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Flashcards in Autonomic nervous system Deck (40)
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1

How is the ANS defined anatomically and physiologically?

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

Physiologically: Homeostasis 

2

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

3

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

4

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

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

5

What are the physiological roles of the ANS?

  • 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

6

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

A ganglion

7

What is a ganglion?

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

8

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

9

How do drugs influence the ANS?

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

10

Drugs that mimic neurotransmitters are referred to as what?

How do they effect receptors?

receptor agonists

These drugs activate receptors 

11

Drugs that block neurotransmitters are referred to as what? 

How do these effect receptors?

They are known as receptor antagonists 

These drugs block the endogenous neurotransmitters from activating receptors 

12

What does the sympathetic nervous system innervate? 

Where is the preganglionic neuron located?

It innervates many different tissues 

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

13

What does the ganglia form in the sympathetic nervous system?

A sympathetic chain

14

What does the sympathetic nervous system provide?

Provides diffuse innervation of target tissues 

15

What does the parasympathetic nervous system innervate ? 

Where is the preganglionic neuron located?

Located in meduall or sacral segment of the spinal cord 

16

Where are the ganglia located in the parasympathetic nervous system?

In the target tissue

17

What does the parasympathetic nervous system provide?

Discrete innervation of target tissues

18

What is the role of the following:

  • Amygdala 
  • Hypothalamus 
  • Reticular formation

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

19

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

Where are they located in the kidney?

In the renal vascular bed 

release Dopamine 

20

What two organs are exceptions to the sympathetic nervous system?

Kidneys 

Adrenal gland

21

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

  • 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

22

Tell me the three important points about the ANS?

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

23

Overview of neurotransmission in the ANS

24

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

25

What does the enteric nervous system consist of?

Neurons that regulate the gastrointestinal tract 

26

What does the enteric nervous system recieve inputs from?

It recieves inputs from the sympathetic and parasympathetic nervous system

It is neurochemically and functionally complex 

27

What does the enteric nervous system express?

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 

28

Dysautonomia or autonomic dysfunction usually is of what origin?

Usually of neuropathic origin: damage to autonomic nerves 

29

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

  • 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

30

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

Its patency (openess) 

Also described the use of this maneuver to expel pus from the middle ear