1. Comparison of coordination by hormones and the nervous system

2. Control and coordination
A system which matches specific responses to particular stimuli to ensure “the right thing happens in the right place at the right time to the right degree

3. Achieved by: The endocrine system.
Hormones secreted by endocrine glands carried in the bloodstream to particular target organs whose cells have hormone-specific receptors in their membranes e.g.
adrenal glands/adrenaline,
pancreas/insulin
thyroid gland/thyroxine
pituitary gland/ADH
kidney/EPO
Hormones are chemicals affect chemical processes in the target cells e.g.
insulin: glucose  glycogen
testosterone  protein synthesis
Most of these responses are
long term
permanent

4. The nervous system
Coordination and control is achieved by the transmission of electrical signals -nerve impulses - along specialised cells –- neurones.
Nerve impulses cause a response in effectors e.g.
contraction in muscles
secretion by glands
Responses are
short duration
not permanent

5. Nervous system
Signal = nerve impulses (electrical)
+chemicals at synapses
Nerve impulses transmitted by neurones (=cells)
Hormones
(endocrine system)
Signal = hormones (chemicals)
Hormones transmitted by blood stream

6. Nervous system
Signals transmitted very rapidly
Responses are rapid
Reponses short term; only while impulses arrive
Hormones
Signals transmitted slower
Responses are generally slower
Responses normally more long term, until hormone broken down

7. Response local in specific effectors only
Nervous
Response local in specific effectors only
Effectors are muscles or glands
Response is contraction or secretion
Hormones
Response more widely spread
Effectors are target cells with specific receptors in membranes
Response is a chemical change e.g.
glucose  glycogen,
protein synthesis

8. Nervous
Response is not permanent
Controls specific rapid responses to rapid changes in the environment
Hormones
Response often a permanent change
Controls more longer duration responses to changes in the environment e.g. insulin/blood sugar, ADH/water and long term changes associated with growth and development