Autonomic nervous system

Question 1

How is the ANS defined anatomically and physiologically?

Answer 1

Anatomically: it is defined as all those neural pathways that leave the brain that do not innervate the volntary muscles

Physiologically: Homeostasis

Question 2

What are the levels to the organisation of the nervous system?

Answer 2

Question 3

Homeostasis can trigger two types of responses, what are they and the length of their effect?

Answer 3

Question 4

What are the divisions of the ANS and what does each system help with?

Answer 4

• Sympathetic: Fight or flight
• Parasympathetic: Rest and digest
• Enteric: sometimes considered part of the ANS and sometimes considered an independent system

Question 5

What are the physiological roles of the ANS?

Answer 5

• pupillary dilation
• accommodation for near vision
• dilation and constriction of blood vessels
• force and rate of heartbeat
• movements of the gastrointestinal tract
• secretions from most glands
• energy metabolism, particularly in liver and skeletal muscle

Question 6

The point of contact between the first and second efferent neuron in the pathway pccurs in a neural structure called what?

Answer 6

A ganglion

Question 7

What is a ganglion?

Answer 7

A group of nerve cell bodies that lie outside the central nervous system

Question 8

With the sympathetic and parasympathetic nervous systems, tell me about the length of ganglion before and after the target tissue

Answer 8

Question 9

How do drugs influence the ANS?

Answer 9

They mimic or block the effects of the two primary neurotransmitters, Ach and Noradrenaline/ adrenaline

Question 10

Drugs that mimic neurotransmitters are referred to as what?

How do they effect receptors?

Answer 10

receptor agonists

These drugs activate receptors

Question 11

Drugs that block neurotransmitters are referred to as what?

How do these effect receptors?

Answer 11

They are known as receptor antagonists

These drugs block the endogenous neurotransmitters from activating receptors

Question 12

What does the sympathetic nervous system innervate?

Where is the preganglionic neuron located?

Answer 12

It innervates many different tissues

The preganglionic neuron is located in the midbrain, medulla or lateral horn of the spinal cord

Question 13

What does the ganglia form in the sympathetic nervous system?

Answer 13

A sympathetic chain

Question 14

What does the sympathetic nervous system provide?

Answer 14

Provides diffuse innervation of target tissues

Question 15

What does the parasympathetic nervous system innervate ?

Where is the preganglionic neuron located?

Answer 15

Located in meduall or sacral segment of the spinal cord

Question 16

Where are the ganglia located in the parasympathetic nervous system?

Answer 16

In the target tissue

Question 17

What does the parasympathetic nervous system provide?

Answer 17

Discrete innervation of target tissues

Question 18

What is the role of the following:

• Amygdala
• Hypothalamus
• Reticular formation

Answer 18

• Amygdala: Main limbic region for emotions
• Hypothalamus: Main integration center
• Reticular formation: Most direct influence over autonomic function

Question 19

What do the postganglionic neurons to the smooth muslce in the kidney release?

Where are they located in the kidney?

Answer 19

In the renal vascular bed

release Dopamine

Question 20

What two organs are exceptions to the sympathetic nervous system?

Answer 20

Kidneys

Adrenal gland

Question 21

Tell me about the preganglionic neurons in the adrenal glands and what they release

Answer 21

• Preganglionic neurons do not synapse in the paravertebral sympathetic ganglion
• Preganglionic neurons synapse directly on the adrenal gland, release acetylcholine, and activate nicotinic receptors on the adrenal gland
• Adrenal glands release adrenaline into systemic circulation

Question 22

Tell me the three important points about the ANS?

Answer 22

IMPORTANT POINT NO 1:

excitatory transmission at ALL the autonomic ganglia, sympathetic and parasympathetic, involves the transmitter Acetylcholine acting on Nicotinic acetylcholine receptors

IMPORTANT POINT NO 2:

transmission at the postganglionic sympathetic synapse usually involves Noradrenaline acting on either -adrenoceptor or -adrenoceptors

IMPORTANT POINT NO 3:

transmission at the postganglionic parasympathetic synapse usually involves Acetylcholine acting on Muscarinic receptors

Question 23

Overview of neurotransmission in the ANS

Answer 23

Question 24

For the following organ systems, describes the responses that the sympathetic and parasympathetic system would have on this organ

Answer 24

Question 25

What does the enteric nervous system consist of?

Answer 25

Neurons that regulate the gastrointestinal tract

Question 26

What does the enteric nervous system recieve inputs from?

Answer 26

It recieves inputs from the sympathetic and parasympathetic nervous system It is neurochemically and functionally complex

Question 27

What does the enteric nervous system express?

Answer 27

A wide diversity of neurotransmitters It expresses mechanoreceptors and chemoreceptors and is involved in local reflex pathways that regulate the activity of the gut independent of neural input from higher centres

Question 28

Dysautonomia or autonomic dysfunction usually is of what origin?

Answer 28

Usually of neuropathic origin: damage to autonomic nerves

Question 29

What are the diagnosis/ symptoms of dysautonomia or autonomic dysfunction?

Answer 29

* **dizziness** and fainting upon standing up, or (or intolerance) orthostatic hypotension * an inability to alter **heart rate** with exercise * **sweating abnormalities** * **digestive difficulties**, such as a loss of appetite, bloating, diarrhea, constipation, or difficulty swallowing * **urinary problems,** such as difficulty starting urination, incontinence, and incomplete emptying of the bladder * **sexual problems** in men, such as difficulty with ejaculation or maintaining an erection * **sexual problems** in women, such as vaginal dryness or difficulty having an orgasm * **vision problems**, such as blurry vision or an inability of the pupils to react to light quickly

Question 30

Valvsalva, a physician and anatomist from bologna described the **Eustachian tube** and the maneuver to test what?

Answer 30

Its patency (openess) Also described the use of this maneuver to expel pus from the middle ear

Question 31

With transmission at the post-ganglionic sympathetic synapse... 1. what hormone is involved 2. classification and pharmacology of receptors 3. drugs that interfere with what

Answer 31

Transmission at the post-ganglionic sympathetic synapse 1. synthesis, release, uptake and metabolism of **noradrenaline** 2. classification and pharmacology of **noradrenaline receptors** 3. drugs that interfere with **post-ganglionic sympathetic transmission**

Question 32

Tell me the following about transmission at cholinergic synapses in the ANS... 1. synthesis and release of? 2. ganglionic neurotransmission hormone? 3. Post-ganglionic neurotransmitter hormone?

Answer 32

1. synthesis and release of acetylcholine 2. ganglionic neurotransmission, nicotinic receptors 3. post-ganglionic neurotransmission, muscarinic receptors

Question 33

Draw a sympathetic organ synapse and label

Answer 33

Question 34

What was adrenaline identified from?

Answer 34

Adrenal extracts

Question 35

What was adrenaline shown to mimic?

Answer 35

sympathetic nerve stimulation

Question 36

What does the **Finkelman preparation** provide evidence for?

Answer 36

That the sympathetic nervous system releases an adrenaline like compound

Question 37

What did Von Euler demonstrate?

Answer 37

That noradrenaline is the main endogenous catecholamine in the sympathetic nerves

Question 38

The Finkel preparation

Answer 38

Question 39

Noradrenaline is the main transmitter at the post-ganglioic sympathetic synapse, except when?

Answer 39

* in **sweat glands** (ACh, therefore atropine blocks sweating) * **resistance blood vessels** in skeletal muscle; activation of the sympathetic nervous system causes vasodilation in this tissue * n.b. there are other neurotransmitters (NANC, for non-adrenergic, non-cholinergic) these will be discussed later

Question 40

What is noradrenaline and what is its structure/ groups in the structure?

Answer 40

Noradrenaline is a Catecholamine