muscular & nervous system

-Nervous System
3 functions of the nervous system:
-Receives and relays information
-Monitors and responds to internal and external changes
-Controls and coordinates all body functions
Sensory: become aware of stimuli: change in environment
Integative: memory, emotions, conscience, decisions
Response: muscles, what did you do?
Neuron- (nerve cell) cells that carry messages throughout the nervous system
Nerve impulse- electrical signals, coded method from neuron
Sensory neuron: neuron that carries impulses from the sense organs to the brain and spinal cord
Motor neuron: neuron that carries impulses from the brain and spinal cord to muscles and glands
Interneuron: cell that connects the motor and sensory neurons (only found in brain)
Cell body- center part of the neuron that contains the nucleus and much of the cytoplasm
Dendrite- part of the neuron that is an extension from the cell body of a neuron that carries impulses from the environment to the cell body
Axon- long fiber that carries impulses away from the cell body of a neuron
Axon terminals- small swellings in a neuron at the end of an axon that makes connections with next neuron
Myelin- substance composed of liplids and protein that forms an insulated sheath around an axon, and makes a better impulse
Neurilemma- outermost covering of a neuron allows nerve to grow back
Threshold stimulus- minimum level of a stimulus required activating a neuron
Receptor- special sensory neuron in a sense organ that receives stimuli from external environment (nose, eyes, ears)
Effector- muscle of gland that brings about a coordinated response to a stimuli
Synapse- point of contact at witch an impulse is passed from one cell to another
Neurotransmitters- substance used by one neuron to signal another
Sclera- white part of the eye that helps maintain the shape and provides muscle that moves the eye
Choroid- pigmented, contains blood vessels of eye, and becomes the disk-like structure called the iris
Iris- part of the eye that gives it its color
Pupil- in the middle of the iris, small opening light enters here, (black disk)
Retina- innermost layer of eye contains photoreceptor cells (rods, cones)
Rods- photoreceptor cells, really sensitive to color of light, DONT detect colors
Cones- photoreceptor cells, gives us color vision
Conjunctiva- transparent coat on outside of eye (pink eye)
Cornea- outer, part of eye where light enters transparent layer
Lens- part of eye you see out of, it focuses things
Suspensory Ligaments- holds lens in place
Ciliary Body- allows us to focus close-up
Vitreous Humor- behind lens, filled with transparent jelly fluid, keeps eye rounded
Aqueous Humor- inside cornea filled with fluid keeps cornea rounded shape
Optic nerve- nerve cell carries information to brain for interpreting
Fovea- cells are cones, can see color and bright light
Myopia- near sided, long strong
Hyperopia- far sided, short weak
-Spinal Cord and Brain
2 major divisions of the nervous system:
-Central: control center, consists of brain and spinal cord, relays messages, processes information, compares and analyzes information
-Peripheral: outside the central, all nerves, receptors, and ganglions
The cerebrum has a left and a right hemisphere; it is the biggest part of the brain.

Fissures- valleys on the brain
Convolutions- ridges on the brain
Lobes- regions of the brain
Cerebral Cortex- gray matter on the surface of the brain
Functions include: voluntary muscles/activities, instincts, behavior, intelligence, emotions learning, memory, and senses
The cerebellum coordinates muscle actions
Brain Stem- structure that connects the brain with the spinal cord and is composed of the medulla, pons, and mid-brain, coordinates information coming into brain
Medulla Oblongata- contains white matter that conducts impulses between spinal cord and brain, controls involuntary functions such as; breathing, blood pressure, swallowing, coughing, and heart rate
Pons- contains white matter that provides link between the cerebral cortex and cerebellum
Mid-brain- involved with hearing and vision reflex
Thalamus- gray matter, serves as the switching station for sensory input, passes information to the proper region
Hypothalamus- serves as the control center for hunger, thirst, fatigue, anger, and body temperature
EGG- electroencephalogram, shows activities of the brain
Short-term memory- only last a few days, such as what you had for breakfast
Long-term memory- memories that are permanent and last a long time
Structure of the spinal cord:
Acts as a communications link between the brain and the peripheral nervous system. Carries impulses and regulates reflexes. (2 types of nerve tissue)
What are ways in which the brain and spinal cord are protected?
Bone-hard over-top of the brain and spinal cord
Meninges- membranes on surface of brain and spinal cord protect against rubbing
Cerebrospinal fluid- surrounds brain and spinal cord and acts as shocks or cushions
Peripheral Nervous System: takes information and sends it to the brain and spinal cord and back (31 pair of vertebrate nerves, 31 pair of spinal nerves, and 12 pair of cranial nerves)
Parts of the Peripheral Nervous System:
Somatic- regulates activities we have control over such as moving, talking, running, and jumping
Autonomatic- regulates activities we dont have control over such as digestion, breathing, and heart rate
What is a reflex arc?
-Path that an impulse will travel during a reflex
3 parts of the reflex arc:
-Sensory neuron
-Motor neuron
Auricle- outside ear, channels sound waves into ear
Auditory Canal- contains small hairs and wax producing glands (then sound waves go to eardrum)
Eardrum- the beginning of the middle ear
Malleus-tiny bone
Incus- tiny bone, transfers sound from the outer ear to the inner ear
Stapes- tiny bone, transfers sound from the outer ear to the inner ear
Eustachian tube- mid ear, where yawn air comes in and out or swallow, also transfers sound from the outer ear to the inner ear
Oval window- transmits the vibrations to the cochlea
Cochlea- begins the inner ear, snail shaped cavity full of fluid
Acoustic nerve- carries impulses from cochlea to brain where we hear
Semicircular canals- 3 canals that lie at right angles, sense of balance
Compare senses of taste and smell:
Chemoreceptors detect taste and smell
Olfactory receptors: detect smell
Taste buds: detect taste with saliva (found on lips, roof of mouth, and tongue)
4 types of tastes:
Cerumen: ear wax, prevents anything from getting into direct contact with eardrum, and also keeps eardrum soft and flexible
Pitch: high or low a sound is
Quality: a persons voice, unique to each others, (telling the difference)
Loudness: loud or soft a sound is

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