Nervous System Flashcards

Flashcards covering the structure and function of the nervous system.

Nervous System Function

Detects impulses from the senses; control center.

Nervous System Major Organs

Brain, Spinal cord, Senses, Nerves

Central Nervous System (CNS)

Consists of the brain and spinal cord.

Peripheral Nervous System (PNS)

Consists of the nerves outside the brain and spinal cord; cranial and spinal nerves.

Motor (Efferent) Division

Sends impulses from the CNS to the muscles and glands.

Sensory (Afferent) Division

Sends impulses from the senses to the CNS.

Autonomic Nervous System

Involuntary muscle control.

Somatic Nervous System

Voluntary muscle control.

Sympathetic Division

Used in emergency situations (“fight or flight”).

Parasympathetic Division

Reduces sympathetic response and provides resting functions such as digestion and urination.

Sensory Input

Detects changes (stimuli) inside and outside the body.

Integration

Processing and interpreting sensory information.

Response

Activation of muscles (motor output) or glands.

Neurons

Conduct impulses around the body (make up only 10% of nerve cells).

Neuroglia

Support, insulate & protect neurons (90% of nerve cells).

Dendrites

Bring impulses towards the cell body.

Axons

Send impulses away from the cell body.

Axon terminals

Release neurotransmitters to pass impulse to the next neuron.

Unipolar Neurons

Neurons with one process.

Bipolar Neurons

Neurons with two processes.

Multipolar Neurons

Neurons with many processes.

Afferent Neurons

Carry impulses toward the CNS.

Efferent Neurons

Carry impulses away from the CNS.

Interneurons

Connect afferent & efferent neurons.

Myelin

Waxy insulation wrapped around axons.

Schwann Cell

Type of neuroglia that forms myelin by wrapping itself around the axon.

Neurilemma

Outer layers of the Schwann cell.

Myelin Sheath

Collective myelin wrappings around axon.

Nodes of Ranvier

Gaps in the myelin sheath between Schwann cells.

Astrocytes

Support & anchor neurons to surrounding capillaries (in CNS).

Microglia

Provide immune response to central nervous system.

Ependymal Cells

Secrete and circulate cerebrospinal fluid.

Oligodendrocytes

Provide myelin insulation to neurons in the central nervous system.

Satellite Cells

Support and anchor neurons in the peripheral nervous system.

Resting Potential

Neuron's intracellular space is negatively charged and the extracellular space is positively charged.

Action Potential

Depolarization of a neuron due to sodium rushing into the cell.

Repolarization

Potassium diffuses out of the neuron as the impulse passes.

Sodium-Potassium Pump

Restores ion concentrations to normal after an impulse.

Synapse

Where 2 neurons meet.

Synaptic Cleft

The space between two neurons at a synapse.

Neurotransmitters

Chemicals released across the synaptic cleft to stimulate the next neuron.

Meninges

Three layers of connective tissue protecting the brain and spinal cord.

Dura Mater

Thick, tough outermost layer of the meninges.

Arachnoid Membrane

Thin, cobweb-like middle layer of the meninges.

Pia Mater

Thin innermost layer of the meninges containing lots of blood vessels.

Cerebrospinal Fluid (CSF)

Fluid between the arachnoid layer and the pia mater; protects the brain and maintains the blood-brain barrier.

Ventricles

Spaces within the brain where CSF is produced.

Choroid Plexuses

Clusters of capillaries in the ventricles that secrete CSF.

Cerebrum

Largest part of the brain, divided into 2 hemispheres.

Corpus Callosum

Bundle of nerve fibers connecting the two hemispheres of the cerebrum.

Gyri

Ridges on the surface of the cerebrum.

Sulci

Grooves on the surface of the cerebrum.

Fissures

Deeper grooves dividing portions of the brain.

Cerebral Cortex

Gray matter on the surface of the cerebrum, made of cell bodies & dendrites.

Cerebral Medulla

White matter of the cerebrum, made of myelinated axons.

Basal Nuclei

Islands of gray matter within the cerebral medulla.

Frontal Lobe

Controls voluntary movements, reasoning, decision-making, memory, and verbal communication.

Parietal Lobe

Controls sensations (pain, temperature, touch), visual-spatial processing, and body position.

Occipital Lobe

Controls visual processing- vision & memory of objects.

Temporal Lobe

Controls memory, comprehension & pronunciation of words, sensations of smell and sound, and emotional association of memories.

Diencephalon

Small region within the cerebrum containing the thalamus, hypothalamus, and pineal gland.

Thalamus

Relays sensory impulses to the cerebral cortex for processing and sorting.

Hypothalamus

Responsible for autonomic processes, controls hormones released by pituitary gland, and part of the limbic system.

Brain Stem

Located between the cerebrum and the spinal cord; includes the midbrain, pons, and medulla oblongata.

Midbrain

Relays information to cerebrum and controls body movements and posture.

Pons

Links the cerebral cortex and the cerebellum and controls breathing.

Medulla Oblongata

Transmits impulses between the spinal cord and the brain; controls blood pressure, heart rate, swallowing, and coughing.

Cerebellum

Coordinates movements directed by the cerebrum so they are graceful and efficient.

Spinal Cord

Relays impulses between the peripheral nervous system and the brain through 31 pairs of spinal nerves.

Reflexes

Preprogrammed responses.

Reflex Arc

The pathway reflexes travel: Receptor, Sensory neurons, Integration, Motor neurons, Effector