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68 terms

Bio 35 (Nervous System)

The Human Body
STUDY
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Neuron
Cell that carries messages throughout the nervous system.
Dendrite
Extension of the cell body of a neuron that carries impulses from the environment or from other neurons toward the cell body.
Myelin Sheath
Insulating membrane surrounding the axon in some neurons.
Resting Potential
Electrical charge across the cell membrane of a resting neuron.
Action Potential
Reversal of charges across the cell membrane of a neuron; also called a nerve impulse.
Threshold
Minimum level of a stimulus required to activate a neuron.
Synapse
Location at which a neuron can transfer an impulse to another cell.
Neurotransmitter
Chemical used by a neuron to transmit an impulse across a synapse to another cell.
Cell Body
Largest part of a typical neuron; conatins the nucleus and much of the cytoplasm.
Axon
Long fiber that carries impulses away from the cell body of a neuron.
Specialized Cell
Cell that is uniquely suited to performing a particular function.
Epithelial Tissue
Tissue that covers the surface of the body and lines internal organs.
Connective Tissue
Tissue that holds organs in place and binds different parts of the body together.
Nervous Tissue
Tissue that receives messages from the body's external and internal environment, analyzes the data, and directs the response.
Muscle Tissue
Tissue that controls the internal movement of materials in the body, as well as external movement.
Homeostasis
Process by which organisms maintain a relatively stable environment.
Feedback Inhibition
Process in which the product or result stops or limits the process.
Meninges
Three layers of connective tissue in which the brain and spinal cord are wrapped.
Cerebrospinal Fluid
Fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system.
Cerebrum
Area of the brain responsible for all voluntary activities of the body.
Cerebellum
Region of the brain that coordinates body movements.
Brain Stem
Structure that connects the brain and spinal cord; includes the medulla oblongata and the pons.
Thalamus
Brain structure that receives messages from the sense organs and relays the information to the proper region of the cerebrum for further processing.
Hypothalamus
Brain structure that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature.
Reflex
Quick automatic response to a stimulus.
Reflex Arc
Sensory receptor, sensory neuron, motor neuron, and effector that are involved in a quick response to a stimulus.
Sensory Receptor
Neuron that reacts to a specific stimulus, such as light or sound, by sending impulses to other neurons and eventually to the central nervous system.
Pupil
Small opening in the middle of the iris through which light enters the eye.
Lens
Transparent object behind the iris that changes shape to help adjust the eye's focus to see near or distant objects.
Retina
Innermost layer of the eye; contains photoreceptors.
Rod
Photoreceptor in eye that is sensitive to light but not to colors.
Cone
A photoreceptor that responds to the light of different colors, producing color vision.
Cochlea
Fluid-filled part of the inner ear; sends nerve impulses to the brain through the cochlear nerve.
Semicircular Canal
One of three structures within the inner ear that help monitor the position of the body.
Taste Bud
Sense organ that detects the flavor of a substance.
Drug
Any substance, other than food, that causes a change in the structure or function of the body.
Stimulant
A signal to which an organism responds.
Depressant
Drug that decreases the rate of functions regulated by the brain.
Fetal Alcohol Syndrome
Group of birth defects caused by the effects of alcohol on a fetus.
Drug Abuse
Intentional misuse of any drug for nonmedical purposes.
Addiction
Uncontrollable dependence on a drug.
Levels of organization in multicellular organisms
cell, tissue, organ, organ system
Nervous system
coordinates the body's response to changes in its internal and external environments.
Integumentary System
skin etc., serves as a barrier, regulates temp, protects against uv radiation
Respiratory system
provides oxygen and removes carbon dioxide from the body
Digestive System
Converts food into simpler molecules that can be used by cells of the body, absorbs food.
Excretory system
eliminates waste products of metabolism from the body, maintains homeostasis
Skeletal System
supports the body, protects internal organs, allows movement, stores mineral reserves, provides a site for blod cell formation
Muscular system
works with skeletal system to produce voluntary movement, help sto circulate blood and move food thru the digestive system
Endocrine system
controls growth, development, and reproduction.
Reproductive system
produces reproductive cells, in females nurtures and protects developing embryo
Lymphatic system
helps protect the body from disease, collects fluid lost from blood vessels and returns it to circulatory system
Glands
made from epithelial tissue - is a structure that makes and secretes a particular product
Sensory neurons
carry impulses from the sense organs to the spinal chord and brain.
Motor neurons
carry impulses from the brain and the spinal chord to muscles and glands.
Interneurons
connect sensory and motor neurons and carry impulses between them.
Axon terminals
axon ends in a small series of swellings
Nerve impulse
begins when a neuron is stimulated by another neuron or by its environment.
Corpus callosum
band of tissue that connects the hemispheres of the brain.
Gray matter
consists of desnsely packed nerve cell bodies.
Cerebral cortex
outer surface of cerebrum.
Peripheral nervous system
Divided into sensory and motor divisions.
Central nervous system
relays messages, processes info, analyzes info. Consists of the brain and spinal chord.
Somatic nervous system
regulates conscious activities. Also involved with reflex arcs.
Autonomic nervous system
regulates involuntary activities like hearbeats.
Sympathetic and parasympathetic nervous systems
both control autonomic nervous system responsibilities oppositely.
Sensory division
transmits impulses from sense organs to the c.n.s.
Motor division
transmits imuplses from the central nervous system to muscles or glands. Divided into somatic nervous system and autonomic nervous system.