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5. Nervous System Functional Organization
N/A
100
Physiology
Undergraduate 2
09/20/2012

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Term
What are neurons?
Definition
electrically excitable cells in the nervous system
Term
What are glial cells?
Definition
non-neuronal cells that prvide support and nutrition; they form myelin in the nervous system
Term
What is ganglion?
Definition
a group or cluster of nerve cell bodies
Term
What is a cranium?
Definition
the skull of a vertebrae
Term
What is the thorax?
Definition
the trunk between the neck and the abdomen (chest)
Term
What is the viscera?
Definition
the organs in the cavity of the body, especially in the abdominal cavity
Term
What is the spine?
Definition
backbone
Term
What is the lumbar region?
Definition
it is the region between the ribs and the hipbones
Term
What is the sacrum?
Definition
the bone at the base of the spine
Term
The central nervous system consists of the _______ and _________.
Definition
brain, spinal cord
Term
The peripheral nervous system is made up of the ________ division and the _________ division.
Definition
afferent, efferent
Term
What does the afferent division of the peripheral nervous system do?
Definition
it carries information from the sensors to the CNS
Term
What does the efferent division of the peripheral nervous system do?
Definition
it transmits instructions from the CNS to the effector organs
Term
What are the other two nervous systems that are part of the peripheral nervous system? Are these systems afferent or efferent?
Definition
somatic and autonomic nervous systems; efferent
Term
Which nervous system of the peripheral nervous system is voluntary and which one is involuntary?
Definition
the somatic is volunatary and the autonomic is involuntary
Term
What consists the somatic nervous system?
Definition
it consist of the fibers of the motor neurons that supply the skeletal muslces
Term
What consists of the autonomic nervous system?
Definition
smooth muscle and cardiac muscle
Term
How many neurons make up a single pathway in the somatic nervous system?
Definition
one
Term
How many neurons make up a single pathway in the autonomic nervous system?
Definition
two
Term
The ________ nervous system in analogous to the gas pedal in a car while the _________ nervous system is analogous to the brake pedal in a car.
Definition
sympathetic, parasympathetic
Term
What are the three types of effector organs?
Definition
skeletal muscle, smooth muscle, and cardiac muscle
Term
What are effector organs made up of?
Definition
muscle and gland tissue
Term
What are the three classes of neurons?
Definition
efferent, afferent, and interneurons
Term
How does an afferent neuron function?
Definition
it has a sensory receptor that generates action potentials in response to particular stimuli
Term
How does an efferent neuron function?
Definition
it has cell bodies that originate in the CNS which leave to the muscles and glands
Term
What are interneurons?
Definition
they are integrator neurons that make up the majority of neurons in the CNS
Term
How are interneurons related to afferent and efferent neurons?
Definition
interneurons lie between them and integrate them
Term
What are interneurons responsible for?
Definition
mind: learning, memory, creativity, intellect, and motivation
Term
The sympathetic and parasympathetic nervous systems innervate most _____________.
Definition
visceral organs
Term
What region of the CNS do sympathetic neurons originate from?
Definition
thoracic and lumbar
Term
What region of the CNS do parasympathetic neurons originate from?
Definition
cranial and sacral
Term
How many neurons does a single sympathetic or parasympathetic neural pathway have?
Definition
two
Term
The sympathetic neural pathway has a (shorter/longer) first neuron and a (short/longer) second neuron.
Definition
shorter, longer
Term
The parasympathetic neural pathway has a (shorter/longer) first neuron and a (shorter/longer) second neuron.
Definition
longer, shorter
Term
What do the sympathetic and parasympathetic nervous systems do to the heart?
Definition

S: increased force and rate of contraction

P: decreased force and rate of contraction

Term
What do the sympathetic and parasympathetic nervous systems do to the blood vessels?
Definition

S: constriction

P: dialation

Term
What do the sympathetic and parasympathetic nervous systems do to the lungs?
Definition

S:dialation of bronchioles

P: constriction of bronchioles

Term
What do the sympathetic and parasympathetic nervous systems do to the digestive system?
Definition

S: decresed motility, constriction of sphincters, and inhibition of digestive secretions

P: increased motility, relaxation of sphincters, and stimulation of digestive secretions

Term
What do the sympathetic and parasympathetic nervous systems do to the urinary bladder?
Definition

S: relaxation

P: contraction

Term
What do the sympathetic and parasympathetic nervous systems do to the eye?
Definition

S: dialation of the pupil

P: constriction of the pupil

Term
What do the sympathetic and parasympathetic nervous systems do to the liver?
Definition

S: glycogenolysis

P: none

Term
What do the sympathetic and parasympathetic nervous systems do to the adispose tissue?
Definition

S: lipolysis

P: none

Term
What do the sympathetic and parasympathetic nervous systems do to the sweat glands?
Definition

S: stimulation of secretion of most sweat glands

P: stimulation of secretion of some sweat glands

 

Term
What do the sympathetic and parasympathetic nervous systems do to the brain?
Definition

S: increased alertness

P: none

Term
The sympathetic nervous system dominates in times of ____________.
Definition
fight or flight
Term
The parasympathetic nervous system dominates in times of ____________.
Definition
rest and digest
Term
What is dual innervation?
Definition
the fact that each organ is innervated by both the sympathetic and parasympathetic nervous system
Term
What is the purpose of dual innervation?
Definition
it gives precise antagonistic control
Term
Because of dual innervation, autonimic neural pathways consist of a ___________.
Definition
two neuron chain
Term
Sympathetic preganglionic nerves synapse in paired _______ adjacent to the __________.
Definition
ganglia, spinal cord
Term
What endocrine gland is functionally a part of the sympathetic nervous system? 
Definition
the adrenal medulla
Term
Parasympathetic preganglionic nerves synapse on ______ on or near the innervated ________.
Definition
ganglia, organ
Term
What neurotransmitter do sympathetic preganglionic nerves secrete? Postganglionic?
Definition
acetylcholine, norepinephrine
Term
What neurotransmitter do parasympathetic preganglion fibers secrete? Postganglion?
Definition
acetylcholine, acetylcholine
Term
Does the adrenal medulla have preganglionic and postganglionic fibers?
Definition
it has no postganglionic fiber but it does have preganglionic fibers
Term
What nervous system is the adrenal medulla part of?
Definition
sympathetic nervous system
Term
How does the adrenal medulla work as far as secreting its products?
Definition
it secretes hormone directly into the blood in respose to the preganglionic fiber
Term
What hormones/neurotransmitters does the adrenal medulla secrete?
Definition
norepinephrine and epinephrine
Term
What are the two main types of receptors available for autonomic neurotransmitters?
Definition
cholinergic (for acetylcholine) and adrenergic (for epinephrine and norepinephrine)
Term
What are the two types of cholinergic recetors?
Definition
nicotinic and muscarinic
Term
Where are nicotinic receptors found?
Definition
on the postganglionic cell bodies in all autonomic ganglia
Term
Where are muscarinic receptors found?
Definition
on effector cell membranes (smooth muscle, cardiac muscle, and glands)
Term
All adrnergic receptors are coupled to ___________.
Definition
G proteins
Term
What are the two major classes of adrenergic receptors?
Definition
alpha and beta receptors
Term
What are five sites where acetylcholine is released?
Definition
  • all preganglionic terminals of the autonomic nervous system
  • all parasympathetic postganglion terminals
  • sympathetic postganglionic terminals at some sweat glands and some blood vessels in skeletal muscle
  • CNS
  • terminals of efferent neurons supplying skeletal muscle (motor neurons)
Term
What are three sites of release for norepinephrine?
Definition
  • most sympathetic postganglionic terminals
  • adrenal medulla
  • CNS
Term
What are the two types of nerves?
Definition
cranial and spinal nerves
Term
What are cranial nerves? What nervous system are they part of?
Definition
peripheral nerves from the skull and part of the autonomic nervous system
Term
How many cranial nerves are there?
Definition
12
Term
What do the cranial nerves affect?
Definition
targets in the head and throat
Term

What is so importanty about cranial nerve #10? What is it called?

 

Definition
it is called the vagus and it innervates the viscera including the heart
Term
What is the conformation of spinal nerves like?
Definition
the dorsal root is afferent (sensory) and the ventral root is efferent (motor)
Term
What nervous system are spinal nerves part of?
Definition
somatic
Term
What is the other main type of cell in the nervous system?
Definition
glial cell
Term
What are the five main functions of glial cells?
Definition
  • to surround the neurons and hold them in place
  • to supply nutrients and oxygen to the neurons
  • to insulate one neuron from another
  • to destroy pathogens and remove dead neurons
  • to modulate transmission
Term
What does "glial" mean?
Definition
glue
Term
What are the four types of glial cells?
Definition
astrocytes, oligodendrocytes, microglia, and ependymal cells
Term
What are some of the main functions of astrocytes?
Definition
  • physically support neurons in proper spatial relationships
  • serve as scaffold during fetal brain develoment
  • induce formation of the blood brain barrier
  • form neural scar tissue
  • take up and degrade released neurotransmitters into raw materials for synthesisof more neurotransmitters by neurons
  • take up excess K+ to maintain proper ECF ion concentration and normal neural excitability
  • possess receptors for neurotransmitters, which may be important in a chemical signaling system
Term
What is the main function of oligodendrocytes?
Definition
they form the myelin sheath in the CNS
Term
What is the main function of microglia?
Definition
play a defense role in the brain as phagocytic scavengers
Term
What are the three main functions of ependymal cells?
Definition
  • line internal cavities of brain and spinal cord
  • contribute to formation of cerebrospinal fluid
  • serve as neural stem cells with the potential to form new neurons and glial cells
Term
What is the blood brain barrier?
Definition
it is a highly selective barrier that carefully regulates exchanges between the blood and the brain
Term
What part of the brain is not subject to the blood brain barrier? Why?
Definition
the hypothalamus because it needs to be able to sample the blood in order to maintain homeostasis
Term
The brain depends on the delivery of _______ and ________ by the blood.
Definition
glucose, oxygen
Term
Brains of virtually all vertebrates display a degree of __________.
Definition
plasticity
Term
What is plasticity?
Definition
an ability to be changed or functionally remodeled in response to the demands placed on it
Term
Where is the site of origin for the autonomic nervous system?
Definition
the brain or lateral horn of the spinal cord
Term
Where is the site of origin for the somatic nervous system?
Definition
the ventral horn of the spinal cord for most; those supplying muscles in the head originate in the brain
Term
In the autonomic nervous system, how many neurons are there from the origin in the CNS to the effector organ?
Definition
two neuron chain (preganglionic and postganglionic)
Term
In the somatic nervous system, how many neurons are there from the origin in the CNS to the effector organ?
Definition
one (motor neuron)
Term
Which organs does the autonomic nervous system innervate?
Definition
cardiac muscle, smooth muscle, exocrine glands, and some endocrine glands
Term
Which organs does the somatic nervous system innervate?
Definition
skeletal muscle
Term
In the autonomic nervous system, what is the type of innervation?
Definition
most effector organs are dually innervated by the two antagonist branches of this system (sympathetic and parasympathetic)
Term
In the somatic nervous sytem, what is the type of innervation?
Definition
effector organs are only innervated by motor neurons
Term
In the autonomic nervous system, what neurotransmitter is released at the effector organs?
Definition
acetylcholine (parasympathetic terminals) and norepinephrine (sympathetic terminals)
Term
In the somatic nervous system, what neurotransmitter is released at the effector organs?
Definition
acetylcholine
Term
How does the autonomic nervous system affect the effector organs?
Definition
either stimulation or inhibition (antagonist actions of two branches)
Term
How does the somatic nervous system affect the effector organs?
Definition
stimulation only (inhibition possible only through IPSPs on cell body of motor neuron)
Term
What are four higher centers of control in the autonomic nervous system?
Definition
spinal cord, medulla, hypothalamus, and the prefrontal association cortex
Term
What are fiver higher centers of control in the somatic nervous system?
Definition
spinal cord, motor cortex, basal nuclei, cerebellum, and the brain stem
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