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Biology
Control & Communication:
Nervous & Hormonal Control
Nervous System
Endocrine System
Learning Intentions
1. What is the nervous system?
2. What is the CNS?
3. What are the 3 main parts of the brain?
4. a) What is a reflex action?
b) What makes up the reflex arc?
c) What is a synapse?
1.
What is the Nervous System?
The nervous system is made up of the:-
Brain
Spinal Cord
Nerves
Sense Organs
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.
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
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
Sensory Neurone
RELAY NEURONES send electrical impulses to the MOTOR NEURONES, which make the
muscles move
Relay
Neurone
Motor Neurone
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
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
4d) Synapse
Axon
(End of
Sac of chemical
Neurone) transmitter
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
Receptors
Learning Intentions
5. What is the Endocrine System?
6. a)What are Hormones?
b)Where do Hormones have an effect?
7. a) What is Homeostasis?
Why is it important that our Glucose,
Water & Body Temperature are
controlled?
b) & c) Describe Blood Glucose Control
8. Diabetes
5.What is the Endocrine System?
The Endocrine System is made up of endocrine glands which secrete
hormones into the bloodstream.
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
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
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 Blood
around the body?
Nerves
How long does the
message last?
Short lasting
Long lasting
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
7b) Homeostasis & Blood Glucose Levels
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
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
Genetics
Exercise
Weight loss
Diet Control
Sometimes insulin