neuro exam 1

When Neuroscience first appeared in Sumeria what was it used to understand?

Euphoria

What is phrenology?

It essentially assigned different functions to cortical areas. Scientists who studied phrenology believed that "bumps" on the skull signified an enlarged cortical area.

What did the Neuron Doctrine state?

It stated that the brain is composed of independent cells and that neuronal signals are transmitted from cell to cell across synapses.

Santiago Ramon y Cajal VS Camillo Golgi

Golgi came up with a staining method known as 'Golgi staining' that essentially allowed Santiago Ramon y Cajal to understand how neurons worked. Golgi misunderstood the neuron and believed that neurons communicated via electrical conduction. Cajal believed that there was a gap (synapse) along the neuron which meant that there must be some type of chemical transmission going on.

Is a neuron directional?

Yes they are very directional.

What is a unipolar neuron?

It is a single extension that branches out in two directions. It has a receptive pole and an output zone.

What are bipolar neurons and where are they usually found?

These neurons have one axon and one dendrite. They are usually sensory.
The most common place to find bipolar neurons is in the retina. (visual system)

What is a multipolar neurons?

This type of neuron has one axon and multiple dendrites. This is the neuron you visualize when you dream about the nervous system

What is the most common type of neuron in the human nervous system?

multipolar neurons

Whats the main difference between the unipolar and bipolar neuron?

In the case of a unipolar neuron the information does not have to flow through the cell body (soma)

What's so special about unipolar neurons?

Unipolar neurons are the fastest of the neurons, they are used in cases that require fast responses such as reflexes.

Where are multipolar neurons mostly found?

In the brain

What is the input zone?

This is essentially the receiving dock of the neuron. This is where all the information comes in. This is the dendrites.

What is the integration zone?

This is where all the inhibitory and excitatory signals are processed and the neuron decides if it should fire an action potential or not. This happens in the soma

What is the conduction zone?

This is where the information travels down the axon. Axon acts like a wire.

What is the output zone?

This is where the neuron communicates with other neurons. This is the axon terminals.

Sensory neurons vs motor neurons

Sensory neurons essentially respond to the environment (it's all about perception - touch, odor, light)
Motor neurons are in contact with muscles and glands (don't forget about the glands!!!)

What are interneurons? Where are they mainly found?

They're the middle man/woman. Receive input from one neuron and send it to another. MOST NEURONS IN THE CNS ARE INTERNEURONS.

What's an example of where the motor neurons stimulate a gland?

The release of adrenaline (epinephrine) from the adrenal medulla by the sympathetic nervous system

What is the main function of glial cells?

Support the brain. (cheerleaders, sort of)

What are the 4 types of glial cells?

Astrocytes, oligodendrocytes, ependymal cells, and microglia.

What are astrocytes?

They are the MOST NUMEROUS GLIAL CELL, they fill spaces between neurons for support, and regulate the composition of the extracellular space. It is important to note that Astrocytes form a connection between neurons and capillaries. Astrocytes are ONLY found in the brain.

What happens when astrocytes aren't doing their job?

Potassium concentration outside the neuron is high leading to migraines. Hangovers are also caused by a dysfunctional astrocyte.

What is the term used to describe a tumor of an astrocyte?

Astrocytoma. (Astro- for astrocyte and -oma for mass/tumor) A previous test question was, *What is a tumor of a Schwann Cell? Answer is Schwannoma* Moral of the story: be familiar with this medical terminology.

What is the prognosis of Alexander's disease?

astrocytes begin to fill up with GFAP which eventually lead to their failure. This happens due to the fact that they can not metabolize GFAP properly.

What are Oligodendrocytes?

They wrap the axon with myelin sheath. These are only found in the CNS and myelinate multiple axons.

What is a Schwann cell?

They wrap the axon with myelin sheath. These are found in the PNS and only myelinate one axon at a time.

What is a node of Ranvier?

It is a section of an axon that has no myelin sheath. There is a high concentration of sodium channels at these nodes which allow for fast conduction across the axon. This type of conduction is known as saltatory conduction.

What is MS?

It is characterized by an autoimmune attack that leads to oligodendrocyte injury. Damage to oligodendrocytes prevents the formation of myelin which leads to problems with conduction. This is a progressive disorder that gets worse with time.

What are microglia?

It's easiest to think of these as the 'clean up crew' of the nervous system. They clean up debris from dying cells (neurons and glia) through phagocytosis

What are ependymal cells?

Line ventricles and secrete/absorb CSF. (cerebral spinal fluid). Ependymal cells help your brain develop.

Under what circumstances do Glial cells do us harm?

In the case where an individual has AIDs, viral activated microglia release neurotoxins glutamate and Nitric oxide which lead to brain damage.

What is a synapse?

It is a chemical gap

What do dendritic spines do? What;s so special about these spines?

They increase surface area.
They show neural plasticity and are important when it comes to learning and memory.

What is neural plasticity?

number and structure are rapidly altered by experience.

What makes up the CNS?

The brain and spinal cord

What two systems is the PNS divided into?

The autonomic and the somatic system

What is the somatic system responsible for?

Voluntary movements. Things you can consciously control.

What is the autonomic nervous system and what is it divided into?

It is responsible for involuntary movements, things that you cannot consciously control.
It is divided into the sympathetic and parasympathetic nervous system.

Sympathetic vs Parasympathetic

Sympathetic is responsible for the 4 Fs (Fight, flight, fear and sex), gets your body ready for action. (running away from a bear)
Parasympathetic is responsible for 'Rest and Digest' (when you're sitting down watching netflix instead of studying behavioral neuroscience this is the system that is activated)

Preganglionic vs Postganglionic neurons

Pre- goes from CNS to autonomic ganglia.
Post- goes from the autonomic ganglia to target)
These are both found in the autonomic nervous system.

Why does the brain pulse?

This is due to the fact that the heart is pumping blood into the brain.

Medial?

Towards the middle

Lateral?

towards the side

Ipsilateral?

same side

Contralateral?

opposite side

Anterior?

head end

Posterior?

tail end

Proximal?

near center

Distal ?

toward periphery

Dorsal?

toward the back

Ventral?

toward the belly

Afferent vs Efferent

Afferent carries impulses toward the region of interest. For instance, any input coming into the brain is considered to be afferent. (sensory)
Efferent carries impulses away from the region of interest. For instance, any output from the brain will be efferent (motor)

How does coronal split the brain?

Front to back. Looks like a butterfly.

How does a sagittal view split the brain?
(AKA midsagittal)

slices the brain down the midline.

How does a horizontal view split the brain?

Top to bottom

White matter vs Gray matter

White matter is composed of axon bundles. It's easy to remember this because the myelin sheath that covers the axons is made up of white fatty tissue.
Gray matter is essentially where all the cell bodies (soma) are located. This has a dark gray appearance.

What are the two types of tissue in the brain?

Neurons and glial cells

What are the Parietal and Occipital lobes named according to?

They are named according to the bone that overlies them.

What is the basal ganglia responsible for? Where is it located in the brain?

Movement control. The basal ganglia is the innermost portion of the brain and can be considered to be the oldest part.

What is the thalamus responsible for?

It acts as the sensory relay where all sensory information synapses. It is considered to be the geometric center of the brain.

What is the limbic system responsible for?

Your pain and suffering, this is where all emotions are regulated and where your emotional memories are located.

In terms of movement, what is the cortex responsible for?

Cognitive control of movement

What makes up the Diencephalon?

Thalamus, Hypothalamus and Mammillary bodies. It is important to note that this is our first brain in human evolution, and it is responsible for the reflexive control of our behavior.

What is the important structure in the Midbrain and what is it's function?

Reticular formation. It regulates sleep and arousal, as well as temperature and motor control. Reticular formation is also referred to as the Reticular activating system (RAS).

What happens when the reticular formation is damaged?

Coma

What does the Pons contain?

Contains motor and sensory nuclei to face

What is the medulla and what is it responsible for?

It is the transition between brain and spinal cord. It is responsible for regulating heart rate and breathing.

What structures make up the brain stem? (Hint: 3 structures)

Midbrain, pons, and medulla

What is the cerebellum responsible for?

Motor coordination and learning

Which of layer of the meninges is the hardest and outermost?

Dura Mater

Where are the blood vessels located in the brain. (What layer of the meninges)

Subarachnoid space.

Which layer of the meninges is soft and innermost?

Pia mater

Where is the subdural space?

Between the Dura mater and the Arachnoid membrane. (If you didn't know the answer to this just know that sub- means below so subdural would mean below dura. This could help you eliminate some choices on the exam.)

Where is the subarachnoid space located?

Below the arachnoid would be the most obvious choice, but also be aware that the answer choice on the exam could be between the arachnoid membrane and Pia mater. This is where blood vessels and CSF are found.

What is a Meningioma?

Tumor of the Meninges

What is a Hematoma?

It is the accumulation of blood due to head trauma that severs a blood vessel. This accumulation causes the brain to compress which leads to the build up of pressure in the brain. Not sure if you should know this but just in case, There are 2 types of hematomas, epidural and subdural hematomas. Epidural hematomas are generally a lot worse than subdural due to the fact that you sever an artery in epidural which leads to a rapid accumulation of blood and a much quicker death. Subdural is a severed vein usually and takes time for blood to accumulate. Both are bad.

What do ventricles do?

They make CSF which essentially surrounds and cushions the brain.

When looking at the pathway of CSF circulation, where is CSF produced?

Ependymal cell

What is the pathway of CSF circulation?

Produced by ependymal cells-\>Flows through cerebral aqueduct -\> Exits brain at medulla -\> Absorbed into blood system

Via what structure does CSF exit the brain and go into the blood stream?

Arachnoid villi

What is hydrocephalus caused by?

CSF circulation failure

How many layers does the cortex have?

6 layers

Which layer of the brain is the receiving portion (afferent)?

Layer 4

Which layer(s) of the brain is information leaving (efferent)?

Layer 5 and 6

What is pachygyria characterized by?

3 cortical layers

What are the characteristics of a CT scan?

X-ray absorption shows tissue density. The denser the tissue the whiter the image. (White is bone, black is CSF. Bone is more dense and hence white. Blood appears as white too)

How does an MRI work?

Strong magnets line up protons in the brain, a pulse of radio waves then knocks the protons over. The protons then reconfigure, emitting radio waves that differ in tissue density. It measures the water content of the brain.

What does a PET scan measure?

It measures brain activity. It uses radioactive chemicals to figure out which brain regions contribute to specific functions.

What is does an fMRI do?

It detects changes in brain metabolism (oxygen use for instance). Shows how networks of brain structures work together.

Nucleus?

DNA in chromosomes, mRNA transcribed from DNA, gene expression

Rough endoplasmic reticulum (RER)?

contains ribosomes and it is the site of protein synthesis.

Smooth endoplasmic reticulum (SER)?

regulates cytoplasm and is responsible for lipid synthesis (this might be out of the scope of this course but know just in case)

Golgi apparatus?

Stacks of flat membrane compartments that package products for shipment.

What was wrong with Alex?

Alex had Lowe syndrome which is a disorder of the Golgi due to the fact that the proteins are not being transported to where they need to go, impairing development.

What is the Neuron membrane?

It is a lipid bilayer that surrounds the cytoplasm from the extracellular fluid acting as a charge separator.

What are examples of Intrinsic proteins and what do they do?

Receptors and ion channels. They give neurons the necessary properties for signaling.

What are microtubules?

tracks for movement within the neuron. Spirals of tubulin

What are neurofilaments?

Static support structures.

What are microfilaments?

Associated with cell membrane, they are dynamic structures. double helix of actin