Autonomic Nervous system Flashcards
1
Q
- Describe general characteristics of the autonomic nervous system
- describe and compare the general functions of the sympathetic and parasympathetic systems
A
- General characteristics of ANS
- can change visceral function rapidly and intensely
- Heart rate can be increased to twice normal within 3-5 seconds
- Arterial pressure can be doubled within 10-15 seconds
- sweating can begin within seconds
- can change visceral function rapidly and intensely
2
Q
Compare the basic morphological pattern of the sympathetic and parasympathetic systems
A
3
Q
Be able to trace a typical pathway for a sympathetic neuron, including the three alternatives
A
4
Q
Describe the thoracic sympathetic chain and the ganglia and splanchnic nerves associated with it
A
- Lies against neck of ribs and costovertebral junctions.
- 12 thoracic ganglia pairs:
- First one often fused with inferior cervical ganglion
- Referred to as stellate ganglion collectively
- Cervical ganglia
- Superior
- Middle
- Inferior
- The preganglionic sympathetic supply to the thoracic viscera are from T1-T5
- The postganglionics are from:
- Superior, middle, and inferior cervical ganglia
- T1-T5 paravertebral ganglia
- They exit the chain as direct fibers and travel downwards to enter the thorax:
- As cardiopulmonary splanchnic nerves
- The postganglionics are from:
5
Q
Describe characteristics of splanchnic nerves, including origin and site of synapse
A
- Characteristics:
- Composed of preganglionic fibers and visceral sensory fibers
- Supply abdominal viscera
- Synapse in prevertebral ganglia
- Greater:
- T5-T9
- Synapses in celiac ganglion
- Lesser:
- T10-T11
- Synapses in the superior mesenteric ganglion
- Least:
- T12
- Synapses in aorticorenal ganglion
6
Q
- Describe the input and ouputs of the adrenal medullae
- explain why circulating norepinephrine has a greater effect on raising arterial pressure
A
- Stimulated by the sympathetic system
- output
- Secretes about 80% epinephrine and 20% norepinephrine
- Circulating norepinephrine:
- Constricts most of blood vessels of body:
- Has greater effects on blood vessels in skeletal muscles so has greater effect on raising arterial pressure
- Increases heart activity
- Inhibits heart activity
- Inhibits GI tract
- Dilates pupils
- Constricts most of blood vessels of body:
7
Q
What is the alarm/stress response and what are the characteristic physiological changes that occur as a result of it
A
- Occurs when there is a mass discharge of the entire sympathetic system (Fright, Fear, Severe Pain)
- Increased arterial pressure
- Rerouting of blood flow to active muscles
- Increased rates in cellular metabolism
- Increased blood glucose concentration
- Increased glycolysis in liver and muslce
- Increased muscle strength
- Increased mental activity
- Increased blood coagulation rate
8
Q
Where are most preganglionic parasympathetic fibers located
A
- About 75 percent of all parasympathetic fibers are in the vagus nerve (CN 10)
- most preganglionci fibers pass all the way to the organ that is to be innervated
9
Q
Identify the four cranial nerves that carry parasympathetic fibers and what they innervate
A
- Occulomotor (III)
- Facial (VII)
- Glossopharyngeal (IX)
- Vagus (X)
10
Q
- Identify structures innervated by the vagus nerve
- identify the branches of the vagus nerve
A
- Motor suppply to muscles of the fourth and fifth pharyngeal arches and is important in swallowing and speaking
- Parasympathetic function:
- Major parasympathetic supply to thoracic and abdominal organs
- Preganglionic:
- From dorsal motor nucleus
- Postganglionic:
- Myenteric plexus of wall of gut tube all the way to the left colic flexure
- Branches:
- Cardiac branches to cardiac plexus
- Pulmonary branches to pulmonary plexus
- Esophageal branches to esophageal plexus
- Left recurrent layngeal nerve from left vagus:
- Hooks around arc of aorta to left of ligamentum arteriosum
- Right recurrent laryngeal nerve from right vagus:
- Arises in neck, not thorax
11
Q
Describe the synthetic pathways for acetylcholine and norepinephrine
A
*
12
Q
Describe the inactivation/removal of acetylcholine and norepinephrine
A
- Reuptake
- Diffusion
- Destruction by monamine oxidase
- Found in nerve endings
- Destruction by catechol-O-Methyl transferase (COMT)
- Present in all tissues
13
Q
Describe the acetycholine receptors and state where they are found
A
- Muscarinic:
- Muscarine is a poison from toadstools
- Receptors are found on all effector cells stimulated by postganglionic cholinergic neurons
- Nicotinic:
- Found in autoimmune ganglia at synapse between preganglionic and postganglionic neurons
- Present in neuromuscular junctions in skeletal muscles
14
Q
List the adrenergic receptors and state where they are found
A
- Alpha (alpha1 and alpha2)
- Beta (Beta1, Beta2, and Beta3)
15
Q
List the adrenergic receptors and list what they are associated with
A
- Alpha receptors are associated with:
- Vasoconstriction
- iris dilation
- Intestinal relaxation
- Intestinal sphincter contraction
- Pilomotor contraction
- Bladder sphincter contraction
- Inhibition of neurotransmitter release (alpha2)
- Beta1
- Cardioacceleration
- Increased myocardial strength
- lipolysis
- Beta2
- Vasodilation
- Intestinal relaxation
- Uterus relaxation
- Bronchodilation
- Calorigenesis
- Glycogenolysis
- Bladder wall relaxation
- Beta3
- Thermogenesis
