Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHSL231 > Lecture 17- Autonomic Nervous System > Flashcards

Lecture 17- Autonomic Nervous System Flashcards

1
Q

What does the autonomic nervous system do?

A
  • Perform sub-conscious functions to help maintain a constant internal environment (homeostasis), so is continually active
  • Modulate function of various organs in response to external stimuli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What types of neurons is the autonomic nervous system made of?

A

Collection of central and peripheral neurons, with peripheral
neurons mostly organized into ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the broad subdivisions of the autonomic nervous system?

A
  • Sympathetic (fight or flight)
  • Parasympathetic (rest and digest)
  • Enteric (located within the wall of the GI tract)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the autonomic nervous system receive input from and what does it output to?

A
  • Receives input from somatic, visceral, & special senses, and endocrine system
  • Delivers output to autonomic motor and endocrine system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many motor neurons does the output (sympathetic and parasympathetic) of the autonomic nervous system have and what are these called?

A

2 neurons:
-Preganglionic neuron cell body in CNS, postganglionic neuron in
peripheral ganglia
-Postganglionics synapse on target organs (eg cardiac & smooth muscle & glands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Summarize the sympathetic output….

A
  • Preganglionic neurons in thoracic & upper lumbar spinal cord
  • Postganglionic neurons in paravertebral (“sympathetic chain”) or prevertebral ganglia (Celiac & mesenteric ganglia in abdomen)
  • Because sympathetic ganglia are (mostly) remote from target, symp. postganglionic neurons have relatively long axons (short then long)
  • Use acetylcholine at the preganglionic synapse and noradrenaline at the post ganglionic synapse.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the actions of the sympathetic output?

A

Typically prepares the body for action eg. Incr blood pressure, incr heart rate, decr GI activity, incr. blood flow to lungs & muscles etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Do preganglionic neurons in the sympathetic branch of the autonomic nervous system project to the same side or different side? What is the exception to the rule?

A

Most preganglionic project to ganglia on same side of body & control function ipsilaterally (not intestines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What’s special about the adrenal medulla in the sympathetic division of the autonomic nervous system?

A

Adrenal medulla directly innervated by preganglionic fibres, target cells (chromaffin cells) have no axon & release their neurotransmitter directly into bloodstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Summarize the parasympathetic division of the autonomic nervous system…

A

-Preganglionic neurons in cranial nerve nuclei in brainstem, and
sacral spinal cord
-Postganglionic neurons in cranial ganglia (ciliary, submandibular, otic ganglia) and in ganglia in or near visceral organs
-Because parasymp ganglia are near target, postganglionic axons are short (long then short)
-Acetylcholine at both preganglionic synapse and postsynaptic synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the actions of the parasympathetic division of the nervous system?

A

Activation balances & opposes actions of symp system (eg decr. heart rate, incr activity of digestive tract, salivation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Contrast distribution of the sympathetic and parasympathetic divisions….

A
  • Sympathetic: Widely distributed: salivary glands, eyes, skin, viscera, smooth & cardiac muscles
  • Parasympathetic: Distributed less widely than symp. Many axons carried in vagus nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What neurotransmitter is released by all preganglionic autonomic neurons?

A

AcetylCholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the receptor type for acetylcholine differ and different parts of the autonomic nervous system/ different branches?

A

-Nicotinic ACh receptors (nAChR) in peripheral ganglia and adrenal
medulla
-Parasympathetic postganglionic neurons release ACh onto Muscarinic AChR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What receptor is used by the sympathetic nervous system due to release of noradrenaline by postganglionic neurons?

A

Sympathetic postganglionics release Noradrenaline onto adrenergic
receptors (several receptor subtypes, capable of triggering opposing actions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do nicotinic acetylcholine receptors and muscarinic acetylcholine receptors differ? i.e what type of receptor is each?

A 
Nicotinic= ion channel 
Muscarinic= G-protein receptor (trigger downstream effects)
17
Q

Explain what happens when beta adrenergic receptors are stimulated? How does this differ according to type?

A
  • Beta receptor activated when noradrenaline/epinephrine binds. This activates a G protein
  • The G protein causes adenylyl cyclase to convert ATP to cyclic AMP
  • If beta 1 effect is cardiac muscle stimulation and increased tissue metabolism
  • If beta 2 effect is the relaxation of smooth muscle in the respiratory passages and in the blood vessels of skeletal muscle
  • If beta 3 effect is release of fatty acids and adipose tissue for metabolic use in other tissues
18
Q

Why does ANS trigger a variety of functions?

A

As a consequence of different transmitter/ receptor combinations

19
Q

What is the result of norprenphrine interaction with an alpha receptor? How does this differ under different receptor types?

A
  • G protein is activated
  • If a1 receptor then secondary messengers are activated and there is the release of calcium from the ER leading to smooth muscle contraction and gland cell secretion
  • If its an a2 receptor then reduced levels of cAMP is the result and there is the inhibition of the cell.
20
Q

What is the main CNS center invovled in autonomic control?

A

The hypothalamus= coordinates sensory information and then output (not at level of consciousness usually)

21
Q

What are long reflexes?

A
  • Autonomic nervous system makes use of them
  • Goes within the spinal chord but not above
  • Involves interneuron
  • Organization similar to somatic reflexes
22
Q

What is the enteric nervous system + its role?

A
  • Can operate independently of symp & parasymp, but is typically modulated by them
  • Has own network of sympathetic and parasympathetic fibres (embedded in layers of GI tract)
  • Generates GI activity patterns (peristalsis, segmentation) to propel and mix food thru the GIT
  • Regulates secretion of GI hormones (eg gastrin, secretin)
23
Q

What receptors/ transmitters does the enteric nervous system make use of? (Give some examples)

A

Multiple transmitters & receptors (eg. ACh, VIP, 5-HT, substance P)

24
Q

What are the roles of the different plexus’ in the enteritic nervous system?

A
  • Submucosal plexus: has sensory & motor neurons, innervates mucosal epithelium & muscle
  • Myenteric plexus: includes sensory chemoreceptors & mechanoreceptors and drives GI smooth muscle
25
Q

What type of reflexes does the enteric nervous system make use of?

A

-”short reflexes”: involves ENS sensory & motor neurons whose
cell bodies are in peripheral structure (eg intestine)

  • Used in simple, localized reflex actions
  • Allow ENS to operate independently of CNS

PHSL231 (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions