Bio 231 @ Oit - Lecture 2

Front 1

What is diffusion?

Back 1

-The movement of solutes from an area of higher concentration to lower concentration in solution.
-- A concentration gradient represents the difference in the number of soljutes from one area to another
-- Eventually an equilibrium will be acheived

Front 2

What are osmosis and osmotic pressure?

Back 2

- Diffusion of water (solvent) across a selectively permeable membrane.
- Water moves from an area of low concentration of solute to an area of high concentration of solute.
- Osmotic pressure: force required to prevent water from moving across a membrane by osmosis.

Front 3

How does osmosis affect cell behavior?

Back 3

- Important because large volume changes caused by water movement disrupts normal cell function
- Cell shrinkage or swelling
-- Isotonic - cell neither shrinks nor swells
-- Hypertonic - cell shrinks (crenation)
-- Hypotonic - cell swells (lysis)

Front 4

Define tissue

Back 4

-Tissues are defined as a population of cells having a similar morphology and function

Front 5

How are tissues classified?

Back 5

-- Cell type and cell morphology
-- The extracellular matrix

Front 6

What are the four major tissue groups?

Back 6

--epithelial
--connective
--muscle
--nervous

Front 7

What are the three types of embryonic tissues? Give an example of each

Back 7

-Endoderm
--Inner layer
--Digestive tract and derivatives (Liver/trachea)
-Mesoderm
--Middle layer
--Muscle, bone, blood, and blood vessels
-Ectoderm
--Outer layer
--Epidermis and nervous tissue

Front 8

What are the characteristics of epithelial tissue?

Back 8

- Composed primarily of cells, little extracellular material, close contact with neighboring cells.
- Associated with glandular tissue, lines tubes and ducts, and covers parietal and visceral surfaces.
- Free surface, basement layer, underlying layer of connective tissue
- Avascular
- Damaged cells are replaced (mitosis)

Front 9

What are the five functions of epithelial tissue?

Back 9

- Protection - multiple cellular layers as seen with the epidermis.
- Physical barrier - dehydration and pathogens.
- Filtration - Fenestrated capillaris with the glomerulus of the kidney
- Secretion - Forms the glandular tissue of both exocrine or endocrine
- Absorption - Intestinal epithelium with microvilli

Front 10

How are the types of epithelium classified?

Back 10

- Number of layers of cells
-- Simple - single layer of cells
-- Stratified - two or more layers of cells. Shape of cells of the apical layer used to name the tissue.
-- Pseudostratified - cells appear stratified, however, each cell in contact with basement membrane
- Shape of cells
-- Squamous - flat
-- Cuboidal - equal in height and width
-- Columnar - taller than wide

Front 11

What are the three types of cellular contacts in epithelial tissue?

Back 11

- Desmosomes: disc-shaped regions of cell membrane; often found in areas that are subjected to stress
-- Protein filaments extend into cytoplasm of cells
- Tight junctions: hold cells together, form permeabiltiy barrier
- Gap junctions: protein channels aid intercellular communication.
-- Allows ions and small molecules to pass though.
-- Coordinate function of cardiac and smooth muscle

Front 12

What are the two types of glands found in the epithelium?

Back 12

- Two types of glands formed by the invagination of surface epithelium:
-- Endocrine: no open contact with exterior; no ducts; produce hormones
-- Exocrine: open contact maintained with exterior; ducts
- Exocine glands classified either by structure or by the method of secretion
- Classified by structure
-- Unicellular (goblet cell).
-- Multicellular glands have simple or compound ducts

Front 13

What are the six functions of connective tissue? What kind of connective tissue represents each function?

Back 13

- Binds structures (tendons and ligaments)
- Support and movement (bone)
- Energy storage (adipose tissue)
- Cushion and insulate (hypodermis)
- Transportation of waste and nutrients (blood)
- Protection (bones and immune system)

Front 14

What cell types are found in connective tissue?

Back 14

- Fibroblasts - fibers and ground substance (jam)
- Mast cells - release heparin, histamine, and proteolytic enzymes in response to injury
- White blood cells - response to injury or infection
- macrophages - phagocytic cells
-- Fixed: stay in position in connective tissue
-- Wandering: Move by amoeboid movement through the connective tissue

Front 15

Describe the three types of fibers found in the extracellular matrix of connective tissue

Back 15

- Protein fibers
-- Collagen - most common protein in body; strong, flexible, inelastic
-- Reticular - Fills spaces between tissues and organs (thin collagen fiber)
-- Elastic - returns to shape after distension or compression. Contain molecules of protein elastin that resemble coiled springs; molecules are cross-linked

Front 16

What are the two most common molecules found in ground substance?

Back 16

- Most common molecules are:
-- Hyaluronic acid: polysaccharide, a good lubricant found in synovial fluid
-- Proteoglycans: protein and polysaccharide. Protein part attaches to hyaluronic acid. Trap large amounts of water

Front 17

How is connective tissue classified?

Back 17

- Fibrous
-- Loose, adipose, reticular
-- Dense regular
-- Dense irregular
- Supportive
-- Cartilage - hyaline, elastic, fibro
-- bone - Compact, spongy
- Fluid
-- blood

Front 18

What are the two types of fibrous connective tissue?

Back 18

- Loose (areolar) - collagen fibers are loosely arranged
- Dense - the collagen fibers form thick bundles that nearly fill all extra cellular space

Front 19

How is dense regular connective tissue identified? What are the two types?

Back 19

- Has abundant collagen fibers in parallel arrangement
-- Tendons - attach muscles to bones
-- Ligaments - hold bones to bone. Collagen often less compact, usually flattened, form sheets or bands

Front 20

How is dense irregular connective tissue identified? Where is it found?

Back 20

- Collagen (protein) fibers arranged in a randomly oriented network
- Forms innermost layer of the dermis of the skin, scars, capsules of kidney and spleen

Front 21

Describe the composition of cartilage

Back 21

- Composed of chondrocytes in a semi-solid matrix
- Ground substance - Proteoglycans attract water, the cartilage will spring back after being compressed
- Avascular and no blood supply (nerve?)
- The perichondrium (dense irregular connective tissue ) encloses cartilage. Fibroblasts of perichondrium can differentiate into chondrablasts

Front 22

Describe hyaline cartilage - where is it found?

Back 22

- Support and some flexibility: rib cage, trachea, and bronchi
- Embryonic skeleton
- Epiphyseal plate

Front 23

What is the structure of fibrocartilage? Where is it found?

Back 23

- Structure - Thick collagen fibres distributed in proteoglycan matrix, slightly compressible and very tough
- Locations: found in areas of body where a great deal of pressure is applied to joins
-- Knee, jaw, between vertebrae

Front 24

What is the structure of elastic cartilage? Where is it found?

Back 24

- Structure-elastic and collagen fibers embedded, rigid by elastic proterties
- Locations - External ears and epiglottis