Autonomic Nervous System (slide 8 on) - 25 Flashcards
A1 Adrenergic Receptor (AR) Genes:
A1a, A1b, A1d
A1 AR Functions:
Contraction of smooth muscle: Blood pressure, Baroreflex (heart rate), Temperature… Also, Broncho-constriction, regulation of lipid metabolism, glucose uptake by adipocytes, contractile functions in tissues such as the vas deferens
A1 AR agonists will treat:
Hypotension
A1 AR Antagonists will treat:
Hypertension
Common nonselective agonist of A1ARs:
Phenylephrine
A2AR Genes
A2a, A2b, A2c
NOTE: there is a lack of truly specific agonists and antagonists for A2ARs so difficult to discern their true functions. (Knockout mice have helped)
NOTE: there is a lack of truly specific agonists and antagonists for A2ARs so difficult to discern their true functions.
What is A2aAR important for?
Agonist mediated lowering of blood pressure and sedation.
What is A2bAR involved in?
Vascular hypertensive effects (opposite of A2aAR)
What function do Imidazole compounds have? Where are they applied when having this effect?
When applied peripherally, they lower blood pressure
What are 2 drugs that, when applied peripherally, will have the effect of lowering blood pressure?
Imidazoles: moxonidine and rilmenidine
What effect will a partial agonist of A2aAR have?
It will lower blood pressure without sedation.
What effect do A2-ARs have?
They tend to lower blood pressure (strange for an adrenergic receptor)
Genes of Beta Adrenergic Receptors (BARs)
B1, B2, B3
B1-AR effect/location
Acts in the heart to increase heart rate and blood pressure (most common in body)
B2-AR effects/location
Acts in the lungs to induce bronchodilator and vasodilation; also can increase blood pressure (depends on GPCR it is coupled to)
B3-AR effects/location
Acts in adipocytes for lipolysis as well as relaxation of uterus and bladder.
What is the most common reason for use of B-blockers? How do they typically act?
Treatment of hypertension and heart failure. They typically act as antagonists of B1-AR
What are the most common B-blockers?
Metoprolol, atenolol and propranolol (acts on B2-AR as well)
What would you use to treat bronchoconstriction associated with asthma? What drug?
A B2-AR selective agonist. Albuterol
Nuclei of the Parasympathetic Nervous System and the nerves they travel with.
(Midbrain)Edwinger-Westphal nucleus»_space; Oculomotor nerve (CN III)
(Upper medulla) Salivatory Nuclei»_space; Facial nerve (VII) and glossopharyngeal nerve (IX)
(Middle medulla) Dorsal motor nucleus»_space; Vagus nerve (X)
(Middle medulla) Nucleus Ambiguus»_space; Vagus nerve (X)
EWN full path
EWN>CN III> ciliary ganglion > Pupillary constrictor and cilia muscle
Salivatory nucleus full path
Salivatory nuclei > CN VII > Pterygopalatine ganglion > Lacrimal gland/palatal/pharyngeal/nasal mucous glands
Salivatory nuclei > CN VII > submandibular ganglion > submandibular and sublingual glands/mucous glands of oral cavity
Inferior Salivatory Nucleus > CN IX > Otic Ganglion > Parotid/oral cavity
Dorsal Vagal Nucleus/Nucleus Ambiguus full path
DVN/NA > CN X > Terminal ganglia > most of the organs in the body
Sacral spinal cord path
Sacral cord > splanchnic nerve….
What do you keep sweating for a long time after a workout?
Not all sympathetic neurons are innervated by parasympathetic neurons. Sweat glands and the adrenal medulla are 2 examples
Where do preganglionic parasympathetic neurons of the sacral spinal cord reside?
In the Intermediate Gray Zone
What are the targets of the splanchnic nerve?
Colon, rectum, genitalia
What are the muscle layers that line the enteric system?
2 layers of circular muscle and 1 layer of longitudinal muscle
What is the myenteric plexus?
Auerbach’s plexus - The outermost plexus of the enteric system - regulates musculature of the gut (forces food through the bowels)
What is the Submucus plexus?
Meissner’s plexus - Glandular secretion and chemical monitoring.
What mechanism controls the Enteric Nervous System?
Sympathetic and Parasympathetic innervation modulates the activity of the ENS according to the needs of the organism.
T/F : The ENS function is dependent on stimulation by the SNS and PsNS.
F. The ENS functions independently to regulate gut motility and digestion.
What are examples of times that the sympathetic and parasympathetic nervous systems would regulate activity of ENS?
When you’re stressed/active, the sympathetic will tell the ENS to stop so the body can put energy toward other necessities.
When you are resting, the parasympathetic will kick up the ENS to tell it to digest.
(Thats why when you’re stressed all day you forget to eat)
How do we have visceral sensation?
The Vagas nerve relays information from our organs to the Caudal division of the Solitary Tract. Which is the nucleus for visceral sensory information
Why can we not feel things as well in our stomachs as we can on our hands?
Because there are far fewer visceral sensory neurons than mechanosensory neurons on our skin.
Why do we feel pain in our organs more readily than we feel food passing through?
Typically, painful visceral information is sent to higher order regions and enters our consciousness.
