Main idea: Complex organisms have many typesof cells. Each cell has special structures thatallow it to carry out specific tasks.
Both plants and animals have tissues thatperform specific jobs.Tissues are groups of cells with a commonstructure and function.
Types of TissuesEpithelial tissues:sheets of cells thatcover surfaces and linecertain body cavitiesand blood vessels.Connective tissues:joins other tissuestogether, stores fat,and makes blood cells.Bone and cartilage areexamples
Types of TissuesMuscle tissues: createmovement in onedirection only bygetting longer orshorter.Nervous tissue: Somesends signals tomuscles and othersprotects nerves andprovide them withnutrients
Organs: made up ofseveral tissue typesworking together toperform one or morefunctionsPlants have leaves, roots,and flowers as theirorgansHumans have brains,hearts, stomachs, andlivers.
Organ SystemsOrgan systems aregroups of organs thatwork together toperform complex tasks.Plants have vascularsystems. All of theplants leaves togetherare an organ system.
Organisms that are larger and morecomplex need more complex organ systemsto maintain life.Some organs are part of more than onesystem. The hypothalamus is part of the nervous system and the endocrine system.
Organ System FunctionCirculatory System Provides body with oxygenUrinary System Removes liquid wastesMusculoskeletal System Supports body and enables movementDigestive System Obtains nutrients from foodsEndocrine System Chemical messenger systemNervous System Controls movements and other organ systems
Endocrine system is achemical messengersystem that makes andsends out hormonesHormones have manyfunctions, such asregulating growth andblood sugar.Plants use hormones tocontrol growth andother functions.