Patrax
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I've been learning about the autonomous nervous system and I am confused. Is the release of CRH into the pituitary gland (which results in release of ACTH and eventually cortisol) part of the sympathetic or parasympathetic systems?
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macpatgh-Sheldon
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Hi sorry you are confused.com

The answer is neither - the neuro-hypophysis (junction of hypothalamic outflow neurons to the pituitary gland) has a comparison made to the autonomic nervous system because this synaptic level and its function is analogous to the release of a neurotransmitter at a synapse in the sympathetic nervous system.

The adrenal gland acts as though it was a sympathetic ganglion in that the "pre-ganglionic" axon releases acetylcholine [ACh] and this stimulates the post-ganglionic neuron [effectively the adrenal medulla] to release adrenaline and NA, which then produce their usual effects e.g. tachycardia, anxiety, dilatation of muscular arterioles.

Please look at the latest info on this as this is what I learnt 15 years ago.

M
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Patrax
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Thank you very much for the quick reply. So if I understood what you are saying correctly, the process by which cortisol is released is compared to the sympathetic nervous system in that its end result is 'similar', but it is a process entirely seperate from the sympathetic nervous system? (sorry my knowledge of human biology is inadequate )
(Original post by macpatgh-Sheldon)
Hi sorry you are confused.com

The answer is neither - the neuro-hypophysis (junction of hypothalamic outflow neurons to the pituitary gland) has a comparison made to the autonomic nervous system because this synaptic level and its function is analogous to the release of a neurotransmitter at a synapse in the sympathetic nervous system.

The adrenal gland acts as though it was a sympathetic ganglion in that the "pre-ganglionic" axon releases acetylcholine [ACh] and this stimulates the post-ganglionic neuron [effectively the adrenal medulla] to release adrenaline and NA, which then produce their usual effects e.g. tachycardia, anxiety, dilatation of muscular arterioles.

Please look at the latest info on this as this is what I learnt 15 years ago.

M
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macpatgh-Sheldon
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Hi, no need to apologize about inadequate knowledge - it comes with time and perseverance!

I hope I am not confusing even more, but although you have now got the right idea (yes, the adrenal medulla is separate from the autonomic nervous system and your understanding is correct), the analogy of the adrenal to the sympathetic NS relates to the adrenal medulla (central area of the gland), which secretes the catecholamines (adrenaline and NA) NOT to the adrenal cortex (the outer layer of the gland), which secretes the corticosteroids (like cortisol). Apologies for this extra complication, but I brought in this additional info based purely on the fact that you mentioned "part of the sympathetic and parasympathetic systems" in your original post.

THE PITUITARY AND ADRENAL GLANDS ARE ENDOCRINE ORGANS whereas the sympathetic & parasympathetic systems are PART OF THE EFFERENT (OUTGOING) NERVOUS SYSTEM. (although both have a [partly] homeostatic function).
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Jpw1097
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(Original post by Patrax)
Thank you very much for the quick reply. So if I understood what you are saying correctly, the process by which cortisol is released is compared to the sympathetic nervous system in that its end result is 'similar', but it is a process entirely seperate from the sympathetic nervous system? (sorry my knowledge of human biology is inadequate )
Just as macpatgh-Sheldon has clarified, the adrenal medulla is indeed innervated by the sympathetic nervous system. In fact, the cells that make up the adrenal medulla (chromaffin cells) are essentially post-ganglionic neurones which secrete catecholamines (noradrenaline, adrenaline and dopamine) into the bloodstream. When the sympathetic nervous system is activated, the adrenal medulla secretes more catecholamines into the blood.

However, the sympathetic nervous system does not have any influence on the release of cortisol from the adrenal cortex (at least as far as I'm aware) - this is controlled by a negative feedback mechanism. As cortisol goes up, ACTH and CRH go down and vice versa, allowing the levels of cortisol to remain relatively constant.
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Patrax
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thank you very much, I appreciate your input enormously and it has helped hugely!
(Original post by Jpw1097)
Just as macpatgh-Sheldon has clarified, the adrenal medulla is indeed innervated by the sympathetic nervous system. In fact, the cells that make up the adrenal medulla (chromaffin cells) are essentially post-ganglionic neurones which secrete catecholamines (noradrenaline, adrenaline and dopamine) into the bloodstream. When the sympathetic nervous system is activated, the adrenal medulla secretes more catecholamines into the blood.

However, the sympathetic nervous system does not have any influence on the release of cortisol from the adrenal cortex (at least as far as I'm aware) - this is controlled by a negative feedback mechanism. As cortisol goes up, ACTH and CRH go down and vice versa, allowing the levels of cortisol to remain relatively constant.
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Patrax
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Thank you very much for your time and patience. I shall put macpatgh-Sheldon in my references section!
(Original post by macpatgh-Sheldon)
Hi, no need to apologize about inadequate knowledge - it comes with time and perseverance!

I hope I am not confusing even more, but although you have now got the right idea (yes, the adrenal medulla is separate from the autonomic nervous system and your understanding is correct), the analogy of the adrenal to the sympathetic NS relates to the adrenal medulla (central area of the gland), which secretes the catecholamines (adrenaline and NA) NOT to the adrenal cortex (the outer layer of the gland), which secretes the corticosteroids (like cortisol). Apologies for this extra complication, but I brought in this additional info based purely on the fact that you mentioned "part of the sympathetic and parasympathetic systems" in your original post.

THE PITUITARY AND ADRENAL GLANDS ARE ENDOCRINE ORGANS whereas the sympathetic & parasympathetic systems are PART OF THE EFFERENT (OUTGOING) NERVOUS SYSTEM. (although both have a [partly] homeostatic function).
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Leah.J
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(Original post by Jpw1097)
Just as macpatgh-Sheldon has clarified, the adrenal medulla is indeed innervated by the sympathetic nervous system. In fact, the cells that make up the adrenal medulla (chromaffin cells) are essentially post-ganglionic neurones which secrete catecholamines (noradrenaline, adrenaline and dopamine) into the bloodstream. When the sympathetic nervous system is activated, the adrenal medulla secretes more catecholamines into the blood.

However, the sympathetic nervous system does not have any influence on the release of cortisol from the adrenal cortex (at least as far as I'm aware) - this is controlled by a negative feedback mechanism. As cortisol goes up, ACTH and CRH go down and vice versa, allowing the levels of cortisol to remain relatively constant.
Hello, could any of you please help me in my question ?
https://www.thestudentroom.co.uk/showthread.php?p=82918592&highli ght=transcription%20factors
Last edited by Leah.J; 9 months ago
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Patrax
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the link provided does not work for me
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Leah.J
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(Original post by Patrax)
the link provided does not work for me
Does this one https://www.thestudentroom.co.uk/sho...tion%20factors work ?
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