Psych Chapter 2 Flashcards
Biological Psychology
The scientific study of the links between biological (genetic, neural, hormonal) and psychological processes.
Neurons
Nerve cells; the basic building block of the nervous system.
Dendrite’s
A neuron’s often bushy, branching extensions that receive messages and conduct impulses toward the cell body.
Axon
The neuron extension that passes messages away from the cell body to its terminal branches to other neurons or to muscles or glands.
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 (gaps between the myelin sheath) to the next.
Nodes
Gaps between the myelin sheath.
Multiple Sclerosis
Degeneration of myelin sheath, resulting in slowing of communication to muscles, with eventual loss of muscle control.
Glial Cells (Glia)
Cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory.
Action Potential
A neural impulse; a brief electrical charge that travels down an axon.
Ions
Electrically charged atoms.
The fluid outside of an axon’s membrane has mostly…
…positively charged sodium ions.
A resting axon’s fluid interior consists of…
…both large, negatively charged protein ions and smaller, positively charged potassium ions and has a mostly negative charge.
The axon’s surface is selective about what it allows through its “doors,” this is called…
…selectively permeable.
Resting Potential
Positive-outside/negative-inside state
Depolarization
The axon opens its gates and the positively charged sodium ions flood the axon, resulting in a loss of inside/outside charge difference (causing the next section of axon channels to open and then the next like falling dominos).
Excitatory Neural Signal
Pushing a neuron’s accelerator
Inhibitory Neural Signal
Pushing a neuron’s brake
Threshold
The level of stimulation required to trigger a neural impulse (about -55 mV).
What combined signals trigger an action potential?
Excitatory signals exceed the inhibitory signals by a minimum intensity (threshold).
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.
All-or-None-Response
A neuron’s reaction of either firing (with a full-strength response) or not firing. (Increasing the level of stimulation above the threshold will not increase the neural impulse’s intensity.)
How do we detect the intensity of a stimulus? How do we distinguish a gentle touch from a big hug?
A strong stimulus can trigger more neurons to fire and to fire more often, but it does not affect the action potential’s strength or speed.
List the order in which an action potential travels through a neuron’s parts.
Dendrites, cell body, axon.
Terminal branches of axons form…
…junctions with other cells.
Junction
A point where two or more things are joined.
Synapse
The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
Synaptic Gap (Cleft)
The tiny gap between two neurons (at the junction b/w axon tip and dendrite/cell body).
Tiny gap at the synapse.
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 neutron, thereby influencing whether that neuron will generate an action potential.
Reuptake
A neurotransmitter’s reabsorption by the sending neuron.
What happens in the synaptic gap?
Neurons send neurotransmitters from their terminal branches of axon across the synapse to the receiving neurons’ dendrites or cell body where they attach to receptor sites.
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. Excess neurotransmitters can also drift away or be broken down by enzymes.
Acetylcholine (Ach)
A neurotransmitter involved with learning and memory. It is the messenger at every junction between motor neurons and skeletal muscles (carries information from the brain and spinal cord to the body’s tissues).
Endorphins
“morphine within” - natural, opiate-like neurotransmitters linked to pain control and to pleasure.
Dopamine
“Feel-good hormone” (pleasure, satisfaction, motivation) - influences movement, learning, attention, and emotion.
Serotonin
Affects mood, hunger, sleep, and arousal - happiness, sleep and waking cycle, sexual desire, etc.
Norepinephrine
Helps control alertness, arousal, and attention.
GABA (gamma-aminobutyric acid)
A major inhibitory neurotransmitter.
Glutamate
A major excitatory neurotransmitter; involved in memory.
Agonist
A molecule that increases a neurotransmitter’s action.
Antagonist
A molecule that inhibits or blocks a neurotransmitter’s action.
Central Nervous System (CNS)
The brain and spinal cord, the body’s decision maker.
Peripheral Nervous System (PNS)
The sensory and motor neurons that connect the CNS to the rest of the body.
Nerves
Bundled axons that form neural cables connecting the central nervous system (brain and spinal cord) with muscles, glands, and sense organs.
Sensory (Afferent) Neurons
Carry messages from the body’s tissues and sensory receptors inward to the brain and spinal cord for processing.
Motor (Efferent) Neurons
Carry instructions from the CNS out to the body’s muscles and glands.
Interneurons
Neurons within the brain and spinal cord; communicate internally and process information between the sensory inputs and motor outputs.
Somatic Nervous System
The division of the PNS that controls the body’s skeletal muscles. Also called the skeletal nervous system.
Autonomic Nervous System
The part of the PNS that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
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.
Homeostasis
Steady internal state
Reflex
A simple, automatic response to a sensory stimulus, such as the knee-jerk response.
Endocrine System
The body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.
Hormones
Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.
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.
Pituitary Gland
The endocrine system’s most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.
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.
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.
The neuron fiber that passes messages through its branches to other neurons or to muscles and glands is the _______.
axon