Flashcards in Module 3 - Automatic Nervous System & Experimental Pharmacology Deck (22):
What did Henry Dale do?
Studied acetylcholine as an agent in the chemical transmission of nerve impulses (neurotransmission). Distinguished two types of action of ACh - muscarine and nicotine.
What did Otto Loewi do?
In 1921, he showed that a denervated beating frog's heart was slowed and stopped by fluid taken from an innervated heart, when stimulated by the vagus.
What are the two major neurotransmitter systems in the Autonomic Nervous System (ANS)?
1. Acetylcholine - both sympathetic and parsympathetic release ACh
2. Norepinephrine - most sympathetic post-ganglionic neurons release noradrenaline
What processes are regulated by the Autonomic Nervous System?
Contraction and relaxation of vascular (blood vessels) and visceral (e.g. gut) smooth muscle
Exocrine and endocrine secretion
Heart rate and force of contraction
Autonomic vs. Somatic
Autonomic nervous system = the part of the peripheral nervous system that controls visceral functions that occur below the level of consciousness.
Somatic nervous system = the part of the peripheral nervous system associated with the voluntary control of body movements through the skeletal muscles and mediation of involuntary reflex arcs
Efferent vs. Afferent
Efferent neurons = motor neurons that carry neural impulses away from the central nervous system and towards muscles to cause movement.
Afferent neurons = sensory neurons that carry nerve impulses from sensory stimuli towards the central nervous system and brain.
Parasympathetic vs. Sympathetic vs. Enteric
Parasympathetic = REST and DIGEST
Sympathetic = FIGHT OR FLIGHT
Enteric = consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract
A structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fibre
Vascular vs. Visceral
Vascular smooth muscle = refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels
Visceral smooth muscle = involuntary muscles that line the blood vessels, stomach, digestive tract, and other interal organs. Are composed of bundles of specialised cells capable of contraction and relaxation to create movement.
Contraction vs. Constriction
Muscle contraction = the activation of tension-generating sites within muscle fibres
Muscle constriction = e.g. the sphincter is a circular muscle that normally maintains constriction of a natural body passage which relaxes by normal physiological functioning
Which two spinal roots does the sympathetic nervous system operate off?
T and L
T = thoraic
L = lumbar
Which two spinal roots does the parasympathetic nervous system operate off?
M and S
M = medullary
S = sacral
What did Alquist do?
Alquist distinguished two types of receptors based on the response to adrenaline, noradrenaline and isprenaline which he named alpha and beta
4 Major Catecholamines
Noradrenaline; adrenaline; dopamine; isoprenaline
What transporter out of neuronal noradrenaline transporter (NET) and extraneuronal monoamine transporter (EMT) removes the most noradrenaline
Extraneuronal monoamine transporter (EMT)
List the subtypes, main locations and cellular and functional responses for alpha-adrenoceptors
- alpha1: smooth muscle (e.g. vascular, gut)
- alpha2: nerve terminals (presynaptic)
Cellular and functional responses:
- alpha1: stimulates PLC, increase IP3, increase CA2+, stimulatory
- alpha2: inhibits AC, decreases cAMP, decreases CA2+ conductance, inhibitory (decreases neurotransmitter release)
List the subtypes, main locations and cellular and functional responses for beta-adrenoceptors
- beta1: heart (pacemaker and cardiomyocytes)
- beta2: smooth muscle
Cellular and function responses:
- beta1: stimulates AC, increase cAMP, increase CA2+ conductance, stimulatory (increase heart rate)
- beta2: stimulates AC, increase cAMP, PKA, (smooth muscle relaxation)
What does blood pressure equal?
Blood pressure = cardiac output x total peripheral resistance
Cardiac output = heart rate and actual stroke volume
Total peripheral resistance = resistance in the systemic system
What is anaphylaxis and why use adrenaline?
Acute and severe allergic reaction. It has two main features: hypotension and bronchospasm (adrenaline addresses both of these problems).
Adrenaline rapidly reverses these two potentially life threatening symptoms. Addressed through beta1 effects on hypotension and bronchospasm on the beta2 to relax the muscles
Chronic airway inflammation
Prevalence of asthma in people
1 in 10 people
More children are diagnosed with asthma, this may be because their airways are more immature and undeveloped.