Introduction to the Nervous System

These flashcards cover key vocabulary and concepts from the nervous system, including definitions of terms such as neurons, neurotransmitters, and various functions of the nervous system.

Neuron

A cell that is part of the nervous system.

Central Nervous System (CNS)

Includes the brain and spinal cord.

Peripheral Nervous System (PNS)

Includes all other components of the nervous system, such as nerves throughout the body.

Hindbrain

Region of the brain that includes the medulla, pons, and cerebellum.

Medulla

Regulates vital functions like breathing, blood pressure, and heart rate.

Pons

Coordinates signals between different parts of the brain.

Cerebellum

Responsible for balance and movement coordination.

Midbrain

Involved in alertness, sleep-wake cycle, and motor activity.

Forebrain

Contains the cerebrum, thalamus, and hypothalamus.

Cerebrum

Largest part of the brain, divided into two hemispheres, responsible for many functions including reasoning and emotion.

Thalamus

Processes sensory and motor information.

Hypothalamus

Controls the endocrine system and regulates various bodily functions.

Somatic Nervous System (SNS)

Controls voluntary motor functions of skeletal muscle.

Autonomic Nervous System (ANS)

Regulates involuntary body functions.

Sympathetic Nervous System

Part of the ANS involved in the fight or flight response.

Parasympathetic Nervous System

Part of the ANS that promotes rest and digestion.

Action Potential

Rapid change in the electrical charge across a neuron membrane.

Resting Potential

The electrical charge of a neuron at rest, typically around -70 mV.

Dendrites

Branch-like structures on neurons that receive signals.

Axon

The part of a neuron that carries electrical signals away from the cell body.

Synapse

The junction between two neurons where communication occurs.

Glial Cells

Support cells in the nervous system that maintain homeostasis and protect neurons.

Myelin Sheath

A fatty layer that insulates axons and speeds signal transmission.

Neurotransmitter

Chemical released from the end of an axon to transmit signals across a synapse.

Cerebrospinal Fluid (CSF)

Fluid that protects the brain and provides cushioning.

Excitatory Neurotransmitter

Increases the likelihood of action potentials in the postsynaptic neuron.

Inhibitory Neurotransmitter

Decreases the likelihood of action potentials in the postsynaptic neuron.

Homeostasis

The body's ability to maintain stable internal conditions.

Nerve

A bundle of axons in the PNS.

Tract

A bundle of axons in the CNS.

Reflex Arc

The pathway followed by nerve impulses in a reflex action.

Afferent Neuron

Sensory neuron that transmits impulses to the CNS.

Efferent Neuron

Motor neuron that carries impulses away from the CNS.

Astrocytes

Star-shaped glial cells that support neurons and regulate extracellular fluid.

Oligodendrocytes

Glial cells that form the myelin sheath in the CNS.

Parasympathetic nervous system

Secretes tears

Epineurium

A membrane that surrounds an entire nerve

Perineum

Surrounds each fascicle or each group of fibers

Endonerium

Surrounds individual nerve fiber

NeuralimmaNeurilemma

Outermost membrane of myelin sheath

Microglia

Glial cells that act as immune cells in the nervous system.

Schwann Cells

Produce myelin sheath in the peripheral nervous system.

Action Potential All-or-None Principle

A neuron either fires an action potential or it doesn't, with no partial firings.

Saltatory Conduction

Faster signal transmission along myelinated axons as the action potential jumps between nodes.

Chemical Synapse

A synapse where neurotransmitters are released to transmit signals between neurons.

Electrical Synapse

A synapse that allows direct electrical communication between neurons.

Dorsal Root

A nerve root that contains sensory fibers entering the spinal cord.

Ventral Root

A nerve root that contains motor fibers leaving the spinal cord.

Dermatome

An area of skin supplied by a single spinal nerve.

Spinal Reflex

A reflex that involves only the spinal cord, not the brain.

Neuropathy

Any disease of the nerves.

Multiple Sclerosis

An autoimmune disease resulting in demyelination of CNS axons.

Amyotrophic Lateral Sclerosis (ALS)

A degenerative disorder where motor neurons are destroyed.

Poliomyelitis (Polio)

A viral disease that can cause paralysis via nerve infection.

Herniated Disc

A condition where a spinal disc protrudes and compresses nerves.

Carpal Tunnel Syndrome

A condition resulting from compression of the median nerve in the wrist.

Guillain-Barré Syndrome

An autoimmune disorder affecting the peripheral nervous system.

Synaptic Cleft

The small gap between two neurons at a synapse.

Reuptake

The process of neurotransmitters being reabsorbed into the presynaptic neuron.

Norepinephrine

A neurotransmitter involved in the body's metabolism and response to stress.

Serotonin

A neurotransmitter that affects mood and cognition.

Dopamine

A neurotransmitter important for reward and motor control.

Acetylcholine (ACh)

A neurotransmitter used in the nervous system and at neuromuscular junctions.

Limbic System

Part of the brain involved in emotions and memory.

Neuron

A cell that is part of the nervous system.

Central Nervous System (CNS)

Includes the brain and spinal cord.

Peripheral Nervous System (PNS)

Includes all other components of the nervous system, such as nerves throughout the body.

Hindbrain

Region of the brain that includes the medulla, pons, and cerebellum.

Medulla

Regulates vital functions like breathing, blood pressure, and heart rate.

Pons

Coordinates signals between different parts of the brain.

Cerebellum

Responsible for balance and movement coordination.

Midbrain

Involved in alertness, sleep-wake cycle, and motor activity.

Forebrain

Contains the cerebrum, thalamus, and hypothalamus.

Cerebrum

Largest part of the brain, divided into two hemispheres, responsible for many functions including reasoning and emotion.

Thalamus

Processes sensory and motor information.

Hypothalamus

Controls the endocrine system and regulates various bodily functions.

Somatic Nervous System (SNS)

Controls voluntary motor functions of skeletal muscle.

Autonomic Nervous System (ANS)

Regulates involuntary body functions.

Sympathetic Nervous System

Part of the ANS involved in the fight or flight response.

Parasympathetic Nervous System

Part of the ANS that promotes rest and digestion.

Action Potential

Rapid change in the electrical charge across a neuron membrane.

Resting Potential

The electrical charge of a neuron at rest, typically around -70\text{ mV}.

Dendrites

Branch-like structures on neurons that receive signals.

Axon

The part of a neuron that carries electrical signals away from the cell body.

Synapse

The junction between two neurons where communication occurs.

Glial Cells

Support cells in the nervous system that maintain homeostasis and protect neurons.

Myelin Sheath

A fatty layer that insulates axons and speeds signal transmission.

Neurotransmitter

Chemical released from the end of an axon to transmit signals across a synapse.

Cerebrospinal Fluid (CSF)

Fluid that protects the brain and provides cushioning.

Excitatory Neurotransmitter

Increases the likelihood of action potentials in the postsynaptic neuron.

Inhibitory Neurotransmitter

Decreases the likelihood of action potentials in the postsynaptic neuron.

Homeostasis

The body's ability to maintain stable internal conditions.

Nerve

A bundle of axons in the PNS.

Tract

A bundle of axons in the CNS.

Reflex Arc

The pathway followed by nerve impulses in a reflex action.

Receptor

First step in the reflex arc

Sensory neuron

Second step of the reflux arc

Motor neuron

Fourth step in the reflex arc

Descending tracts

Carry motor impulses through the spinal cord

Ascending tracks

Carry sensory impulses through the spinal cord toward the brain