Tissues

Cells→tissues→organs→system→organism Tissues: a group of cells working together to perform a specific function 4 major types: 1)epithelial 2) connective 3) muscle 4) nervous

Epithelial Structure Covers all body surfaces Always has a free surface Reproduces frequently Tightly packed Lack Blood vessels Function Protection Secretion Absorption Excretion Sensory perception

Types of Epithelium Simple Squamous: Thin, flat cells that fit tightly together Ex: capillaries, air sacs in the lung Thin for diffusion

Types of Epithelium Simple Cuboidal: Single layer of cube- shaped cells Ex: covering of the ovaries and lines the ducts of glands

Types of Epithelium Simple Columnar: Elongated cells making up a single layer; contain goblet cells Ex: lining of stomach and intestines Long and skinny for absorption

Types of Epithelium Pseudostratified Columnar: Appear to be layered, but they are not; commonly possess cilia and goblet cells Ex: lining of respiratory airways and tubes of reproductive system of female

Types of Epithelium Stratified Squamous: Many layers of cells; continually reproducing to replace those that are lost Ex: outer layers of skin, mouth, throat protection

Types of Epithelium Transitional: Specialized to undergo changes in response to increased tension Ex: lining of bladder and urinary system-provides expandable lining

Connective Tissue Structure: Function: Most abundant type of tissue(by weight) Contains intercellular material called matrix Function: Binding structures together; support; storing fat; protection Cells that make up connective tissue: 1-fibroblasts-make fibers 2-mast cells-release heparin and histamine 3-macrophage-gobble stuff

Types of Connective Tissue Adipose: Stores fat within the cytoplasm of the cell; protects and cushions joints and organs; insulates Ex: under skin; around heart and other organs

Types of Connective Tissue Fibrous Connective: Made of closely packed fibers that bind body parts together Ex: tendons & ligaments

Types of Connective Tissue Cartilage: Rigid tissue that provides framework, protects, and forms models for developing bones; chondrocytes Ex: ears, nose, and ends of bones

Types of Connective Tissue Bone: Very rigid tissue that serves as an internal support for body structure; matrix is made of Calcium/Phosphorus Ex: femur, skull, patella

Types of Connective Tissue Blood: Liquid connective tissue that serves to transport substances through the body Ex: ummm…blood

Muscle Tissue Structure: Function: Contractile Made of elongated cells called muscle fibers When relaxed, long and thin, when contracted, short and fat Function: Provide for movement, posture, body heat, peristalsis(smooth muscle contraction), and heart beat

Types of Muscle Tissue Skeletal: Muscles that are attached to bones; controlled by conscious effort; contain striations(stripes) Ex: biceps, triceps, trapezius

Types of Muscle Tissue Smooth: Muscles found in the walls of internal organs(stomach, intestines) and walls of blood vessels Lack striations involuntary

Types of Muscle Tissue Cardiac: Found only in heart Dark, intermittent bars called intercalated discs involuntary

Nervous Tissue Structure: Function: Nerve cells are called neurons Neuroglial cells bind and support neurons Neurons do not undergo mitosis Ex: sense organs, brain, spinal cord, peripheral nerves Function: Transmit nervous impulses

Neurons cannot be replaced…. Wear your seatbelt/helmet and be careful what you put into your body