1. Control & Communication: Nervous & Hormonal Control
Biology
Control & Communication:
Nervous & Hormonal Control
Nervous System
Endocrine System

2. Learning Intentions What is the nervous system? What is the CNS?
What are the 3 main parts of the brain?
a) What is a reflex action?
b) What makes up the reflex arc?
c) What is a synapse?

3. 1. What is the Nervous System?
The nervous system is made up of the:-
Brain
Spinal Cord
Nerves
Sense Organs

4. 2. What is the CNS?
The central nervous system (CNS) is made up of the:-
Brain
Spinal Cord
Nerves carry information from the senses
to the CNS and from the CNS to the
muscles
The job of the CNS is to sort out information
from the senses and send information to the
muscles so they make a response.

5. 3. Parts of the Brain Part Function Cerebrum
control thought, memory, emotions, personality
Cerebellum
control balance and co-ordination
Medulla
control some automatic responses such as heart rate, breathing, peristalsis

6. 4a) Reflex Action
The nervous system is made up of cells called neurons
There are 3 basic types of neurons
Sensory Neurones Relay Neurones Motor Neurones
A Reflex Action in an involuntary response to a stimulus to avoid harm
SENSORY NEURONES detect the hot stimulus & send electrical impulses to the RELAY NEURONES in the spinal cord
Relay Neurone
RELAY NEURONES send electrical impulses to the MOTOR NEURONES, which make the muscles move
Motor Neurone
Sensory Neurone

7. 4b) Reflex Arc
Sense organs contain sensory neurones which carry information (via electrical impulses) from receptors to the CNS
Relay neurones are found in the CNS and transfer information (via electrical impulses) from sensory neurones to motor neurones
Motor neurones transfer information (via electrical impulses) from the relay neurone to the muscles

8. 4c) Reflex Response
Describe the steps involved in the following REFLEX ACTIONS
Remember to use the SENSORY NEURONE, RELAY NEURONE, MOTOR NEURONE
Hammer on Knee Cap
Touching hot plate
Sneezing due to dust

9. 4d) Synapse Axon (End of Neurone) Sac of chemical transmitter
Receptors
Two neurones meet at a gap called a synapse.
Chemical transmitters are released into the synapse from the leading neurone which allows an electrical impulse to be transferred to the next neurone

10. Learning Intentions What is the Endocrine System? a)What are Hormones?
b)Where do Hormones have an effect?
a) What is Homeostasis?
Why is it important that our Glucose,
Water & Body Temperature are
controlled?
b) & c) Describe Blood Glucose Control
Diabetes

11. 5.What is the Endocrine System?
The Endocrine System is made up of endocrine glands which secrete hormones into the bloodstream.

12. 6a) What are Hormones?
Hormones are chemical messengers produced at one site and have their effect at another site
Hormones are proteins that act as chemical messengers
Endocrine Gland
Hormone
Effect
Pituitary Gland in the brain
Human Growth Hormone
Stimulates growth of long bones
Pituitary Gland
in the brain
Anti-diuretic Hormone
Controls water reabsorption in the kidneys
Islets of Langerhans in the Pancreas
Insulin
Controls conversion of excess glucose in the liver

13. 6b) Where do Hormones have an effect?
Hormones travel in the blood to their Target Tissues.
Target tissues have specific receptors for particular hormones, so when the hormone reaches the target tissue it stimulates an effect.
Non- Target tissues don’t have specific receptors for the hormones so they remain unaffected

14. 6c) Differences between Messages
Feature
Messages via
Hormones
Messages via Nerves
How is the information passed on?
Chemicals
Electrical Impulses
How is the message carried around the body?
Blood
Nerves
How long does the message last?
Long lasting
Short lasting

15. 7a) What is Homeostasis?
Homeostasis is the control of the internal environment in the body
Homeostasis is important so that body cells can function properly
Homeostasis controls water concentration in the blood (osmoregulation).
This prevents cells from bursting or shrinking due to osmosis
Homeostasis controls body temperature (thermoregulation).
This ensures enzymes are working at an optimum temperature
Homeostasis controls glucose concentration in the blood.
This ensures that cells receive the correct levels of glucose required for respiration

16. 7b) Homeostasis & Blood Glucose Levels

17. 7c) Controlling Blood Glucose Levels
The pancreas monitors the concentration of glucose in the blood
Receptor cells in the pancreas detect changes in blood glucose concentration
When blood glucose INCREASES
pancreas releases the hormone insulin
insulin travels in the blood to the liver
liver then converts the glucose to glycogen (an insoluble storage carbohydrate)
blood glucose concentration decreases
When blood glucose DECREASES
pancreas releases the hormone glucagon
glucagon travels in the blood to the liver
liver converts glycogen to glucose
blood glucose concentration increases

18. 8. Diabetes Diabetes is a disease caused by a failure to
control blood glucose concentration.
There are 2 types of Diabetes
Diabetes Type
Communication pathway problem
Thought to be caused by
Treatment
Type 1 Diabetes
Pancreatic cells can no longer make insulin
Genetics
Environmental Factors
Autoimmune Factors
Insulin injections
Insulin pump
Careful diet
Type 2 Diabetes
Target tissues do not respond to insulin
Unhealthy diet leading to obesity
Physical Inactivity
Exercise
Weight loss
Diet Control
Sometimes insulin