Unit 7 Nervous System

Schwann cells

Schwann cells are specialized cells that myelinate the fibers of neurons found in the PNS.

Sensory Division

Sensory Division is made up of the PNS and divided into sensory, or afferent, neurons that convey information to the CNS from sensory receptors that monitor the external and internal environment.

Sensory Input

Sensory input is Information gathered by sensory receptors about internal and external changes.

Axon terminals

Axon terminals are bulb like structers at end of axon contain neuro transmitters that carry neuron message into synapse.

Axons

Axons are a part of a neuron that carries impulses away from the cell body.

Satellite cells

Satellite cells are a type of neuroglia, surround soma of neurons in ganglia of PNS. Mostly unknown function, but thought to be linked to regeneration.

Bipolar neuron

A bipolar neuron is a neuron with two processes, one axon and one dendrite.

Cerebrospinal fluid

A clear fluid the circulates around through the brain and spinal cord that helps to physically support the brain and act as a shock absorber, and that also exchanges nutrients and wastes with the brain and spinal cord.

choroid plexus

A highly vascular tissue that protrudes into the ventricles and produces cerebrospinal fluid.

limbic system

A loosely connected network of structures located roughly along the border between the cerebral cortex and deeper sub cortical areas.

Neural tube

A neural tube is formed when the neural folds meet at the midline and fuse.

medulla oblongata

A portion of the brain that is the control center of various unconscious bodily functions and via the autonomic nervous system.

Lumbar tap

A procedure in which a needle is carefully inserted into the spinal canal low in the back, or in the lumbar area, and samples of CSF are collected.

Blood-brain barrier

A specialized capillary arrangement in the brain that restricts the passage of most substances into the brain, thereby preventing dramatic fluctuations in the brain's environment.

pineal body

A structure in the brain that separates the two cerebral hemispheres. It produces the hormonelike substance melatonin that appears to influence the body like biological clock.

synapse

A synapse is a junction between two neurons or a neuron and another cell where electrical or chemical signals are relayed.

Synaptic Cleft

A synaptic cleft is a space between nerve cells where chemical transmitters act to move impulses from one neuron to the next.

Action potential

Action potential is a brief electrical impulse by which information is transmitted along the axon of a neuron.

Astrocytes

Astrocytes are star-shaped supporting cells in the CNS that are the most abundant & versitile; assists in exchanges between blood in capillaries and neurons

Cauda Equine

Cauda equine is a Collection of dangling nerve roots past the terminal end of the spinal cord.

Cerebral hemispheres

Cerebral hemispheres are the nearly symmetrical left and right halves of the cerebral cortex.

Dendrites

Dendrites are short fibers that branch out from the cell body and pick up incoming messages

Depolarization

Depolarization is the movement of an electrical charge within a cell in a more positive direction.

Neurilemma

Neurilemma is an additional sheath external to myelin that is formed by schwann cells and found only on axons in the peripheral nervous system.

Dorsal root ganglion

Dorsal root ganglion is a group of sensory neuroon cell bodies found just posterior to the spinal cord, and part of the peripheral nervous system.

Ependymal Cells

Ependymal cells are a type of neuroglial cell found in the ventricles, circulate cerebrospinal fluid

Ganglia

Ganglia are cell bodies outside the CNS that carries impulses to the involuntary muscles and glands.

Glia

Glia are supporting cells that are essential for the structural integrity of the nervous system and for the normal functioning of neurons.

Glioma

Glioma is a cancer that arises from the glial cells of the nervous system.

Gray Matter

Gray matter is the tissue within the central nervous system. It consists of unsheathed or uncovered nerve cell bodies and dendrites.

Gyri

Gyri are elevated ridges of brain tissue, separated by shallow grooves called sulci.

Neuroglia

Neuroglia are cells within both the CNS and PNS, which, although they are external to neurons, form an essential part of nerve tissue.

Neurons

Neurons are the long, thin cells of nerve tissue along which messages travel to and from the brain.

parietal lobe

Lobe at the upper middle of the cortex. Contains the somatosensory area where feeling sensations are processed.

Microglia

Microglia are very small neurons that remove waste materials and microorganisms from the central nervous system

Motor Division

Motor divisions carry signals from the CNS to gland and muscle cells that carry out the body's response.

Motor Output

Motor output is the conduction of signals from a processing center in a central nervous system to effector cells.

Multipolar Neuron

Multipolar neurons are the most common structural type of neuron, that has many dendrites and a single axon.

Myelin

Myelin is a fatty material that forms a sheathlike covering around some axons.

Myelin Sheath

Myelin sheath are insulating membrane surrounding the axon in some neurons.

cerebral aqueduct

Narrow passageway that carries cerebrospinal fluid between the third ventricle and the fourth ventricle

Nerve Impulse

Nerve impulses are message that travels from the dendrites of a neuron to the axon.

Neurotransmitter

Neurotransmitters are chemicals that are released by a neuron for the purpose of carrying information across the gaps (synapses) between neurons.

Nodes of Ranvier

Nodes of Ranvier are breaks in the myelin sheath that allow ions to flow in and out of the cell, causes the message to move down the axon.

Oligodendrocytes

Oligodendrocytes are supporting cells in the CNS that wrap their cytoplasmic extensions around the nerve fibers, producing insulating covering called myelin sheaths.

Reticular activating system

Part of brain stem involved in arousal and attention, sleep and wakefulness, and control of reflexes.

Polarized

Polarized is possessing a membrane potential or resting state.

Posterior Horns

Posterior horns are two dorsal horn projections of gray matter that form columns of gray matter that run the entire length of the spinal cord.

Receptors

Receptors are parts of the cell membrane that receive the neurotransmitter and initiate a new electric signal

Reflex arc

Reflex arc is a nerve pathway, consisting of a sensory neuron, interneuron, and motor neuron, that forms the structural and functional bases for a reflex.

Reflexes

Reflexes is an action that happens before the brain has time to think about it.

Stimuli

Stimuli is information in the environment that activates the nerves in a sense organ.

Autonomic Nervous System

The autonomic nervous system is a division of the peripheral nervous system that regulates involuntary functions; made up of sympathetic and parasympathetic nervous systems

Nervous System

The body system of nervous tissues is organized into the brain,spinal cord, and nerves, that send and receive messages and integrate the body's activities.

Central Nervous System

The central nervous system is the portion of the vertebrate nervous system consisting of the brain and spinal cord.

epithalimus

The epithalmus has the pineal gland that regulates wake and sleep cycles, which is a part of diencephalon.

fissures

The large, deep groves in the cerebral hemispheres.

brain stem

the part of the brain that controls functions including heart rate, breathing, and body temperature. It includes the midbrain, pons, and medulla oblongata.

Dura mater

The outermost of the three meninges that surround the brain and spinal cord.

Parasympathetic Nervous System

The parasympathetic nervous system is a subdivision of the autonomic nervous system that calms the body after action and also retains the body functioning at is normal state (homeostasis)

Peripheral Nervous System

The peripheral nervous system the sensory and motor neurons that connect the central nervous system to the rest of the body.

diencephalon

The portion of the brain that contains two of the most critical areas of the brain, the thalamus and the hypothalamus.

Somatic nervous system

The somatic nervous system is the division of the peripheral nervous system that controls the body's skeletal muscles.

Spinal Cord

The spinal cord is composed of nerves that run down the length of the back and transmit most messages between the body and the brain.

Sympathetic Nervous System

The sympathetic nervous system involves the division of the autonomic nervous system that is concerned primarily with preparing the body in stressful or emergency situations.

Arachnoid mater

The web-like threads between the two other meninges, which contains cerebrospinal fluid in the spaces.

Unipolar neuron

Unipoliar neuron is a neuron with one process extending from its cell body.

Ventral Horns

Ventral horns are two anterior projections of the gray matter of the spinal cord that surrounds the central canal of the cord.

Ventral root

Ventral root is a bundle of motor neuron axons that emerge from the ventral spinal cord and joins sensory fibers to form a spinal nerve. Ventral root axons carry information away from the spinal cord.

Ventricles

Ventricles are a series of interconnected cavities within the cerebral hemispheres and brainstem filled with cerebrospinal fluid.

White Matter

White matter is an areas of the nervous system rich in fat-sheathed neural axons that form the connections between brain cells.

pons

a brain structure located at the top of the brain stem that is involved in respiration, movement, and sleep.

hypothalamus

a structure found near the base of the forebrain that is involved in the regulation of basic biological needs

temporal lobe

an area on each hemisphere of the cerebral cortex near the temples that is the primary receiving area for auditory information

Brocas area

anterior speech area in the left hemisphere that functions with the motor cortex to produce the movements needed for speaking

basal nuclei

collections of neural cell bodies responsible in part for motor control, muscle relaxation -particularly important in rhythmic movements

tyramidal/icorticospinal tract

controls voluntary and skilled movement ability such as writing

cerebral peduncles

descending bundles of nerve fibers on the ventrolateral surface of the midbrain

Arachnoid villi

fingerlike projections of the arachnoid that act as valves projecting through the dura into the dural blood sinuses

Integration

integration is the process and interpretation sensory input and decide if action is needed

cerebral cortex

intricate fabric of interconnected neural cells that covers the cerebral hemispheres

pituitary gland

located at the base of the hypothalamusit is the gland that sends hormonal signals controlling the release of hormones from endocrine glands

frontal lobe

located in the front most portion of the brain, involved with motor movements, speech, and executive functions

corpora quadrigemina

nuclei scattered around white matter in midbrain; raise four domelike protrusions on the dorsal midbrain surface

mammillary bodies

pair of rounded nuclear masses located inferior to the hypothalamus which part of the limbic system. It function as a sense of smell.

occipital lobe

section of the brain located at the rear and bottom of each cerebral hemisphere containing the visual centers of the brain

sulci

shallow depressions on cortical surface of the cerebral hemisphere

lobes

shallow grooves in various regions that correspond to the major bones of the cranium

thalamus

the brain's sensory switchboard, located on top of the brainstem that directs messages to the sensory receiving areas in the cortex

Pia mater

the innermost of the layers of meninges, found in both the central and peripheral nervous systems

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Meninges

three membranes that cover the brain and spinal cord, consisting of the sura mater, pia mater, and arachnoid mater