topic 4

nerves and hormones are involved in sensing and responding to changes in the environment

nerves:
*fast
*electrical
*travel along nerve cells
*specific actions

animal nervous system:
*receptor - a receptor is stimulated - something must trigger them

*coordinator (which is the brain and spinal cord [CNS] ) - information is sent for the receptor which determines what response is required

*effector - produces a respose (usually a muscle or a gland)

insulin:
*helps to lower blood glucose level
*release from pancreas into the blood

when blood glucose levels are low, less insulin is released so glycogen is converted into glucose in the liver. the rate of respiration is decreased. it causes less glucose to enter cells.

most common symptoms are:
*high blood glucose levels
*glucose in the urine
*constant thirst
*frequent toilet visits
*irritability and confusion

plant hormones
plants like animals respond to stimuli as light. plants grow towards the light, this is called phototropism. the hormones responsible for this are auxins