Ch. 5: Tissues!!

Let’s create a beating heart https://www.youtube.com/watch?v=AjPu9esr1HQ

Objectives To explain the difference between different kinds of tissues To identify the types of epithelial tissue To list the locations of each type of epithelial tissue

Do Now!!  What is the definition of a tissue? What are some functions of tissues? Where are some locations in the body where you can find tissues?

Important Terms Histology: The study of tissues Tissues: Groups of specialized cells which are similar in structure and perform common functions

4 Types of Tissues Epithelial Connective Muscle Nervous Make some observations! Epithelial Connective Muscle Nervous

4 Types of Tissues (cont.) Epithelial: Form protective coverings Function in secretion, absorption and diffusion Connective: Provide support and protection Bind structures together Muscle: Produce body movements Nervous: Control and coordinate body activities * Most organs contain all 4 types

Epithelial Tissue Forms covering of body surfaces Lines body cavities, organs, tubes, ducts, blood vessels Major tissue in glands Covers organs

Epithelial Tissue (cont.) Functions: Protection from physical/chemical injury and invasion Secretion, filtration and reabsorption of materials Secretion of serous fluids to lubricate structures Diffusion Sensory reception

Do Now!  How is the structure of a tissue related to its function? Epithelial tissue is categorized based on 2 properties. Hypothesize what those 2 properties could be.

Epithelial Tissue Factoids One free surface always exposed to the outside or open internal space: apical surface Attached to basement membrane on the other side Tightly packed Avascular: NO blood vessels!! Rely on diffusion from underlying connective tissue Divides rapidly Classified according to top layer of cells

Classes of Epithelia (Layers) Stratified: multiple layers Simple: just one layer

Classes of Epithelia (Shape) Squamous: squashed (thin and flat, like an egg) Ex: Endothelium (lines blood vessels) and mesothelium (lines pleural, peritoneal and pericardial cavities) Columnar: columns Ex: Lining of gut tube; sometimes with cilia like lining Cuboidal: cubed (square shaped) Ex: Walls of glands

Squamous Simple Diffusion and filtration Ex: alveoli, capillary walls, lines blood and lymph vessels 2. Stratified Squamous Physical protection against abrasion Protection against pathogens Ex: Epidermis, oral cavity, esophagus, vagina and anal canal

Squamous (cont.) 3. Keratinized Stratified Squamous: Aging skin cells produce keratin, harden then die “keratinization”: produces dry, tough, protective covering layers of dead squamous cells prevents water/substance loss barrier to organisms

Columnar 1. Simple Columnar provides some protection cells can be ciliated or non-ciliated absorption/secretion usually contain “goblet” cells Ex: Uterus, most organs of digestive tract 2. Stratified Columnar - *rare secretion/absorption - Ex: small portion of male urethra

Columnar (cont.) 3. Pseudostratified Ciliated Columnar - Appears stratified - All cells touch basement membrane and have exposed end Ex: passageway of respiratory system

Cuboidal Simple Cuboidal secretion/absorption secretes sweat line ducts Ex: ovaries, kidney tubules, ducts of glands (salivary, thyroid, pancreas and liver) 2. Stratified Cuboidal *rare usually only 2-3 layers Larger ducts of glands Ex: mammary glands, sweat glands, Salivary and pancreas

Transitional Stratified Tolerates repeated stretching Ex: bladder, ureters, and urethra

Can You Identify the Classes of Epithelium? Quiz!! E Can You Identify the Classes of Epithelium? D A B C

Slides Simple Squamous *Lung

Slides Simple Cuboidal *Kidney

Ciliated Pseudostratified Columnar Slides Ciliated Pseudostratified Columnar *Trachea

Slides Stratified Cuboidal *Sweat gland duct

Slides Simple Columnar *Small intestine

Slides Stratified Squamous *Skin

Slides Transitional *Bladder

Glands Glandular Epithelium: cells that produce and secrete chemical substances Exocrine Glands Secrete substance onto body surface or into body cavity Have ducts Ex: salivary, mammary, pancreas, liver, sweat, mucous

Glands (cont.) Endocrine Glands Secrete product into blood stream Hormones travel to target organ to increase response No ducts Ex: pancreas, thyroid, hypothalamus, adrenal, testes, ovaries

Types of Glands Merocrine: release watery, protein-rich fluids by exocytosis Ex: salivary and pancreas glands Apocrine: lose small portions of their cell bodies Ex: mammary glands Holocrine: entire cell filled with secretory products lyses Ex: sebaceous glands

1. Epithelial! 2. Connective!