|
Nervous system:
Part 2. Comparing
response-control systems: endocrine - hormones and nerve cells - nervous system
[Author
©
Dr WP Brown PhD:
Doc Brown's biology exam revision notes suitable for students of UK
IGCSE & GCSE level biology courses & ~ US grades 9-10 biology, updated
August 26th 2025]
[Key
points and learning objectives for this page, after the main body of
notes]
Sub-index of biology notes on the nervous system
(2)
Comparing two control systems
(endocrine-hormone systems and nerve cells-nervous system)
The nervous system and endocrine hormone
system are two quite different mechanisms of control in the body,
BUT, in principle they function in similar ways AND interact with each other
too.
The endocrine system uses chemical
molecule messengers (hormones) to communicate information.
See
Homeostasis - introduction to how it functions (negative
feedback systems explained)
and
Hormone system - Introduction to the endocrine
system - role of thyroxine
The nervous system uses electrical
impulse messages to communicate information.
|
Endocrine hormone system |
Receptor detects changes in the environment |
Chemical messenger - hormone molecule
signal
Slower, but acts for much longer - carried in
blood to all organs, but only affects target organ |
Coordination centre
A gland
e.g. pancreas
Receives signal and processes information |
Chemical messenger - hormone molecule
signal
Slower, but acts for much longer - carried in
blood to all organs, but only affects target organ |
Effector
A gland that secretes a hormone to restore an
optimum level or trigger some other chemical response |
|
Nervous system |
Receptor detects changes in the environment |
Electrical signal - nerve impulse
Rapid and short duration - carried in nerve
fibres to specific locations like muscles |
Coordination centre
Brain or
spinal cord
Receives signal and processes information |
Electrical signal - nerve impulse
Rapid and short duration - carried in nerve
fibres to specific locations like muscles |
Effector
Muscles that respond to the signal |
Comparing nerve
and hormone functions
Hormones effectively act as
'chemical messages' to trigger particular biochemical reactions and their
effects are ..
more general around the body, but
tend to affect particular cells in particular organs,
and relatively long-lasting compared to e.g. the
fast but short-term nervous impulses and responses of a reflex arc.
Compared to the hormone
system of response and control in the body, nerve signals are
electrical (not chemical, except at synapses), the nerves act very fast - a short burst of a
nervous impulse for a short time, acting from one precise area to
another in the body.
Key points
-
comparing the hormone and nervous control systems of the human body
Source of information is based on textbooks
and syllabus-specifications for students taking the AQA
GCSE, Edexcel GCSE and OCR
GCSE level biology examinations (~US grades 9-10)
Comparing the Human Body’s Two
Control Systems
The human body needs coordination and control to respond to internal and external changes.
It does this through two main systems:
-
The Nervous System
– using electrical impulses via neurons.
-
The Endocrine System
– using chemical messengers (hormones) in the blood.
Comparison Table
|
Feature |
Nervous System |
Endocrine System |
|
Type of signal |
Electrical impulses |
Chemical hormones |
|
Speed of response |
Very fast (milliseconds) |
Slower (seconds to hours or longer) |
|
Duration of response |
Short and brief |
Longer-lasting |
|
Pathway |
Neurons (nerve cells) |
Bloodstream |
|
Target area |
Specific muscles or glands |
Widespread; affects various organs |
|
Examples |
Reflexes, muscle movement |
Blood sugar control, puberty,
metabolism |
Nervous System – Quick Overview
-
Uses neurons
to carry fast signals from receptors to effectors.
-
Responsible for
reflexes, conscious movement, sensing danger.
-
Includes the brain,
spinal cord, and peripheral nerves.
Example: Moving your
hand away from a hot object is an automatic reflex involving
sensory and motor neurons.
Endocrine System – Quick Overview
-
Glands release
hormones into the blood.
-
Hormones travel to
target organs with specific receptors.
-
Controls growth,
development, metabolism, and
homeostasis.
Example:
The pancreas releases insulin to lower blood glucose levels.
Importance in Understanding Human
Biology
Knowing how these systems work is
vital because:
-
They help maintain
homeostasis (e.g. temperature, glucose levels).
-
Disruptions can cause health
issues like diabetes or thyroid problems.
-
Understanding them supports
knowledge of reflexes, adrenaline response,
and hormonal regulation (e.g. menstrual cycle, puberty).
Exam Tips
You may be asked to:
-
Compare
the two systems.
-
Give examples
of their actions.
-
Interpret data related to
hormonal changes or nervous responses.
-
Explain which system is
involved in specific situations.
Keywords, phrases and learning objectives for this part on comparing the
endocrine and nerve control systems
Be able to compare the endocrine-hormone systems
and the nerve cells-nervous systems control systems and understand
how they operate in completely different ways.
WHAT NEXT?
TOP OF PAGE
INDEX
of biology notes on the nervous system
INDEX of all my BIOLOGY NOTES
This is a BIG website, so try using the [SEARCH
BOX], it maybe quicker than the many indexes!
email doc
brown - comments - query?
Basic Science Quizzes for
UK KS3 science students aged ~12-14, ~US grades 6-8
Biology * Chemistry
* Physics for UK
GCSE level students aged ~14-16, ~US grades 9-10
Advanced Level Chemistry
for pre-university age ~16-18 ~US grades 11-12, K12 Honors
Find your GCSE/IGCSE
science course for more help links to all science revision notes
SITEMAP Website content © Dr
Phil Brown 2000+. All copyrights reserved on Doc Brown's biology revision notes, images,
quizzes, worksheets etc. Copying of website material is NOT
permitted. Exam revision summaries and references to science course specifications
are unofficial.
|
