A&P The Nervous System Definitions

Questions and Answers

What is the Central Nervous System (CNS)?

Nervous system subdivision that is composed of the brain and spinal cord.

What does the somatic nervous system control?

Voluntary activities such as the activation of skeletal muscles.

What is the Peripheral Nervous System (PNS)?

Nervous system subdivision that is composed of the cranial nerves and spinal nerves.

What is the autonomic nervous system?

Subdivision of the PNS that regulates the activity of cardiac muscle, smooth muscle, and glands. Signup and view all the answers

What are neuroglia?

Cells that support, insulate, and protect neurons. Signup and view all the answers

What are neurons?

Cells that transmit electrical messages from one area of the body to another area. Signup and view all the answers

What is the function of an axon?

End of neuron that releases neurotransmitters away from the cell body. Signup and view all the answers

What is a dendrite?

End of neuron that conducts electrical currents toward the cell body. Signup and view all the answers

What is myelin?

White, fatty material that covers long nerve fibers. Signup and view all the answers

What is the cell body of a neuron?

Location of the nucleus in a neuron. Signup and view all the answers

What are Schwann cells?

Specialized cells that myelinate the fibers of neurons found in the PNS. Signup and view all the answers

What is a synapse?

Junction or point of close contact between neurons. Signup and view all the answers

What is a tract in the CNS?

Bundle of nerve processes inside the CNS. Signup and view all the answers

What are Nodes of Ranvier?

Gaps in the myelin sheath between Schwann cells. Signup and view all the answers

What are ganglia?

Collection of nerve cell bodies found outside the CNS. Signup and view all the answers

What is an efferent neuron?

Neuron that conducts impulses away from the CNS to muscles and glands. Signup and view all the answers

What are stimuli?

Changes occurring within or outside the body that affect nervous system functioning. Signup and view all the answers

What is an afferent neuron?

Neuron that conducts impulses toward the CNS from the body periphery. Signup and view all the answers

What are neurotransmitters?

Chemicals released by neurons that stimulate other neurons, muscles, or glands. Signup and view all the answers

What is depolarization?

State in which the polarity of the neuron is reversed as sodium ions rush into the neuron. Signup and view all the answers

What does polarized mean in the context of neurons?

Electrical condition of the plasma membrane of a resting neuron when it is inactive. Signup and view all the answers

What is repolarization?

Period during which potassium ions diffuse out of the neuron returning to its resting state. Signup and view all the answers

What are potassium ions in relation to a neuron?

The chief positive ion found inside a neuron during its resting state. Signup and view all the answers

What is the sodium-potassium pump?

Process by which ATP is used to move sodium ions out of the cell and potassium ions back into the cell. Signup and view all the answers

What is the function of the hypothalamus?

Site of regulation of water balance, body temperature, and metabolism. Signup and view all the answers

What does the cerebellum regulate?

Posture and coordination of skeletal muscle movements. Signup and view all the answers

What is the role of the thalamus?

Important relay station for afferent fibers traveling to the sensory cortex. Signup and view all the answers

What does the medulla oblongata regulate?

Blood pressure, heart rate, breathing, swallowing, and vomiting. Signup and view all the answers

What is sodium in relation to a neuron?

Chief positive ion found outside of the neuron during its resting state. Signup and view all the answers

What is the parasympathetic division?

Part of the autonomic nervous system that allows us to unwind and conserve energy. Signup and view all the answers

What is the sympathetic division?

Part of the autonomic nervous system that mobilizes the body during extreme situations. Signup and view all the answers

Study Notes

Central Nervous System (CNS)

Comprises the brain and spinal cord.
Key component of the nervous system.

Peripheral Nervous System (PNS)

Includes cranial and spinal nerves.
Functions as a communication network between the CNS and the body.

Somatic Nervous System

Controls voluntary actions.
Activates skeletal muscles for movement.

Autonomic Nervous System

Regulates involuntary functions (cardiac muscle, smooth muscle, glands).
Crucial for maintaining homeostasis in the body.

Neuroglia

Supportive cells for neurons that provide insulation and protection.
Capable of division; significant in brain tumor formation.

Neurons

Specialized cells for transmitting electrical signals throughout the body.

Axon

End portion of a neuron responsible for releasing neurotransmitters away from the cell body.

Dendrite

Receives electrical signals and conducts them toward the cell body.

Myelin

Fatty substance that insulates nerve fibers, increasing impulse transmission speed.

Cell Body

Contains the nucleus, essential for neuronal function.

Schwann Cells

Myelinate nerve fibers in the PNS, enhancing signal conduction.

Synapse

Connection point between neurons where neurotransmitter exchange occurs.

Tract

Bundle of nerve fibers located within the CNS, facilitating information processing.

Nodes of Ranvier

Gaps in the myelin sheath that enhance signal transmission.

Ganglia

Collections of nerve cell bodies outside the CNS, involved in processing peripheral nervous signals.

Efferent Neuron

Carries signals away from the CNS to effectors like muscles and glands.

Afferent Neuron

Transmits sensory signals from body periphery toward the CNS.

Neurotransmitters

Chemicals released from neurons that influence other neurons, muscles, or glands.

Depolarization

Process where sodium ions enter the neuron, reversing its polarity and initiating action potentials.

Polarized State

Condition of a resting neuron where the inside is less positively charged than the outside.

Repolarization

Phase restoring the resting state of a neuron as potassium ions flow out.

Potassium Ions

Predominant positive ion within a resting neuron, vital for maintaining resting potential.

Sodium Potassium Pump

ATP-driven process that maintains ion balance by transporting sodium out and potassium into the cell.

Hypothalamus

Regulates essential functions such as body temperature and water balance.

Cerebellum

Coordinates movement and maintains posture, essential for motor control.

Thalamus

Acts as a sensory relay station, processing afferent signals before reaching the sensory cortex.

Medulla Oblongata

Located in the brain stem; controls vital autonomic functions like heart rate and breathing.

Sodium

Main positive ion present outside a resting neuron, crucial for action potential initiation.

Parasympathetic Division

Part of the autonomic system focusing on energy conservation and relaxation (rest-and-digest).

Sympathetic Division

Mobilizes body resources in stress-related scenarios (flight or fight), increasing physiological readiness.

Fight or Flight Response

Instinctual reaction to danger, triggering physiological changes like increased heart rate and blood flow.

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Test your knowledge with flashcards focused on the definitions related to the nervous system. This quiz covers key components like the central nervous system, somatic nervous system, and peripheral nervous system. Perfect for students studying anatomy and physiology.