"The nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body."
The study of the brain, spinal cord, and nerves, and their role in controlling bodily functions and sensation.
Neurons: Cells that transmit electrical and chemical signals between the brain, spinal cord, and peripheral nerves.
Glial cells: Cells that provide support and protection to neurons.
Central Nervous System (CNS): The brain and spinal cord.
Peripheral Nervous System (PNS): Nerves outside the CNS that connect the CNS to other parts of the body.
Spinal cord: The long, tubular structure that extends from the brain and contains the cord of nerve tissue that conducts nerve impulses to and from the brain.
Brainstem: The lowest part of the brain, consisting of the medulla oblongata, the pons, and the midbrain, and responsible for controlling various vital functions such as heart rate, breathing, and blood pressure.
Cerebellum: The part of the brain that controls movement and coordination.
Cerebrum: The largest part of the brain and responsible for thought, memory, and processing sensory information.
Lobes of the brain: The four main sections of the cerebrum: frontal, parietal, temporal, and occipital.
Cranial nerves: Nerves that originate in the brainstem and exit through openings in the skull to control various functions such as vision, hearing, and facial expression.
Autonomic Nervous System: The part of the nervous system that controls involuntary bodily functions such as heart rate, breathing, and digestion.
Sympathetic Nervous System: The part of the autonomic nervous system responsible for the "fight or flight" response in stressful or dangerous situations.
Parasympathetic Nervous System: The part of the autonomic nervous system responsible for "rest and digest" functions.
Neurotransmitters: Chemicals released by neurons to transmit signals to other cells.
Receptors: Proteins on the surface of cells that receive signals from neurotransmitters.
Synapse: The junction between two neurons where neurotransmitters are released and signals are transmitted.
Action potential: The electrical signal that travels along a neuron.
Myelin: The fatty substance that covers some axons and speeds up the transmission of signals.
Neural circuits: Groups of neurons that work together to perform specific functions.
Plasticity: The ability of the nervous system to adapt and change in response to experience or injury.
Central Nervous System (CNS): It is the major coordinating center of the body and includes the brain and spinal cord.
Peripheral Nervous System (PNS): This system includes all the nerves outside the CNS and connects the CNS to the rest of the body.
Autonomic Nervous System (ANS): It regulates involuntary activities of the body, such as heartbeat, breathing, and digestion. ANS further divides into two subtypes, the sympathetic nervous system and parasympathetic nervous system.
Enteric Nervous System (ENS): This is also known as the second brain, found in the gastrointestinal tract. It regulates activities such as digestion, nutrient absorption, and gut motility.
Somatic Nervous System (SON): This system is responsible for voluntary activities of the body, such as movement of limbs, sensory perception, and reflex action.
Cranial Nervous System: These are twelve pairs of nerves that originate from the brain and help in vital activities such as vision, hearing, taste, smell, and movement of facial muscles.
Spinal Nervous System: These are thirty-one pairs of nerves that originate from the spinal cord and connect the body to the CNS.
"Nervous tissue first arose in wormlike organisms about 550 to 600 million years ago."
"The vertebrate nervous system consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS)."
"The central nervous system (CNS) consists of the brain and spinal cord."
"The peripheral nervous system (PNS) consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body."
"Nerves that transmit signals from the brain are called motor nerves or efferent nerves."
"The PNS is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems."
"The sympathetic nervous system is activated in cases of emergencies to mobilize energy."
"The parasympathetic nervous system is activated when organisms are in a relaxed state."
"The enteric nervous system functions to control the gastrointestinal system."
"At the cellular level, the nervous system is defined by the presence of a special type of cell, called the neuron."
"Neurons send these signals in the form of electrochemical impulses traveling along thin fibers called axons."
"The connections between neurons can form neural pathways, neural circuits, and larger networks that generate an organism's perception of the world and determine its behavior."
"Along with neurons, the nervous system contains other specialized cells called glial cells (or simply glia), which provide structural and metabolic support."
"The only multicellular animals that have no nervous system at all are sponges, placozoans, and mesozoans."
"The medical specialty of neurology studies disorders of the nervous system and looks for interventions that can prevent or treat them."
"In the peripheral nervous system, the most common problem is the failure of nerve conduction."
"Demyelinating disorders such as multiple sclerosis and amyotrophic lateral sclerosis."
"Neuroscience is the field of science that focuses on the study of the nervous system."
"The size of the nervous system ranges from a few hundred cells in the simplest worms, to around 300 billion cells in African elephants."