A&P 2.16 Autonomic Nervous System Flashcards
Membrane potential
Difference in electrical charge across the plasma membrane caused by differing concentrations of ions
Resting membrane potential
- 70 mV. Inside number. Outside are different numbers
Local potential
Minor shifts from resting potential but no action potential
Excitation
When sodium triggers gated channels to open and allow sodium into the cell causing depolarization
Structures of the nervous system
CNS - brain and spinal cord
PNS - nerves and sensory receptors
Basic divisions of the nervous system
CNS
PNS - SNS & ANS
SNS
Somatic - skin, skeletal muscles, fascia and joints
ANS
Autonomic - viscera, blood vessels, smooth muscles
Sympathetic - fight or flight
Parasympathetic - rest or digest
Motor Effectors of the somatic divisions
Skin
Skeletal muscles
Fascia
Joints
Motor Effectors of the autonomic divisions
Smooth muscle - organs- viscera
Cardiac muscles
Glands
Major functions of the ANS
To regulate everything that is not skeletal muscle (smooth muscles, glands, cardiac ) via the sympathetic and parasympathetic systems
TO INCREASE TONE IN ONE DIVISION YOU MUST DECREASE TONE IN THE OTHER
Most structures in the ANS are
Dually innervated
Autonomic effector tissues and organs
Viscera - organs
Eyes Heart Respiratory structures Blood vessels Liver Digestive glands
Motor pathways of the somatic divisions
Motor neuron runs from CNS and synapses directly with skeletal muscle fiber
ACh always neurotransmitter
Excitatory - contraction always
Voluntary
ONE NEURON
Motor pathways of the autonomic division
Motor neuron from CNS to another motor neuron (ganglion) to synapse with autonomic effector (2 synapses)
ACh (acetylcholine ) or NE (norepinephrine ) neurotransmitter
Excitatory or inhibitory
Involuntary
TWO SYNAPSES
Ganglia
A group of neural cell bodies found in the PNS
Ganglia are necessary because
So many different target tissues are affected all at one time in the ANS due to parasympathetic and sympathetic
The ANS has how many synapses?
2 - two motor neurons
Preganglionic and post ganglionic
1st synapse uses what neurotransmitter
ACh used in both sympathetic and parasympathetic
Neurotransmitter used in 2nd synapse
Sympathetic uses NE because it is longer lasting and will maintain fight or flight longer
Parasympathetic uses ACh and is short lived
Pre and post ganglionic nerves allow the body to
Affect multiple target tissues at multiple levels at the same time with the release of limited neurotransmitters
Two different efferent divisions of the ANS
Sympathetic and parasympathetic
Structure of sympathetic division
Pre ganglionic neurons arise from spinal nerves T1-L3 (thoracolumbar division)
Ganglia are close to the spinal cord
Pre ganglionic neurons are short and synapse with MANY post-ganglionic fibers: DIVERGENT
Post-ganglionic neurons are LONG and go to MANY effectors
Sympathetic chain
Sympathetic ganglia - chain of ganglia near spine
Structure of the parasympathetic division
Pre-ganglionic neurons arise from the cranial nerves III, VII, IX, X and spinal nerves from S2-S4 (craniosacral division)
Ganglia are FAR from the spinal cord (close to the effectors)
Pre-ganglionic neurons are LONG and synapse with FEW post-ganglionic fibers: CONVERGENT
Post-ganglionic neurons are SHORT and go to a SINGLE effector
Sympathetic division response
Pupils dilate
Heart rate, force (contraction), and bp increase
Respiratory passages dilate
Blood vessels to GI tract and kidneys constrict
Blood vessels to skeletal muscles, cardiac muscle, brain, liver and adipose tissue dilate
Liver cells BREAK DOWN glycogen into glucose and release glucose into the blood
Nonessential activities are inhibited (e.g. Salivary and other digestive secretions, GI tract mobility)
Parasympathetic division response
Pupils constrict
Heart rate, force (contraction) and BP decreases
Respiratory passages constrict
Blood vessels supplying GI tract and kidneys dilate
Blood vessels to skeletal muscles, cardiac muscle, brain, liver, and adipose tissue constrict
Liver cells SYNTHESIZE glycine from glucose and absorb glucose from the blood
Salivary and other digestive secretions and GI tract mobility are stimulated
Somatic versus Autonomic
effectors
S - skeletal muscles
A - cardiac muscle, smooth muscle, glands
Somatic versus Autonomic
type of control
S - mainly voluntary
A - mainly involentary
Somatic versus Autonomic
neural pathway
S - one motor neuron: extends from CNS and synapses directly with a skeletal muscle fiber
A- two motor neurons: one from CNS to ganglion, one from ganglion to effector
Somatic versus Autonomic
neurotransmitter
S - acetychlorine
A - acetychlorine or norepinephrine
Somatic versus Autonomic
action of neurotransmitter on effector
S - always exicitory
A - excitory or inhibitory
Tensor fascia latea
A, I, O
O - superior attachment - ASIS and adjacent lateral and posterior surface of the ilium
I - the IT band and the lateral condyle of the tibia
A - flex the hip, medially rotate the hip, abduct the hip and help stabilize the knee
Named for action: tenses the broad bandage
