1. The Nervous System
And the Senses

2. Human Organ System Overview
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

3. Human Organ System Overview (continued)
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

4. Human Organ System Overview (continued)
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

5. Human Organ System Overview (continued)
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

6. Human Organ System Overview (continued)
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

7. Human Organ System Overview (continued)
Respiratory System
Digestive System
Excretory System
Endocrine System
Reproductive System
Lymphatic System

8. The Nervous System
Basic and smallest unit of nervous system is the neuron
Controls and coordinates functions throughout the body and responds to stimuli

9. The Neuron
Neurons conduct impulses throughout nervous system and consists of three regions – cell body, dendrites, and axons
Dendrites – receive impulses and carry them to the cell body
Cell body – where nucleus of cell is
Axon – carries impulses away from cell body to other neurons, muscles, or glands

10. The Neuron Nucleus Axon terminals Cell body Myelin sheath Axon Nodes
Dendrites

11. Three Types of Neurons
Sensory neurons – carry impulses from body to spinal cord and brain
Motor neurons – carry response impulses away from brain and spinal cord to a muscle or gland
Interneurons – found within the brain and spinal cord – connect sensory and motor neurons

12. Connections Between Neurons
Neurons don’t touch one another – there is a tiny space between axons and dendrites called a synapse – need neurotransmitters (chemicals) to cross this gap and carry the “message” on

13. Connections Between Neurons

14. Neurotransmitters

15. A Nerve Impulse

16. Central Nervous System (CNS) vs. Peripheral Nervous System (PNS)
CNS – brain and spinal cord
PNS – all nerves carrying “messages” to and from CNS
Sensory – sense organs to CNS
Motor – CNS to muscles/glands

17. Parts of the Brain
Cerebrum – thinking and learning center – conscious activities of the body
Cerebellum – balance and coordination
Medulla – involuntary activities

18. The Brain Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum
Pons
Pituitary gland
Hypothalamus
Cerebrum
Medulla oblongata
Spinal cord
Cerebellum
Pineal gland
Thalamus

19. The Senses Eyes – Complex organ sensing light
Retina – thin layer of tissue made up of light receptors and sensory neurons
Two types of light receptor cells:
Rods – detect shape and movement
Cones – detect color

20. The Eye Choroid Retina Blood vessels Optic nerve Fovea Vitreous humor
Sclera
Ligaments
Iris
Pupil
Cornea
Aqueous humor
Lens
Muscle

21. The Senses
Ears –
Complex system detecting sound and helping to maintain a sense of balance/equilibrium

22. The Ear Auditory canal Tympanum Round window Eustachian tube Bone
Cochlea
Cochlear nerve
Semicircular canals
Oval window
Stirrup
Anvil
Hammer