The Nervous System And the Senses
Human Organ System Overview Nervous System Integumentary System Skeletal System Muscular System Circulatory System
Human Organ System Overview (continued) Nervous System Integumentary System Skeletal System Muscular System Circulatory System
Human Organ System Overview (continued) Nervous System Integumentary System Skeletal System Muscular System Circulatory System
Human Organ System Overview (continued) Nervous System Integumentary System Skeletal System Muscular System Circulatory System
Human Organ System Overview (continued) Nervous System Integumentary System Skeletal System Muscular System Circulatory System
Human Organ System Overview (continued) Respiratory System Digestive System Excretory System Endocrine System Reproductive System Lymphatic System
The Nervous System Basic and smallest unit of nervous system is the neuron Controls and coordinates functions throughout the body and responds to stimuli
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
The Neuron Nucleus Axon terminals Cell body Myelin sheath Axon Nodes Dendrites
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
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
Connections Between Neurons
Neurotransmitters
A Nerve Impulse
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
Parts of the Brain Cerebrum – thinking and learning center – conscious activities of the body Cerebellum – balance and coordination Medulla – involuntary activities
The Brain Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum Pons Pituitary gland Hypothalamus Cerebrum Medulla oblongata Spinal cord Cerebellum Pineal gland Thalamus
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
The Eye Choroid Retina Blood vessels Optic nerve Fovea Vitreous humor Sclera Ligaments Iris Pupil Cornea Aqueous humor Lens Muscle
The Senses Ears – Complex system detecting sound and helping to maintain a sense of balance/equilibrium
The Ear Auditory canal Tympanum Round window Eustachian tube Bone Cochlea Cochlear nerve Semicircular canals Oval window Stirrup Anvil Hammer