Neuroscience exam #1

written from the study guide

What are the main components of neurons?

• dendrites

• soma

• axon

• terminal

dendrites

• the main receiver of information from other neurons

soma

• where the nucleus and DNA is found

axon

• where action potentials propagate

terminal

• where neurotransmitters are released

what are the major sub divisions of the nervous system?

• Central Nervous System

• Peripheral Nervous System

  • Somatic Nervous System

  • Autonomic Nervous System

    • Sympathetic Nervous System

    • Parasympathetic Nervous System

Central Nervous System: function and associated structures

• function: takes in sensory information, processes information, and sends out motor skills

• associated structures: the brain and spinal cord

Peripheral Nervous System: function and association structures

• function: conveys information to and from the muscles, glands, organs, etc.

• associated structures: neurons and nerve processes outside the Central Nervous System

Somatic Nervous System: function and associated structures

• function: voluntary muscle control

• associated structures: sensory and motor nerves

Autonomic Nervous System: function and associate structures

• function: involuntary control of organs

• associated structures: eyes, nose, and salivary glands

Sympathetic Nervous System: function and associated structures

• function: “fight or flight” response

Parasympathetic Nervous System: function and associated structures

• function: “rest and digest” response

what does dorsal mean?

• upper side or back

what does ventral mean?

• under side or abdomen

what does afferent mean?

• conducting inward

what does efferent mean?

• conducting inward

what does rostral mean?

• beak or snout

What does caudal mean?

• tail or tail-like

what does lateral mean?

• to the side

what does medial mean?

• middle or toward the middle

What are the systems and structures that protect the brain?

1. Meninges

2. Cerebral Spinal Fluid

3. Generous blood supply through multiple sources

4. Blood- Brain barrier

What three layers make up the Meninges?

• dura mater

• arachnoid membrane

• pia mater

What is cerebral spinal fluid?

• fluid secreted in hollow places in the brain

How does generous blood supply reach the brain?

• blood enters through the vertebral and carotid arteries

What is a Computerized Axial Tomography (CT scan)?

How is one produced?

• a quick and “cheap” tool used to find structural damage from stroke

• uses x-rays to produce an image

What is a Positron Emission Tomography (PET) scan?

How is one produced?

• tool used to asses function or structure of the brain over a slow time period

• can identify the presence and location of proteins of interest

• uses radio active isotopes, then injected into the brain

• de

What is Magnetic Resonance Imaging (MRI)? How is it produced?

• structural resolution of the brain is measured

• with a giant magnet, this aligns protons of water molecules in body tissue

• when these protons “relax”, they release energy found by the machine

What is a Functional MRI (fMRI) How is it produced?

• a fast measure of brain function by this tool

• by measuring blood flow in the brain (as activity increases, blood flow does as well)

What principles do the resting potential follow?

• during resting potential, the sodium and potassium channels are closed

• the resting membrane is being maintained by intracellular and extracellular fluid

How does the generation of an action potential start?

• the process begins if the threshold is reached (collected at the axon hillock)

• all- or- none response

Where does propagation of an action potential begin?

• along the cell membrane of an axon until it reaches the terminal button

How does propagation of an action potential work?

1. Rising phase

2. Absolute Refractory phase

3. Relative Refractory period

4. Resting phase

What is the Rising phase?

• when EPSPs are summed at the axon hillock

What is the Absolute refractory period?

• when the threshold of membrane potential is reached, sodium channels open

What is the Relative Refractory period?

• when potassium rushes down the concentration gradient and approaches reversal potential before the channels close

What is resting phase?

• when both sodium and potassium channels are closed

why do action potentials only travel in one direction?

• the refractory period doesn’t allow the reopening of sodium channels

What is the purpose of a refractory period?

• to recover and become ready for the next stimulus

• the membrane is unable to be polarized due to te ion channels being closed

What are EPSPs?

• excitatory post-synaptic potential

• inflow of positive ions (a positive current)

What are IPSPs?

• inhibitory post-synaptic potential

• inflow of negative ions (a negative current)

How are EPSPs and IPSPs summed by the post-synaptic cell?

• summed at the axon hillock

• spatial summation or temporal summation

What is spatial summation?

• when many EPSPs from different sources happen in a small space start to add up

What is temporal summation?

• when many EPSPs from the same source in a short amount of time start to add up

what is an agonist?

• a substance that mimics or boosts the actions of a transmitter

what is an antagonist?

• a substance that blocks the actions of a transmitter

what is a gyrus?

• a bump in the surface of the cortex

what is a sulcus?

• a “valley” or crevice in the surface of the brain

what is a fissure?

• a large sulcus

what does the left hemisphere do?

• in control of the side side of the body

what does the right hemisphere do?

• in control of the left side of the body

what is the longitudinal fissure?

• vertical fissure that divides cerebrum into tw hemispheres

what is the lateral fissure

• horizontal fissure that divides the e portal lobe from the frontal and parietal lobes

what is the central sulcus?

• the crevice in the cortex that divides the frontal lobe from the parietal lobe

What are the lobes of the brain?

1. Frontal

2. Temproal

3. Parietal

4. Occipital

What functions and processes are associated with the Frontal Lobe?

• motor control

• working memory

• executive function

• decision making

• weighing consequences

What functions and processes are associated with the Temporal Lobe?

• auditory function

• facial recognition

What functions and processes are associated with the Parietal Lobe?

• mathematical calculation

• spatial processing

• touch

What functions are associated with the Occipital Lobe?

• vision

What unctions are associated with the Insula?

• interocpetion

• cravings

• taste

• pain

What function is associated with the Pituitary Gland?

• releasing various hormones throughout the body

• Endocrine Gland is referred to as the “master gland”

What functions are associated with the Hypothalamus?

• helps regulate hormonal release → involved in the stress response

• homeostatic controls:

  • fighting, fleeing, feeding, and mating

  • regulates circadian rhythm

  • thirst, hunger, sleep

What functions are associated with the Hippocampus?

• regulates the stress response by providing a break

• learning

• memory

What functions are associated with the Amygdala?

• processes emotional learning

• detects threat and fear

What function is associated with the Cerebellum?

• coordinates movement

• motor learning

What is depolarization?

• when sodium channels open

• the cell membrane is close to 0 mV than the resting potential (less polarized)

What phase of an action potential is associated with depolarization?

• the first half of the Absolute Refractory period

What is repolarization?

• potassium channels open and sodium channels close

• the change in membrane potential is returned back to negative

What phase of an action potential is related to repolarization?

• the second half of the Absolute Refractory period

What is hyperpolariation?

• when potassium rushes down its concentration gradient

• the membrane is more negative than the resting potential (more polarized)

What phase of the action potential is related to hyperpolarization?

The Relative Refractory period

What happens in the resting phase of an action potential?

• sodium and potassium channels are closed

what are te main ions involved in neutral signaling?

• potassium

• sodium

• calcium

• chloride

What are the two types of receptors?

• Ionotropic

• Metabotropic

What is an Ionotropic receptor?

• fast acting

• ligand-gated

• can cause EPSP or IPSP

• neurotransmitter binding to a receptor opens an ion channel

What is a Metabotropic receptor?

• neurotransmitter binding to a receptor activates a G-protien

• variable time scale (slower than ionotropic)

• G-protien coupled

• wide range of effects

What structures are involved in regulating the amount of neurotransmitter in the synapse?

• autoreceptors

What are autoreceptors?

• presynaptic receptors that detect neurotransmitters released by the neuron

• shuts off or reduces the amount of neurotransmitter released

What is the primary excitatory neurotransmitter in the nervous system?

• Glutamate

What is the primary inhibitory neurotransmitter in the nervous system?

• GABA

  • when bound to a receptor, chloride channel is opened → leads to an IPSP

What are the two main types of receptors associated with Glutamate?

• AMPA

  • allows sodium to pass through

• NMDA

  • allows sodium and calcium to pass through

Where does Dopamine originate?

• substantia migra

• ventura tegmentl area (VTA)

Where does Norepinephrine originate?

• locus coeruleus

Where does Epinephrine (adrenaline) originate

• medulla

What are the neurotransmitter systems targeted by drugs/toxins ?

• periaqueductal gray

• inferior colliculus

• hippocampus

• medical thalamus

• caudate nucleus

• olfactory bulb

What is the most common feature shared by addictive drugs?

• basic dose response curve: increasing drug dosage with diminishing strength in response to that drug (tolerance)

What function is associated with the thalamus?

• relays sensory and motor signals

• regulation of consciousness and alertness

What function is associated with the corpus callosum?

• allows communication between the two hemispheres in the brain

What function and structures are associated with the Limbic system?

• related to emotion

• hypothalamus

• hippocampus

• amygdala

What is associated with cerebrum?

• gray mater (made up of axons)

• white matter (made up of cell bodies and synaptic connections)

What is the function of the corpus callosum?

• connects the two hemispheres of the brain

What is the function of the basal ganglia?

• movement initiation

• prevents unwanted movements

what is the function of the Pons in the brain?

• involuntary processes (breathing, heartbeat, etc)

what is the function of the medulla

• autonomic involuntary actions

all or none phenomena

• the amplitude of the action potential is independent of the size of the stimulus

How is the resting membrane of an action potential maintained?

• diffusion

• electrostatic pressure

• acting upon potassium

What is a stroke?

• when there is brain damage caused by a reduction or blockage of blood flow to the brain

What does the ventricular system contain?

• cerebrospinal fluid

WHat does the brainstem consist of?

• midbrain

• medulla

• pons

How do axons of the sympathetic nervous system leave the central nervous system?

• through the thoracic and lumbar regions of the spinal cord

How do neurons receive information from other neurons?

• at the input zone information is transferred through the dendrites