Any internal or external change that brings about a response
can be stimuli within body
one control systems used by your body to maintain homeostasis.
balance in the body
nerve cell made up of a cell body and dendrites(branches)
message carried by a neuron (moves one direction only)
branch like parts of the neuron which receive impulses from other neurons and send them to the cell body.
carry impulses away from the cell body to muscles, other neurons, or glands
Three types of neurons
sensory neurons, motor neurons, and interneurons
receive information and send impulses to the brain or spinal cord
relay impulses to motor neurons
conduct impulses from the brain or spinal cord to muscles or glands throughout your body.
Space between neurons
the chemical that flows across the synapse and to the dendrite of the next neuron.
central nervous system
brain and spinal cord
The Peripheral Nervous System
connects the brain and spinal cord to other body parts
12 pairs of nerves from your brain
31 pairs of nerves from your spinal cord
controls voluntary actions. It is made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles.
controls involuntary actions-such as your heart rate, breathing, digestion, and glandular functions.
the loss of muscle movement.
an involuntary, automatic response to a stimulus
a simple nerve pathway from sense to action without thought
the transparent section at the front of the eye
directs the light onto the retina
tissue at the back of the eye made up of rods and cones. Cones respond to bright light and color. Rods respond to dim light..
route of an image
rods and cones send impulse to optic nerve which carries the impulses to the vision area of the brain. The brain turns image right-side up and blends images from both eyes to create depth.
created by vibration
route of hearing
sound waves stimulate nerve cells deep within your ear which take impulse to brain.
parts of the ear
(1)the outer ear,(2) middle ear, and (3)inner ear.
intercepts sound waves and funnels them to the middle ear.
three tiny bones called the hammer, anvil, and stirrup. The stirrup bone rests against a second membrane on an opening to the inner ear.
cochlea(fluid filled,lined with hair) and the semicircular canals.
the part of the semicircular canals that senses rotation
the part of the semicircular canals that responds to tilt of head
route of a smell
molecules from the food enter your nasal passages, dissolves in mucus, stimulate olfactory nerve cells, an impulse starts in these cells, then travels to the brain where the stimulus is interpreted. Memory tells what it is or stores for later ID
part of the tongue that are the major sensory receptors for taste.
five taste sensations
sweet, salty, sour, bitter, and the taste of MSG
route of a taste
saliva and food washes over taste buds, impulses are sent to your brain. The brain interprets the impulses, and you identify the tastes.
example of a depressant
slows responses, too much can destroy brain and liver cells
example of a stimulant
speeds up nervous system, can cause restlessness, sleeplessness, and overwork kidneys