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| The function of the human nervous system is... | controls and coordinates functions throughout the body and responds to internal and external stimuli |
| Neurons are... | cells that transmit inpulses (electrical signals) |
| The types of neurons are... | sensory, motor, and interneurons |
| Ssensory neurons | carry impulses from the sense organs to the spinal cord |
| Motor neurons | carry impulsed from the brain and spinal cord to muscles and glands |
| Interneurons | connect sensory and motor neurons and carry impulses between them |
| The cell body is... | the largest part of a typical neuron, contains the nucleus and cytoplasm, most metabolic activity of the cell takes place here |
| Dendrites are | branched extensions, carry impulses from the environment or from other neurons toward the cell body |
| Axon is | long fiber that carries impulses away from the cell body, ends with axon terminals (small swellings) |
| Myelin sheath | insulating membrane that surrounds some of the axons, increases the speed at which the impulse can travel |
| Nerve impulse | production depends on the movement of positively charged ions across a cell membrane |
| resting potential | difference in electrical charge across the cell membrane of a resting neuron, negative charge build up inside the membrane, positive charge builds up on the outside of membrane |
| A nerve impulse begins when... | a neuron is stimulated by another neuron or by its environment |
| action potential | reversal of charges, inside membrane gains a positive charge and the outside gains a negative charge |
| threshold | minimum level of a stumulus that is required to activate a neuron, |
| Any stimulus that is stronger than the threshold.. | will produce an impulse |
| Any stimulus that is weaker than the threshold ... | will product no impulse |
| Synapse | location at which a neuron can transfer and impulse to another cell, gap (small cleft) which separated the axon terminal from the dendrites of the adjacent cell, terminial contain tiny sacs filled with neurotransmitters |
| Neurotransmitters | chemicals used by a neuron to transmit an impulse across a synapse to another cell |
| Neurotransmitters | diffuse across the gap and attache themselves to receptors on the menbrane of the neighboring cell |
| Central Nervous System | relays messages, processed information and analyzes information |
| Central Nervous system | consists of the brain and spinal cord, wrappend in connective tissue (meninges |
| Cerebrospinal fluid... | protects the brain and spinal cord and serves as a site for exchange |
| Brain consists of... | cerebrum, cerebellum, brain stem, thalamus, hypothalmus |
| Cerebrum... | site of intelligence, learning, and judgment |
| cerebellum | coordinates and balances the actions of the muscles |
| brain stem (pons + medulla oblongata) | "switchboard" regulating the flow of information between the brain and the rest of the body |
| thalamus | receives messages from the sense organs and relays the information to the proper region of the cerebrum |
| hypothalamus | control center for recognition and analysis of hunger, thirst, fatigue, anger and body temperature |
| spinal cord | connects the brain to the body, process quick, automatic response (reflex) to stimuli |
| peripheral nervous system | receives information from the environment and relays commands from the central nercous system to organs and glands |
| peripheral nervous system | consists of all the nerves and associated cells that are not part of the brain and spinal cord |
| Divisions of peripheral nervous system are... | sensory, motor,somatic and autonomic |
| Sensory | transmits impulses from sense organs to the central nervous system |
| motor | transmits impulses from the central nervous system to the muscles or glands |
| somatic nervous system | regulates activities that are under conscious control, ex: moving skeletal muscles |
| autonomic nervous system | regulates activities that are automatic or involuntary Ex, heartbeat, contraction of smooth muschles in digestive system |
| The levels of organization in a multicellular organism are... | cells, tissues, organs, organ systems, organism |
| tissues | groups of similar cells that perform a single function |
| organs | groups of tissues that work together to perform a complex function |
| organ systems | groups of organs that perform closely related functions |
| Humans contain ---- organ systems | ll |
| Human organ systems work together to maintain a stable internal environment called | homeostasis |
| Organ systems of humans include: | nervous, integumentary, skeletal, muscular, circulatory, respiratory, digestive, excretory, endocrine, reproductive, lymphatic |
| What are the types of tissues? | muscle, epithelial, connective, and nervous |
| Muscle tissue is... | most abundant, controls the internal movement of materials (ex. pushing food through digestive sys.) controls the external movements of entire body or parts of the body |
| epithelial tissue is... | covers the surface of the body and line internal organs, consists of closely packed cells (ex. lines chambers of the heart) |
| connective tissue | holds organis in place and binds different parts of the body together Ex. tendons, ligaments, provides support for the body, pads and insulates the body |
| tendons... | connect muscle to bone |
| ligaments | connect bone to bone |
| nervous tissue | receives messages from the body's external and internal environment, analyzed the data and directs the response |
| feedback inhibition | process by which the product of a system shuts down the system or limits it operation Es; temperature regulation in the body |
| Protist have... | no nervous system, living materials of the cell control and coordinate the life activities |
| Paramecium | have fibrils that transmit impulses to cilia regulating locomotion and ingestion of food |
| Paramecium... | have specialized structures that receive stimuli and produce responses |
| Hydra... | nerve net of neurons, no central nervous system |
| Hydra... | has modified neurons that fora , impulses may travel in any direction over the nerve net |
| Earthworm | has a nervous system...main parts are brain, nerve cord and nerve branches |
| The earthworm's brain... | is a mass of ganglia (many neurons grouped together and interconnected) |
| The earthworm's nerve cord... | is the main nerve, connected to the brain...runs the entire length |
| The earthworm's nerve branches... | many smaller nerves branch from the ventral nerve cord to all parts of the body |
| The grasshopper... | has similar system to that of the earthwork, |
| Humans | have a nervous system which includes a highly developed brain and a dorsal nerve cord |
