The Nervous System: Tissues, Cells, & Molecules to Gross Anatomy

Practice flashcards covering the tissues, cells, molecules, and gross anatomy/physiology of the Nervous System based on lecture notes.

Homeostasis

The process of detecting, responding, and adapting to changes occurring inside and outside the body.

Central Nervous System (CNS)

A major division of the nervous system consisting of the brain and spinal cord.

Peripheral Nervous System (PNS)

A major division of the nervous system consisting of the spinal nerves and cranial nerves.

Neurons

Nerve cells that serve as the basic unit of function in the nervous tissue.

Glial cells (glia)

Cells that nourish and support neurons.

Cell body (Soma)

The main part of a neuron containing the nucleus and most organelles.

Dendrites

Short extensions of a neuron that receive signals and carry information toward the soma.

Axon

A single, long extension of a neuron that carries information away from the soma.

Axon terminals

The end of an axon where messages are passed to the next cell.

Motor neurons

Neurons that carry information from the CNS to an effector, such as a muscle or gland.

Sensory neurons

Neurons that take impulses from a sensory receptor to the CNS.

Interneurons

Neurons located completely within the CNS that receive information and send it to other neurons, connecting sensory and motor neurons.

Afferent Path

The sensory pathway along which information travels from sensory receptors to the CNS.

Efferent Path

The motor pathway along which information travels away from the CNS to an effector.

Sensory receptors

Special structures that detect changes in the environment known as stimuli.

Schwann cells

A type of glial cell in the PNS that electrically insulates axons with a white lipid coating.

Myelin sheath

A white lipid coating made by Schwann cells that allows nerve conduction to occur faster.

Nodes of Ranvier

Uninsulated gaps in the myelin sheath between Schwann cells.

Synapse

A specialized area where information transfer between neurons occurs via chemical signals.

Neurotransmitters

Signal chemicals, such as acetylcholine, dopamine, or serotonin, that cross the synaptic cleft to bind to receptors on the next cell.

Synaptic vesicles

Small packets in the axon terminals where neurotransmitters are stored.

Action Potential

Electrical impulses or flashes that represent the transmission of a nerve impulse within a neuron.

Somatic Nervous System

A division of the PNS involved in voluntary movement and reflexes, sending signals to skeletal muscles.

Autonomic Nervous System

A division of the PNS that regulates involuntary activity in glands, smooth muscle, and cardiac muscle.

Sympathetic Division

The "fight or flight" division of the autonomic nervous system that coordinates stress responses like increased heart rate.

Parasympathetic Division

The "rest and digest" division of the autonomic nervous system that counters stress by slowing heart rate and returning functions to normal.

Cranial Nerves

Nerves that extend from the brain; there are $12$ pairs.

Spinal Nerves

Nerves that arise from the spinal cord; there are $31$ pairs.

Reflex Arc

An automatic, predicted response that occurs quickly without conscious thought, involving a stimulus, sensory receptor, control center, interneurons, and an effector.

Gray matter

Mass of the CNS made of cell bodies and non-myelinated axons.

White matter

Mass of the CNS made of myelinated axons.

Meninges

Three layers of membranes (Dura mater, Arachnoid mater, and Pia mater) that protect the CNS.

Dura mater

The outermost, tough, thick layer of the meninges.

Arachnoid mater

The spider-like middle layer of the meninges where CSF circulates.

Pia mater

The delicate, translucent innermost layer of the meninges attached to the surface of the brain and spinal cord.

Cerebrospinal Fluid (CSF)

Fluid that cushions and protects the CNS, circulating between meninges and in the brain's ventricles.

Blood-Brain Barrier

A highly selective semipermeable border made of epithelial cells linked by tight junctions that protects the brain from circulating pathogens.

Cerebrum

The largest region of the brain, consisting of four lobes, which controls voluntary movement and higher brain functions.

Frontal Lobe

The division of the cerebrum responsible for voluntary movement, thinking, and language.

Parietal Lobe

The division of the cerebrum responsible for touch, pain, and the relation of body parts.

Temporal Lobe

The division of the cerebrum responsible for hearing.

Occipital Lobe

The division of the cerebrum responsible for vision.

Diencephalon

A major brain region containing the Thalamus, Hypothalamus, and Pineal gland.

Thalamus

A relay station in the diencephalon that receives sensory input and sends it to the cerebral cortex.

Hypothalamus

Part of the diencephalon that maintains homeostasis (thirst, hunger, temperature) and controls the pituitary gland.

Pineal gland

An organ in the diencephalon that secretes melatonin to control daily rhythms.

Cerebellum

The brain region located under the occipital lobe that maintains posture, balance, and coordination.

Arbor vitae

The tree-like pattern of white matter seen in a cross-section of the cerebellum.

Brainstem

The brain region comprised of the Midbrain, Pons, and Medulla oblongata that maintains breathing and heart rate.

Medulla oblongata

A structure in the brainstem that merges with the spinal cord.