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March 29, 2024, 05:41:57 am

Author Topic: Intro to homeostasis  (Read 1999 times)

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Bri MT

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Intro to homeostasis
« on: June 25, 2019, 02:30:05 am »
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There are lots of elements inside us which require a narrow range of specific conditions – therefore, it’s important that we are to maintain these conditions. In other words, we need homeostasis.
We use the ‘homeo’ –> similar to   part of the word to remind us that homeostasis is about keeping things the same or very similar.

So how does it work?
When there’s a change (stimulus), we learn about it through receptors, the message is then passed along to a control centre which interprets the stimulus, and then passes the message on to the appropriate muscles or glands (effectors) to reduce the impact of this change.

The above process is also known as a negative feedback loop as the effectors role is to reduce (have negative impact on) the stimulus . For example, if a photoreceptor noticed the stimulus of high light levels, a negative feedback loop would result in the pupil constricting so that less light is incident on the eye. If this then meant there was too little light on the photoreceptors, a negative feedback loop would result in the pupil dilating so that there was more light incident on the eye.

What types of sensory receptors are there?
We can classify receptors by the type of stimulus that they respond to as follows:
- chemoreceptor: responds to the presence or concentration of a chemical
- thermoreceptor: responds to heat
- mechanoreceptor: responds to mechanical stimuli (eg touch, stretching)
- photoreceptor: responds to the presence of light
- nociceptor: responds to the presence of damaging or potentially damaging stimuli (pain receptor)

What are the types of effector?
- muscles, which contract in response to neural stimuli
- glands, which produce secretions (eg. might be responsible for release of a particular hormone)


tips for this topic
- use diagrams everywhere
- focus on understanding rather than just memorisation
- practice! here's a question below to get you started:

The role of a receptor in a negative feedback loop is to:
a) interpret the appropriate response to minimise a change
b) detect a change in the environment
c) release a secretion to reduce a stimulus
d) release a secretion to increase a stimulus

answer
b