the action potential is an all-or-none phenomenon

Once the threshold potential is reached, an action potential is generated. It either occurs fully or not at all; there is no partial action potential.

Absolute relative refractory period

No new action potential can be initiated because Na+ channels are inactivated.

Relative relative refractory period

A stronger-than-normal stimulus can initiate an action potential as the membrane is hyperpolarized.

Explain the roles of voltage-gated ion channels in the action potential

Open in response to changes in membrane potential, allowing specific ions (Na+ and K+) to flow, generating and propagating the action potential.

Identify where the action potential is initiated in a stereotypical multipolar neuron

The axon hillock, where there is a high density of voltage-gated Na+ channels

Explain how the myelin sheath impacts the speed of conduction of the action potential

By insulating axons and allowing action potentials to jump between nodes of Ranvier in a process called saltatory conduction which greatly increases conduction speed.

Explain what gap junctions are

Direct connections between cells that allow ions and other small molecules to pass, facilitating rapid and direct electrical communication between neurons

Describe where amino acid neurotransmitters are synthesized

The neuron’s cytoplasm

Describe where amine neurotransmitters are synthesized

The presynaptic terminal

Describe where peptide neurotransmitters are synthesized

The rough Endoplasmic Reticulum and Golgi apparatus and then transported to the axon terminal

Identify the most common excitatory neurotransmitter in the central nervous system

Glutamate

Identify the most common inhibitory neurotransmitter in the central nervous system

Gamma-Aminobutyric Acid (GABA)

Describe how neurotransmitters are released at the synapse

When an action potential reaches the axon terminal, it triggers the opening of voltage-gated calcium channels, causing calcium influx, which then leads to the fusion of synaptic vesicles with the presynaptic membrane and release of neurotransmitters into the synaptic cleft and into the other neuron’s dendrites.

Explain the differences between transmitter-gated ion channels and G-protein coupled receptors

Transmitter-gated ion Channels open directly in response to neurotransmitter binding, allowing ions to flow and cause rapid changes in membrane potential. G-Protein Coupled Receptors trigger slower, more prolonged responses through intracellular signaling cascades.

Articulate why it is misleading to describe a neurotransmitter as excitatory or inhibitory

Because the effect depends on the type of receptor it binds to and the cellular context

Describe how excitation and inhibition work at the synapse and the principles of synaptic integration

Excitatory postsynaptic potentials (EPSPs) bring the membrane closer to the threshold, while inhibitory postsynaptic potentials (IPSPs) make the membrane more negative, moving it away from the threshold. Synaptic integration is the process by which these signals are summed to determine if an action potential will occur

Explain Dale’s principle and identify whether or not most neurons follow it

States that a neuron releases the same neurotransmitter at all its synapses. Most neurons do not strictly follow this principle as they can release multiple neurotransmitters under certain conditions.

Cholinergic Neurons

• Neurotransmitter: Acetylcholine (ACh).

• Role: Involved in muscle activation, memory, and learning.

Serotonergic Neurons

• Neurotransmitter: Serotonin.

• Role: Regulates mood, sleep, appetite, and cognition.

Amino Acidergic Neurons

• Neurotransmitters: Include GABA (inhibitory) and glutamate (excitatory).

• Role: Critical for balancing excitation and inhibition in the brain.

Identify the dorsal direction at the level of the cerebrum

Towards the top of the brain

Identify the ventral direction at the level of the cerebrum

Towards the bottom of the brain

Identify the superior direction at the level of the cerebrum

Up toward the head

Identify the inferior direction at the level of the cerebrum

Down away from the head

Identify the anterior direction at the level of the cerebrum

Back of the brain to front of the brain

Identify the posterior direction at the level of the cerebrum

Front of the brain to back of the brain

Identify the rostral direction at the level of the cerebrum

Towards the front of the brain

Identify the caudal direction at the level of the cerebrum

Towards the back of the brain

Identify the medial direction at the level of the cerebrum

Toward the center or midline of the brain

Identify the lateral direction at the level of the cerebrum

Toward the sides

Identify the coronal sections of the cerebrum

Divides the brain into anterior (front) and posterior (back) parts

Identify the horizontal section of the cerebrum

Divides the brain into superior (top) and inferior (bottom) parts

Identify the sagittal sections of the cerebrum

Divides the brain into left and right halves (mid-sagittal section cuts through the midline)

Central Nervous System

• Central Nervous System (CNS): Includes the brain and spinal cord.

• Peripheral Nervous System (PNS): Includes all neural elements outside the CNS (nerves and ganglia), which connect the CNS to the rest of the body.

Peripheral Nervous System

Includes all neural elements outside the CNS (nerves and ganglia), which connect the CNS to the rest of the body

Recognize the lobes of the cerebrum

• Frontal Lobe

• Parietal Lobe

• Temporal Lobe

• Occipital Lobe

Frontal Lobe

Involved in decision-making, voluntary movement, planning, and personality

Parietal Lobe

Processes sensory information like touch, temperature, and pain

Temporal Lobe

Involved in auditory processing, language, and memory

Occipital Lobe

Primarily responsible for vision

Central Sulcus

Separates the frontal and parietal lobes

Longitudinal Fissure

Separates the two cerebral hemispheres

Lateral Fissure (Sylvian Fissure)

Separates the frontal and parietal lobes from the temporal lobe

Gray Matter

Composed of neuronal cell bodies, dendrites, and synapses; found in the cerebral cortex, brainstem nuclei, and spinal cord’s dorsal and ventral horns.

White Matter

Composed of myelinated axons; found in subcortical areas, brainstem tracts, and the spinal cord's outer regions

Recognize how many layers are found in the neocortex

Six

Describe what a sulcus is

A groove or depression on the brain’s surface, usually separating gyri.

Describe what a gyrus is

A ridge or fold on the brain's surface, between sulci.

Explain what ventricles are

Cavities in the brain that produce and circulate cerebrospinal fluid

Explain what cerebrospinal fluid is

A clear fluid that cushions the brain, removes waste, and circulates nutrients

Explain what the choroid plexus is

A specialized structure in the ventricles that produces CSF

Explain where the hippocampus is and describe its general functions

Located in the temporal lobe, involved in memory formation

Explain where the thalamus is and describe its general functions

Near the center of the brain, relays sensory information to the cerebral cortex

Explain where the hypothalamus is and describe its general functions

Below the thalamus, controls homeostatic functions like temperature regulation, hunger, and hormone release

Explain where the corpus callosum is and describe its general functions

Near the center of the brain, a large band of white matter connecting the two cerebral hemispheres, allowing communication between them

Know the major divisions of the brainstem

• Midbrain

• Pons

• Medulla Oblongata

Identify the general functions of the brainstem

• Controls basic life-sustaining functions like heart rate, respiration, and sleep.

• Serves as a conduit for information between the brain and spinal cord.

Describe the general structure and functions of the cerebellum

• Located at the back of the brain, it has two hemispheres and a highly folded surface.

• Involved in motor control, balance, coordination, and motor learning.

Name the major white matter pathways that connect the cerebellum to the brainstem

Superior, Middle, and Inferior Cerebellar Peduncles: Connect the cerebellum to different parts of the brainstem and relay information.

Describe the general organization of the spinal cord

• Gray Matter (central): Organized into dorsal (sensory) and ventral (motor) horns.

• White Matter (outer): Contains ascending sensory tracts and descending motor tracts

Describe what a cranial nerve is and how many there are

Nerves that arise from the brain, there are 12 pairs of them

Identify the two cranial nerves that are considered to be part of the central nervous system

• Optic Nerve (CN II)

• Olfactory Nerve (CN I)

Optic Nerve (CN II)

A bundle of nerve fibers that carries visual information from the retina at the back of the eye to the brain

Olfactory Nerve (CN I)

Sensory nerve responsible for your sense of smell

Differentiate the autonomic from the somatic nervous system

• Autonomic Nervous System: Controls involuntary functions (e.g., heart rate, digestion).

• Somatic Nervous System: Controls voluntary movements and sensory processing (e.g., reaching out to grab your coffee)

Differentiate the sympathetic from the parasympathetic nervous system with respect to the levels of the CNS that their nerves arise from and the locations of their ganglia.

• Sympathetic: Arises from the thoracolumbar region; ganglia are close to the spinal cord. Prepares the body for "fight or flight."

• Parasympathetic: Arises from the craniosacral region; ganglia are close to target organs. Responsible for "rest and digest" functions.

Describe the relative wavelengths associated with red, blue, and green perception (i.e., long, medium, or short)

• Blue: Short wavelengths (~450-495 nm)

• Green: Medium wavelengths (~495-570 nm)

• Red: Long wavelengths (~620-750 nm)

Describe the three ways in which light can interact with physical objects

• Reflection

• Absorption

• Transmission

Reflection

Light bounces off the surface of an object

Absorption

Light is absorbed by the object and converted to energy (e.g., heat)