CHAPTER 5 Body Tissues and Membranes

What are tissues? Cells are organized into groups and layers called TISSUES Each tissue is composed of similar cells that are specialized to carry on a particular function ◦ Secretion ◦ Absorption ◦ Support

Tissue Types Epithelial Connective Muscle Nervous

Epithelial Tissue Covering of all major body surfaces Makes up glands Always has one free surface and one that’s attached to connective tissue ◦ Basement Membrane Free Surface Basement Membrane Connective Tissue

Epithelial Tissue Lacks blood vessels ◦ Nutrients diffuse from capillaries of underlying tissue Rapid rate of reproduction ◦ Constantly sloughed off Tightly packed ◦ Create good barriers

Epithelial Terms Shape ◦ Squamous-flat, thin cells ◦ Cuboidal-cube shaped cells ◦ Columnar-tall, elongated cells Layers ◦ Simple-single layer ◦ Stratified-two/more layers

Types of Epithelial Tissue Simple Squamous Epithelium ◦ Single layer of “pancake” cells ◦ Easy diffusion ◦ Lung alveoli (air sacs), capillaries Nucleus

Simple Cuboidal ◦ Single layer of cube-shaped cells  Primarily secretory cells  Ovaries, kidneys, salivary glands Types of Epithelial Tissues Centrally located nucleus

Types of Epithelial Tissue Simple Columnar ◦ Protection / Absorption ◦ Microvilli  Increase surface area ◦ Digestive tract Nuclei located on same level

Types of Epithelial Tissue Pseudostratified Columnar ◦ Similar to S.C. ◦ Have cilia along edge  Line respiratory system Note: how nuclei are at two or more layers Goblet cell: secretes mucus ?

Types of Epithelial Tissue Stratified Squamous ◦ Many layers thick ◦ New ones push old ones up  Epidermis Stratified Cuboidal ◦ 2 or 3 layers of cuboidal cells Stratified Columnar ◦ 2 or 3 layers of columnar cells

Types of Epithelial Tissue Transitional Epithelium ◦ Responds to tension - stretches out ◦ Creates protective barriers ◦ Lining of bladder & ureters

Glandular Epithelium Specialized to produce and secrete substances Make up glands ◦ Exocrine glands - dump secretions into ducts ◦ Endocrine glands - dump secretions into bloodstream

Epithelial Tissue -Cells readily divide -Cells are continually replaced -Cells are tightly packed -Classified by shape and number of layers

Connective Tissue Most abundant type of tissue by weight Functions: ◦ Support ◦ Stores fat ◦ Produces blood cells ◦ Protection from infection

Connective Tissue Cells spaced further apart than epithelia

Types of Fibers Collagenous fibers - thick, made of collagen ◦ Strong, slightly elastic, flexible ◦ Ligaments, tendons Elastic fibers- made of elastin ◦ Branched, stretch easily ◦ Vocal cords

Loose Connective Tissue ◦ Binds skin to underlying tissue ◦ Lies beneath most epithelial tissue

Adipose Tissue (FAT) Form of loose connective tissue ◦ Protective cushion ◦ Stores energy

Dense Connective Tissue ◦ Binds body parts together ◦ Make up tendons, ligaments

Cartilage Rigid Protection, support Ends of bones, nose, external ears, larynx, between vertebrae

Bone Most rigid Functions: ◦ Internal structure ◦ Attachment for muscles ◦ Blood formation ◦ Inorganic mineral storage

Other Connective Tissues Blood ◦ Transports substances between cells and external environment

Muscle Tissue Contractile - tissue can contract, becoming shorter and longer ◦ Causes body parts to move 3 types: ◦ Skeletal muscle-bones ◦ Smooth muscle-organs ◦ Cardiac muscle-heart only

Nervous Tissue Found in brain, spinal cord, nerves Neurons - basic nerve cells Respond to changes in environment and send messages

Epithelial tissue Smooth muscle