Biology - Coordination and Response

what is homeostasis

the control or regulation of the internal conditions of a cell or organism

what are some examples of homeostasis

1. water content

2. temperature

3. pH

4. blood pressure

5. blood glucose concentration

what are the four things that all control systems need to function

1. stimulus

2. receptor

3. coordination centre

4. effector

what is it called when plants grow in response to light

phototropism

what is geotropism

when plants grow in response to gravity

when a plant grows upwards, why is it known as negative geotropism

because the plant is growing away from the force of gravity pushing downwards, and a negative tropism is when you grow away from a stimulant

what are the plant growth regulators known as in plants

auxin

what is the endocrine system responsible for

producing chemical substances known as hormones, via the endocrine glands

what are the components of the CNS and PNS

1. the CNS contains the brain and spinal cord

2. the PNS contains the nerves

what is the word used to describe the information sent through the nervous system

electrical impulses

what is a nerve

a bundle of neurones

name the reflex arc

stimulus → sensory neurone → relay neurone → motor neurone → effector → response

where are synapses found

the dendrites of two neurones

what is the chemical molecule used to carry the electrical impulse across a synapse

neurotransmitter

where are neurotransmitters released from

vesicles found in the presynaptic neurone

describe how an electrical impulse crosses a synapse

electrical impulses travel along the axon to the presynaptic neurone. This triggers the end of the presynaptic neurone to release neurotransmitters from the vesicles. These vesicles fuse with the presynaptic membrane, releasing their contents into the synapse. The neurotransmitters diffuse across the synapse and bind with the postsynaptic membrane. This stimulates the postsynaptic membrane to generate an electrical impulse which travels down the second axon.