Homeostasis and response Flashcards
How do some drugs affect how impulses pass from one neuron to the next across a synapse?
Some drugs and toxins stop impulse passing across synapse, Drugs like curare used in arrow poison cause complete paralysis and can even stop person breathing.
What is serotonin?
Chemical released into synapses in brain, increase in serotonin levels in synapses make us feel happier.
What is ecstasy?
AKA MDMA drug blocks serotonin receptor sites in synapses in brain prevents serotonin being absorbed by receptor molecules.
Why do animals need stimulus?
Moving to somewhere warmer if they are cold.
Moving towards food if they are hungry.
Moving away from danger to protect themselves.
Animals that don’t respond to stimulus do not survive for long.
What is homeostasis?
Homeostasis is all about the regulation of the conditions inside your body (and cells) to maintain a stable internal environment, in response to changes in both internal and external conditions. You have lots of automatic control systems in your body that regulate your internal environment - these include both nervous and hormonal communication systems. For example, there are control systems that maintain your body temperature, blood glucose level and your water content. All your automatic systems are made up of three main components which work together to maintain a steady condition - cells called receptors, coordination centres (including the brain, spinal cord and pancreas) and effectors.
What are the negative feedback counteracts chanes?
Your automatic control systems keep your internal environment stable using a mechanism called negative feedback. When the level of something (e.g. water or glucose) gets too high or too low, your body uses negative feedback to bring it back to normal.
1) Receptor detects a stimulus - level is too high.
2) The coordination centre receives and processes the information, then organises a response.
3) Effector produces a response, which counteracts the change and restores the optimum level - the level decreases.
1) Receptor detects a stimulus - level is too low.
2) The coordination centre receives and processes the information, then organises a response.
3) effector produces a response, which counteracts the change and restores the optimum level - the level increases.
The effectors will just carry on producing the response for as long as they are stimulated by the coordination centre. This might cause the opposite problem - making the change too much (away from the ideal). Luckily the receptor detects if the level becomes too different and negative feedback starts again.
What are the parts and functions of the parts in the nervous system?
Central Nervous System (CNS): in vertebrates (animals with backbones) this consists of the brain and spinal cord only. In mammals, the CNS is connected to the body by sensory neurones and motor neurones.
Sensory Neurones: the neurones that carry information as electrical impulses from the receptors to the CNS.
Motor Neurones: the neurones that carry electrical impulses from the CNS to effectors.
Effectors: all your muscles and glands, which respond to nervous impulses.
How can Receptors and Effectors form part of Complex Organs?
1) Receptors are the cells that detect stimuli.
2) There are many different types of receptors on the tongue and sound receptors in the ears.
3) Receptors can form part of larger, complex organs e.g. the retina of the eye is covered in light receptor cells.
4) Effectors respond to nervous impulses and bring about a change.
5) Muscles and glands are known as effectors - they respond in different ways. Muscles contract in response to a nervous impulse, whereas glands secrete hormones.
