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Cells and tissues. Structure and function of cells Organization of cells into tissues. A “generalized” cell All living things are made of cells. Major components of the cell. Membrane Nucleus Cytoplasm Cytosol Organelles.
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Cells and tissues Structure and function of cells Organization of cells into tissues
Major components of the cell • Membrane • Nucleus • Cytoplasm • Cytosol • Organelles
The plasma membrane controls the movement of materials into and out of cells
The nucleus • Most cells have one nucleus • Contains chromosomes (genetic material) • Nucleolus • Nuclear pores control movement across membrane
Components of the cytosol • Cytosol • Fluid part of cell • Many ions, proteins, etc. dissolved in it • Many chemical reactions occur there • Organelles • Specialized structures • Compartmentalized functions
Functions of organelles • Movement, support • cytoskeleton • Protein synthesis • Ribosomes, rough ER, Golgi • Waste disposal • lysosomes • Metabolism • mitochondria • Genetic information • nucleus • Transport • Plasma membrane
Cell division • Reproduction, replacement • Some cells divide rapidly • Some cells divide slowly • Some cells divide abnormally
Specialized cells form tissues • Epithelial tissue • One or more continuous sheets of cells • Tightly bound together • Basement membranes are formed beneath epithelia • Major functions • Covering or lining • Glandular
Types of epithelium • Epithelium is categorized by shape and arrangement • General functions: protection, secretion, absorption
Some types of epithelium • Simple squamous • Lines blood vessels, alveoli, etc. • Materials move through it (diffusion, osmosis) • Simple columnar • Lines intestines • Secretion and absorption
More epithelium • Stratified squamous • Skin, mouth, esophagus, vagina • Protection • Pseudostratified ciliated columnar • Upper respiratory tract • Cilia help move mucus
Connective tissue • Protection • Insulation • Compartmentalization • Component of body membranes • Cutaneous • Serous • Mucous • synovial
Types of connective tissue • Loose • Dense • Cartilage • Bone • Blood and lymph • See plates starting p. 63
Membranes • Cutaneous • Covers the body • Keratinized cells • Serous • Line peritoneal, pleural, pericardial cavities • Mucous • Line passageways that connect to the exterior • Synovial • At joints • Anti-inflammatory function
Muscular tissue • Skeletal, cardiac, smooth • Voluntary or involuntary • Location in body • See table 3.4
Nervous tissue • Neurons • Glial cells • Conduct electrical stimuli • Support neurons
Summary • Living organisms are composed of one or more cells • Cells are organized into tissues • Type and arrangement of cells (and extracellular materials) are unique to the tissue • Organs are formed from tissues that perform characteristic functions