1. Nervous System and Neurones

2. What is Psychology: It is based on three processes:
Gathering factual information.
Forming theories to explain this factual information.
Testing these theories.

3. The Nervous System

4. Human Nervous System
A communication system that controls all parts of your body.
Made up of two parts:
Central Nervous System (CNS)
Made up of your brain and spinal cord
Peripheral Nervous System (PNS)
Made up of the nerves that send messages from the CNS to other parts of the body

5. Human Nervous System

6. Function of Parts of the Nervous System
Central Nervous system (CNS)
Transmits and receives messages to and from Peripheral Nervous System (PNS).
The spinal cord runs from the base of the brain (brain stem), inside the bones of the spine (vertebrae) to the lower middle section of the spine.

7. Function of Parts of the Nervous System
2. Peripheral Nervous system (PNS)
Communicate information from the body’s organs, glands and muscles to the CNS, via sensory neurons.
Communicate information from the CNS to the body’s organs, glands and muscles, via motor neurons.
The PNS has two subdivisions: the somatic nervous system and the autonomic nervous system.

8. Somatic Nervous System
Carries messages between CNS and the body.
Responsible for voluntary movement of skeletal muscles.

9. Somatic Nervous System
Sensory organs include mouth, skin, ears, eyes, nose. These organs/ tissues have receptor cells which detect changes.
The changes stimulate a message which is then sent to the brain for a response.
Types of receptors:
Mechanoreceptors
Photoreceptors
Thermoreceptors
Chemoreceptors
Pain receptors

10. Autonomic Nervous System
Carries messages from the CNS to the internal muscles, organs and glands.
Operates without voluntary control.

11. Autonomic Nervous System
Responsible for: breathing, heart beat, sweating, pupil size, movement of food in your intestines.
Two parts of the autonomic nervous system:
Sympathetic
Parasympathetic

12. Sympathetic Nervous System
During times of danger or stress, the Sympathetic Nervous System is responsible for:
Increases blood flow
Releases adrenaline
Stops other body functions such as digestion
Opens the bronchioles in the lungs which increases the amount of air entering the lungs
Increases heart rate
Diverts blood away from the digestive system and to muscles.

13. Parasympathetic Nervous System
During rest, the Parasympathetic Nervous System is responsible for:
Reduces diameter of the bronchioles
Slows down heart rate & blood flow
Increases blood flow to the digestive tract

14. Activity Complete the following activities:
Revision from Year 9 Body Coordination
Functions of the nervous system

15. Nerve Cells (Neurones)

16. Neurones
Trillions of neurones which carry electrical messages (nerve impulses) at very high speeds.
Can only travel in one direction (don’t travel backwards).
Two types of neurones:
Motor neurones
Sensory neurones

17. Structure of a neurone

18. Part
Function
Axon
Carries information away from the cell body to their ends. These impulses are called action potentials – changes in electric charge of the axon.
Cell body (Soma)
Makes energy and protein for the cell. Contains the nucleus
Dendrites
Receives information from other neurones or sensory receptors.
Myelin sheath
Layer of fat to insulate the axon. Increase the speed of electrical conduction.
Node of Ranvier
Gaps between the myelin sheath. They are not covered by myelin which helps generate electrical activity.
Synaptic terminal
Connects one neurone to another. Secrete a chemical called a neurotransmitter.

20. Sensory neurone Motor neurone
Also known as affectors or afferent neurons
Also known as efferent neurons or effectors
Receives information from external environment such as sense organs (skin) and inside the body (muscles and organs)
Transmits messages from the brain to muscles, organs, glands.
Sends a message to the brain via the spinal cord.
Tells muscles to move, organs to secrete hormones.