1. Module 4 Responding to the environment
2.4.6 Organising the nervous system

2. Learning Objectives Success Criteria
To understand what affects the transmissions of action potentials
Outline why animals need to respond to the environment
(Grade E - D)
Outline the organisation of the nervous system
(Grade C –B)
Outline the roles of the autonomic nervous system
(Grade B – A) 2

3. Recap – 2 marks each. Question 1 Question 2
Saxitoxin is a chemical that blocks voltage gated sodium ion channels.
What effect is it likely to have on the nervous system?
Guillane-Barre syndrome is an auto-immune disease whereby the myelin sheath around certain neurones is damaged.
How does this result in muscle weakness and paralysis?
Sodium ions unable to diffuse into the neurone through the channels.
Neurone will not be depolarised so no action potentials
Conduction of impulses slower – similar effect to an unmyelinated neurone.
Nerve impulse may be conducted more slowly or not at all

4. Starter
D, B,C

5. Why animals need to respond to the environment.
Write down one reason on your paper why animals need to respond to the environment. Pass your paper to your neighbour, repeat.

6. The Nervous System Major division - Central vs. Peripheral
Central Nervous System
Peripheral Nervous System
Major division - Central vs. Peripheral
Central or CNS- brain and spinal cord
Peripheral- nerves connecting CNS to muscles and organs

7. Organisation of the nervous system – draw a flow chart to summarise the below:
The mammalian nervous system is composed of two systems.
The central nervous system and the peripheral nervous system. The PNS consists of all the neurones that connect the CNS to the body, divided into two groups, the somatic nervous system and the autonomic nervous system. One is under conscious control, for voluntary actions and the other is under subconscious control – involuntary actions.
This is further subdivided by function into two groups; parasympathetic and sympathetic nervous systems. An increase in activity is associated with the sympathetic nervous system and a decrease in activity is parasympathetic.

8. Peripheral Nervous System
3 kinds of neurons connect CNS to the body
sensory
motor
interneurons
Motor - CNS to muscles and organs
Sensory - sensory receptors to CNS
Interneurons: Connections Within CNS
Spinal
Cord
Brain
Nerves
key words: peripheral nervous system

9. Peripheral Nervous Systemk e l t a ( o m i c ) y p h P r s A u n N v
key words: peripheral nervous system; skeletal nervous system; somatic nervous system; autonomic nervous system; sympathetic nervous system; parasympathetic nervous system
Use pages to add to flow chart the roles of autonomic nervous system

10. Somatic System Nerves to/from spinal cord
control muscle movements
somatosensory inputs
Both Voluntary and reflex movements
Skeletal Reflexes
simplest is spinal reflex arc
Muscle
Motor
Neuron
Interneuron
Skin receptors
Sensory
Brain

11. Autonomic System Two divisions: Control involuntary functions
sympathetic
Parasympatheitic
Referred to as antagonistic systems in many cases the action of one system opposes the action of the other.
Under normal resting conditions, impulses are passing along the neurones of both systems at a low rate. Changes to internal conditions, alter the balance of stimulation between 2 systems, which leads to a response
Control involuntary functions
Can be influenced by thought and emotion

12. The Autonomic Nervous System
The system can have different effects on the same kinds of muscles because the motor neurones involved secrete different kinds of neurotransmitters at the synapses.
Sympathetic NS uses noradrenaline
Parasympathetic NS uses acetylcholine

14. Sympathetic “ Fight or flight” response
CENTRAL NERVOUS SYSTEM
Brain
Spinal
cord
SYMPATHETIC
Dilates pupil
Stimulates salivation
Relaxes bronchi
Accelerates heartbeat
Inhibits activity
Stimulates glucose
Secretion of adrenaline,
nonadrenaline
Relaxes bladder
Stimulates ejaculation
in male
Sympathetic
ganglia
Salivary
glands
Lungs
Heart
Stomach
Pancreas
Liver
Adrenal
gland
Kidney
“ Fight or flight” response
Release adrenaline and noradrenaline
Increases heart rate and blood pressure
Increases blood flow to skeletal muscles
Inhibits digestive functions
keywords: sympathetic nervous system; fighlt or flight response

15. Parasympathetic “ Rest and digest ” system
CENTRAL NERVOUS SYSTEM
Brain
PARASYMPATHETIC
Spinal
cord
Stimulates salivation
Constricts bronchi
Slows heartbeat
Stimulates activity
Contracts bladder
Stimulates erection
of sex organs
Stimulates gallbladder
Gallbladder
Contracts pupil
“ Rest and digest ” system
Calms body to conserve and maintain energy
Lowers heartbeat, breathing rate, blood pressure
key words: parasympathetic nervous system; rest and digest system

16. Plenary – comparison of autonomic nervous system
Organ
Sympathetic System
Parasympathetic System
Eye
Tear glands
Salivary glands
Lungs (Bronchi)
Heart rate
Gut (digestion)
Liver (chemicals produced)
Bladder
Blood vessels
Sweat glands
Dilates pupil
No effect
Inhibits saliva production
Dilates bronchi
Speeds up heart rate
Inhibits peristalsis
Stimulates glucose production
Inhibits urination
Vasoconstriction
Secretion of sweat
Constricts pupil
Stimulates tear secretion
Stimulates saliva production
Constricts bronchi
Slows down heart rate
Stimulates peristalsis
Stimulates bile production
Stimulates urination

17. Plenary - answers Organ Sympathetic System Parasympathetic System Eye
Tear glands
Salivary glands
Lungs
Heart
Gut
Liver
Bladder
Blood vessels
Sweat glands
Dilates pupil
No effect
Inhibits saliva production
Dilates bronchi
Speeds up heart rate
Inhibits peristalsis
Stimulates glucose production
Inhibits urination
Vasoconstriction
Secretion of sweat
Constricts pupil
Stimulates tear secretion
Stimulates saliva production
Constricts bronchi
Slows down heart rate
Stimulates peristalsis
Stimulates bile production
Stimulates urination

18. Keywords
Neurons that receive information from our sensory organs (e.g. eye, skin) and transmit this input to the central nervous system are called afferent neurones. (think a – into brain)
Neurons that send impulses from the central nervous system to your limbs and organs are called efferent neurones. (think e – to receptors)
Ganglia are the clusters of cell bodies typically linked by a synapse. Ganglia contain the cell bodies of afferent neurones.

19. Progress check
State and explain why breathing, which is an involuntary response, can also be controlled by the somatic nervous system.(2)
Sort these into those which are controlled by the somatic ns and those by the autonomic ns (2)
Pupil dilation, throwing a ball, blood pressure, walking

20. Answers
Breathing can be controlled when you (eg) swim underwater (1) to prevent water from entering the lungs (1)
Somatic – throwing a ball, walking (1)
Autonomic – pupil dilation, blood pressure (1)

21. Compare and contrast the sympathetic and parasympathetic systems
Refer to: length of pre and post ganglionic neurones, location of ganglions, neurotransmitter used, general action of the system, action at most active times
Compare and contrast the sympathetic and parasympathetic systems
Just outside CNS
Each lead to separate effector
In the effector tissue

22. Compare and contrast

23. Why does the sympathetic nervous system inhibit digestion?
What changes are made in your body when you walk down a quiet road late at night and you think that you’re being followed?
The sympathetic system prepares the body for activity – oxygen and nutrients must be supplied to the muscles.
Therefore blood is diverted towards the muscles and away from the digestive system.
Increase in: heart rate, stroke volume, breathing rate, depth of breathing, blood pressure.
Diversion of blood towards muscles.

24. Learning Objectives Success Criteria
To understand what affects the transmissions of action potentials
Outline why animals need to respond to the environment
(Grade E - D)
Outline the organisation of the nervous system
(Grade C –B)
Outline the roles of the autonomic nervous system
(Grade B – A) 24

25. Homework
Revise: Structure and cardiac cycle of the heart Discover: The gross structure of the brain