General Structure of the Human Nervous System

A comprehensive set of vocabulary flashcards covering the anatomy, protection, and embryonic development of the human nervous system as detailed in the Psychobiology lecture.

Spinal cord

A long bundle of nerve tissue extending from the base of the brain running inside the spinal column; it transmits nerve signals between the brain and body for movement, sensation, and automatic functions.

Peripheral Nervous System (PNS)

The communication relay system connecting the central nervous system to the limbs, organs, and glands; it carries vital information back and forth to enable bodily functions.

Somatic System

A division of the nervous system providing voluntary control or skeletal movement, including involuntary reflexes like jerking a hand back from a hot pan.

Autonomic Nervous System

The system responsible for involuntary and unconscious reactions of the inside of the body, such as heart rate, often coordinating responses during exercise or stress.

Sympathetic division

A division of the autonomic system associated with danger that spends stored energy to increase adrenaline secretion and heart rate.

Parasympathetic division

A division of the autonomic system associated with rest that functions to increase stored energy.

Preganglionic neuron

The first neuron in the effector pathway, found in the brain's grey matter of the spinal cord, consisting of a myelinated axon.

Postganglionic neuron

The second neuron in the effector pathway that goes from the autonomic ganglion to the effector organ; it consists of an unmyelinated axon.

Telencephalon

A primary division of the embryonic brain that develops into the adult cerebral hemispheres.

Diencephalon

A primary division of the embryonic brain that forms the thalamus, hypothalamus, epithalamus, and subthalamus.

Mesencephalon

A primary division of the embryonic brain that develops into the midbrain.

Metencephalon

A division of the embryonic brain that forms the pons and cerebellum.

Myelencephalon

A division of the embryonic brain that becomes the medulla oblongata.

Neuroaxis

An imaginary line that runs through the CNS from the lower end of the spinal cord to the front of the brain.

Vertebral Column Structure

The spine consists of $7$ cervical ($C$), $12$ thoracic ($T$), $5$ lumbar ($L$), the Sacrum, and the Coccyx.

Meninges

Three layers of connective tissue (dura mater, arachnoid, and pia mater) that protect the CNS and prevent direct contact with bone.

Dura mater

The tough, resistant, non-flexible external layer of the meninges composed of periosteal and meningeal layers.

Superior sagittal sinus

An intracranial venous structure that splits the periosteal and meningeal parts of the dura mater.

Arachnoid

The middle, soft, and spongy membrane layer of the meninges that has an appearance similar to a spider's web.

Subarachnoid space

The space between the arachnoid and the pia mater that is filled with cerebrospinal fluid ($CSF$).

SLYM

A barrier found in the subarachnoid space that controls the flow and quality of the cerebrospinal fluid ($CSF$).

Pia mater

The most internal, highly vascularized layer of the meninges that is attached directly to the brain and spinal cord.

PNS Nerve Coverings

The three layers covering the peripheral nerves derived from the transformation of the dura and pia mater: Epineurium, perineurium, and endoneurium.

Ventricular System

A set of interconnected cavities in the brain responsible for Producing cerebrospinal fluid ($CSF$) from the choroid plexus.

Cerebrospinal Fluid (CSF)

A fluid used for protection, nutrient transport, and blood pressure modulation that is replaced $6$ times a day and eliminated in arachnoid granulations.

Foramen of Monro

Also known as the interventricular foramen, it connects the $1st$ and $2nd$ (lateral) ventricles.

Cerebral aqueduct

The structure that connects the $3rd$ ventricle (located in the diencephalon) with the $4th$ ventricle.

Magendie and Luschka foramens

Openings in the $4th$ ventricle that guide $CSF$ to the subarachnoid space outside the brain and spinal cord.

Hydrocephalus

An increase in $CSF$ pressure leading to ventricle enlargement, caused by space-occupying lesions, excessive production, or poor absorption.

Blood-Brain Barrier (BBB)

A protective filtering system that controls substance entry into the CNS, maintains chemical stability, and provides protection against infections.

Circle of Willis

An arterial ring connecting blood supply from the internal carotid arteries, vertebral-basilar system, and medial circulation.

Gastrulation

The process during the $2nd$ or $3rd$ week where the epiblast invaginates to form three primary layers: ectoderm, mesoderm, and endoderm.

Ectoderm

The primary embryonic layer that gives rise to the skin and the nervous system.

Mesoderm

The primary embryonic layer that gives rise to skeletal, muscle, and connective tissues.

Endoderm

The primary embryonic layer that gives rise to the digestive, respiratory, and genitourinary tracts.

Neurulation

The process in the $3rd$ or $4th$ week where the neuroectoderm thickens to form the neural plate, which then closes to form the neural tube and crest.

Neural tube

The embryonic structure formed during neurulation that will eventually become the central nervous system (CNS).

Neural crest

The edges of the neural folds that will eventually become the peripheral nervous system (PNS).

Somite

Blocks of mesodermal tissue that give rise to body structures.

Neuropore Defects

Failure of the anterior neuropore to close causes anencephaly or encephalocele; failure of the posterior neuropore causes myeloschisis (spina bifida).

Alar plate

The part of the neural tube that forms the posterior horn of the spinal cord, responsible for sensory functions.

Basal plate

The part of the neural tube that forms the anterior horn of the spinal cord, responsible for motor functions.

Intermediate zone

The part of the neural tube that forms the lateral horn of the spinal cord, responsible for vegetative functions of the ANS.

Primary Brain Vesicles

The initial three structures created from the neural tube: Prosencephalon, Mesencephalon, and Rhombencephalon.