Secrete into the blood to carry chemical messages throughout the body Epithelial Tissues Classification Summary Chapter 4 Tissues Groups of cells with a common function Four primary tissues Epithelia Connective tissues Muscle Nervous Epithelial Tissues Line body cavities and cover surfaces Glandular epithelia Epithelial cells adapted to make up glands Secrete into ducts to exterior of body Exocrine glands Endocrine glands Shape Squamous Flattened cells Cuboidal Cube shaped Columnar Column shaped Line vessels part of lungs body surface Form lining of tubules glandular tissue Line respiratory digestive reproductive tracts Number of layers Simple single layered Adapted for diffusion across cell barriers Line glands and respiratory digestive reproductive systems Stratified multiple layered Provide protection as in the skin surface The Basement Membrane Provides Structural Support Basement membrane Provides structural support to overlying cells Attaches epithelial layer to underlying tissues Junctions hold epithelial cells together Adhesion junctions spot desmosomes Some movement between cells Tight junction Nothing passes Gap junctions Protein channels Connective Tissue General functions Supports softer organs of body Connects parts of body Stores fat Produces blood cells Matrix provides the strength Two general types Fibrous and special Fibrous Connective Tissue Contains cells embedded in nonliving extracellular matrix Function provides strength and elasticity Contains fibers and cells embedded in gel like ground substance matrix Matrix intercellular material giving the CT its characteristics Cells fibroblasts macrophages lymphocytes and neutrophils Fibers collagen elastic and reticular Four general types Loose surrounds many organs lines cavities around blood vessels Dense forms tendons ligaments deeper layers of skin Elastic surrounds stomach and bladder maintains shape Reticular makes up internal framework of soft organs liver and the lymphatic system Specialized Connective Tissues Serve Special Functions Cartilage produced by chondroblasts found in lacunae no blood vessels high collagen content Bone inorganic matrix with calcium salts for hardness Blood fluid matrix of plasma red blood cells white blood cells and platelets Adipose tissue fat cells function in insulation protection and energy storage Muscle Tissue Contracts to Produce Movement Skeletal muscle Moves body parts Voluntary multi nucleated Cardiac muscle Functions in the heart Involuntary single nucleus Smooth muscle Surrounds hollow structures Involuntary single nucleus Nervous Tissue Transmit Impulses Neuron specialized nervous system cell Function generate and transmit electrical impulses Structural components cell body dendrites axon Glial cells support neurons Organs and Organ Systems Perform Complex Functions Contain two or more tissue types joined together perform specific functions Organs Organ Systems Examples Body Cavities Groups of organs that perform a common function Digestive system mouth throat stomach intestines and liver Lymphatic system lymph nodes tonsils and spleen Anterior cavity Thoracic cavity Two pleural cavities Pericardial cavity Abdominal Posterior cavity Cranial cavity Spinal cavity Tissue Membranes Tissue membranes serous membranes line body cavities Serous membrane reduces friction between organs Mucous membrane lubricates surface captures debris Synovial membrane lines spaces in movable joints Cutaneous membrane skin The Skin as an Organ System The proper name is integumentary system Includes skin hair nails glands Functions Prevents dehydrationProtects from injury Serves as defense against microorganisms Regulates body temperature Makes vitamin D Provides sensation Epidermis Outer layer Skin Consists of Epidermis and Dermis Stratified squamous epithelial cells No blood vessels Two major cell types Specialized keratinocytes Melanocytes Dermis Lies underneath the epidermis Supports tissues Fibers Collagen Elastic Cells Fibroblasts Fat cells Hair Shaft Follicle Mast cells White blood cells Accessory Structures of Dermis Smooth muscle Attached to hair follicle raises hair to upright position Oil glands sebaceous glands Secretion moistens and softens skin Sweat glands Blood vessels Secrete sweat help in temperature regulation Supply nutrients remove waste assist in temperature regulation Sensory nerve endings Detect heat cold touch deep pressure vibration Multicellular Organisms Must Maintain Homeostasis Maintenance of relative constancy of the conditions of the internal environment Negative feedback control system deviations from normal are detected and Components of a negative feedback control system counteracted Controlled variable Sensor Control center Effector Negative Feedback Helps Maintain Core Body Temperature Controlled variable body temperature Sensors temperature sensors in skin and internal organs Control center hypothalamus Effectors Blood vessels Sweat glands Skeletal muscles