PSY Module 3
endorphins
"morphine within"—natural, opiate-like neurotransmitters linked to pain control and to pleasure.
How are the nervous and endocrine systems alike, and how do they differ?
Both of these communication systems produce chemical molecules that act on the body's receptors to influence our behavior and emotions. The endocrine system, which secretes hormones into the bloodstream, delivers its messages much more slowly than the speedy nervous system, and the effects of the endocrine system's messages tend to linger much longer than those of the nervous system.
Curare poisoning paralyzes its victims by blocking ACh receptors involved in muscle movements. Morphine mimics endorphin actions. Which is an agonist, and which is an antagonist?
Morphine is an agonist; curare is an antagonist.
What happens in the synaptic gap?
Neurons send neurotransmitters (chemical messengers) across this tiny space between one neuron's terminal branch and the next neuron's dendrite or cell body.
How do neurotransmitters influence behavior, and how do drugs and other chemicals affect neurotransmission?
Neurotransmitters travel designated pathways in the brain and may influence specific behaviors and emotions. Acetylcholine (ACh) affects muscle action, learning, and memory. Endorphins are natural opiates released in response to pain and exercise. Drugs and other chemicals affect brain chemistry at synapses. Agonists increase a neurotransmitter's action, and may do so in various ways. Antagonists decrease a neurotransmitter's action by blocking production or release.
The _____ gland triggers ovaries and testes to release sex hormones.
Pituitary
Why are psychologists concerned with human biology?
Psychologists working from a biological perspective study the links between biology and behavior. We are biopsychosocial systems, in which biological, psychological, and social-cultural factors interact to influence behavior.
Why is the pituitary gland called the "master gland"?
Responding to signals from the hypothalamus, the pituitary releases hormones that trigger other endocrine glands to secrete hormones, which in turn influence brain and behavior.
What bodily changes does your ANS direct before and after you give an important speech?
Responding to this challenge, your ANS sympathetic division will arouse you. It accelerates your heartbeat, raises your blood pressure and blood sugar, slows your digestion, and cools you with perspiration. After you give the speech, your ANS parasympathetic division will reverse these effects.
What is reuptake? What two other things can happen to excess neurotransmitters after a neuron reacts?
Reuptake occurs when excess neurotransmitters are reabsorbed by the sending neuron. They can also drift away or be broken down by enzymes.
How does our nervous system allow us to experience the difference between a slap and a tap on the back?
Stronger stimuli (the slap) cause more neurons to fire and to fire more frequently than happens with weaker stimuli (the tap).
What are the functions of the nervous system's main divisions, and what are the three main types of neurons?
The central nervous system (CNS)—the brain and the spinal cord—is the nervous system's decision maker. The peripheral nervous system (PNS), which connects the CNS to the rest of the body by means of nerves, gathers information and transmits CNS decisions to the rest of the body. The two main PNS divisions are the somatic nervous system (which enables voluntary control of the skeletal muscles) and the autonomic nervous system (which controls involuntary muscles and glands by means of its sympathetic and parasympathetic divisions). Neurons cluster into working networks. There are three types of neurons: (1) Sensory (afferent) neurons carry incoming information from sensory receptors to the brain and spinal cord. (2) Motor (efferent) neurons carry information from the brain and spinal cord out to the muscles and glands. (3) Interneurons communicate within the brain and spinal cord and between sensory and motor neurons.
How does the endocrine system transmit information and interact with the nervous system?
The endocrine system is a set of glands that secrete hormones into the bloodstream, where they travel through the body and affect other tissues, including the brain. The endocrine system's master gland, the pituitary, influences hormone release by other glands, including the adrenal glands. In an intricate feedback system, the brain's hypothalamus influences the pituitary gland, which influences other glands, which release hormones, which in turn influence the brain.
Hailey's 2-year-old nephew touches his index finger to the pan she just took out of the oven. He pulls his finger away quickly, but doesn't cry until a few seconds later. Why does it take longer for him to cry than to pull his finger away?
The hand-withdrawal reflex involves only the spinal cord, but the pain message has to reach the brain.
What are neurons, and how do they transmit information?
The often bushy dendrite fibers receive information and conduct it toward the cell body. From there, the cell's single lengthy axon fiber passes the message through its terminal branches to other neurons or to muscles or glands.Dendrites listen. Axons speak. Neurons are the basic building blocks of the nervous system, the body's speedy electrochemical information system. A neuron receives signals through its branching dendrites, and sends signals through its axons. Some axons are encased in a myelin sheath, which enables faster transmission. Glial cells provide myelin, and they support, nourish, and protect neurons; they may also play a role in learning and thinking. If the combined signals received by a neuron exceed a minimum threshold (about negative 55 millivolts), the neuron fires, transmitting an electrical impulse (the action potential) down its axon by means of a chemistry-to-electricity process. The neuron's reaction is an all-or-none process. Absolute or relative refractory periods are tiny (millisecond) breaks between action potentials.
How do nerve cells communicate with other nerve cells?
When action potentials reach the end of an axon (the axon terminals), they stimulate the release of neurotransmitters. These chemical messengers carry a message from the sending neuron across a synapse to receptor sites on a receiving neuron. The sending neuron, in a process called reuptake, then normally reabsorbs the excess neurotransmitter molecules in the synaptic gap. If incoming signals are strong enough, the receiving neuron generates its own action potential and relays the message to other cells.
refractory period
a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.
Myelin sheath
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next.
agonist
a molecule that increases a neurotransmitter's action.
antagonist
a molecule that inhibits or blocks a neurotransmitter's action.
neuron
a nerve cell; the basic building block of the nervous system.
action potential
a neural impulse; a brief electrical charge that travels down an axon.
dendrites
a neuron's often bushy, branching extensions that receive messages and conduct impulses toward the cell body.
all-or-none response
a neuron's reaction of either firing (with a full-strength response) or not firing.
reuptake
a neurotransmitter's reabsorption by the sending neuron.
adrenal glands
a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.
reflex
a simple, automatic response to a sensory stimulus, such as the knee-jerk response.
The __________ secrete(s) epinephrine and norepinephrine, helping to arouse the body during times of stress.
adrenal glands
A drug that blocks the reuptake of a particular neurotransmitter is called a(n) _____.
agonist
People who suffer from schizophrenia have, among other things, an excess of dopamine. Therefore, medications used to treat this disorder are dopamine:
antagonist
The sympathetic nervous system arouses us for action and the parasympathetic nervous system calms us down. Together, the two systems make up the __________ nervous system.
autonomic
nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs.
sensory neurons
carry incoming messages from sensory receptors to the CNS.
motor neurons
carry outgoing messages from the CNS to muscles and glands.
glial cells
cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory.
hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.
neurotransmitters
chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
interneurons
communicate within the CNS and process information between incoming and outgoing messages.
When a neuron fires an action potential, the information travels through the axon, the dendrites, and the cell body, but not in that order. Place these three structures in the correct order.
dendrites, cell body, axon
People who suffer from schizophrenia have an excess of _____.
dopemine
Myelin is produced by:
glial cell
Melissa is very hungry. Her interest in food at the moment may be a result of _____ acting on her brain.
hormones
The peripheral nervous system consists of sensory and _____ neurons.
motor
The peripheral nervous system includes the _____ neurons, which carry messages from the central nervous system to the body's muscles and glands.
motor
sensory (afferent) nuerons
neurons that carry incoming information from the sensory receptors to the brain and spinal cord.
motor efferent nuerons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.
interneurons
neurons within the brain and spinal cord; communicate internally and process information between the sensory inputs and motor outputs.
In a sending neuron, when an action potential reaches an axon terminal, the impulse triggers the release of chemical messengers called
neurotransmitters
Serotonin, dopamine, and endorphins are all chemical messengers called
neurotransmitters
Endorphins are released in the brain in response to
pain or vigorous exercise
The _____ nervous system helps us to conserve energy as it calms us down after a stressful event.
parasympathetic
The autonomic nervous system controls internal functions, such as heart rate and glandular activity. The word autonomic means
self regulating
Although Nasem has no genital sensation, he is capable of an erection if his genitals are stimulated. Nasem's experience is MOST indicative of a:
severed spinal cord
It is almost impossible to study thoughts, feelings, and actions without focusing on _____ first and foremost.
the body
endocrine system
the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream.
nervous system
the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.
central nervous system
the brain and spinal cord.
sympathetic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy.
parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy.
somatic nervous system
the division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system.
pituitary gland
the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.
threshold
the level of stimulation required to trigger a neural impulse.
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands.
autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
biological psychology
the scientific study of the links between biological (genetic, neural, hormonal) and psychological processes. (Some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists.)
peripheral nervous system
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
Regarding a neuron's response to stimulation, the intensity of the stimulus determines
whether or not an impulse is generated
