2.85

describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object

2.84

understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses

2.83

recall that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves

2.82

describe how responses can be controlled by nervous or by hormonal communication and understand the differences between the two systems

Hormones: are produced by endocrine glands and is released directly into the bloodstream where it easily finds its target cells at a small distance from the point of release.

Neurotransmitters are secreted by vesicles in the synaptic bulb and travel across the synapses of neurons as opposed to hormones traveling in the bloodstream.

2.77b Thermoregulation

understand that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are examples of homeostasis.

Homeostasis uses a negative feedback loop to control or maintain constant conditions inside the body.

Receptor(Hypothalamus in brain) ---> co-ordinator (body temperature 37C) ----> effector (skin)
Response (decrease of body temperature) ---> stimuli (temperature of blood) ---> Receptor

2.77a Thermoregulation

understand that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are examples of homeostasis.

Homeostasis refers to a constant of conditions.
Homeothermic means the same temperature.

Homeothermic organisms have a constant body temperature in relation to environmental temperature. They maintain this condition by usage of a process called thermoregulation.
Mammals maintain a constant body temperature because the optimal temperature of their enzyme catalysed biological reactions is approximately the same as their body temperature.

2.76 Sensitivity

Understand that organisms are able to respond to changes in the environment.