Chapter 3: Neuroscience Flashcards
________ is associated with Parkinson’s disease, whereas ________ is associated with certain forms of schizophrenia.
A) Too little dopamine; too much dopamine
B) Too much dopamine; too little dopamine
C) Too little dopamine; too much serotonin
D) Too much serotonin; too much dopamine
Answer: A) Too little dopamine; too much dopamine
A main function of the medulla is to
A) regulate the functioning of the pons.
B) control sleep and dreaming.
C) coordinate fine motor movement in the fingers and face.
D) control automatic functions such as respiration and heart rate.
Answer: D) Control automatic functions such as respiration and heart rate.
Messages from the eyes are relayed to the visual cortex through the ________ of the ________.
A) medial geniculate nucleus; hypothalamus
B) lateral geniculate nucleus; thalamus
C) lateral geniculate nucleus; striatum
D) medial geniculate nucleus; thalamus
Answer: B) lateral geniculate nucleus; thalamus
Which of the following reflects the correct order for the structure of a neuron?
A) cell body — dendrite — terminal button — axon
B) terminal button — dendrite — cell body — axon
C) axon — cell body — terminal button — dendrite
D) dendrite — cell body — axon — terminal button
Answer: D) dendrite- cell body- axon- terminal button
________ is to into the brain as ________ is to away from the brain.
A) Sensory; autonomic
B) Autonomic; sensory
C) Afferent; efferent
D) Efferent; afferent
Answer: C) Afferent; efferent
The gap between two neurons where neurotransmission takes place is called the
A) terminal gap.
B) neurochemical gap.
C) synapse.
D) terminal cleft.
Answer: C) synapse
The frontal, parietal, temporal, and occipital lobes make up the
A) subcortical area of the brain.
B) association areas of the brain.
C) reticular formation.
D) cerebral cortex.
Answer: D) cerebral cortex
An action potential is generated
A) in the cell body.
B) in the axon.
C) at the point where the axon leaves the cell body.
D) in the dendrites.
Answer: C) at the point where the axon leaves the cell body.
This structure, which is part of the hindbrain, is involved in respiration, movement, waking, sleep, and dreaming.
Incorrect Response
A) reticular formation
B) medulla
C) cerebellum
D) pons
Answer: D) pons
The Nodes of Ranvier are
A) regularly spaced gaps of unmyelinated portions of an axon.
B) fluid-filled sacs containing neurotransmitters.
C) areas of an axon that are wrapped in myelin.
D) networks of neurons working in unison to produce patterns of neural activity.
Answer: A) Regularly spaced gaps of unmyelinated portions of an axon
Two pathways for incoming sensory information:
- Receptors in skin feel touch-> Afferent sensory neurons ->Dorsal
root -> Spinal cord (Dorsal horn)-> sensory nerves->Brain-
>Motor neurons->Ventral horn-> Effector motor neuron->
Muscles of arm to remove spider (shakes arm to remove
spider) - Receptors in skin feel touch-> Afferent sensory neurons ->Dorsal
root of Spinal cord-> Interneurons->Ventral horn -> Effector
motor neurons-> Muscles (Reflex arc pathway) Reflex shaking
arm to remove spider from arm
Central Nervous System:
Brain understands the information
given to it by the PNS. CNS also consists of the Spinal cord.
Peripheral Nervous System:
Sends information from body’s
sensory receptors to CNS; Brain understands information-> PNS relays
information out to body parts.
Somatic Nervous System:
–involved in voluntary movement;
sensory neurons carry impulses to spinal cord then to brain and
back for movement; or to spinal cord then movement.
E.g., You feel the touch of a spider on your arm, signal sent to
brain, you see the spider, then make motor movement to
remove spider.
Autonomic Nervous System (ANS):
neurons that control the heart,
intestines, and other organs.
E.g., Your heart rate increases because of the spider on your arm
The spinal cord:
The spinal cord carries information from various parts of the body to and from the brain.
Spinal cord controls simple reflexes, but is very important for carrying sensory information up to the
brain and motor information back out to the body.
e.g., Individual in severe car accident, suffers
injury to spinal cord. As a result, can’t move legs.
Has to undergo rehabilitation.
Quadriplegic:
A person paralyzed everywhere but the head and neck, likely due to breaking neck and damaging spinal
cord close to brain, losing touch and pain sensation everywhere but their heads and faces.
Paraplegic:
Damage to spinal cord farther down the back, retain sensation and usage of the upper limbs and torso.
The brain:
The brain plays a central role in the control of most
bodily and cognitive functions, including awareness,
movements, sensations, thoughts, speech, and
memory.
Frontal:
Reasoning, Memory &
Planning
Parietal:
Touch, Pain, &
Attention
Temporal:
Language, Memory, &
Auditory processing
Occipital:
Visual processing
The Nervous System: On Being Wired
The nervous system:
- is a system of nerves that control thought processes,
heartbeat, visual–motor coordination, and many
other abilities - contains the brain, spinal cord, and other parts,
enabling us - to receive information from the world outside, and
- to act on that world
Neurons: A complex living network:
Neurons:
* are specialized cells of the nervous system
* receive and transmit electrochemical signals to and from neighbouring neurons
* signal by “firing”
Function of the Neuron:
- Neuron: Receives, assimilates, analyzes and transmits information via action
potentials. Many types of neurons: Sensory, motor and interneurons found in central
nervous system (CNS) and peripheral nervous system (PNS). - A neuron is composed of three main parts:
- A cell body: Cellular machinery for production of proteins and cellular
macromolecules - Dendrites: Receive information from neighboring neurons, spines on dendrites. Many
dendrites also have spines, little knobs where dendrites receive inputs from the
neurons. - Axon: Information flows from the dendrites through the cell body to the axon.
Transmission through synapses - Axon collaterals: Can transmit signals to more than one cell.
- Myelin: Fatty substance that wraps axons, essential for accelerating signal
transmission.
Glia- Astrocytes or Astroglia
- Wrap around the synapses of functionally related axons.
-By surrounding connection between neurons, astrocyte shields axons
from chemicals circulating in surround. Astroglia are important for
creating blood-brain barrier
-By taking up ions and neurotransmitters released by axons and releasing
them back, astroctyes helps synchronize closely related neurons, enabling
their axons to send messages in waves.
-Responsible for dilating blood vessels to bring more nutrients into brain
areas with heightened activity.
Glia- Microglia
Remove waste material, viruses, and fungi from the brain
Also remove dead, dying, or damaged neurons
Proliferate or increase in number after brain damage, removing dead
or damaged neurons.
Glia- Oligodendrocytes and Schwann cells
- Oligodendrocytes (in central nervous system- brain and spinal cord)
and 4. Schwann cells (in the periphery of the body)
Build the myelin sheath that surrounds and insulates certain
vertebrate axons
Glia- Radial glia
-Guide the migration of neurons and the growth of their
axons and dendrites during embryonic development.
-When embryonic development finishes, most radial
glia differentiate into neurons and a smaller number
differentiate into astrocytes and oligodendrocytes
The Neural Impulse: “The Body Electric”
Neural impulses are:
- electrochemical messages that travel within neurons
- In myelinated neurons, this impulse can travel at a
speed of up to 360 km/hr.
Three key terms to understand the generation of the
neural impulse: - Resting Potential, Depolarization, Action Potential
How is resting potential maintained in a neuron and how does it changes?
Electrostatic gradient or Electrostatic pressure: The force that drives ions
that are of a similar charge away from one another or attracts two ions of
opposite charges toward each other.
E.g., Sodium is positively charged, inside of neuron is more negatively
charged.
Concentration gradient: the difference in concentration of ions inside and
outside of a neuron.
E.g., Sodium is more concentrated outside, than inside.
How is action potential (i.e., Neutral impulse) generated?
- When the neuron is at rest, (Sodium) Na + ions and (Chloride) Cl- ions are
higher in concentration outside of the cell than inside, and K+ ions and anions
(A-) are higher in concentration inside than outside the cell. When the neuron
is at rest, it’s more negative inside than outside cell. - The entry of Na+ ions into the cell causes the inside of cell to be less negative
than outside, resulting in depolarization associated with generation of the
action potential. After which, there is repolarization (Sodium channels are
closed, potassium ions going to outside of cell), a refractory period (i.e.,
Hyperpolarization due to lots of potassium ions going to the outside of the
cell) where neuron does not fire action potential and finally neuron is back at
resting state due to action of sodium-potassium pump.
The Neural Impulse: “The Body Electric”
An Electrochemical Voyage
* Neural impulses travel by electrical and chemical processes.
- Polarization is the difference in electrical charge that readies a neuron for
firing. - An internal negative charge is created in relation to the body fluid outside the cell
membrane.
How is signal transmitted across neuron or neurons? Depolarization leads to an action potential
- The action potential is a large amount of electrical activity that is created by
a depolarizing current. - This means that some event (a stimulus) causes the resting potential to
move toward 0 mV. That is, there is an entry of Sodium ions into the cell. - When the depolarization reaches about -40mV to -55 mV a neuron will fire
an action potential.
The Neural Impulse: “The Body Electric” An Electrochemical Voyage
Resting potential is a neuron’s electrical potential when it is not responding to
other neurons. Usually at -70mV.
The Neural Impulse: “The Body Electric” Depolarization
Depolarization occurs when an area on the surface of the resting neuron is
chemically stimulated by other neurons. Threshold is between -40 mV to
-55mV.
The Neural Impulse: “The Body Electric” Action potential
Action potential is the electrical potential when a neural impulse is being
conducted along a neuron’s axon. It is generated when a stimulus changes the
membrane potential to values of threshold potential, around -40 to -55 mV.
Firing: How Messages Voyage from Neuron to Neuron
- Firing is the conduction of a neural impulse along the length of a neuron.
- Works on the all-or-none principle
- The neural impulse is always of the same strength whenever action potential is triggered.
- Refractory period follows, is a recovery period during which the neuron does not
fire.
Excitatory Postsynaptic Potentials (EPSPs)
depolarize the
neuron and increase the likelihood of an action potential.
