AnaPhy Chapter 8: Nervous System (Fuctions of the NS - Cells of the NS)

A communication system, receiving signals from and sending commands to different areas of the body; It helps coordinate body functions to maintain homeostasis

Major functions of the Nervous system

Monitor numerous external and internal stimuli

Stimuli processed at a conscious level

Stimuli processed at a subconscious level

Major organs for processing sensory input and initiating responses

Skeletal muscles normally expand only when stimulated by the nervous system
True False

Center of mental activity, including consciousness, memory, and thinking

2 Major divisions of the Nervous system

The central nervous system (CNS) consists of the ___ and the ____.

The brain and spinal cord connect at?

Is the communication link between the CNS and the various parts of the body

2 subdivisions of the Peripheral Nervous System

Afferent (toward) division; Conducts action potentials from sensory receptors to the CNS

Neurons that transmit action potentials from the periphery to the CNS

Efferent (away) division; Conducts action potentials from the CNS to the effector organs

Neurons that transmit action potentials from the CNS toward the periphery

It is a bundle of many axons that connects the CNS to sensory receptors, muscles, and glands

How many pairs of nerves originate from the brain (Cranial nerves)?

How many pairs of nerves originate from the spinal cord (Spinal nerves)?

It is a collection of neuron cell bodies located outside the CNS

It is an extensive network of axons and, in some cases, neuron cell bodies, located outside the CNS

2 components of the Motor division

Transmits action potentials from the CNS to skeletal muscles; Voluntary movement of the Skeletal muscles

Transmits action potentials from the CNS to cardiac muscle, smooth muscle, and glands; Involuntary movement

2 divisions of the Autonomic Nervous System

A unique part of the PNS; It has both sensory and motor neurons contained wholly within the digestive tract

Receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs

3 parts of a Neuron

Contains a single nucleus

Cytoplasmic extension of the cell; Receives information from other neurons; Transmits information to the cell body

Conducts sensory signals to the CNS; motor signals away from the CNS

Area where the axon leaves the neuron cell body

Branched axons

Located primarily in the cell body and dendrites; Primary sites of protein synthesis in neurons

Site where action potentials are generated

Have many dendrites and a single axon

Has one dendrite and one axon; Located in some sensory organs such as the retina of the eye and in the nasal cavity

Have a single process extending from the cell body; Divides into two extensions where one extends to the CNS and the other extends to the periphery

Major supporting cells of the CNS & PNS; does not conduct action potentials; neuroglia

4 types of Glial cells in the CNS

Serve as the major supporting cells in the CNS; Stimulate or inhibit the signaling activity of nearby neurons; Participate in the process of forming the blood-brain barrier; help with neural tissue repair

Cells that line fluid-filled cavities within the CNS; Form structures, choroid plexuses, that secrete cerebrospinal fluid

Acts in an immune function in the CNS by removing bacteria and cell debris; Become phagocytic in response to inflammation

Provide an insulating material that surround axons; Provide myelin to neurons in the CNS

Provide an insulating material that surround axons; Provide myelin to neurons in the PNS

Cells that provide support and nutrition to the neurons and protect the neurons from heavy-metal poisons, such as lead and mercury

Protects and electrically insulates axons from one another; prevents ion movement across the cell membrane

Specialized layers that wrap around the axons of some neurons

Gaps in the Myelin Sheath

Axons that lack myelin sheaths; rest in the indentions in oligodendrocytes and schwann cells

Groups of neuron cell bodies and dendrites; very little myelin

Gray matter on the surface of the brain (CNS)

Clusters of gray matter located deeper within the brain

Bundles of parallel axons with myelin sheaths