1. The Nervous System

2. The Nervous system receives, processes, stores, and transmits information that comes from various parts of the body and the external world

3. Neuron and Nerve Impulses
The Neuron- a specialized nerve cell in the nervous system that receives and transmits messages Nerve Impulse- an electrical signal transmitted by a neuron Stimulus is anything that can be perceived by a living organism and can trigger a reaction. Ex. Sound, light, heat, odours, electrical shock, hormones

6. Parts of Neuron Nerve cell with 4 parts: dendrites, a cell body,
an axon,
axon terminals

8. Characteristics Can be stimulated, changed into an electrical impulse
Conductive: transmits a nerve impulse from neuron to neuron
Consumes a great deal of oxygen and glucose

9. 4. People keep same neurons their whole life.
5. Cannot reproduce:
Amitotic (not able to divide by mitosis)

11. Transmission of Nerve Impulses
Impulse travels from neuron to neuron until it reaches the target:
1. Dendrites receive stimuli and transform them into nerve impulses.
Nerve impulses transmitted along axons to axon terminals
Neurotransmitters (chemical substances) secreted by axon terminals across the synapse between two neurons

13. Synapse
Synapse is the transition zone between two neurons that allows a nerve impulse to be transmitted
Myelin: Insulating sheath which covers the axon like rubber and plastic on an electrical wire (insulates the impulse)

14. Synapse

16. Nerve Axons of neurons can combine to form nerves
Nerve: a structure that helps transmit information between the central nervous system and various regions of the body

18. The Peripheral Nervous System
Connects different parts of the body to the central nervous system
Made up of all the nerves that run throughout the body

20. Distribution of Information
Stimulus →
Sensory receptor→
Sensory Nerve →
Central Nervous System
(Brain & Spinal) →
Motor Nerves→
MUSCLES

21. Sensory Receptors
Specialized nerve cells, that pick up stimuli and turn them into nerve impulses
Ex. Smell, sound, muscles stretching etc.

22. Sensory Nerves Receive and transmit info. from the sense
receptors to the central nervous system (CNS)
Ex. Sight (optic nerve connected to eye)

23. Optic Nerve

24. Motor Nerves
Transmit impulses from the CNS to the muscles in order to produce voluntary and involuntary movements
(Transmit commands to the muscles to contract)
Ex. Light is bright, pupils in eyes contract

26. Main Parts CNS can be divided into three main parts 1. Brain
2. The Spinal cord

28. The Brain

29. Cranial Nerves
Brain communicates with the body through pairs of cranial nerves.

31. Parts of the Brain
Cerebrum: control centre of voluntary movement, sensory interpretations and intelligence, centre of emotion

32. Cerebrum contiued Cerebral cortex- outer layer of grey matter
that directs higher functions
Ex. Planning, reasoning, logic
White Matter- inner layer, made of axons

35. Cerebrum Functions
-Different areas for different sensations and commands Ex. Taste, visual, language etc.

37. Cerebellum Centre of balance and coordination
Regulates the contraction of the proper muscles for specific movements
- collects data from parts of body (eyes etc.)
- determines force and speed

38. Brain Stem
Controls internal stimuli as well as of involuntary movement
Ex. Respiratory, digestive, circulatory etc.

39. Spinal Cord The spinal cord is a nervous system organ
that carries information from the various parts of the body to the brain

42. Reflexes & Reflex Arc Reflexes - automatic and involuntary reactions
- let body perform rapid gestures

43. Reflex Arc
Involve voluntary muscles, which react without the person having to think
Spinal reflexes
- triggered by the action of the spinal cord
- protect body in dangerous situations
- reaction quicker than if it had to travel to
the brain

44. Ex. Hand touches hot stove
Doctor taps patient’s knee during exam