Biological Basis of Behavior Flashcards
These cards cover neurotransmitters, parts of the brain, reflexes, and the wide array of other biological concepts that form the basis for MCAT psychology.
Fill in the blank.
The _________ and _________ nervous systems are responsible for regulating the physiology and behavior of the individual in response to the environment.
Hint: These two systems are the two largest divisions of the nervous system.
central, peripheral
These systems are often abbreviated CNS and PNS, respectively.
What are the two structures that contain all the nerves within the central nervous system?
- brain
- spinal cord
What division of the nervous system includes all nerves located outside the brain and spinal cord?
peripheral nervous system
What are the two subsystems into which the peripheral nervous system is generally divided?
Hint: These divisions are delineated based on whether or not they require conscious input.
- somatic nervous system
- autonomic nervous system
The somatic nervous system governs conscious movement, such as the movement of skeletal muscle. The autonomic nervous system controls unconscious, or automatic, functions such as heart rate and peristalsis.
Note that breathing is a rare example of a function that is under both voluntary and involuntary control to some extent.
Fill in the blank.
Vasodilation is controlled by the _________ [autonomic/somatic] nervous system, which is a subdivision of the ________ [central/peripheral] nervous system.
Choose one term from each box above to accurately complete the sentence.
autonomic, peripheral
Since vasodilation is performed unconsciously, it is governed by the autonomic nervous system. Both the autonomic and the somatic nervous systems are subdivisions of the peripheral nervous system (PNS).
Fill in the blank.
Contraction of the biceps muscle when lifting weights is controlled by the _________ [autonomic/somatic] nervous system, which is a subdivision of the _________ [central/peripheral] nervous system.
Choose one term from each box above to accurately complete the sentence.
somatic, peripheral
This statement describes a conscious function, so it is governed by the somatic nervous system. Both the autonomic and the somatic nervous systems are subdivisions of the peripheral nervous system (PNS).
Fill in the blank.
The official name for the “fight-or-flight” division of the nervous system is the _________ nervous system.
sympathetic
It is activated when the individual is stressed or in acute danger. Epinephrine is released to cause an increase in heart rate, respiratory rate, and blood flow to muscles to escape or fight off the threat.
What is the official name of the “rest-and-digest” division of the nervous system?
parasympathetic nervous system
This branch of the nervous system is active when the individual is not in danger (that is, when he or she is resting, eating, or otherwise in a relaxed state). Heart rate and breathing rate are slowed, and blood flow is diverted to the digestive system.
What branch of the autonomic nervous system inhibits peristalsis when activated?
sympathetic nervous system
Inhibition of peristalsis (and of digestive activity in general) is characteristic of the sympathetic, or fight-or-flight, nervous system.
What branch of the autonomic nervous system is associated with increased secretion of saliva?
parasympathetic nervous system
An easy way to remember this is to note that the parasympathetic (or rest-and-digest) system is generally associated with digestion and related functions (which include salivation).
What branch of the autonomic nervous system is associated with an increase in blood glucose levels?
sympathetic nervous system
Sympathetic activation results in the release of epinephrine, which increases blood glucose level by stimulating the breakdown of glycogen and subsequent release of glucose from the liver.
What branch of the autonomic nervous system is activated when pupils dilate?
sympathetic nervous system
Pupil dilation is a result of sympathetic (fight-or-flight) activation. You can remember this by imagining the pupils letting in a larger amount of light to better visualize a threat.
What branch of the autonomic nervous system is associated with decreased blood flow to skeletal muscles?
parasympathetic nervous system
Overall, parasympathetic activation results in decreased blood flow to muscles and increased blood flow to the digestive system.
What neurological circuit is shown in the image below?
reflex arc
Reflex arcs are nerve pathways involved in a reflex action. At its simplest, a reflex arc is just a sensory neuron, a synapse, and a motor neuron.
The image shows a person touching a hot surface. The neurons contained within the reflex arc will immediately react, causing him to withdraw his hand.
Where do reflex arcs typically synapse, allowing them to bypass involvement of which structure?
brain
Reflex arcs typically do not require input from the brain. It is crucial that reflexes occur quickly; sending information to and from the brain would be too time-consuming.
Name the three types of nerve cells (neurons) in the human nervous system.
- motor neurons
- sensory neurons
- interneurons
Describe:
The general function of sensory neurons.
They transmit sensory information (both external and internal) from the periphery of the body to the central nervous system.
Describe:
The general function of motor neurons.
They transmit signals from the central nervous system to the periphery of the body (specifically, to targets such as muscles and glands).
Motor neurons provide the neural impulses that tell our muscles to contract, allowing movement.
Name the type of neuron that is commonly found between a sensory neuron and a motor neuron in a reflex arc.
interneuron
Interneurons are the third type of neurons in the nervous system (with the other two being motor and sensory neurons). Interneurons are always located between other neurons.
Fill in the blank.
A gap between neurons into which neurotransmitter molecules are released is termed a _________.
synapse
Interestingly, neurons do not directly contact each other. Instead, they are separated by small gaps termed synapses.
How many neurons are involved in a monosynaptic reflex arc, and what type(s) of neurons are they?
Two neurons are involved in a monosynaptic reflex arc:
- sensory neuron
- motor neuron
“Monosynaptic” means “one synapse.” A synapse is a gap between neurons, so this reflex arc must involve two neurons.
How many neurons are involved in a disynaptic reflex arc, and what type(s) of neurons are they?
Three neurons are involved in a disynaptic reflex arc:
- sensory neuron
- motor neuron
- interneuron
“Disynaptic” means “two synapses.” To have two synapses (gaps between neurons), this reflex arc must involve three neurons.
Fill in the blank.
Due to the direction in which they transmit information (from the periphery toward the brain), sensory neurons are also termed ________ neurons.
afferent
In general, “afferent” refers to movement or transmission toward a point of reference.
True or false.
A neuron that transmits impulses from the spinal cord toward skeletal muscle fibers is an afferent neuron.
False
This statement describes a motor neuron. Motor neurons transmit impulses away from the central nervous system (here, the spinal cord), and are thus termed efferent, not afferent, neurons.
What molecules are responsible for communication between neurons and the propagation of nerve signals throughout the body?
neurotransmitters
True or false.
GABA, serotonin, and epinephrine are inhibitory neurotransmitters.
False
This statement is false because epinephrine is not inhibitory. Excitatory neurotransmitters include acetylcholine and epinephrine, while inhibitory neurotransmitters include dopamine, GABA, and serotonin.
What neurotransmitter is strongly associated with feelings of euphoria and happiness and often contributes to addiction to recreational drugs?
Many antidepressants function by inhibiting the reuptake of this neurotransmitter.
serotonin
While both serotonin and dopamine are associated with feelings of euphoria, only serotonin is a treatment target for depression via selective serotonin reuptake inhibitors.
Fill in the blank.
________ neurons synthesize dopamine, while ________ receptors are stimulated by nicotine.
Dopaminergic, nicotinergic
Defective dopaminergic neurons can cause impaired motor movements, loss of feelings, changes in mood, and impaired memory.
List the seven primary neurotransmitters or neurotransmitter types used in the body.
- Gamma-aminobutyric acid (GABA)
- Acetylcholine
- Epinephrine
- Norepinephrine
- Serotonin
- Dopamine
- Endorphins
Fill in the blank.
The main inhibitory neurotransmitter in the adult human brain is _____-_________ _____.
gamma-aminobutyric acid
(GABA)
What neurotransmitter is involved in the reward pathway that plays a crucial role in drug addiction?
As an additional hint, neurons that produce it deteriorate in patients with Parkinson’s disease.
dopamine
Dopamine is the neurotransmitter most classically associated with pleasure. It plays an important role in drug addiction via the brain’s reward pathway. In patients with Parkinson’s disease, dopaminergic neurons in a brain region termed the substantia nigra degenerate.
What neurotransmitter is alternatively known as noradrenaline?
norepinephrine
Norepinephrine has many of the same effects as epinephrine (adrenaline), such as increasing heart rate and increasing blood glucose level.