1. The Nervous System

2. Nervous System
The control system that enables animals to detect a stimulus and coordinate a response

3. Stimulus and Response
Stimulus: change in the environment that is detected by your body
Response: Your body’s reaction to this stimulus

4. Stimuli and Responses Eg. Stimulus: you are in a sauna…it’s very hot!
Stimulus: someone yawns in front of you
Stimulus: someone is about to poke you in the eye
Reponse:

5. Structural Features Central Nervous System Peripheral Nervous System
Brain and Spinal Cord
Peripheral Nervous System
Carries signals between the CNS and the Body
Relays information about the internal and external environments to the brain
Relays instructions from the brain to other parts of the body

6. Parts of the Human Nervous System
Central nervous system
made up of the brain and spine
coordinates all components of the nervous system

7. Parts of the Human Nervous System
Peripheral nervous system
All other nerves
Relays information between
central nervous system and
other body parts

8. Parts of the Peripheral Nervous System
Somatic nervous system
Nerves that control voluntary muscles
Nerves that carry information from the sensory organs (eyes, ears, taste buds, touch receptors)
Autonomic Nervous system
Motor neurons that are unconsciously controlled
Eg. Heart, body temp, blood pressure, pupil dilation, gland secretions

9. Nervous System Central Nervous System Peripheral Nervous System Brain
Spinal Cord
Somatic Nerves
Somatic Nervous System
Autonomic Nerves
Autonomic Nervous System
Voluntary
Involuntary
Sensory
Motor
Sympathetic
Parasympathetic

10. Parts of the Autonomic Nervous System
Sympathetic nerve
Prepares body for danger
Parasympathetic nerve
Returns body to normal relaxed state after stress
Sympathetic nerves counteract the effect of parasympathetic nerves

11. Sympathetic and Parasympathetic Nerves

12. Parts of the Nervous System

13. Nerve Tissue Nerve tissue is made up of special cells called neurons
Functional unit of the nervous
system.
Uses electrical signals called
impulses to communicate with
other cells

14. Parts of a Neuron Dentrites Axon Myelin sheath
carry impulses from outside
the cell into the cell body
Axon
carries the impulse away from
the cell body towards neighbouring cells
conducting wire
Myelin sheath
sometimes covers the axon, speeds up transmission of the nerve impulse

16. Parts of a Neuron Terminal knobs attach the neuron to other
cells (other neurons or
target cells)
Neurotransmitters
Chemical released by the terminal knobs
that carries the impulse from 1 neuron
to another
Synapse
Space between the axon of
one neuron and dentrites of
an adjacent neuron
Direction of impulse is always from
the dentrites to the terminal knobs

17. Synapse

18. Nerve
Nerves are bundles of neurons that are surrounded by connective tissue

19. Did you know? Average number of neurons
human brain= 100 billion
octopus brain= 300 billion
Longest axon of a neuron = around 15 feet (Giraffe primary afferent axon from toe to neck)
Velocity of a signal transmitted through a neuron= 1.2 to 250 miles/hour
adult brain:
Human = 3 pounds (1,300-1,400 g)
elephant = 6,000 g
longest axon of a human neuron can be over a meter long, reaching from the base of the spine to the toes

20. Types of Neurons Sensory neurons Motor neurons Interneurons
carry impulses from sensory receptors (eye, ear, nose, skin, tongue) to the brain
Motor neurons
carry impulses from the brain or spinal cord to muscles for movement or glands for hormone secretion
Interneurons
link the sensory and motor neurons in the brain and spinal cord

21. Types of Neurons

22. The Human Endocrine System

23. The Human Endocrine System
The organ system that regulates the internal environment by releasing hormones into the bloodstream.

24. Hormone
chemical released into the bloodstream by one type of cell that has an effect on another type of cell in a different location
help regulate and coordinate the functions of almost all organ systems
important in maintaining a constant internal environment
control many developmental changes

25. Gland Organ that manufactures and secretes hormones
Pituitary gland and Hypothalamus control the hormone secretions of several other glands in the body
Pituitary gland secretes the most hormones in the body

26. Glands of the Endocrine System

27. Homework Activity: Mapping Sensory Receptors p.105
Equipment & Materials: paper clip and ruler
p. 107 # 1, 2, 4, 5