Autonomic Nervous System Flashcards
The control of smooth muscle, cardiac muscle and secretory tissues by the CNS involves what two neurons?
Preganglionic and postganglionic
What neuron has the cell body in an autonomic ganglion?
Postganglionic
Parasympathetic ganglia are near what?
The organ they innervate
What ganglia are paravertebral or preaortic?
Sympathetic ganglia
Preganglionic parasympathetic neurons are present in what cranial nerves?
CN III, VII, IX and X
Where are preganglionic sympathetic neurons located?
T1 - L2
Where does the efferents end on?
Smooth mucsle, cardiac muscle and secretory tissues
What are the preganglionic and postgamglionic neurons linked by?
A peripheral synapse
What do visceral afferents provide?
Sensory information to the CNS
The two divisions of the ANS are?
Sympathetic and parasympathetic
What nervous system is the “flight or fight”?
Sympathetic
What does the sympathetic nervous system involve?
Heart, Arterioles, Skin, Lungs, Gut, Pupils and Liver
How does the sympathetic system affect the heart?
Increases heart rate
How does the sympathetic system affect the arterioles?
Dilate (skeletal muscle) or constricts (skin feels cold)
How does the sympathetic system affect the skin?
Makes hair stand on end and produces sweat
How does the sympathetic system affect the lungs?
Dilates bronchioles
How does the sympathetic system affect the gut?
Reduces motility and closes sphincters
How does the sympathetic system affect the pupils?
Dilates
How does the sympathetic system affect the liver?
Releases glucose
What nervous system involves the “rest and digest”?
Parasympathetic
What nervous system supplies the same organs?
Parasympathetic
What opposes the sympathetic system?
Parasympathetic
What nerves do not synapse in the sympathetic chain?
Splanchnic nerves
What does the grey rami communicantes contain?
Unmyelinated axons of postganglionic axons
What does white rami communicantes contain?
Myelinated axons of preganglionic axons
What are the different ways a preganglionic sympathetic fibre can take when they exit the spinal cord through the thoracolumbar outflow?
Enter the sympathetic chain, ascend and synapse
Enter the ganglion and synapse at the same level
Enter the sympathetic chain, descend and synapse
Pass through the sympathetic chain without synapsing, enter abdominopelvic splanchnic nerve, synapse in one of several pre vertebral ganglia and synapse
Where is the thoracolumbar outflow?
T1 - L2
What is an example of a modified sympathetic ganglion?
Adrenal medulla
What does the postganglionic neurons lack?
Axons
What delivers adrenaline and noradrenaline into the local vasculature?
Postganglionic neurons
What flexure is the transition from vegal to sacral parasympathetic input?
Colic
Postsynaptic sympathetic and parasympathetic fibres travel with the lingual nerve to?
sublingual and submandibular glands
Postsynaptic sympathetic and parasympathetic fibres travel with the auriculotemporal nerve to?
Parotid gland
What is a good example of complex interaction between autonomic and somatic elements?
Male sexual function
Parasympathetic activation leads to secretion from?
Prostate and semial vesicles
What activation of smooth muscle of vas deferens, seminal vesicles, prostate and internal urethral sphincter in bladder cause semen to be expelled into urethra?
Sympathetic
Entry of semen into urethra activates?
Somatic afferent endings in the pudendal nerve
What activates a reflex arc innervating the bulbospongiosus muscle causing ejaculation?
Somatic afferent endings in the pudendal nerve
Activation of sympathetic fibres cause?
Constriction of arterioles and detumescence
What homeostatic mechanisms are involved in the hypothalamus?
Body temperature, satiety and water intake
What does the hypothalamus receive afferents from?
The cortex, hippocampus, amygdala, spinal cord and brainstem visceral afferents
Where are cell bodies of visceral afferent located?
Dorsal root ganglia and in the ganglia associated with the vagus and glossopharyngeal nerves
What does the peripheral axons cross?
Autonomic ganglia or follow the spinal cord to reach the organ they innervate
What does pain afferents tend to travel with?
Sympathetic fibres
What does the carotid sinus contain?
Baroreceptors for monitoring blood pressure