Nervous System Flashcards

Comprehensive vocabulary flashcards covering the structure, function, and divisions of the nervous system, including brain anatomy, neural transmission, and reflex types.

Coordination

The working together of the various parts of the organism to produce a proper reaction to a stimulus.

Nervous coordination

A form of coordination where information flows in the form of nerve impulses, allowing for fast flow of information and rapid, short-lived responses.

Hormonal coordination

A form of coordination where information flow is by chemicals, resulting in slower flow of information and more prolonged, involuntary responses.

Fibrils

A system in the Paramecium that coordinates its movement.

Nerve net

A diffuse network of nerves around the body used for coordination in organisms like Hydra.

Central nervous system (CNS)

Part of the vertebrate nervous system divided into the brain and spinal cord; it collects, stores, and processes information.

Peripheral nervous system (PNS)

Part of the vertebrate nervous system divided into the somatic nervous system and the autonomic nervous system.

MENINGES

Three membranes called Dura, Arachnoid, and Pia mater that cover both the brain and the spinal cord.

Cerebrospinal fluid

A fluid found between the arachnoid and pia mater that flows through the central canal of the spinal cord and four ventricles of the brain.

Cranium

The bony structure that protects the brain, which weighs about $1.4\,kg$ in adults.

Grey matter

The outer part of the brain formed when the cell bodies of neurons are packed together.

White matter

The inner part of the brain formed when axons are packed together.

Fore brain

A division of the brain consisting of the olfactory lobe, cerebrum, thalamus, and hypothalamus.

Mid brain

The smallest portion of the brain, consisting of the optic lobe and pineal body.

Hind brain

A division of the brain consisting of the cerebellum, pons, and medulla oblongata.

Olfactory lobes/bulbs

Structures located at the base of the brain responsible for the function of smell.

CORPUS CALLOSUM

The structure that separates the two cerebral hemispheres and transfers information between them.

GYRI

The folds found on the convoluted surface of the cerebrum.

SULCI

The grooves found on the convoluted surface of the cerebrum.

Occipital lobe

The lobe at the back of the cerebrum responsible for visual processing and color recognition.

Temporal lobe

The lobe at the side of the cerebrum responsible for auditory processing, memory, and language comprehension.

Parietal lobe

The lobe on top of the cerebrum responsible for sensory integration, spatial awareness, and mathematical processing.

Frontal lobe

The lobe in front of the cerebrum responsible for executive functions, motor control, and language production.

Thalamus

Two ovoid structures that serve as a relay station for sensory information from sense organs to the cerebral cortex.

Hypothalamus

A small, cone-shaped structure that plays a role in homeostasis, regulates the autonomic system, and controls thirst and hunger.

MELATONIN

A hormone produced by the pineal body to control circadian rhythms.

Cerebellum

Also called the 'little brain,' it coordinates movements and controls posture, balance, and fine motor movement.

Pons

A broad band of fibres in the brainstem that connects the cerebrum to the hindbrain and relays messages between the cerebrum and cerebellum.

Medulla oblongata

The triangular-shaped lower part of the brainstem that controls involuntary actions like vomiting, coughing, and heartbeat.

Dorsal roots

Parts of the spinal cord that carry the afferent nerves.

Ventral roots

Parts of the spinal cord that carry the efferent nerves.

Somatic nervous system (SNS)

Part of the PNS made up of $12$ pairs of cranial nerves and $31$ pairs of spinal nerves, responsible for voluntary actions.

Autonomic nervous system

Part of the PNS divided into the sympathetic and parasympathetic systems which are antagonistic to each other.

Sympathetic nervous system

The system that governs the 'flight or fight' response and prepares the body for violent actions.

Parasympathetic system

The system responsible for 'rest and digest' stimulation when the body is at rest.

Neurons

Specialized cells that serve as the functional unit of the nervous system.

Axon

A long fibre that arises from the cell body of a neuron.

Dendrites

Small extensions on the cell body or dendrons of a neuron.

Myelin sheath

A fatty layer that surrounds some axons, produced by Schwann cells.

Nodes of Ranvier

Regular constrictions found on myelin sheaths.

Nissl’s granules

Sites of protein synthesis found on neurons.

Synaptic knobs

Structures on neurons that release neurotransmitters.

Motor neurons

Neurons with short dendrites and long axons that carry impulses from the CNS to effectors.

Sensory neurons

Neurons with long dendrites and short axons that carry impulses from sense organs to the CNS.

Resting potential

The state when an axon is not transmitting impulses, where the outside is positively charged and the inside is negatively charged.

Action potential

A state created when a stimulus flow reaches about $50\,mV$, making the inside of the axon positively charged and the outside negatively charged.

Depolarization

The phase where sodium channels open, allowing sodium ions to move inside the axon, making the inside more positive than the outside.

Repolarization

The phase where potassium channels open and sodium channels close, restoring the polarity of the axon.

Synapse

The small space between the dendrites of two axons where impulses are transmitted chemically.

Reflex action

A rapid, unlearned, and mainly protective response to a stimulus controlled by the spinal cord and medulla.

Voluntary actions

Conscious actions initiated by the brain that are under the control of our will, such as walking or talking.

Conditioned reflex

Learned behaviours, such as writing or knitting, that can be performed as if they are reflexes.