Nervous System and Endocrine System Study Pack

Kibin's free study pack on Nervous System and Endocrine System includes a 4-section study guide, 8 quiz questions, 10 flashcards, and 1 open-ended Explain review question. Sign up free to track your progress toward mastery, plus upload your own notes and recordings to create personalized study packs organized by course.

Last updated May 21, 2026

Topic mastery0%
Save progress →

Nervous System and Endocrine System Study Guide

Trace how the body's two great communication systems operate — from action potentials firing along neurons and neurotransmitters crossing synapses, to hormones released by the pituitary, adrenal, and thyroid glands. Cover the CNS and peripheral divisions, the sympathetic and parasympathetic branches, negative feedback loops, and the hypothalamus as the critical bridge linking neural and endocrine control.

Key Takeaways

  • •The nervous system is divided into the central nervous system (brain and spinal cord) and the peripheral nervous system (all nerves outside the CNS), with the peripheral system further split into somatic and autonomic divisions.
  • •Neurons transmit information via electrical signals called action potentials, which travel along the axon and trigger the release of neurotransmitters across the synapse to the next cell.
  • •The autonomic nervous system regulates involuntary functions through two opposing branches: the sympathetic division mobilizes the body for stress responses, while the parasympathetic division restores rest and digestion.
  • •The endocrine system communicates through hormones released into the bloodstream by glands such as the pituitary, adrenal, thyroid, and pancreas, producing slower but longer-lasting effects than neural signaling.
  • •The hypothalamus serves as the critical link between the nervous and endocrine systems, directing the pituitary gland to release hormones that regulate much of the endocrine network.
  • •Negative feedback loops are the primary mechanism by which the endocrine system maintains hormonal balance, detecting deviations from set points and signaling glands to reduce or increase output.
  • •The two systems work in concert — the nervous system handles rapid, precise responses while the endocrine system sustains longer-term physiological and behavioral states.

Structural Organization of the Nervous System

The nervous system is organized into two major anatomical divisions, each with distinct structures and roles in receiving, processing, and transmitting information throughout the body.

Central Nervous System (CNS): Brain and Spinal Cord

  • •The brain integrates sensory input, generates voluntary movement, regulates homeostasis, and produces higher cognitive functions such as memory, language, and emotion.
  • •The spinal cord serves as the primary conduit for signals traveling between the brain and the rest of the body, and also mediates spinal reflexes independently of the brain.
  • •The CNS is protected by the bony skull and vertebral column, and by three membrane layers called meninges, as well as the blood-brain barrier, which limits which substances can enter neural tissue from the bloodstream.

Peripheral Nervous System (PNS): Cranial and Spinal Nerves

  • •The PNS consists of all neural tissue outside the brain and spinal cord, including 12 pairs of cranial nerves and 31 pairs of spinal nerves that carry signals to and from the CNS.
  • •Afferent (sensory) neurons carry information from sensory receptors in the body toward the CNS; efferent (motor) neurons carry commands from the CNS out to muscles and glands.

Somatic and Autonomic Divisions of the PNS

  • •The somatic nervous system governs voluntary skeletal muscle movement and transmits sensory information from the skin, muscles, and joints.
  • •The autonomic nervous system controls involuntary functions — including heart rate, digestion, respiration rate, and glandular secretion — without conscious effort.

Neurons: Structure and Electrical Signaling

Neurons are the specialized cells that carry electrical information throughout the nervous system, and their structure directly supports their function of receiving, integrating, and transmitting signals.

Anatomical Components of a Neuron

  • •Dendrites are branched extensions that receive incoming signals from other neurons or sensory receptors and carry that input toward the cell body (soma).
  • •The soma contains the nucleus and metabolic machinery; it integrates incoming signals to determine whether to fire.
  • •The axon is a single long projection that conducts the electrical signal away from the soma toward the axon terminals, where communication with other cells occurs.
  • •Many axons are wrapped in myelin, a fatty insulating sheath produced by Schwann cells (in the PNS) or oligodendrocytes (in the CNS), which dramatically increases signal conduction speed.
  • •Gaps in the myelin sheath called nodes of Ranvier allow the electrical signal to jump from node to node in a process called saltatory conduction.

The Action Potential

  • •At rest, a neuron maintains a negative internal charge (around −70 mV) relative to the outside — a state called the resting membrane potential.
  • •When sufficient excitatory input arrives, voltage-gated sodium channels open, sodium ions rush into the cell, and the membrane rapidly depolarizes, generating an action potential.
  • •After depolarization, potassium channels open and potassium flows out, repolarizing the membrane; a brief hyperpolarization follows before the neuron returns to resting potential.
  • •Action potentials follow an all-or-nothing principle: a neuron either fires at full strength or not at all, and signal intensity is encoded by the frequency of firing, not the size of individual potentials.

Glial Cells: Support and Regulation

  • •Glial cells outnumber neurons and perform essential supportive functions rather than transmitting signals directly.
  • •Astrocytes regulate the extracellular environment and support the blood-brain barrier; microglia serve as immune defenders; oligodendrocytes and Schwann cells produce myelin.

About this Study Pack

Created by Kibin to help students review key concepts, prepare for exams, and study more effectively. This Study Pack was checked for accuracy and curriculum alignment using authoritative educational sources. See sources below.

Sources

More in Psychology 101

See all topics →

Browse other courses

See all courses →