Module 3 - Automatic Nervous System & Experimental Pharmacology

Question 1

What did Henry Dale do?

Answer 1

Studied acetylcholine as an agent in the chemical transmission of nerve impulses (neurotransmission). Distinguished two types of action of ACh - muscarine and nicotine.

Question 2

What did Otto Loewi do?

Answer 2

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.

Question 3

What are the two major neurotransmitter systems in the Autonomic Nervous System (ANS)?

Answer 3

1. Acetylcholine - both sympathetic and parsympathetic release ACh
2. Norepinephrine - most sympathetic post-ganglionic neurons release noradrenaline

Question 4

What processes are regulated by the Autonomic Nervous System?

Answer 4

Contraction and relaxation of vascular (blood vessels) and visceral (e.g. gut) smooth muscle

Exocrine and endocrine secretion

Heart rate and force of contraction

Question 5

Autonomic vs. Somatic

Answer 5

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

Question 6

Efferent vs. Afferent

Answer 6

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.

Question 7

Parasympathetic vs. Sympathetic vs. Enteric

Answer 7

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

Question 8

Ganglion

Answer 8

A structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fibre

Question 9

Vascular vs. Visceral

Answer 9

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.

Question 10

Contraction vs. Constriction

Answer 10

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

Question 11

Which two spinal roots does the sympathetic nervous system operate off?

Answer 11

T and L

T = thoraic
L = lumbar

Question 12

Which two spinal roots does the parasympathetic nervous system operate off?

Answer 12

M and S

M = medullary
S = sacral

Question 13

What did Alquist do?

Answer 13

Alquist distinguished two types of receptors based on the response to adrenaline, noradrenaline and isprenaline which he named alpha and beta

Question 14

4 Major Catecholamines

Answer 14

Noradrenaline; adrenaline; dopamine; isoprenaline

Question 15

What transporter out of neuronal noradrenaline transporter (NET) and extraneuronal monoamine transporter (EMT) removes the most noradrenaline

Answer 15

Extraneuronal monoamine transporter (EMT)

Question 16

List the subtypes, main locations and cellular and functional responses for alpha-adrenoceptors

Answer 16

Subtypes:

• alpha1
• alpha2

Main location:

• 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)

Question 17

List the subtypes, main locations and cellular and functional responses for beta-adrenoceptors

Answer 17

Subtypes:

• beta1
• beta2
• beta3

Main location:

• 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)

Question 18

What does blood pressure equal?

Answer 18

Blood pressure = cardiac output x total peripheral resistance

Cardiac output = heart rate and actual stroke volume
Total peripheral resistance = resistance in the systemic system

Question 19

What is anaphylaxis and why use adrenaline?

Answer 19

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

Question 20

Define asthma

Answer 20

Chronic airway inflammation

Question 21

Prevalence of asthma in people

Answer 21

1 in 10 people

More children are diagnosed with asthma, this may be because their airways are more immature and undeveloped.

Question 22

How many people die from asthma yearly?

Answer 22

Approximately 300-400 people