Chapter 3 Flashcards
Allele
A variant form of a gene at a particular locus on a chromosome.
Example: The gene for eye color has alleles for blue, brown, and green.
Epigenetic
Changes in gene expression caused by mechanisms other than changes in the DNA sequence.
Example: Environmental factors can influence epigenetic changes.
Gene
A unit of heredity made up of DNA that carries instructions for the development and functioning of an organism.
Example: Genes determine traits like hair color and height.
Gene (DNA) Methylation
The addition of a methyl group to DNA, often affecting gene expression without altering the DNA sequence.
Example: Methylation can regulate gene activity.
Heterozygous
Having two different alleles of a gene.
Example: If one allele codes for blue eyes and the other for brown eyes, the individual is heterozygous for eye color.
Homozygous
Having two identical alleles of a gene.
Example: Homozygous individuals for a recessive gene will express that trait.
Mutation
A change in the DNA sequence that can lead to variations in gene function or expression.
Example: Mutations can be caused by errors in DNA replication.
Transgenic Animal
An animal that has had a foreign gene deliberately inserted into its genome.
Example: Transgenic mice are often used in research to study specific genes.
Wild Type
The typical form of a species as it occurs in nature.
Example: Wild type fruit flies have red eyes.
Astrocyte
A type of glial cell that supports neurons, regulates the blood-brain barrier, and maintains the extracellular ion balance.
Example: Astrocytes play a crucial role in brain homeostasis.
Axon
The long, slender projection of a neuron that conducts electrical impulses away from the cell body.
Example: Axons can be several feet long in some neurons.
Axon Collateral
A branch of an axon that allows a neuron to send signals to more than one target.
Example: Axon collaterals enable complex neural signaling pathways.
Axon Hillock
The area of the neuron where the axon originates and where action potentials are initiated.
Example: The axon hillock is critical for integrating signals and initiating nerve impulses.
Bipolar Neuron
A type of neuron with two extensions, one axon and one dendrite, often involved in sensory pathways.
Example: Bipolar neurons are found in the retina of the eye.
Cell Body (Soma)
The central part of a neuron containing the nucleus and most of the organelles.
Example: The cell body processes incoming signals and generates outgoing signals.
Dendrite
Branch-like extensions of a neuron that receive signals from other neurons.
Example: Dendrites are covered in synapses to receive neurotransmitter signals.
Dendritic Spine
Small protrusions on dendrites where synapses with other neurons are formed.
Example: Dendritic spines are dynamic structures that can change in response to synaptic activity.
Interneuron
A neuron that connects other neurons within the central nervous system.
Example: Interneurons play a crucial role in processing information within the brain.
Motor Neuron
A neuron that transmits signals from the central nervous system to muscles or glands.
Example: Motor neurons control muscle contractions and movement.
Myelin
A fatty substance that surrounds and insulates axons, speeding up the transmission of electrical signals.
Example: Myelin is essential for efficient nerve conduction.
Oligodendroglia
A type of glial cell in the central nervous system that produces myelin.
Example: Oligodendrocytes wrap around axons to form myelin sheaths.
Purkinje Cell
A type of large neuron found in the cerebellum with extensive dendritic trees, involved in motor control.
Example: Purkinje cells are crucial for coordinating movement and balance.
Pyramidal Cell
A type of excitatory neuron found in the cerebral cortex, characterized by a pyramid-shaped cell body.
Example: Pyramidal cells are key players in cortical information processing.
Schwann Cell
A type of glial cell in the peripheral nervous system that produces myelin.
Example: Schwann cells wrap around peripheral nerve axons to form myelin sheaths.
Sensory Neuron
A neuron that carries sensory information from the body to the central nervous system.
Example: Sensory neurons transmit signals about touch, temperature, and pain.
Somatosensory Neuron
A sensory neuron that conveys information about touch, temperature, and pain from the skin and muscles.
Example: Somatosensory neurons play a role in perceiving the environment.
Blood-Brain Barrier
A selective barrier formed by endothelial cells that protects the brain from harmful substances in the blood.
Example: The blood-brain barrier prevents toxins from entering the brain.
Channel
A protein structure in the cell membrane that allows specific ions to pass through, facilitating electrical signaling.
Example: Ion channels are essential for nerve cell communication.
Efferent
Nerve fibers that carry motor commands from the central nervous system to muscles and glands.
Example: Efferent neurons control muscle contractions.
Excitation
The process by which a nerve or muscle cell becomes activated, usually by an increase in electrical activity.
Example: Excitation leads to the generation of action potentials.
Gate
A mechanism in ion channels that opens or closes to regulate ion flow.
Example: Ion channel gates control the flow of ions in response to signals.
Glial Cell
Non-neuronal cells in the nervous system that support, protect, and nourish neurons.
Example: Glial cells play a role in maintaining the health of neurons.
Microglia
A type of glial cell that acts as the main form of immune defense in the central nervous system.
Example: Microglia are involved in immune responses in the brain.
Neural Network
A network of interconnected neurons that process specific kinds of information.
Example: Neural networks are the basis of brain function and information processing.
Neuroplasticity
The ability of the brain to change and adapt in response to experience, injury, or learning.
Example: Neuroplasticity allows the brain to rewire and recover from damage.
Nuclei (sing. Nucleus)
Clusters of neuron cell bodies in the central nervous system.
Example: Nuclei in the brain are involved in specific functions like motor control.
Pump
A protein that actively transports ions or molecules across a cell membrane against their concentration gradient.
Example: Sodium-potassium pumps maintain the cell’s resting membrane potential.
Synapse
The junction between two neurons where communication occurs through neurotransmitter release.
Example: Synaptic transmission is essential for neural signaling.
Terminal Button (End Foot)
The end of an axon where neurotransmitters are released into the synapse.
Example: Terminal buttons contain vesicles filled with neurotransmitters.
Down Syndrome
A genetic disorder caused by the presence of an extra chromosome 21, characterized by developmental delays and physical abnormalities.
Example: Down syndrome is the most common chromosomal disorder.
Dystonia
A movement disorder causing involuntary muscle contractions, resulting in repetitive movements or abnormal postures.
Example: Dystonia can affect one or multiple body parts.
Ependymal Cell
A type of glial cell that lines the ventricles of the brain and the central canal of the spinal cord, involved in the production of cerebrospinal fluid.
Example: Ependymal cells help circulate cerebrospinal fluid in the brain.
Huntington Disease
A genetic disorder causing the progressive breakdown of nerve cells in the brain, leading to motor, cognitive, and psychiatric symptoms.
Example: Huntington disease is inherited in an autosomal dominant pattern.
Hydrocephalus
A condition characterized by the accumulation of cerebrospinal fluid within the ventricles of the brain, causing increased pressure.
Example: Hydrocephalus can lead to brain damage if not treated.
Paralysis
The loss of the ability to move or feel sensations in part of the body, typically due to nerve damage.
Example: Paralysis can result from spinal cord injuries.
Tay-Sachs Disease
A genetic disorder resulting in the destruction of nerve cells in the brain and spinal cord.
Example: Tay-Sachs disease is more common in certain ethnic groups.
Huntington Disease
A genetic disorder causing the progressive breakdown of nerve cells in the brain, leading to motor, cognitive, and psychiatric symptoms.
Example sentence: Huntington Disease is characterized by involuntary movements and cognitive decline.
Hydrocephalus
A condition characterized by the accumulation of cerebrospinal fluid within the ventricles of the brain, causing increased pressure.
Example sentence: Hydrocephalus may require surgical intervention to relieve the pressure.
Paralysis
The loss of the ability to move or feel sensations in part of the body, typically due to nerve damage.
Example sentence: Paralysis can result from a spinal cord injury.
Tay-Sachs Disease
A genetic disorder resulting in the destruction of nerve cells in the brain and spinal cord, leading to severe neurological symptoms and early death.
Example sentence: Tay-Sachs Disease is more common in certain ethnic populations.
Tumor
An abnormal mass of tissue resulting from uncontrolled cell growth, which can be benign or malignant.
Example sentence: A biopsy is often necessary to determine if a tumor is cancerous.
Phenotypic Plasticity
The ability of an organism to change its phenotype in response to environmental influences.
Example sentence: Phenotypic plasticity allows plants to adapt to different climates.
Protein
A molecule composed of amino acids that performs various functions in the body, including structural, enzymatic, and regulatory roles.
Example sentence: Proteins are essential for muscle growth and repair.
Wild Type
The typical form of a species as it occurs in nature.
Example sentence: Genetic mutations can alter the wild type phenotype.
