4- The Tissue Level of Organization- anatomy and physiology
Terms
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- What is a tissue?
- a group of similar cells that usually have a common embryonic origin that function together to carry out specialized activities.
- What are the 4 basic types of tissue?
- Epithelial tissue, connective tissue, muscle tissue, and nervous tissue.
- Epithelial tissue purpose:
- forms a barrier to protect exosed srfaces, lines insides of body cavities and organs, and forms glands.
- Connective Tissue purpose:
- all tissues that provide support (skeleton) and fill space (fat), tendons, cartilage.
- muscle tissue purpose:
- support, movement, heat generation
- Nervous tissue purpose:
- controls other organs, receives and transmits information
- Epithelial:
- made up of epithelia; cells are polar (top[functional] and bottom [organelles])
- basement membrane
- holds epithelial tissues together and make them stronger
- 2 layers of basement membrane
-
basal lamina- closest to epithelial layer
reticular lamina- coarse fibers that provide strength - 3 functions of epithelial tissue
-
1. protection
2. provides structure for sensory nerves
3. secretory - 6 classes of epithelial tissue:
-
1. simple squamous (heart, alveoli)
2. simple cuboidal (pancreas, kidneys)
3. simple columnar (intestines, stomach)
4. stratified squamous (lining skin surface, mouth)
5. Stratified cuboidal (ducts of sweat glands)
6. stratified columnar (urethra, anus) - Pseudostratified columnar epithelia
- looks like multiple layers but only one; some cells don't make it through to the top. (line airways and larger ducts of a lot of glands)
- 2 categories of glands:
- endocrine and exocrine
- endocrine glands
- secrete hormones
- exocrine glands
- secretions excreted out ducts
- merocrine secretion
- product released by exocytosis in rough ER, packaged by Golgi Apparatus
- apocrine secretion
- top part of cell pinches off, rest of cell repairs itself and repeats the process
- holocrine secretion
- cell is packed with secretion and burst (acne)
- Connective tissue:
- connective and support structures of the body; defined by specialized cells within matrix of extracellular protein fibers and filler fluid
- "-blast"
- immature cell
- chondroblasts
- secrete matrix that makes cartilage
- osteoblasts
- secrete matrix that makes bones
- fibroblasts
- not tissue; secrete glycoproteins
- ground substance
- contains many sugars
- hyaluronic acid
- main sugar in Ground substance
- 4 functions of connective tissue
-
1. structural framework
2. support, protection for organs
3. energy reserves (lipids)
4. defense (immune system) - adipocytes:
- not tissues; fat cells
- melanocytes
- not tissue; melanin cells
-
fibroblasts secrete:
(3) - collagen, reticular fibers, and elastin
- collagen
- very ropey and strong; main fibers of tendons and ligaments
- reticular fibers
- fibrous net of collagen fibers; forms stroma (matrix) of organs
- elastin
- able to stretch and retract; important in lungs; have collagen tissue to tell it when to stop stretching
- mesenchymal cells
- undifferentiated precursor cells to fibroblasts, macrophage and other connective tissue cells
- macrophage
- fixed or free; 1st line of defense against a virus/bacterial
- microphage
- smaller phagocytic cells
- lymphocytes
- bind invading cell and kill it
- plasma cells
- produce antibodies
- loose connective tissue:
- less fibers, more fluid; stroma composed of reticular tissue; areolar tissue (between skin and underlying tissue); adipose tissue
- brown fat
- generates heat in infants
- regular dense connective tissue:
- fibers arranged in parallel, strength in one direction
- Irregular dense connective tissue:
- interwoven net of fibers that give strength in all directions
- connective tissue proper
- those types of cells which live and function in extracellular fluid
- fluid connective tissue
- distinct cell populations in fluid matrix (blood)
- normal hematocrit in men and women:
-
men: 42%
Women: 38% - lymphatic system (fluid connective tissue)
- set of tubes next to blood vessels that carries WBC around
- supporting conective tissue
- bone and cartilage
- cartilage
- cartilage cells (chondrocytes) in thick gel of proteoglycans
- 3 types of cartilage:
- elastic, hyaline, fibrocartilage
- elastic cartilage
- lots of elastin fibers (nose, ears, epiglottis)
- hyaline cartilage
- strength and flexibility (ribs, knees, trachea)
- fibrocartilage
- strength (spine, knees, pelvis)
- T/F: there are blood vessels in cartilage.
- false
- Bone
- has minerals for strength and blood vessels; heals quickly; 50% water.