Anatomy Ch. 11-12

Sensory Input

Detects changes in the environment, such as touching a hot stove.

Integration

Processes and interprets sensory input, like recognizing heat as dangerous.

Motor Output

Responds by activating muscles or glands, exemplified by pulling the hand away.

Central Nervous System (CNS)

Processes information and coordinates responses; consists of the brain and spinal cord.

Peripheral Nervous System (PNS)

Connects the CNS to limbs and organs; includes cranial nerves, spinal nerves, and ganglia.

Sensory (Afferent) Division

Transmits signals to the CNS.

Motor (Efferent) Division

Sends responses from the CNS to muscles and glands.

Somatic Nervous System

Voluntary control of skeletal muscles.

Autonomic Nervous System

Regulates internal organs involuntarily.

Sympathetic Division

Increases heart rate and dilates pupils for 'fight or flight' response.

Parasympathetic Division

Slows heart rate and stimulates digestion for 'rest and digest' response.

Astrocytes

CNS glial cells providing structural support and regulating the blood-brain barrier.

Microglia

Act as immune cells in the CNS, removing debris and pathogens.

Ependymal Cells

Line brain ventricles and produce cerebrospinal fluid (CSF).

Oligodendrocytes

Form myelin sheaths in the CNS.

Schwann Cells

Produce myelin sheath in the PNS.

Dendrites

Receive signals from other neurons.

Cell Body (Soma)

Contains the nucleus and organelles of the neuron.

Axon

Conducts electrical impulses away from the cell body.

Axon Terminals

Release neurotransmitters to signal other neurons or muscles.

Myelin Sheath

Insulates axons and speeds up electrical impulses.

Resting Potential

The stable, negative charge of a neuron at -70mV maintained by the Na⁺/K⁺ pump.

Depolarization

Process where voltage-gated Na⁺ channels open and Na⁺ rushes in, making the membrane positive.

Repolarization

Closing of Na⁺ channels and opening of K⁺ channels causes K⁺ to rush out, returning to negative potential.

Hyperpolarization

Brief phase where the membrane is more negative than resting potential due to excess K⁺ exiting.

Neurotransmitter Release

Triggered by an action potential reaching the axon terminal, involving Ca²⁺ influx and vesicle release.