Chapter 2: The Human Nervous System

Comprehensive vocabulary flashcards covering the human nervous system, brain structures, cortical regions, neurons, nerve impulses, reflex actions, and synaptic transmission.

Coordination

The process of making all organ systems in the human body work together while they perform their functions at the right time.

Central nervous system (CNS)

The primary control system made up of the brain and the spinal cord, from which millions of nerves branch out to all parts of the body.

Brain

A wrinkly, grey organ located inside the skull, protected by hard bone and a layer of fluid, that controls thinking, memories, analysis, and automatic body functions.

Forebrain

The largest and most highly developed basic unit of the human brain, which consists primarily of the cerebrum, thalamus, and hypothalamus.

Cerebrum

The largest part of the brain that acts as the 'thinking' center, handling conscious thought, reasoning, memory, emotions, and the voluntary movement of muscles.

Voluntary muscles

Muscles that an individual chooses to move consciously, such as the muscles that control the movements of the arms and legs.

Thalamus

A small structure situated directly above the brain stem responsible for relaying sensory information from sense organs and transmitting signals for movement and coordination.

Hypothalamus

A structure located at the base of the brain just above the pituitary gland that acts as the body's thermostat to regulate body temperature at a constant $37\,^{\circ}\text{C}$.

Midbrain

The smallest and central part of the brain that bridges the forebrain and hindbrain; it transmits signals between them and is associated with vision, hearing, alertness, and temperature.

Hindbrain

The lower region of the brain, composed of the cerebellum, the medulla, and the pons.

Cerebellum

A structure located at the back of the brain beneath the cerebrum that coordinates balance and movement, learning complex physical actions through practice.

Medulla (Brain stem)

The region connecting the brain to the spinal cord that automatically controls vital involuntary actions such as breathing, heartbeat, and peristalsis.

Involuntary actions

Automatic bodily processes that occur without conscious thought, carried out by involuntary muscles in the rib cage, heart, and digestive system.

Pons

A structure within the hindbrain that links the brain to the spinal cord.

Pituitary gland

An endocrine gland attached to the base of the brain that secretes hormones to regulate water levels, sugar levels, and body growth rate.

Cerebral cortex

The folded, creased outer surface of the cerebrum that contains specialized functional areas for processing sensory information and directing movements.

Motor cortex

The specific region of the cerebral cortex that sends out signals to control body movements.

Auditory cortex

The region of the cerebral cortex dedicated to receiving and processing auditory signals from each ear.

Sensory cortex

The region of the cerebral cortex responsible for receiving incoming sensory information from sense receptors such as those in the skin.

Visual cortex

The region of the cerebral cortex that receives and processes visual information transmitted from each eye.

Cerebral hemispheres

The two connected halves of the cerebrum; each controls the opposite side of the body and possesses specialised cognitive functions.

Left cerebral hemisphere

The hemisphere of the cerebrum that controls muscles on the right side of the body and specializes in language, speech, writing, logical thinking, reasoning, and math/science calculations.

Right cerebral hemisphere

The hemisphere of the cerebrum that controls muscles on the left side of the body and specializes in artistic ability, creativity, imagination, musical ability, recognizing shapes/colors, and visual spatial skills.

Dendrites

Special branching extensions of a nerve cell that bring incoming electrical signals and information toward the cell body.

Axons

Special long extensions of a nerve cell that carry electrical signals away from the cell body toward other cells.

Nerve impulse

A tiny electrical signal that travels in one direction along a nerve cell to communicate messages across the body.

Sensory nerve cells (Sensory neurons)

Neurons that carry impulses from sense receptors throughout the body into the central nervous system.

Motor nerve cells (Motor neurons)

Neurons that carry outgoing nerve impulses from the central nervous system to effectors such as muscles and glands.

Nerve

A cord-like bundle of nerve fibres (sensory, motor, or mixed) surrounded and protected by a layer of fatty insulation.

Sciatic nerve

The longest nerve in the human body, extending from the lower back all the way down into the foot.

Stimulus

A detectable change in the environment or sensation (such as touching a hot plate) that activates sensory receptors.

Reflex actions

Rapid, involuntary, and automatic responses that bypass conscious thinking to quickly protect the body from damage or injury.

Relay nerve cell

A specialized neuron located within the spinal cord that transmits impulses from a sensory nerve cell directly to a motor nerve cell.

Synapse

The microscopic junction between two nerve cells where impulses are transmitted across a tiny physical gap via diffusing chemicals.