Chapter 12 Flashcards Pt.1

12.1 - 12.2d

What are the three general functions of the nervous system?

Collect information; process and evaluate information; initiate response to information

How does the nervous system collect information?

Receptors detect stimuli and send sensory signals to the spinal cord and brain

How does the nervous system process and evaluate information?

The brain and spinal cord determine the response to sensory input

How does the nervous system initiate a response to information?

The brain and spinal cord send motor output via nerves to effectors (muscles or glands)

What makes up the CNS?

The brain and spinal cord

What makes up the PNS?

Nerves and ganglia

What is the function of the sensory (afferent) nervous system?

Receives sensory information from receptors and transmits it to the CNS

What does the somatic sensory system detect?

Stimuli we consciously perceive

What does the visceral sensory system detect?

Stimuli we typically do not perceive (e.g., signals from the heart or kidneys)

What is the function of the motor (efferent) nervous system?

Initiates motor output and transmits it from the CNS to effectors

What does the somatic motor system control?

Voluntary signals to skeletal muscles

What does the autonomic motor system control?

Involuntary commands to the heart, smooth muscle, and glands

What two divisions make up the autonomic system?

Sympathetic and parasympathetic divisions

What is a nerve?

A bundle of parallel axons in the PNS

What is the epineurium?

Dense irregular connective tissue that encloses the entire nerve

What is the perineurium?

Dense irregular connective tissue that wraps a fascicle

What is the endoneurium?

Areolar connective tissue that wraps and electrically insulates each axon

How are nerves vascularized?

Blood vessels branch through the epineurium and perineurium to become capillaries

What are cranial nerves?

Nerves that extend from the brain

What are spinal nerves?

Nerves that extend from the spinal cord

What are sensory nerves?

Nerves containing sensory neurons sending signals to the CNS

What are motor nerves?

Nerves containing motor neurons sending signals from the CNS

What are mixed nerves?

Nerves containing both sensory and motor neurons

What is a ganglion?

A cluster of neuron cell bodies in the PNS

What is excitability in neurons?

Responsiveness to a stimulus causing a change in membrane potential

What is conductivity in neurons?

Ability to propagate an electrical signal through voltage-gated channels

What is secretion in neurons?

Release of neurotransmitter in response to conductive activity

What is neuron longevity?

Neurons can live throughout a person’s lifetime

What does it mean that neurons are amitotic?

They lose the ability to divide after fetal development (in most neurons)

What is the cell body (soma)?

Structure containing the nucleus and perikaryon; receives graded potentials and sends them to the axon

What are dendrites?

Short, unmyelinated processes that receive input and transfer it to the cell body

What is an axon?

A long process that makes contact with other neurons, muscle cells, or glands

What is the axon hillock?

The triangular region where the axon attaches to the cell body

What is axoplasm?

Cytoplasm of the axon

What is the axolemma?

Plasma membrane of the axon

What are axon collaterals?

Branches of the axon

What are telodendria?

Axon terminals that branch at the end of the axon

What are synaptic knobs?

Swellings at the tips of telodendria containing neurotransmitter vesicles

What is the function of axons?

Conduct action potentials and release neurotransmitter at synaptic knobs

What are neurofilaments?

Intermediate filaments that form neurofibrils providing tensile strength

What is anterograde transport?

Movement of materials from the cell body to the synaptic knobs

What is retrograde transport?

Movement of materials from the axon to the cell body for recycling

What is fast axonal transport?

Movement along microtubules powered by motor proteins (~400 mm/day)

What moves via fast anterograde transport?

Vesicles, organelles, glycoproteins

What moves via fast retrograde transport?

Used vesicles and potentially harmful agents

What is slow axonal transport?

Flow of axoplasm (0.1

What moves by slow transport?

Enzymes, cytoskeletal components, new axoplasm

What are multipolar neurons?

Neurons with many dendrites and one axon (most common type)

What are bipolar neurons?

One dendrite and one axon; found in retina

What are unipolar neurons?

One process from the cell body that splits into peripheral and central processes

What are anaxonic neurons?

Neurons with dendrites but no axon; found in brain and retina

What are sensory (afferent) neurons?

Neurons conducting input from receptors to the CNS; mostly unipolar

What are motor (efferent) neurons?

Neurons conducting output from CNS to effectors; all multipolar

What are interneurons?

Neurons within CNS that integrate information; 99% of all neurons; multipolar

Example of the nervous system function "collecting information"

Receptors detect stimuli and send sensory signals to spinal cord and brain

Example of the nervous system function "Process and evaluate information"

Brain and spinal cord determine response to sensory input

Example of the nervous system function "initiate response to information"

Brain and spinal send motor output via nerves to effectors (muscles or glands)