BRAIN MIDTERM

What is gray matter made of and its purpose?

Has neural cell bodies and synapses: neurons. It processes and releases info

What is white matter made of and its purpose?

Made of axons that conduct nerve signals, or nerve fibers. Transmits info: like the Corpus Callosum

How many cranial and spinal nerves does the PNS have?

12 cranial, 31 spinal

What does the Somatic Nervous System control?

Voluntary movements and sensory functions, except reflexes. One connection.

What does the Autonomic Nervous System control?

Involuntary, unconscious regulation of organs or homeostasis. 2 connections.

What are the three subunits of the Autonomic Nervous System and their jobs?

Parasympathetic - Rest and digest. Sympathetic - fight or flight. Enteric - digestion

Are Cranial and Spinal nerves sensory, motor, or both?

Cranial can be individually sensory, motor, or both. Spinal are ALL both as they all connect to sensory organs and muscles.

What does CAT scan stand for and what does it do?

Computerized Axial Tomography, uses thousands of x-rays to construct 3D images.

What does MRI stand for and what does it do?

Magnetic Resonance Imaging, uses strong magnetic fields and radio waves to achieve high resolution 3D images. It can detect tumors and abnormalities without surgery

What can MRIs do that CAT scans cannot?

Distinguish gray/white matter tracks and ventricles. CAT scans just see dense and less dense material.

What are the two opposing ideas about cognition?

Cognitive functions are either 1, spread out across large brain networks or 2, focused in one area (localizationist view, mostly right)

What is Broca’s Aphasia and where is Broca’s Area?

When you can understand pretty well but can’t speak. LEFT FRONTAL LOBE

What is Wernicke’s Aphasia and where is Wernicke’s Area?

When you can speak well but can’t understand well. LEFT TEMPORAL LOBE

What are Dorsal v. Ventral pathways, what problem is associated with them, and where in the brain are they located?

Dorsal is the where/how pathway in the Parietal Lobe. Optic Ataxia is when you can recognize objects but can’t reach out and grab them. Ventral is the what pathway in the Temporal Lobe. Visual Agnosia is when you cannot recognize objects.

Who was HM and what was his experiment?

He was a guy who had seizures and wanted to remove part of his Temporal Lobe to get rid of them. But he got Anterograde Amnesia. Pre-surgery memories intact, but couldn’t form new ones.

What were the experiments with dogs and cats that helped early scientists map electrical stimulation of the brain?

Dog, stimulated his motor cortex but couldn’t find any sensory (can’t tell us what he feels). Cat stimulated the hypothalamus and it exhibited behaviors essential for survival. (sniff, pant, eat)

If you stimulate the Auditory or Visual cortex, will you hear or see recognizable things?

No. Distinct recognizable things require dorsal or ventral pathways. They will be random.

What is an Association Area?

When multiple pathways come together in the brain. It’s harder to predict lesion effects in these areas because multiple things may be affected.

What are Experiential v. Interpretive responses and where do they occur?

Experiential are memory flashbacks, usually in the hippocampus. Interpretive are dreamlike, such as deja or jamais vu.

What is Transcranial Magnetic Stimulation?

A non-invasive way to electrically stimulate the brain’s surface with magnetic fields. High frequency increases brain activity, low frequency decreases brain activity.

What does EEG stand for and what does it do?

Electroencephalography. It gives a drawing of brain electricity and uses electrodes on the head. It has a weak signal (b/c it must pass through the skull) and bad spatial resolution because no localization, but fast temporal resolution!

What are the “slow-wave” to “fast-wave” brain frequencies?

Delta (1-3 Hz), Theta (4-7 Hz), Alpha (8-13 Hz), and Beta (13-30 Hz)

What are the sleep stages and the Brain Waves associated with them?

Awake: alpha and beta.

Stage 1: Theta.

Stage 2: similar to Theta, but with sleep spindles and K-complexes.

Stage 3: Delta. Slower frequency, higher amplitude

Stage 4: Delta and higher amplitude. You KNOW someone is asleep.

REM: Theta and Beta! Alert and dreaming! (Paradoxical state)

What sleep stage is considered “slow-wave sleep”?

Stage 3, when the waves are low frequency, high amplitude, or Delta waves. This is when sleepwalking occurs.

What does the Basal forebrain do for sleep?

Promotes slow-wave sleep. If there are lesions, there is insomnia

What does the Hypothalamus do for sleep?

Controls sleep centers and regulates the orderly sleep stages

What does the Reticular Formation do for sleep?

Uses the brain stem to promote wakefulness!

What does the Locus Coeruleus do for sleep?

Promotes REM sleep.

What are functional brain imaging techniques and what do they measure?

Strategies opposing EEG where you can see given structures specifically where brain waves are taking places, including PET scans and fMRIs. They measure blood flow, brain oxygen level, or glucose level.

What does PET scan stand for and what does it do?

Positron Emission Tomography, insert radioactive form of glucose into the brain to release a positron and measure glucose utilization

What is an fMRI and what does it do?

functional Magnetic Resonance Imaging, it measures the oxygen in your brain to see the activity. It has great spatial resolution and localization, but awful temporal and is identical to PET unless you’re told you don’t know which is which.

What are some components of cell theory?

• All living matter is made of cells and products from cells

• Cell is the simplest unit that can contain life

• All cells come from other cells

• Cell surrounded by plasma membrane

• Cells have similar chemical composition with organelles

Where is DNA and RNA in a cell?

In the nucleus! DNA is transcribed into RNA!

What are ribosomes and what do they do?

Pieces of the cell on the rough endoplasmic reticulum (make it rough) and translate RNA into proteins

Nissl: what did they reveal and what do they stain?

Reveals cell bodies organized into six layers in cerebral cortex, stains cell bodies (no fibers). Gray matter.

What is the difference between Nuclei and Ganglia?

Both clusters of neurons, Nuclei in the CNS and Ganglia in the PNS

Weigert/Weil: what did they reveal and what do they stain?

Labeled long fibers that interconnect ALL cell bodies: white matter. Stain only FIBERS!

Golgi: what did they reveal and what do they stain?

Revealed that neurons are cells! Known as “black reaction”, and fills fibers AND cell bodies!

What does a cell body do in a nerve?

Gene expression and protein production

What do dendrites do in a nerve?

Receive and integrate nerve impulses

What do axons do in a nerve?

Transmit nerve impulses to terminals (dendrites)

What do synapses do in a nerve?

Release neurotransmitters to activate neuronal changes

What are the three types of neurons and where are their cell bodies located?

Sensory: dorsal root ganglia. Interneuron: everything in CNS. Motor: ventral cord

What is a converging neuronal network?

Signals from many neurons converge into ONE. Each input is either + or -

What is a diverging neuronal network?

Each neuron can pass signals onto many other neurons. Each input will have the same + or - effect on ALL of them

What is a feedback loop neuronal network?

Signals from one neuron can feedback onto itself or another neuron in the network, can be + or -

How many neurons and synaptic connections are in the human brain?

100 billion neurons, 100 trillion synaptic connections

What is the order of operations in Conscious Sensation?

Sensory neuron, (optional: interneuron), Thalamus neuron, and Cortical neuron

What role does the Cerebral Cortex serve in conscious sensation?

Cerebral cortex is REQUIRED for conscious sensation.

What role does the Thalamus serve in conscious sensation?

It is required for conscious sensation. It is a major relay station for sensory input to and motor output from the cortex. It is made up of many nuclei, each routing specific info.

What Thalamus neuron is present in the sensation of light?

Lateral geniculate nucleus neuron

What Thalamus neuron is present in the sensation of touch?

Ventral Posterior nucleus neuron

What is a neuromuscular junction?

A space between the motor neuron and the muscle fiber

What is voltage and what is it measured in?

The difference in electrical potential between 2 points, volts

What is current and what is it measured in?

The movement of electric charge carriers, amps

What is it called if there is no electrical connection?

Inert

What is Ohm’s Law?

Voltage = current * resistance (V=I*R)

Can ions cross the plasma membrane?

NO! NOT WITHOUT THE HELP OF A PROTEIN!

What are the three action potential proteins?

Voltage-gated sodium channels, voltage gated potassium channels, and Sodium Potassium Pump

What do voltage-gated sodium channels do and when do they open?

Move sodium into the cell, closed -70ish mV or below and open at -50 mV (threshold is met!)

What are voltage-gated potassium channels and when do they open?

Move potassium outside the cell, close -70mV or below and open at 30 mV

What is the order of action potentials?

Resting membrane potential (~-70mV), threshold met, depolarization, repolarization (30 mV), hyperpolarization (too much), refractory period (prevents moving backward), sodium potassium pump returns to resting membrane potential

What is the space between myelin called?

Nodes of Ranvier

What is the transmission in the Nodes of Ranvier called?

Saltatory conduction

How do you distinguish between strong and weak signals in action potentials?

Weak currents may NOT produce potentials, and strong signals vs. stronger ones are determined by frequency, NOT amplitude! (action potential amplitude always stays the same)

What can some mutations in Sodium channels cause?

Different levels of pain sensitivity: either excess, reduced, or even absence

What is the Blood Brain Barrier?

A selective wall of tightly packed cells that control what moves between your blood and the CNS

What is a stem cell?

Cell that can become ANY type of cell

What is a Progenitor cell?

A cell that has passed the stem cell phase, and comes in different varieties based on where they arrive in the neural tube/crest. Can be neuroepithelial or myeloid

What glial cells are in the CNS?

Astrocytes, microglia, oligodendrocytes, microglia, and bergmann glia

What do glial cells help with?

• Learning and memory

• Pruning dead synapses

• Moving, communication, and creating connections

• Cleaning the mess that neurons make

• Mapping and guiding the cells to grow and travel properly

• Protecting the WHOLE NS

What is an astrocyte and what does it do?

• Star-shaped glial cell

• Most numerous in CNS!

• Develop like neurons

• Interact with BBB and vasoconstriction

• Trophic factors to neurons

• Form tripartite synapse

• Recycle excess neurotransmitters

What is a tripartite synapse?

Pre synaptic structure, post synaptic structure, and astrocyte. The astrocyte picks up extra neurotransmitters and stores them for later, which prevents neurotoxicity

What is the glymphatic system?

A macroscopic waste clearance pathway in CNS that uses CSF to wash metabolic waste from brain tissue.

What two things do astrocytes connect with?

Blood Brain Barrier and Glymphatic system

What are Oligodendrocytes and what do they do?

• Glial cells in the CNS!

• Develop like neurons

• Form myelin sheets around axons of neurons

• One can myelinate up to 40 axons (insulation and faster transduction of signal)

• Trophic factors

• NO NEW PRODUCTION!

What are Microglia and what do they do?

• Glial cell in CNS!

• Tiny but mighty: about 10% of total glial cells

• Develop from myeloid progenitor cell (NOT like neurons)

• Innate immune cell in brain, brain immune privileged?

• Interact with basically any cell, surveying and looking for waste to respond to

• Can get REAL bad: start non-activated, if they get activated then dysfunctional they cause BAD SHIT to happen

What are Schwann Cells and what do they do ?

• Glial cells in the PNS!

• Develop from neural crest cells

• Interact with neurons to form myelin sheaths around PNS axons (only one at a time)

• Trophic factors

• Nerve regeneration

What are Ependymal Cells and what do they do?

• Located in CNS! Line the spinal cord and cerebral ventricles

• Develop like neurons

• Make cerebrospinal fluid

• Facilitates distribution of neurotransmitters, nutrients, and filtering out harmful material

What are Bergmann Glia and what do they do?

• Located in CNS, ONLY Cerebellum

• Develop like neurons

• Basically specialized astrocytes

  • clean up extra neurotransmitters

• Support and nourish Purkinje cells

• Guide migrating cells in cerebellular development

How do isotopes and ions change differently?

Isotopes, if added neutrons, increase in mass. Ions, if added electrons, change in CHARGE

What are the four kinds of macromolecules and their functions?

• Proteins! Made in ribosomes in rough endoplasmic reticulum

• Carbohydrates - sugars like glucose for energy/protein decoration

• Nucleic Acids - DNA and RNA. Make up code that tells cells which proteins to make

• Lipids - fats! Cell membranes, signal molecules

What do DNA and RNA stand for?

Deoxyribonucleic acid, and ribonucelic acid

What is a primary protein structure?

Chain of amino acids

What is a secondary protein structure?

Occurs when sequence of amino acids are linked by hydrogen bonds: makes pleated or alpha helix shape

What is a tertiary protein structure?

When pleated and alpha helix shaped proteins smush together! Amino acids start to make proteins!

What is a quaternary protein structure?

Protein consisting of more than one amino acid chain. This is when it becomes a functioning protein!

What are specificity and affinity when it comes to folding proteins?

Specificity: finding proteins, Affinity: binding them HELLA tight

Is the protein structure lock and key?

Not technically. There isn’t one perfect place for a protein to lock in. The affinity or tightness affects how the protein works

What is Axonal Action Potential Conduction protein function?

When neurons conduct signals over great distances at high speed

What is synaptic transmission protein function?

When neurons signal to the next neuron in the network and synapse by neurotransmitters

What is neuronal integration protein function?

When neurons receive inputs (+ or -) and decide whether to pass it along or not

What is synapse formation protein function?

Growth of axons and dendrites regulated to ensure right synaptic partners find one another

What do enzyme proteins do?

Catalyze (increase rate of) all chemical reactions in a cell. They’re important in the production of different neurotransmitters used by neurons

What is the cytoskeleton in relation to proteins?

A long chain of protein subunits that act as “highways” in cells

What are cell adhesion molecules?

Protrude from cell membrane, bind to each other (lock and key or molecular velcro) to keep cells and synapses together

What do mitochondria do in the cell?

Powerhouse, energy production

What do Smooth v. Rough Endoplasmic Reticulum do in the cell?

Smooth: lipid synthesis, Rough: protein synthesis and processing (ribosomes make proteins)

What do lysosomes do in the cell?

Digestion and recycling

What does the nucleus do in the cell?

Holds genetic information (DNA and RNA)