The School of Biomedical Sciences Wiki - User contributions [en]

Placenta

2013-10-17T11:17:25Z

120038534: Created page with "The placenta is an organ that is joined to the uterus in pregnant women in order to provide a connection between the foetus and the mother's blood stream. This allows movement of..."

The placenta is an organ that is joined to the uterus in pregnant women in order to provide a connection between the foetus and the mother's blood stream. This allows movement of nutrients, oxygen, water and IgG antibodies into the foetal blood stream, and removal of waste gases and other waste products. 

The placenta also acts as an endocrine gland, secreting hormones essential for the maintenance of pregnancy, such as oestrogen and progesterone. It also must secrete Neurokinin-B to prevent destruction by the immune system of the mother.

The placenta is expelled after giving birth to the baby, and the umbilical cord cut to separate the baby from the placenta

Acetylcholinesterase

2012-11-09T17:47:42Z

120038534:

Acetylcholinesterase is an enzyme found in a variety of tissues, including both muscle cells and red blood cells ([[Erythrocytes]]), but most notably in the nervous system, in [[Postsynaptic membrane]]s, where its primary function, unsurprisingly, is to break down the [[Neurotransmitter]] [[Acetylcholine]]. Acetylcholinesterase hydrolyses acetylcholine into [[Choline]] and [[Acetic acid|Acetic acid<ref>Marie T. O'Toole, 2003. Miller-Keane Encyclopedia &amp; Dictionary of Medicine, Nursing &amp; Allied Health. 7th Edition. W.B. Saunders Company.</ref>]]. This is important, as if acetlycholine were to be left un-hydrolysed, the [[Ion channels]] in the postsynaptic membrane would remain open, preventing another [[Resting potential]] from forming, which would, in turn, prevent the induction of another [[Action potential]].

Various substances inhibit acetylcholinesterase, including the [[Botulinum toxin]], produced by the bacterium [[Clostridium botulinum]] which thrives in badly-tinned food. Even small amounts of this toxin can kill a grown man, which shows how important acetylcholinesterase is. However, minute amounts of the toxin are used in the well known commercial substance [[Botox]]

 

 

 

 

 

 

= References =

<references />

Acetylcholinesterase

2012-11-09T17:46:10Z

120038534:

Acetylcholinesterase is an enzyme found in a variety of tissues, including both muscle cells and red blood cells ([[Erythrocytes]]), but most notably in the nervous system, in [[Postsynaptic membrane]]s, where its primary function, unsurprisingly, is to break down the [[Neurotransmitter]] [[Acetylcholine]]. Acetylcholinesterase hydrolyses acetylcholine into [[Choline]] and [[Acetic acid|Acetic acid<ref>Marie T. O'Toole, 2003. Miller-Keane Encyclopedia & Dictionary of Medicine, Nursing & Allied Health. 7th Edition. W.B. Saunders Company.</ref>]]. This is important, as if acetlycholine were to be left un-hydrolysed, the [[Ion channels]] in the postsynaptic membrane would remain open, preventing another [[Resting potential]] from forming, which would, in turn, prevent the induction of another [[Action potential]].

Various substances inhibit acetylcholinesterase, including the [[Botulinum toxin]], produced by the bacterium [[Clostridium botulinum]] which thrives in badly-tinned food. Even small amounts of this toxin can kill a grown man, which shows how important acetylcholinesterase is. However, minute amounts of the toxin are used in the well known commercial substance [[Botox]]

 

 

 

 

 

 

= References =

<references />

Acetylcholinesterase

2012-11-09T17:45:11Z

120038534: Created page with " Acetylcholinesterase is an enzyme found in a variety of tissues, including both muscle cells and red blood cells (Erythrocytes), but most notably in the nervous system,..."