Human Bio

Sensory Neurons

Take impulses from sensory receptors to the central nervous system (CNS).

Interneurons

Receive information in the CNS and send it to a motor neuron.

Motor Neurons

Take impulses from the CNS to an effector such as a gland or muscle fiber.

Cell Body

The main cell where organelles and nuclei reside.

Dendrite

Many short extensions that carry impulses to a cell body.

Axon

A single long extension that carries impulses away from the cell body.

Schwann Cells

Neuroglia that make up the myelin sheath in the peripheral nervous system (PNS).

Nodes of Ranvier

Gaps between myelination on the axons.

Saltatory Conduction

Conduction of the nerve impulse from node to node.

Resting Potential

When the axon is not conducting a nerve impulse.

Action Potential

Rapid change in the axon membrane that allows a nerve impulse to occur.

Integration

The summation of the inhibitory and excitatory signals received by a postsynaptic neuron.

Central Nervous System (CNS)

Comprises the brain and spinal cord.

Peripheral Nervous System (PNS)

Consists of nerves and ganglia that are outside the CNS.

Meninges

Three protective membranes that wrap around the CNS.

Cerebral Spinal Fluid

Fluid that cushions and protects the CNS, filling the space between meninges.

Gray Matter

Contains cell bodies and non-myelinated fibers.

White Matter

Contains myelinated axons.

Cerebrum

The largest portion of the brain.

Frontal Lobe

Primary motor area and conscious thought.

Temporal Lobe

Primary auditory, smell, and speech area.

Parietal Lobe

Primary somatosensory and taste area.

Occipital Lobe

Primary visual area.

Cerebral Cortex

Thin outer layer of gray matter.

Primary Motor Area

Involved in voluntary skeletal muscle control.

Primary Somatosensory Area

Processes sensory information from skeletal muscles and the skin.

Association Areas

Regions where integration of information occurs.

Diencephalon

Includes the hypothalamus, thalamus, and pineal gland.

Hypothalamus

Helps maintain homeostasis and controls the pituitary gland.

Thalamus

Masses of gray matter that receive sensory input except smell; involved in memory and emotions.

Pineal Gland

Secretes melatonin, controlling daily rhythms.

Cerebellum

Receives and integrates sensory input about body position.

Midbrain

Relay station between the cerebrum and spinal cord; reflex center.

Pons

Bridge between cerebellum and CNS; regulates breathing rate.

Medulla Oblongata

Regulates breathing, heartbeat, and blood pressure.

Reticular Formation

Regulates alertness as a major component of the reticular activating system.

Limbic System

Connects primitive emotions with higher functions like reasoning.

Amygdala

Processes emotional overtone.

Hippocampus

Important for learning and memory.

Learning

What happens when recalling and using past memories.

Memory

Ability to hold thoughts or recall past events.

Short Term Memory

Retention of information for only a few minutes.

Long Term Memory

Retention of information for more than a few minutes, including episodic and semantic memory.

Episodic Memory

Memory of personal experiences and events.

Semantic Memory

Memory of numbers and words.

Skill Memory

Performing skilled motor activities.

Language

Depends on semantic memory.

Somatic Division

Serves the skin, skeletal muscles, and tendons.

Autonomic Division

Regulates involuntary muscles and glands.

Sympathetic Nervous System

Coordinates 'fight or flight' response, speeding up metabolism and heart rate.

Parasympathetic Nervous System

Counters sympathetic functions, promoting relaxation and restoring normal function.