A&P 1 Ch. 11 Functional Organization of Nervous System
What does the motor (efferent) do?
transmits action potentials from CNS to effectors (muscles, glands). Movement of skeletal muscle in response from CNS to PNS.
What does the sensory (afferent) do?
transmits action potentials from receptors to CNS. Example: Hot burner, Bear. signal gets sent from PNS to CNS.
What are the parts of a neuron?
*Cell body or Soma *Dendrites: input *Axons: output
Identify the functions of the nervous system.
*Controlling muscles and glands *Integrating Information *Receiving sensory input
What are the functions of the Nervous System?
*Maintaining homeostasis *Receiving sensory input *Integrating information *Controlling muscles and glands *Establishing and maintaining mental activity
A single dendrite extends from the soma. Examples of these are found in the retina and nasal cavity.
Bipolar Neuron
a nerve cell that has a single dendrite at one end and a single axon at the other end
Bipolar Neuron
What does the somatic nervous system control?
From CNS to skeletal muscles. Voluntary.
Groups of related nerve cell bodies located outside of the central nervous system are called ______________.
Ganglia
What does the sympathetic nervous system do?
It is responsible for a release of glucose from the liver, increased heart rate, increased blood pressure, increased respiration, and decreased genitourinary action. Prepares body for Physical activity. Fight or Flight response.
What are the divisions of the PNS?
Sensory (afferent) division Motor (efferent) division
What are the divisions of the autonomic nervous system?
Sympathetic Parasympathetic Enteric
Myelinated axons Unmyelinated axons
Types of Axons (Nerve Fibers)
ANS
______________ pathways typically consist of two neurons, with their cell bodies (somas) located in the CNS and PNS, respectively.
What is a trigger zone?
junction between the axon hillock and the initial segment where action potentials are generated
What does the enteric nervous system do?
Plexuses within the wall of the digestive tract. Everything in gut or digestive system.
Which part of a neuron releases neurotransmitters?
presynaptic terminals
A neuron with one axon and no dendrites. single process that divides into two branches.
unipolar neuron
What are the cells of the nervous system?
neurons and glial cells
Idenytify the two functional sub-divisions of the peripheral nervous system.
sensory and motor
The neurons that conduct information towards the CNS are?
sensory neurons
What are the Motor Divisions of PNS?
somatic nervous system and autonomic nervous system
The central nervous system includes the?
spinal cord
Collaterals are?
branches of axon
True or False? Action potentials travel faster on thin, myelinated axons?
False
Place the following structures in the order that an electrical impulse would travel beginning with the postsynaptic membrane. soma presynaptic terminals axon hillock axon dendrite
1. Dendrite 2. Soma 3. Axon hillock 4. Axon 5. Presynaptic terminals
Unipolar neuron
A short process emerges from the cell body and branches like a T. One branch of each of these cells is in the CNS and the other in the PNS.
What does the PNS consist of?
All the nerves that transmit information to and from the CNS. Sensory receptors and nerves.
Nodes of Ranvier
Along myelinated axons of the peripheral nervous system, Ion currents must cross the plasma membrane of the neuron.
The conical region of a neuron's axon where it joins the cell body; typically the region where nerve signals is generated.
Axon hillock
a part of a neuron that carries impulses away from the cell body. Also can branch to form collaterals.
Axons
Contains most of a neuron's organelles and its nucleus.
Cell Body
a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body
Dendrites
What is a Unmyelinated axons?
Do not have myelin surrounding the axon.
What does the autonomic nervous system control?
Exocrine glands, cardiac muscle, smooth muscle, and endocrine glands. Involuntary control. From CNS to the body except for skeletal muscles.
What do neurons do?
Generate & transmit the nerve impulse
threshold
In order for local potentials to trigger an action potential, the membrane must reach a level called the ___________.
sensory
In the PNS, the ______ division transmits action potentials from the sensory receptors to the CNS.
short section of nerve fiber between the axon hillock and the first glial cell
Initial segment
What does the parasympathetic nervous system do?
It creates a reverse response of the sympathetic nervous system to help slow the body down. Regulates resting or vegetative functions such as digesting food or emptying of the urinary bladder. During REST.
A neuron with a single axon and multiple dendrites; the most common type of neuron in the nervous system.
Multipolar Neuron
Many dendrites extend from the soma. Most motor neurons are of this type?
Multipolar neuron
structural classification of neurons
Multipolar neurons Bipolar neurons Unipolar neurons
The ________________ system does all of the following. * monitors internal and external stimuli * transmits information in the form of action potentials. *interprets or assesses information. * maintains homeostasis.
Nervous
the end points of an axon where the release of chemicals to communicate with other neurons occurs.
Presynaptic terminals
What is a myelinated axon?
Protects and insulates axons from one another, speeds transmission (type of axon that moves an action potential faster), functions in repair of axons. *Nodes of Ranvier
The peripheral nervous system includes the?
cranial nerves
motor
The _______ division of the PNS is divided into the somatic nervous system and the autonomic nervous system.
PNS
The ____________ has two functional subdivisions, the sensory division and the motor division.
somatic autonomic
The _____________ nervous system communicates with the skeletal muscles and the _______________ nervous system communicates with the smooth and cardiac muscle as well as glands.
Peripheral organs to the CNS.
The afferent or sensory divison transmits impulses from _________________.
subconscious
The autonomic nervous system controls ____________________ activities.
somatic
The cell bodies of ___________ motor neurons are located in the CNS and their axons connect with skeletal muscle cells.
autonomic somatic
The division of the nervous system that transmits electrical impulses towards cardiac muscle, smooth muscle and glands is the ___________ nervous system; while the division of the nervous system that transmits electrical impulses towards skeletal muscle is the ____________ nervous system.
afferent efferent
The division of the peripheral nervous system that transmits electrical impulses from sensory receptiors to the CNS is the ___________ while the _____________ division of the peripheral nervous system transmits electrical impulses from the CNS toward muscles and glands.
ganglia
The dorsal root ______________ are located near the spinal cord and contain cell bodies of sensory neurons.
the CNS out to the peripheral organs
The efferent or motor divison transmits impulses from ______________________.
skeletal autonomic smooth
The motor division is divided further into a somatic motor division serving ____________ muscle and a(n) _____________ motor division serving _____________ muscle, cardiac muscle, and glands.
central, brain, peripheral
The nervous system is divided into the ________________ nervous system which includes the _______ and spinal cord, and the _________ nervous system which includes cranial nerves, spinal nerves, and ganglia.
Motor
The peripheral nervous system is further subdivided into an afferent (sensory) division and an efferent ___________ division.
conscious
The somatic nervous system directs ____________________ activities.
What does the CNS consist of?
brain and spinal cord
What are the divisions of the Nervous System?
central nervous system and peripheral nervous system
What do the Glial cells do?
support and protect neurons