Organizer 3C - Tissues PDF

Lecture: Tissues Readings: Chapter 4 I. Body organization a. Cells make tissues make organs make organ systems make an organism II. Body Fluids Compartments -- body water is contained within 3 compartments b. Intracellular -- water within cells, makes up most of body wate...

Lecture: Tissues Readings: Chapter 4 I. Body organization a. Cells make tissues make organs make organ systems make an organism II. Body Fluids Compartments -- body water is contained within 3 compartments b. Intracellular -- water within cells, makes up most of body water c. Extracellular -- water outside of cells i. Interstitial -- water in between cells in tissues ii. Plasma -- water within bloodstream d. Things that move between fluid compartments iii. Gases like oxygen and carbon dioxide iv. Water v. Nutrients which are used for energy vi. Electrolytes e. Electrolytes are particles that carry an electric charge vii. Also called ions or salts viii. Examples are sodium (Na+), chloride (Cl-), potassium (K+) ix. Concentrations of electrolytes vary between intra and extracellular compartments 1. The difference in concentration between in and outside cells allows for electrical potential (different change inside vs outside the cell) that is required for nerves to work 2. The difference in charge is also important as a way to maintain the body's pH at a neutral level (not acidic or basic/alkaline). III. 4 tissue types in the body f. Epithelial g. Connective h. Muscle i. Nervous IV. Epithelial Tissues A. Physiology (functions) i. Secretion from glands (ex --sweat, milk) ii. Absorption (ex -- intestine) iii. Protection - covers and lines things (ex -- skin) B. Anatomy -- classified by cell shape and \# of layers i. \# of layers of cells a. Simple -- 1 layer of cells (like a sheet) 1. Better for passage of things like gases, nutrients b. Stratified -- multiple layers (stacked) 1. Better where protection is needed ii. Cell shape a. Squamous (flat) 1. Best for passage of substances between cells b. Cuboidal (square) 1. cells that release a lot of a product -- metabolically active c. Columnar (tall and narrow -- like a column) 2. Cells that release a large amount of something --very metabolically active therefore must be larger iii. Examples a. Simple squamous -- in lungs where gas exchange occurs b. Stratified squamous -- skin where protection is important but cells slough a lot and don't last very long c. Simple cuboidal -- mostly found in glands -- productive cells that must be near the surface so they can release their products d. Simple columnar -- lining of intestine -- very productive cells that release enzymes but must be thin layer to allow absorption on nutrients C. Glands i. Endocrine a. Releases products (mostly hormones) directly into bloodstream so products can act at distant site b. Ex -- thyroid gland releases thyroid hormone which acts at all other organs ii. Exocrine a. Releases products into the external environment through a duct b. Ex -- sweat gland releases sweat into duct that empties onto surface of skin V. Connective tissue -- provides support to other tissues A. All CT is made of cells plus elastic fibers and collagen fibers that give it strength and flexibility. a. CT types vary based on the proportion of cells and fibers B. Connective tissue proper -- ex - tendons, fat i. Loose CT a. Areolar -- most common type of CT, support and cushions everything! b. Adipose -- aka fat, used for cushioning and energy storage ii. Dense CT a. Dense regular 1. Found in tendons and ligaments 2. Very strong in 1 direction because fibers are all aligned (ie regular) b. Dense irregular 1. Found in the dermis of skin 2. Very strong in all directions because fibers are 'irregular', aligned in all directions C. Specialized connective tissue i. Cartilage ii. Bone iii. Blood VI. Body compartments j. Lined by membranes made of mesothelium which is made of simple squamous and loose connective tissue) k. Allows organs to move smoothly and to transfer substances across membranes l. Pleural space x. Lined by pleural membranes or pleura m. Pericardium: covers the heart n. Peritoneal space xi. Lined by peritoneal membranes