Download 5 pairs of sacral nerves

The Nervous System
Master control unit of the body
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Objectives
• Describe the structures of the nervous system: central and
peripheral.
• Discuss the functions of the nervous system: central and peripheral
• State the functions of neuroglia cells in the central nervous system
• Identify the structural parts of a neuron.
• Explain how an impulse is transmitted via a neuron, including the
role of neurotransmitters and their functions.
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Objectives, cont’d
• Identify the lobes of the brain and the function(s) of each lobe.
• Describe a reflex arc.
• List the names and functions of the 12 cranial nerves.
• Apply knowledge of anatomy and principles of physiology,
chemistry, microbiology and physics to nursing situations related to
the coordination.
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Nervous System
Peripheral
Nervous
System
Central
Nervous
System
Brain
Spinal Cord
Autonomic
Nervous System
Sympathetic
Nervous System
Motor
Sensory
(Efferent)
Neuron
(Afferent)
Neuron
Somatic Nervous
System
Parasympathetic Nervous
System
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The Nervous System

Structural divisions
Peripheral (PNS)
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Central (CNS)
Action Potential:
a) A stimulus is received by the dendrites of a nerve cell. This
causes the Na+ channels to open. If the opening is sufficient to
drive the interior potential from -70 mV up to -55 mV, the
process continues.
b) As depolarization reaches threshold of -55mV, the action
potential is triggered and Na+ rushes into cell. Membrane
potential reaches +30mV on action potential
c) Propagation of the action potential at 110 m/sec (which is
225 mph)
d) Repolarization occurs with K+ exiting the cell to return to 70mV RMP
e) Return of ions (Na+ and K+) to their extracellular and
intracellular sites by the sodium potassium (Na+K+) pump
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Neurotransmission
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Name
Dopamine
Type
Amine
Postsynaptic
Effect
Excitatory
Location(s)
CNS, PNS
Function(s)
Controls movement and arousal levels,
creates sense of feeling good
Inhibitory
CNS, intestine
regulates appetite, sleep,
memory and learning,
temperature, mood
Amine
Excitatory
CNS, PNS
Induce arousal, heighten mood, low
levels may lead to depression
Amino acid
Inhibitory
CNS
Control anxiety level
Neuropeptid
Inhibitory
CNS
Reduce stress, promote calm, natural
painkiller (inhibits substance P
Substance P
Neuropeptid
Excitatory
PNS
Transmission of pain
Acetylcholine
(ACH)
Acetic acid
Excitatory &
Inhibitory
CNS, PNS
Role in memory, vasodilation
Controls skeletal muscle actions
Serotonin
Noradrenaline
(norepinephrine)
GABA
Endorphins
Enkephalin
(opiate)
Amine
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The Brain

The Brain is made up of more than 10 billion
nerves

Divided into three parts: Cerebrum, Cerebellum
and Brain Stem

Protected by: Skull mainly but the
Meninges/Cerebral-spinal fluid act as
shock absorbers
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The Brain
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The Brain - Protection
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BRAIN
The Cerebrum
• Largest part of the
brain
Medulla
• Connects the brain
and the spinal cord
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The Cerebellum

The cerebellum is below and to the back of the
cerebrum

The cerebellum controls:
1.Balance
2.Coordination
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Spinal Cord
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Spinal Nerves
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Spinal Nerves
• 31 pairs
• Each pair arise from a spinal segment
- 8 pairs of cervical nerves
- 12 pairs of thoracic nerves
- 5 pairs of lumbar nerves
- 5 pairs of sacral nerves
- 1 pair of coccygeal nerves
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Cranial Nerves
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Cranial Nerves
"On Old Olympic Towering Top
A Famous Vocal German
Viewed Some Hops“
... standing for: Olfactory, Optic, Oculomotor, Trochlear,
Trigeminal, Abducens, Facial, Vestibulocochlear,
Glossopharyngeal, Vagus, Spinal accessory, Hypoglossal.
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Autonomic
Nervous
System
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Peripheral Nervous System
•Somatic nervous system – voluntary control over
skeletal muscle
•Autonomic nervous system – involuntary control over
the contraction of smooth muscle, cardiac muscle, gland
secretion
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Autonomic Nervous System (ANS)
• Sympathetic – “flight or fight”
• Ready for immediate stress
• Increase of body systems
• Parasympathetic – “rest and digest”
• Nonstressful conditions
• Decrease body systems
• Digestion increased
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Parasympathomimetics
•AKA – cholinergic agents
•Cholinergic = parasympathetic
•Classic – acetylcholine
•Does not stay long in body, rapidly destroyed after
receptor binding
•Direct acting – bind to cholinergic receptors to produce
rest/digest response – AKA muscarinic agonist
•Indirect acting – avoids destruction of Ach and allow to
remain on cholinergic receptors for longer time – AKA
cholinesterase inhibitors
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Autonomic Drug Classes
•Adrenergic antagonists or adrenergic blockers –
inhibit SNS
•Anticholinergics or parasympatholytics or muscarinic
blockers – inhibit PNS
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Baroreceptor Reflex
The baroreceptor reflex regulates BP
•The receptors are located in the
carotid sinus and aortic arch
•The brain sends impulses to the ANS
•When there is a decrease in BP
there is vasoconstriction and an
increase in CO
•When there is an increase in BP
vasodilation and a decrease in BP
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Neurotransmitter Disintegration
•Ach
•Destroyed by
acetylcholinesterase
•Norepinephrine (NE)
•Reuptake of NE into nerve
terminals for reuse
•Inactivation by monoamine
oxidase (MAO)
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ANS Transmitters
•Norepinephrine (NE) –
catecholamine
•Alpha receptors – alpha1
and alpha 2
•Beta receptors – beta 1 and beta 2
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ANS Neurotransmitters
• Acetylcholine (Ach) – released by cholinergic nerves
• Nicotinic receptors – Ach receptors in the preganglionic ganglia,
effects similar to effects of nicotine
• Muscarinic receptors – Ach receptors in postganglionic ending in
target tissues, similar to effects of amanita muscaria
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Drug Effects
•Affect synthesis of
neurotransmitters
•Prevent storage of
neurotransmittters
•Influence the release of
neurotransmitters
•Bind to the receptor site of
postsynaptic neuron – increase
autonomic function
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