Chapter 3 Flashcards
Two major cell types in the brain
Glia and neuron
Function of glial cells
Glial cells serve many functions. For example, they supply nourishment to neurons, help remove neurons’ waste products, and provide insulation around many axons
Function of neurons
Individual cells in the nervous system that receive, integrate, and transmit information
Soma
cell body that contains the cell nucleus and much of the chemical machinery common to most cells
Dendrites
the parts of a neuron that are specialized to receive information
Axon
a long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands
Myelin sheath
insulating material that encases some axons
Terminal buttons
Small knobs that secrete chemicals called neurotransmitters
Synapse
a junction where information is transmitted from one neuron to another
Synaptic cleft
A microscopic gap between the terminal button of one neuron and the cell membrane of another neuron
The neurons send signals in this gap. The sender is called the presynaptic neuron and the receiver is called the post-synaptic neuron
Synaptic pruning
Old or less-active synapses withering away while new and often-used synapses stick around
Postsynaptic potential
Voltage change at a receptor site on a postsynaptic cell membrane
Neurotransmitters
Chemicals that transmit information from one neuron to another
Excitatory PSP (postsynaptic potential)
Positive voltage shift that increases likelihood of postsynaptic neuron firing action potentials
Inhibitory PSP (postsynaptic potential)
Negative voltage shift that decreases likelihood of postsynaptic neuron firing action potential
Reuptake
Synapses absorbing neurotransmitters after they trigger a response. This allows the chemical to be recycled
Resting potential of a neuron
its stable, negative charge when the cell is inactive
Action potential
A very brief shift in a neuron’s electrical charge that travels along an axon
The absolute refractory period
The minimum length of time after an action potential, during which another action potential cannot begin. This “down time” isn’t very long, only 1 or 2 milliseconds.
All-or-none law
The neural impulse is an all-or-none proposition, like firing a gun. You can’t half-fire a gun
Even though the action potential is an all-or-nothing event, neurons can convey information about the strength of a stimulus by varying the rate at which they fire action potentials
What are nerves?
Nerves are bundles of neuron fibers (axons)
What is the central nervous system?
Brain and spinal cord
What are the parts of the hindbrain?
Includes the cerebellum, the medulla, and the pons
Functions of the cerebellum
Contributes to coordination and critical to the sense of equilibrium
Funciton of the Medulla
Controls breathing, maintaining muscle tone, and regulating circulation
Function of the pons
Connects the brainstem with the cerebellum
Contributes to sleep and arousal
Functions of the midbrain
Concerned with integrating sensory processes such as vision and hearing
Running through both the hindbrain and the midbrain is the reticular formation. Situated at the central core of the brainstem, the reticular formation contributes to the modulation of muscle reflexes, breathing, and pain perception
Parts of the forebrain
Thalamus, Hypothalamus, The Limbic System, Cerebrum
Function of the thalamus
a structure in the forebrain through which all sensory information (except smell) must pass to get to the cerebral cortex
Function of the hypothalamus
involved in the regulation of basic biological needs
The hypothalamus communicates with, and exerts influence over, virtually every major subdivision of the central nervous system
What is the Limbic System?
a loosely connected network of structures located roughly along the border between the cerebral cortex and deeper subcortical areas
Not well-defined
Deals with emotion processing
What is the function of the cerebrum
It includes the brain areas that are responsible for our most complex mental activities, including learning, remembering, thinking, and consciousness itself
What are the 4 lobes of the cerebral cortex (outermost layer of the cerebrum)?
Occipital
Parietal
Temporal
Frontal
What does the occipital lobe do?
Where visual signals are sent and first processed
What does the parietal lobe do?
Processes touch and the body’s position in space
What does the temporal lobe do?
Auditory processing
What does the frontal lobe do?
Controls movement
What is the corpus callosum?
Thick fibers that connect the cerebral hemispheres
What is the Peripheral nervous system
All the nerves that lie outside the brain and spinal cord
What are the two classes of the peripheral nervous system?
the somatic and automatic nervous systems
What do the somatic nerves do?
Nerves that connect to voluntary skeletal muscles and sensory receptors
What do afferent nerves/axons do?
Afferent nerves carry information from the peripheral system to the central system
What do efferent nerves/axons do?
Efferent nerves carry information from the central system to the peripheral system
Every somatic nerve has two types of what?
Every somatic nerve has afferent and efferent axons, making it a two way street
What do the nerves in the Automatic nervous system do?
Nerves that connect to the heart, blood vessels, smooth muscles, and glands
What are the two divisions of the automatic nervous system?
Sympathetic division and parasympathetic division
What does the sympathetic division do?
Mobilizes the body’s resources for emergencies, like activating the adrenal gland which activates the flight-or-flight response
In an emergency, this slows digestion and drains blood from the periphery
What does the parasympathetic division do?
Activates processes that conserve resources for the body, such as slowing the heart rate, reducing blood pressure, and promoting digestion
What is brain plasticity/neuroplasticity?
the brain’s ability to adapt, reorganize, or grow neural networks
What is the the endocrine system?
Consists of glands that secrete chemicals into the bloodstream that help control bodily functioning
What are hormones?
The chemical substances released by the endocrine glands
What part of the brain largely controls the endocrine system?
hypothalamus
Which gland is essential to the function of most other glands?
Pituitary gland
What are polygenic traits?
characteristics that are influenced by more than one pair of genes
What are family studies?
researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait. If heredity affects the trait under scrutiny, researchers should find trait similarity among relatives
What are twin studies?
researchers assess hereditary influence by comparing the resemblance of identical twins and fraternal twins with respect to a trait
What are adoption studies?
Studies that assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents. If adopted children resemble their biological parents on a trait, even though they were not raised by them, genetic factors probably influence that trait
Why is it difficult to pinpoint what genes determine intelligence, behavior, personality, musical talents, or other psychological tendencies?
Many different genes have a varying level of influence on these thigns.
What is Epigenetics?
The study of heritable changes in gene expression that do not involve modifications to the DNA sequence. This science shows that some traits are not fully expressed due to environmental influences.
What does “fitness” relate to in evolutionary theory?
The reproductive success (number of descendants) of an individual organism relative to the average reproductive success in the population
What is natural selection?
“Survival of the fittest” leads to the prevalence of more useful traits in a population, leading to evolution.
What is an adaptation?
an inherited characteristic that increased in a population (through natural selection) because it helped solve a problem of survival or reproduction during the time it emerged
