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136 Cards in this Set

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What are the two types of nerve cells?
Neuron and Glia
What is the function of a neuron?
Receives info and transmits to other cells.
What are the two types of neurons?
Motor neuron and sensory neuron
What is the function of a motor neuron?
Sends information to muscles
What is the function of a sensory neuron?
Sensitive to stimulation at one end.
What are glia?
Other types of nerve cells that perform functions that neurons do not.
What is the soma of a neuron?
Cell body
What is the function of a dendrite?
Received information from other neurons
What is the function of an axon?
Sends information to other neurons
What is the function of the myelin sheath?
Made by certain glia, helps with faster electric transmissions.
What does an afferent axon do?
Brings information into a structure.
What is an efferent axon?
Carries information away from a structure.
What are the types of glia?
Astrocytes, Microglia, Oligodendrocytes, Schwann Cells, Radial Glia
What is the function of an astrocyte?
Wraps around presynaptic terminals and helps remove wastes
What is the function of microglia?
Removes waste and micro-organisms
What is the function of oligodendrocytes?
Builds the myelin sheath in brain and spinal cord.
What is the function of schwann cells?
Builds the myelin sheath in the peripheral nervous system.
What is the function of radial glia?
Guides migration of neurons during embryonic development.
What are Nodes of Ranvier?
Spaces inbetween myelin sheath on the axon.
What is the blood-brain barrier?
Mechanism that keeps most chemicals out of the brain.
What determines what can and cannot pass through the blood-brain barrier?
Small uncharged particles (i.e. O2, CO2) may pass through passively, as well as fat-soluble molecules due to the makeup of the phospholipid bilayer. Other molecules must enter via active transport.
What is the electrical gradient of a cell?
The difference between electrical charge inside and outside of the cell.
What is resting potential?
In a resting neuron, the difference in voltage is called resting potential.
In how many millivolts is resting potential?
~ -70mV
What is selective permeability?
The principle that some molecules can pass through molecules easier than other because of size, charge, or other factors.
What is an ionic concentration gradient?
The difference in distribution of ions across a membrane.
How does the Na+/Ka+ Pump work?
3 Na+ out of the cell.
2 K+ into the cell.
K+ leaves cell due to concentration gradient.
K+ enters cell due to electrical gradient.
What is an actional potential?
The process by which a neuron electronically sends information.
What is the threshold of excitation?
The stimulation level that must be reached in a neuron in order to produce strong depolarization.
What is depolarization?
The reduction of polarization (in a resting neuron's case, an increase in charge).
What is hyperpolarization?
An increased level of polarization (in a resting neuron, a decrease in charge).
Describe the All-or-None Law.
1. Stimulus must reach threshold of excitation or there is no action potential.

2. Intensity (amplitude) and speed (velocity) of action potentials are independent of the intensity of the stimuli that initiated them.
What is the refractory period of a neuron?
The refractory period is a time where the neuron resists production of further action potentials.
What are the types of refractory periods?
Absolute refractory and relative refractory.
What is absolute refractory?
When a neuron will no longer produce an action potential regardless of stimulation.
What is relative refractory?
When a neuron requires a stronger-than-usual stimulus in order to produce an action potential.
What is a synpase?
A gap between neurons where neurochemicals are transmitted in order to transfer information.
What is temporal summation?
Repeated stimuli have a cumulative effect (in regards to reaching level of excitation).
What is spacial summation?
Several synaptic inputs originating from separate locations combine their effects on a neuron.
What is an Excitatory Postsynaptic Potential (EPSP)?
Graded (slight) depolarization of a neuronal membrane.
What is an Inhibitory Postsynaptic Potential (IPSP)?
Graded (slight) hyperpolarization of a neuronal membrane.
Describe the process of chemical events at the synpase.
1. Neuron synthesizes neurotransmitters (NTs) and transports them to the axon terminal, where they are sealed in vesicles.

2. AP travels down the axon. At the presynaptic terminal, Ca2+ enters the cell.

3. NTs are released from axon terminals into the synaptic cleft.

4. The released NTs cross the cleft, attach to receptors on the opposite dendrite, and alter neuronal activity.

5. Destruction, recycling, and re-uptake of NT molecules.
What are the types of neurotransmitters?
Amino Acids, Peptides, Acetylcholine, Monoamines, Purines, Gases.
What are the two receptor types?
Ionotropic and metabotropic.
Describe the ionotropic receptor type.
When this type of neurotransmitter binds to a receptor on the membrane, it almost immediately opens a 'gate' for an ion.
Describe the metabotropic neurotransmitter type.
This type of neurotransmitter binds to the receptor and initiates a series of events that are slow and longer lasting than ionotropc effects. Normally utilizes a 'second messenger' system.
What is an antagonist drug?
A drug that blocks the effect of a neurotransmitter.
What is an agonist drug?
A drug that mimics or increases the effects of a neurotransmitter.
What is affinity?
The ability of a drug to bind to a receptor.
What is efficacy?
The tendancy of a drug to activate a receptor.
What do stimulant drugs do?
1. Increase excitement, alertness, motor activity while causing elevation in mood.

2. Tend to increase dopamine activity in various areas of the brain, especially the nucleus accumbus.

3. Sample types: Ahmphetamine, cocaine, nicotine.
Describe the function of amphetamines.
Stimulate dopamine synpases by increasing the release of dopamine from the synaptic terminal. Also blocks receptors that inhibit dopamine release.
Describe the function of cocaine.
Blocks reuptake of dopamine, norepinephrine, and serotonin so that they are always present in the synpase. Basically, disrupts the reuptake system.
Describe the function of nicotine.
Binds with acetylcholine receptors on an axon that release dopamine.

Dopamine is then released by the neuron at the postsynaptic terminal.
What are the two parts of the nervous system?
Central Nervous System and Peripheral Nervous System
What does the Central Nervous System consist of?
Brain and Spinal Cord
What does the Peripheral Nervous System consist of?
Nerves outside the CNS, consisting of the somatic nervous system and autonomic nervous system.
What is the somatic nervous system?
Part of the Peripheral Nervous System that conveys information from:

Sense organs -> CNS -> Muscles.
What is the autonomic nervous system?
Controls the heart, intestines, and other organs.
What is a horizontal plane?
Viewed as in cutting a boiled egg standing upright.
What is a Sagital Plane?
Viewed as cutting pickles into spears.
What is a Coronal Plane?
Viewed as slicing a loaf of bread.
What is medial?
Going into body or center.
What is lateral?
Going outwards from body or center.
What is anterior?
Towards the head.
What is posterior?
Towards the tail-end.
What is Dorsal?
Towards the top (in reference to brain + spinal cord)
What is ventral?
Towards the bottom (in reference to brain + spinal cord)
What is the spinal cord?
Part of the central nervous system within the spinal column that communicates with sense organs and muscles below the head.
What is the dorsal root ganglia?
Cell bodies of sensory neurons located outside spinal cord.
What is gray matter composed of?
Gray matter is composed of cell bodies and dendrites.
What is white matter composed of?
White matter is composed of myelinated axons.
What are the two branches of the autonomic nervous system?
Sympathetic and parasympathetic.
What is the sympathetic nervous system?
A mostly spinal cord connection that initiates fight or flight drive.
What is the parasympathetic nervous system?
A mostly brain connection that facilitates nonemergency responses by organs.
What are the three major divisions of the vertebrate brain?
Forebrain, midbrain and hindbrain.
What are the divisions of the forebrain?
Prosencephalon "forward brain"
Diencephalon "between-brain"
Telencephalon "end-brain"
What are the divisions of the midbrain?
Mesencephalon "middle-brain"
What are the divisions of the Hindbrain?
Rhombencephalon "parallelogram-brain"
Metencephalon "after brain"
Myelencephalon "marrow-brain"
What are the different areas of the hindbrain, and their functions?
Medulla (oblongata) - Just above spinal cord; breathing, vomiting, coughing, sneezing.

Pons - Anterior to the medulla

Reticular Formation - Inside medulla, group of neurons that controls arousal/attention.

Raphne system - Projects axons to forebrain.

Cerebellum - Balance and coordination.
What are the different areas of the midbrain, and their functions?
Tectum - Roof of the midbrain.

Superior and inferior colliculus: Swellings on each side of the tectum.
What function is the superior colliculus associated with?
Vision
What function is the inferior colliculus associated with?
Audition
What are the different areas of the forebrain, and their functions?
Cerebral Cortex - Divided into 4 lobes.

Limbic System - Several brain structures that are important for emotin/motivation.

Thalamus - Area in center of forebrain; processes large extent of sensory info.

Hypothalamus - Ventral to thalamus, regulating several behaviors.

Pituitary gland - Endocrine gland attached to base of hypothalamus. Releases hormones into the system.

Basal Ganglia - Made of 3 structures (caudate nucleus/putamen/globus pallidus)

Nucleus Basalis - Receives input from hypothalamus and basal ganglia and sends acetylcholine releasing axons to many areas of crotex (arousal, attention, etc).

Hippocampus - Strucute between thalamus and cortex; function in memory.
What are ventricles of the brain?
4-fluid filled cavities in the brain, filled with cerebrospinal fluid (CSF).
What is the meninges?
Connects the brain together. Comes in three layers;

Druamater (very durable 'bedrock')
Arachnoid (inbetween)
Pia mater (surface)

Covers the brain and spinal cord. Mostly for protection.
What is cerebrospinal fluid?
Fluid that brings nutrients to the brain, and gives cushioning + buoancy.
Where is cerebrospinal fluid produced?
In the choroid plexus, located in the ventricles.
How many ventricles in the brain lead from brain to spinal cord as a circulation system?
Four
Describe the 4 ventricles of the brain.
2 lateral ventricles, 3rd ventricle, fourth ventricle.

Similar to fallopian tubes/female reproductive system.

Lateral Ventricles = Ovaries
Third = Joins
Fourth = Uterus
What is the corpus callosum?
Major bundle of axons that connects the right and left hemispheres of the brain.
What are the lobes of the cortex, and their functions?
Occipital (Vision)
Parietal (Touch Sensation/Somatosensory)
Temporal (Hearing and advanced visual processing)
Frontal (Motor Output)
Prefrontal (Context, behavior, judgment, planning)
What are the layers of the cortex?
Cerebral cortex is composed of 6 distinct layers of cell bodies (laminae).

Each is distinct in thickness + type of cells contained.
What is Layer IV of the cerebral cortex associated with?
Mostly motor input.
What is Layer V of the cerebral cortex associated with?
Mostly motor output.
Describe the early development of the central nervous system.
1. CNS begins formation at ~2 weeks.
2. Neural groove leads to...
3. Neural tube.
4. Neural tube will form the central nervous system.
What are the 5 stages of neural development, and describe these stages.
1. Proliferation - production of new cells.

2. Migration - Movement towards eventual destination in the CNS

3. Differentiation - Movement from primitive neural cell to specific type of neuron.

4. Myelination - Formation of myelin sheath.

5. Synaptogenesis - Formation of synapses.
Describe adult neurogenesis
On-going growth of neurons in the olfactory system (replaced approximately 1/month) and hippocampus.
Describe chemical pathfinding by axons.
Axon is attracted by some chemicals and repelled by others which assist direction of the axon to its final target.
Describe axon competition.
Neurons will synapse with more axons than needed. Later, the axons not wanted will die off.
What is apoptosis?
Programmed mechanism of cell death.
Describe Fetal Alcohol Syndrome in relationship to brain development.
Children born to mothers who drank alcohol heavily during pregnancy display various emotional, developmental and cognitive problems as well as facial abnormalities.
Describe cocaine's effects on brain development.
Cocaine causes a slight decrease in language skills and IQ scores in later neural development.
Describe nicotine's effects on brain development.
Nicotine has been shown to increase the risk of ADHD.
Describe dendritic branching.
The experiences of an organism guides the number and structure of neurons. The brain changes in people developing expertise in a particular area.
Describe axon regrowth.
Axons may regrow in certain instances, though only in short distances.
What is denervation supersensitivity?
Heightened sensitivity to a neurotransmitter after the destruction of the incoming axon.
What is disuse supersensitivity?
Heightened sensitivity to a neurotransmitter as a result of inactivity of the incoming axon.
What is amplitude?
The intensity of a soundwave.
What is frequency?
The number of cycles per second in a soundwave.
Describe the hearing process.
1. Soundwave strikes eardrum.

2. Eardrum vibrates at same frequency.

3. Ossicles (bones inside ear) send vibrations to the oval window.
What is the frequency theory in pitch perception?
The basilar membrane (base of the cochlea) vibrates in synch with a sound causing nerve axons to produce action potentials at the same frequency (1 to 1 action potential ratio).
What is the place theory in pitch perception?
Each area of the basilar membrane responds to a particular frequency and vibrates when it is sensed.
What is the current theory in pitch perception?
Combines modified versions of both frequency and place theory.

For low frequency sounds, 1 action potential is generated per wave.

Certain frequencies of sound excite hair cells in certain areas.
Describe the auditory process in the auditory cortex.
1. Information from ear passes through several subcortical areas.

2. There is a crossover in the midbrain causing information from the right ear to be processed by the left and vice versa.

3. Information reaches primary auditory cortex, located in the superior temporal lobe.

4. Auditory cortex is organized similarly to visual cortex, though not as large or developed in primates.
Describe the vestibular sense.
The sense of balance and where you are.
What is the vestibular organ?
3 semicircular canals in the ear which are filled with a jellylike substance and lined with hair cells. The jellylike substance is pushed against hair cells and causes action potentials when the head is shifted.
What is somatosensation?
Sensation of your body. Numoerous sensory receptors found in skin sense pressure, pain, temperature, vibration, etc.
Describe the input to the brain in somatosensation.
1. Somatosensory input enters Central Nervous System through cranial nerves.

2. Reaches brain through spinal cord.

3. Eventually processed by primary somatosensory cortex (on border of frontal and parietal lobes).
What is the function of pain?
Pain makes the body aware of danger or harmful stimuli.
What conducts pain information?
Unmyelinated axons.
Describe the neural processing of pain.
1. Axons enter spinal cord. Mild pain releases glutamate; stronger pain releases glutamate and substance P.

2. Information is passed from spinal cord to several sites of the brain but is eventually passed to prefrontal cortex.
Where do taste receptors synapse on?
Cranial nerves.
Describe the function of cranial nerves VII, IX, and X.
VII - Facial
IX - Glossopharyngeal
X - Vagus
Where do taste nerves project to?
The nucleus of the tractus solotarius (NTS).
What does the somatosensory cortex focus on in relation to the taste sense?
The 'feel' or texture of the food.
What does the insula focus on in relation to the taste sense?
The cognitive part of the taste (mm, good, bad, etc).
How are olfactory receptor neurons arranged?
In sheets called olfactory epithilium.
Describe the olfactory pathway.
Receptors stimulate the olfactory nerve (cranial nerve I) which synapses on the olfactory bulb.
What is the amygdala's function in the olfactory sense?
Smells that activate emotion. (the Amygdala is part of the limbic system)
What is the hypothalamus' function in the olfactory sense?
Smells that are involved in 'motivation', i.e. sex/hunger/appetite.
What is the function of the vomeronasal organ?
Detects pheromones, located near the olfactory epithilium, that has direct connections with the amygdala and hypothalamus.
Describe the Lee-Boot effect.
Females will ovulate at the same time when placed together due to pheromones.
Describe the Whitten effect.
Females with a non-related male present will result in accelerated ovulation.
Describe the Vandenburgh effect.
Young females with a non-related male present will result in early puberty.
Describe the major histocompatibility complex (MHC).
People that are related generally share the same smell, and it is almost always displeasing to them. This is to discourage attraction between related members.