The Diaphragm..

Duffman

Erm.. not sure if this belongs here but anyway


Anyone like to enlighten some stressed-out LC biology students...?





http://www.boards.ie/vbulletin/showthread.php?postid=952649#post952649

GuanYin

The diaphragm is indeed skeletal muscle.

The reason being is there is no sympathetic or parasympathetic nerves connecting to it.

All movement of the diaphragm is regulated conciously or is a result of lung and/or intestinal wall movement.

dosser

All movement of the diaphragm is regulated conciously or is a result of lung and/or intestinal wall movement.

What about when one is in a coma? Is it conscious then? (and if the diaphragm doesn't move then well then the biology book is wrong!!!! or at the very least doesn't go into the detail required). I don't understand what you mean by "lung.... movement" but it sounds very 'smooth muscley' to me. Intestinal wall movement is in fact smooth muscle movement according to what i have read and if it moves the diaphragm then I think I could safely make the educated conclusion that the diaphragm is moved by smooth muscle.

GuanYin

Originally posted by dosser
What about when one is in a coma? Is it conscious then? (and if the diaphragm doesn't move then well then the biology book is wrong!!!! or at the very least doesn't go into the detail required). I don't understand what you mean by "lung.... movement" but it sounds very 'smooth muscley' to me. Intestinal wall movement is in fact smooth muscle movement according to what i have read and if it moves the diaphragm then I think I could safely make the educated conclusion that the diaphragm is moved by smooth muscle.

*Sigh*

Well if you are going to be pedantic then at least define what type of coma (there are many many different types), some require artificial breathing apparatus, some don't.


The respiratory system has two main components: active components such as respiratory muscles which generate the pressures required to produce airflow between the alveoli and the mouth, smooth muscle in the airways which
regulates the resistance to flow offered by the airways.
Energy is needed for both components.

secondly there are passive components: the airways (their size depends on lung volume) and (always) the
gas exchange surfaces of the lung (alveoli).

Some components can be active and passive (and the diaphragm i sone of thse). These include, in addition to the airways, the abdominal muscles. At rest, people do not use their abdominal muscles (maybe a bit when upright but not when supine); thus, during inspiration, the descent of the diaphragm increases abdominal pressure, which forces the abdominal wall outwards. At higher levels of ventilation, however, the abdominal muscles are active during expiration.

You are thinking about the system in too simple a term, which leads me to believe you don't understand it properly or it isn't taught very well at LC level. None of this, however, takes away from the FACT that the answer to diaphragm question is skeletal muscle.

Capt'n Midnight

Iron Lungs n' Narcolepty (or is narcissus syndorme) - can't remember what it is called - it's where some people only have voluantry control over breathing - if they aren't hooked up to a ventilatior at night - they will simply stop breathing when they fall asleep.

Also there was a way of doing CPR where you moved the arms - to get the chest to moving - breating without muscles.

BTW: mice have a very high surface to volume ratio - even a large dose of carbon monoxide doesn't kill them - they can take in enough O2 via the skin to keep going (though they'd be more or less in coma for a while)