Chapter 12

To detect and respond to external or internal changes in the body, voluntarily or involuntarily.

Sensory input, integration, and motor output.

The detection of stimuli by sensory receptors.

The processing and interpretation of incoming signals.

The transmission of signals that produce a response.

The central nervous system (CNS) and the peripheral nervous system (PNS).

The brain and spinal cord.

To receive, interpret, and integrate signals and coordinate responses.

To carry sensory information to the CNS and motor commands from the CNS to effectors.

Cranial nerves and spinal nerves.

PNS → CNS → PNS.

The division of the nervous system that carries sensory information toward the CNS.

Carrying signals toward the CNS.

The division that carries motor commands from the CNS to effectors.

Carrying signals away from the CNS toward the periphery.

A neuron located exclusively in the CNS that receives, integrates, and relays information between sensory and motor neurons.

The afferent division carries information to the CNS, the CNS integrates the signal, and the efferent division carries the response to effectors.

From the brain; many are associated with the brainstem.

Related to the external body, including the skin, skeletal muscles, and bones.

Related to internal organs, such as digestive organs, the bladder, heart, and lungs.

The sympathetic and parasympathetic divisions.

To regulate involuntary functions of internal organs and structures.

Fight or flight.

Rest and digest.

Information from inside the body or the external environment.

Through afferent, or sensory, nerves.

Relay it to the brain or integrate it locally to produce a spinal reflex.

To process and integrate sensory information and determine how to respond.

Through the spinal cord and peripheral nerves, or through cranial nerves.

Muscles, organs, or glands that carry out a response.

A receptor that detects stimuli from outside the body.

Touch, pressure, pain, temperature, smell, hearing, taste, and vision.

A receptor that detects stimuli originating from internal organs and viscera.

Chemical changes, tissue stretching, and changes such as blood pressure.

A receptor that detects stretching in muscles, joints, tendons, and ligaments.

Information about body position and movement.

The location of the receptor and the type of stimulus it detects.

Receptors that detect mechanical forces, such as touch, pressure, stretching, and vibration.

Changes in pressure, especially blood pressure.

Mechanoreceptors.

Changes in temperature.

Chemical changes, such as changes in blood composition.

Light.

Stimuli associated with pain.

Free nerve endings, encapsulated nerve endings, and specialized receptor cells.

Unencapsulated dendritic endings that mainly detect pain and temperature, while some detect light touch.

In epithelia and the underlying connective tissue.

Pain and temperature; some also detect light touch.

Dendritic endings surrounded by connective tissue that receive sensory stimuli.

It modifies sensitivity to stimuli and helps filter mechanical signals.

Light touch.

In the papillary dermis.

Pressure, especially deep pressure and vibration.

In the reticular dermis and deeper tissues.

Stretching.

In joint capsules and the dermis.

Cells with specialized structures that detect specific stimuli.

Photoreceptors, including rods and cones.

Changes in the chemical composition of blood.

To the cardiorespiratory centers in the medulla oblongata.

Decreased pH and oxygen levels, and increased carbon dioxide levels.

An increase in breathing rate.

By combining its functional classification with its structural classification.

As an exteroceptor, a thermoreceptor, and a free nerve ending.

As interoceptors, chemoreceptors, and specialized receptor cells.

As proprioceptors and mechanoreceptors; many are encapsulated nerve endings.

As specialized photoreceptor cells and exteroceptors.

Neurons and neuroglia.

They are excitable cells that generate and transmit nerve signals.

An electrical signal that propagates along a neuron's membrane.

A group of non-neuronal support cells that help protect, support, and insulate nervous tissue.

About 86 billion.

They have high glucose and oxygen requirements.

No, mature neurons generally do not divide.

The cell body of the neuron.

To receive signals and conduct them toward the cell body.

The region where the axon originates from the cell body and where an action potential usually begins.

The endings of an axon that transmit signals to other cells.

Neurotransmitters.

Clusters of rough endoplasmic reticulum involved in protein synthesis.

To wrap around PNS axons and form myelin sheaths around many of them.

Gaps in the myelin sheath between adjacent myelinated segments.

They allow saltatory conduction, in which the action potential is regenerated from node to node.

Glial cells in the CNS that form myelin sheaths around axons.

Dendrites → cell body → axon → axon terminals → target cell.

According to the number of processes extending from the cell body.

According to the direction and function of their nerve impulses.

Unipolar or pseudounipolar.

Multipolar.

Multipolar.

Multipolar, bipolar, and unipolar.

The site where a nerve signal is transmitted between a neuron and another cell.

Between two neurons or between a neuron and a muscle or gland cell.

The cell that transmits the signal toward the synapse.

The cell that receives the signal across the synapse.

Support, protection, insulation of nerve fibers, and maintenance of the neuronal environment.

Astrocytes, microglia, ependymal cells, and oligodendrocytes.

Satellite cells and Schwann cells.

The most abundant glial cells in the CNS, with processes that contact neurons and capillaries.

They help maintain the barrier that restricts the movement of many substances from the blood into brain tissue.

A selective barrier that limits the passage of substances from the blood into brain tissue.

Water, glucose, ions, and amino acids can cross through selective mechanisms.

They regulate neurotransmitters and extracellular ions, help regulate blood flow, and respond to tissue damage.

Resident immune cells of the CNS that perform phagocytosis and defense.

To remove cellular debris and harmful agents through phagocytosis.

Cells that line the brain's ventricles and the central canal of the spinal cord.

They participate in cerebrospinal fluid production and circulation and form a lining between the fluid and nervous tissue.

Glial cells in the CNS that wrap around axons and form myelin.

They surround neuronal cell bodies in the PNS and regulate their local environment.

They surround axons and form myelin around many of them.

A lipid- and protein-rich covering that electrically insulates certain axons.

It reduces current leakage and increases the speed of nerve impulse conduction.

A bundle of axons located in the PNS.

A bundle of axons traveling together within the CNS.

A ganglion; plural, ganglia.

A nucleus; plural, nuclei.

CNS tracts that carry information toward higher regions, such as the brain.

CNS tracts that carry signals from the brain toward lower regions, such as the spinal cord.

A region consisting mainly of axons, many of which are myelinated, and neuroglia.

Nerve tracts.

A region containing mainly neuronal cell bodies, dendrites, synapses, and neuroglia, along with unmyelinated axons.

Neuronal nuclei, among other structures.

In the gray matter.

The processing of nervous system information that allows sensory input to be converted into motor output.

A rapid, automatic motor response to a sensory stimulus.

The neural circuit that produces a reflex response.

In the spinal cord, without waiting for the brain to process the signal.

A reflex whose basic circuit contains one synapse and no interneurons.

The patellar reflex, or knee-jerk stretch reflex.

A reflex that contains two or more synapses and one or more interneurons.

The withdrawal reflex that moves the hand away from a hot object.

The processing of information through a sequence of steps.

The simultaneous processing of information by different neural pathways.

A withdrawal reflex is activated, allowing the hand to move away quickly.

An ascending tract, such as the spinothalamic tract.

It integrates sensory information and can generate motor commands to modify the response.

Signals travel down motor tracts and activate efferent neurons that stimulate muscles.

A reflex can be integrated rapidly in the spinal cord, while a conscious response requires processing in the brain