NEU 201 Exam I Flashcards: Slides

What are the two large numbers shown early in Lecture 1 before discussing connections, and what do they likely represent (neurons in different structures)

100 million and 1 billion — shown to illustrate scale before the 100,000-connections-per-cell point.

What example was given for objective 4 (neurobiological basis of behavior)?

Activation of the amygdala triggering changes in behavior.

What textbook is used for this course?

A free, virtual textbook (linked in the syllabus); one physical copy is also available for checkout at the library

What are the four brain misconceptions discussed in class, and are they true or false?

(1) We only use 10% of our brain — FALSE;

(2) sleep is when the brain shuts down — FALSE;

(3) left-brain people are logical and right-brain people are creative — FALSE;

(4) brain damage is permanent — "It depends."

In the biology example, what are the six organelles discussed and their functions?

Nucleus (contains genetic material), endoplasmic reticulum (folds proteins, synthesizes lipids), ribosomes (translate genetic material into proteins), mitochondria (generate ATP), Golgi body (packages transport vesicles), microtubules (structural support/cellular scaffolding)

How was Phineas Gage described before his accident, and how was he described afterward?

Before: a "shrewd, smart business man, very energetic and persistent in executing all his plans of operation." After: "impatient, unable to plan, irreverent, and fitful" — friends said he was "no longer Gage.”

What is the approximate electrical charge of a neuron, used as the physics example?

About -70 mV.

What discipline is illustrated by "network computation," and what discipline is illustrated by implanted wearable devices improving Parkinson's disease?

Math (network computation) and engineering (implanted wearable devices)

What are the steps of an experimental study, in order?

Ask a question → develop a hypothesis → design an experiment (pre/post test) → change only one variable (the independent variable) → subjects divided at random into experimental and control groups → read out results (the dependent variable) → analyze data → arrive at a conclusion

 In an experimental study, what happens to the experimental group vs. the control group?

The experimental group experiences the changed (independent) variable; the control group experiences similar conditions without that change.

What are the key defining features of an experimental study?

Can use humans or nonhuman animals, is hypothesis-driven, and involves carefully controlled variables.

What three caveats does the instructor give about the nature of science?

Science is a work in progress, full of exceptions, and simplified by necessity

Why is science described as "dependent on technology"?

Because what we can discover is limited by the tools/technology currently available (e.g., data storage scale of 2–4 TB mentioned as an example).

In the "calcium is necessary for neurotransmitter release" example, what is the instructor illustrating?

That confident-sounding scientific statements are actually simplified shorthand for more hedged, uncertain claims (e.g., "probably one of many necessary prerequisites, under a majority of circumstances")

What are the five main pairs of directional terms used to describe nervous system anatomy?

Dorsal–Ventral, Anterior–Posterior, Medial–Lateral, Proximal–Distal, Contralateral–Ipsilateral

What are the alternate names for Dorsal, Ventral, Anterior, and Posterior?

Dorsal = Superior, Ventral = Inferior, Anterior = Rostral, Posterior = Caudal

In the anatomical terms used in this course, what is the difference between proximal and distal?

Proximal is closer to the midline; distal is farther from the midline.

Why is the nervous system described as "mostly crossed"?

The left hemisphere of the brain controls and receives sensations from the right half of the body (and vice versa).

What is the difference between contralateral and ipsilateral?

Contralateral refers to the opposite hemisphere/side of the body; ipsilateral refers to the same hemisphere/side of the body

What are the three orientations (planes) used to visualize the brain?

Coronal, horizontal, and sagittal.

What does a coronal section look like, and what can often be seen in it?

Nicknamed "crown"; produces symmetrical slices; ventricles (large spaces with no brain matter) are often visible.

What characterizes a horizontal brain section?

Most brain scans are horizontal; usually rostral faces up; the sections are symmetrical.

What characterizes a sagittal brain section?

Nicknamed "arrow"; produces asymmetrical slices.

How is the spinal cord typically imaged?

In cross sections.

In the spinal cord specifically, what does "ventral" correspond to?

Ventral = anterior in the spinal cord.

What is found in the gray matter vs. the white matter of the spinal cord?

Gray matter (center) contains cell bodies; white matter (surrounding) contains communication tracts

What is the spinal cord's role in the nervous system?

It's part of the CNS and communicates with sense organs and muscles posterior to the head

What is a dermatome?

A part of the skin and its corresponding spinal nerve

What happens to the volume of white matter as you move in the posterior direction of the spinal cord?

It generally decreases

The nervous system is composed of what two major systems?

The central nervous system (CNS) and the peripheral nervous system (PNS).

The brain can be divided into how many parts, and how are they arranged evolutionarily?

Five parts, arranged from oldest (bottom) to newest (top) in evolutionary development.

What two structures make up the hindbrain?

The myelencephalon and the metencephalon.

What are the two main structures of the myelencephalon, and what do they do?

Medulla (autonomic functions: cardiovascular, vomiting) and reticular formation (consciousness, motor functions, central pattern generators).

What are the two main structures of the metencephalon, and what do they do?

Pons (respiration) and cerebellum (sensorimotor)

What is the midbrain also called, and what are its two main divisions?

The mesencephalon; divided into the tectum and the tegmentum.

What are the functions of the tectum, and what structures make it up?

Auditory function and visual-motor function; made up of the superior colliculus and inferior colliculus.

What structures make up the tegmentum, and what does each do?

Periaqueductal gray (pain modulation), red nucleus (sensorimotor system), and substantia nigra (sensorimotor system; site of cell loss in Parkinson's disease)

What connects the third and fourth ventricles through the midbrain?

 The cerebral aqueduct

What are the main structures of the diencephalon?

Thalamus, hypothalamus, mammillary bodies, and optic chiasm

What is the function of the thalamus?

Sensory relay nuclei with reciprocal connections

What are the functions of the hypothalamus?

Endocrine function, mediates motivation, and communicates with the pituitary gland

What are the mammillary bodies' inputs and outputs?

They receive inputs from the amygdala and hippocampus and project to the thalamus

What happens at the optic chiasm?

This is where the optic nerves decussate (cross)

What is the telencephalon generally called, and what are its surface features?

Generally called the cortex; features convolutions — gyri (bumps, singular gyrus) and sulci (valleys, singular sulcus).

What connects the two cortices, and what type of tissue are these connections made of?

The corpus callosum and anterior commissure — white matter tracts that carry information between hemispheres.

What are the four main lobes of the cortex and their primary functions?

Occipital (visual), parietal (perception, somatosensory), temporal (auditory, language, memory), and frontal (reasoning, planning, speech).

What two landmarks separate the cortical lobes?

The central sulcus and the lateral fissure.

What are the three branches of the peripheral nervous system?

Somatic, autonomic, and enteric.

What does the somatic branch of the PNS do, and what are its nerve types?

Interacts with the external environment; consists of afferent nerves (sensory signals into the CNS) and efferent nerves (signals to muscle)

What does the autonomic branch of the PNS do, and what are its nerve types?

Deals with the internal environment; afferent nerves carry signals from internal organs into the CNS, efferent nerves send signals to the organs.

What are the two branches of the autonomic nervous system (ANS), and what does each do?

Sympathetic (stimulates to increase energy usage) and parasympathetic (relaxation, energy conservation).

Where does the sympathetic branch originate, and where does the parasympathetic branch originate?

Sympathetic: thoracic and lumbar regions. Parasympathetic: brain and sacral regions.

Q: How do the sympathetic and parasympathetic branches relate functionally on the same organ?

They have opposing functions on the same organ

What does the enteric branch of the PNS do?

Innervates the gut, controlling bowel movements, secretion, and blood flow

How many cranial nerves are there, and where do they exit from?

12 major paired nerves that exit from the brain (not the spinal cord).

What are cranial nerves generally involved with?

Moving parts of the head and/or the senses.

What are the four non-nervous structures covered at the gross anatomical level?

Meninges, cerebrospinal fluid, circulatory system, and blood-brain barrier.

What are the three layers of the meninges, from outermost to innermost?

Dura mater ("tough mother"), arachnoid membrane ("spiderweb-membrane"), and pia mater ("pious mother").

What is meningitis, and why is it dangerous?

Swelling of the meninges; it can be life-threatening because the firm structure of the skull plus inflammation causes increased pressure.

What is cerebrospinal fluid (CSF) similar to chemically, and where is it produced?

It's like "saltwater," high in Na+ and Cl– ions; produced by the choroid plexus in the ventricles.

What are the three functions of cerebrospinal fluid?

Causes the brain to "float," cushions the brain, and transports waste/nutrients.

About how much CSF is present, and at what rate is it produced?

About 200 mL total, produced at roughly 25 mL/hour

How far does CSF extend around the spinal cord?

It extends down around the spinal cord through the central canal

What is hydrocephalus?

A condition caused by improper clearance of cerebrospinal fluid.

What percentage of blood from the heart goes to the brain?

About 15%

What is the Circle of Willis?

A redundant circulatory structure at the base of the brain

What forms the blood-brain barrier (BBB), and what is its function?

Tightly packed endothelial cells of blood vessels; it prevents proteins and large molecules from entering the brain.

What is the difference between afferent and efferent signals?

Afferent signals ascend to the CNS from the PNS (e.g., touch sensation traveling from fingertips to the spinal cord/brain); efferent signals exit the CNS to the PNS (e.g., the brain and spinal cord sending signals to muscles to move)

What problem did Camillo Golgi solve in the late 1800s, and how?

Brain cells were too densely packed to study; Golgi found that about 1% of brain cells would absorb a silver stain (the Golgi stain), staining the entire cell and making it easier to inspect.

What is Golgi's "reticular theory"?

The idea that the nervous system was made up of one interconnected network of cells

What is Ramon y Cajal's "neuron doctrine," and how did he arrive at it?

Using Golgi-stained cells, he concluded the nervous system is composed of individual, separate units (neurons) — the opposite of Golgi's theory

Whose theory turned out to be correct — Golgi's or Ramon y Cajal's?

Ramon y Cajal's neuron doctrine was correct; Golgi's reticular theory was wrong.

What are the two most basic structural components that make a neuron a cell?

The lipid bilayer and cytoplasm.

What is the lipid bilayer made of, and what is cytoplasm mostly composed of?

The lipid bilayer is a series of fatty chain molecules; cytoplasm is mostly water, high in K+ ions and negatively charged anions

What organelle is the site of DNA, and what does the endoplasmic reticulum house?

 The nucleus is the site of DNA; the endoplasmic reticulum houses ribosomes

What do ribosomes do?

Translate mRNA into proteins

What is the function of the Golgi body, using this lecture's metaphor?

Packaging of proteins — described as the cell’s “post office”

 In this lecture, what are neurofilaments vs. microtubules responsible for?

Neurofilaments act as cellular scaffolding; microtubules allow things to move (described as a "highway").

What do "anterograde" and "retrograde" mean in the context of movement within a neuron?

Anterograde is movement away from the cell body; retrograde is movement toward the cell body.

What does mitochondria do, and why is ATP significant?

Mitochondria are the site of cellular respiration and generate ATP, an energy-rich molecule that powers the cell

What are the three main functional regions of a neuron, and what does each do?

Dendrites (receiving end), cell body/soma (integration of signals), and axon (output end).

What is the flow of information through a neuron's regions?

From dendrites → to the cell body → to the axon

What does "dendrite" mean linguistically, and what are the small protrusions on dendrite branches called?

Dendrite comes from the Greek word for "tree"; the protrusions are called spines (a branch may have 1,000+ spines, each roughly 1 micron in diameter)

What is notable about dendritic spines' morphology?

They are highly variable in shape and size and capable of a lot of plasticity; they can be classified by shape and size

What is another name for the cell body, and what does it do?

Also called the "soma"; it contains the nucleus and key organelles, and integrates multiple signals flowing from dendrites to the axon

What are the three parts that make up an axon?

The axon hillock, the axon itself, and the axon terminal (terminal bouton)

What is the axon hillock, and what happens there?

The junction between the cell body and axon; it's the site of action potential propagation (the electrical signal traveling along a neuron).

How many axons does a neuron typically have, and can it branch?

Only one axon, but it can branch extensively.

What is myelin, what does it do to signal transmission, and what are Nodes of Ranvier?

Myelin insulates the axon by filling gaps in the membrane, which speeds up electrical signal transmission; Nodes of Ranvier are the unmyelinated sections of the axon.

What happens at the axon terminal (terminal bouton)?

It's specialized for releasing neurotransmitters — chemical messengers used to communicate with the next neuron.

What is the synapse, and how are neurotransmitters stored before release?

The synapse is the physical gap between the end of the sending neuron and the start of the receiving neuron; neurotransmitters are stored in vesicles until an action potential triggers their release.

What are the terms for the neuron before and after a synapse?

The presynaptic cell (before the synapse) and the postsynaptic cell (after the synapse).

What are the four key ways neurons differ from most other body cells?

They are long-lasting ("forever, ish"), varied in size/structure, electroactive, and highly specialized for receiving and transmitting signals over long distances.

What is neurogenesis, and does the mature nervous system typically undergo it?

Neurogenesis is the creation of new neurons; the mature nervous system largely does not undergo neurogenesis (though ongoing research suggests some brain areas might still).

What are examples of size variation among neurons?

A dorsal root ganglion axon can be as long as the entire spinal cord, while cerebellar granule cells are only a few microns — among the smallest

What is the membrane potential, and what is its typical value?

The inside of a neuron has a more negative charge than the outside solution; this is the membrane potential, generally around -70 millivolts, though it can change rapidly.

What types of environmental cues can neurons convert into electrical signals?

Sound waves, photons of light, and chemicals (in the air or in the mouth).

What are the five general types of glial cells?

Astrocytes, oligodendrocytes, Schwann cells, microglia, and ependymal cells.

What was the old view of glial cells, and whose research overturned it?

They were originally thought to be just "glue" holding neurons together; this view was overturned largely by research from Ben Barres, the first openly transgender scientist elected to the National Academy of Sciences.