Fig. 1.8 Levels of Organization

Cellular Level of Organization the basic unit of life Cells are semi-autonomous. –increasing differentiation / decreasing autonomy

Tissue Level of Organization histology = study of tissues collection of similar cells and associated extracellular materials organization –sheets (e.g., linings of skin, respiratory and digestive tracts) –masses (e.g., skeletal muscle tissue, cardiac muscle tissue) –masses of sheets (e.g., liver tissue)

Organ Level of Organization 2 or more tissues joined together to perform a specific function or functions –e.g., liver liver epithelial tissue bile duct epithelial tissue blood vessel epithelial tissue, smooth muscle connective tissue –e.g., stomach glandular epithelial tissue smooth muscle connective tissue Most organs have a distinct, recognizable shape (including bones), but each major blood vessel is also an organ.

Organ System Level of Organization different organs that have a related function –often connected e.g., respiratory and digestive systems –but not always e.g., endocrine system

Fig. A.1 head neck trunk upper limbs lower limbs Major Body Regions Know terms on Fig. A.5

Head –caput (Latin), cephal- (Greek) skull –cranium –face Neck –cervix (Latin) Trunk –thorax –abdomen Fig. A.6 Fig. A.5 Fig. A.18

Upper Limbs (arms) –shoulder –axilla (-ae, plural) –brachium –elbow (cubit) –antebrachium –hand (manus) Fig. A.5

Lower Limbs (legs) –groin inguinal region –thigh –knee –(lower) leg –ankle –foot (pes, ped-) Fig. A.5

Body Cavities Fig. A.7

coelom Body Plans Wallace, et al., Biosphere, The Realm of Life

ectoderm mesoderm Tube-within-a-tube Body Plan serousmembranes visceral__________ parietal__________ endoderm The coelom is a potential space. Serous fluid provides lubrication. coelom