Chapter 6&7 PNS, efferent division

Efferent divisions

Autonomic, somatic

Autonomic Nervous System Detail

fibers that innervate smooth muscle, cardiac muscle, and glands

Autonomic Nervous system characteristics

helps control HR BP digestion respiration blood pH and bodily functions, controls done unconsciously/automatically, 2 neurons between CNS and effector, ganglia, NT

Subdivisions of ANS

sympathetic, parasympathetic,

Sympathetic come from (on spinal cord)

thoracic and lumbar spine→ thoracolumbar, adrenal medulla

Sympathetic neuron length

pre=short, post=long

sympathetic saying

Fight or flight, emergency

parasympathetic saying

Rest and Digest, status quo

Parasympathetic come from (on spinal cord)

cranial and sacral→ Craniosacral

parasympathetic neuron length

pre=long, post=short

NT of ANS

ACh, NE

pre parasympathetic NT

ACh

pre sympathetic NT

ACh

Post parasympathetic NT

ACh

Post sympathetic NT

NE or E (Epinephrine)

Adrenergic receptors

stimulated by NE and E

Cholinergic receptors

stimulated by ACh

4 types of Adrenergic receptors

Alpha 1, Alpha 2, Beta 1, Beta 2

Alpha 1

excitatory for vessels, vasoconstriction

Alpha 2

inhibitory for GI tract, visceral s.m. relaxation

Beta 1

excitatory for heart, inc. HR and force of contraction

Beta 2

Inhibitory relax s.m. = dilate bronchi, some blood vessels dilate (coronary &skeletal muscletous)

2 types of cholinergic receptors

Nicotinic, Muscarinic

Nicotinic

found in autonomic ganglia, both sympathetic and parasympathetic, opens Na+ channels

Muscarinic

found on all organs with parasympathetic nerves, gives para response

Dual Innervation

sympathetic and parasympathetic axons, different NT used, they produce opposite effects, allows precise control over organ activity

SLUDD

salvation, lacrimation, urination, deification, digestion

Agonists

bind with receptor and mimics NT, ex: albuterol

Antagonists

bind with receptor and block NT,

Somatic Characteristics

uses 1 neuron to connect to CNS, releases ACh at synapse, excitatory only at skeletal, one effector

motor neuron

nerve fiber that innervates skeletal muscle, cell body is in ventral horn of spinal cord, receives signals from spinal cord and brain, EPSP or IPSP signal

MEP

contains ACh receptors (nicotinic)

SEB

contains ACh

Events occurring at Neuromuscular junction

1.)AP travels down motor neuron to SEB 2.) Voltage gated Ca++ channels open 3.) Ca++ diffuses into SEB 4.) ACh is released into cleft via exocytosis 5.) ACh diffuses across cleft and binds to nicotinic cholinergic ACh receptors on MEP 6.) Chemically gated Na+ channels open 7.) Na+ diffuses in and depolarizes the MEP 8.) AP in muscle begins 9.) Muscle contracts 10.) NT is degraded via ACh E (enzyme)

Botulism

Blocks ACh release= paralysis

Curare

ACh antagonist= paralysis

Myasthenia gravis

immune system destroys ACh receptors= paralysis