Homeostasis

What can organisms survive in?

Organisms survive must effectively within their tolerance limits.

What is a tolerance range?

The maximum and minimum tolerance limits.

Why would plants have tolerance limits for light?

Photosynthesis

What is homeostasis?

The maintenance of a stable internal state despite changes to environmental conditions.

Why should body temperature be kept within tolerance limits?

To ensure optimum enzyme function, as they will denature outside the tolerance limits.

What is a stimulus?

An internal or external change that is detected by a sensory receptor.

Pathway of the stimulus-response model

Stimulus, sensory receptor, sensory neuron, interneuron, motor neuron, effector, response.

What is the central nervous system (CNS)?

Comprised of the brain and spinal cord.

What is the peripheral nervous system (PNS)?

All other nerves aside from the brain and spinal cord.

What is the function of an interneuron?

To transmit information from sensory neurons to motor neurons.

Describe the structure of a nerve pathway from receptor to effector

A sensory receptor detects a change in the environment (stimulus) and transmits the message to a sensory neuron, and then to an interneuron in the CNS. The interneuron transmits the message to a motor neuron, which carries the message to an effector (muscle or gland) causing a response.

What is a synapse?

The gap between neurons, where neurotransmitters (chemical signals) are released by exocytosis by one neuron and then diffused across the synapse to reach the other neuron, where they bind to 3D complementary receptors.

What is a reflex response?

An automatic response to a stimulus without conscious thought