tissues

Question 1

name the four tissue layers

Answer 1

nervous, muscle, epithelial, and connective

Question 2

what does epithelial layer do

Answer 2

forms boundaries between different enviroment, protects, secrets, absorbs and filters.

Question 3

epithelial cells distinct surfaces. and what are epithelial cells

Answer 3

basal (attaches to underlying epithelial cells), apical (cell surface that faces opposite direction of basal) and lateral .
they are without a blood supply. they exchange nutirents, gases with blood in the underlying connective tissue via diffusion. have a nerve supply.

Question 4

explain simple and stratified epithelium

Answer 4

simple consists of a simple bases layer of cells. stratified consists of two or more layers of cells. btoh can be squamous, cubodial or columnar

Question 5

explain transitional and pseudostratified (other types of epithelium)

Answer 5

transitional - cells are rounded but an change to more flattened shape found in structures that need to regularly stretch
pseudostratified - simple epithelium in which all cells are attached to underlying connective tissue, variously sized and shape.

Question 6

what are the two epithelial glands

Answer 6

endocrine - secretes hormones into the blood stream
exocrine - secrete their own substance to the external environment )eg surface of skin)

Question 7

example of exocrine glands

Answer 7

sweat glands, mucous, salivary, sebaceous (oil)

Question 8

explain exocrine structure

Answer 8

unicellular for mucous cells as they secret mucin and are independtly scattered throughout epithelium. multicellular glands are composed of duct cells and secretory cells.

Question 9

explain merocrine and holocrine glands

Answer 9

holocrine - secret substances via rupture of secretory cells. only gland is sebaceous gland. the cell is damaged and neighbour cell perform mitosis

medicine - all other exocrine glands. secret substances via exocytosis the cell survives

Question 10

connective tissue

Answer 10

most abundant tissue. it binds and supports other body tissues as well as provides protection, insulation and transportation of substances throughout the body.

Question 11

main elements of connective tissue

Answer 11

cells and extra cellular matrix
ecm consists of stuff outside of and surronding cells composed of ground substance - material composed of the ecf which contains various proteins and proteoglycans. fibers - protein strands suspended within the ground substance that provide support. collegen fibres, elastic fibres and reticular fibers (support cells smaller blood vessels or nerves passing through CT)

Question 12

types of connective tissue

Answer 12

connective tissue proper, fluid connective tissues, caritlage and bone

Question 13

explain loose connective tissue

Answer 13

has areolar, adipose and reticular. areolar - most widely distributed, supports epithelium including glands, surronds small blood vessels and nerves and forms part of the subcutaneous tissue, protects organs and provides support. sepreates skin from facisa. adipose - composed of mostly fat cells with little ECM. adipose cells store more lipid nutrients and provide insulation and protection. mostly found in subcutaneous tissue. reticular - containd complex network of reticular fibers which support macrophages and fibroblasts

Question 14

explain dense connective tissue

Answer 14

regular, irregular and elastic. regular - closely packed bundles of collegan fibers arranged in parallel to eachother. provide sgreat resistance to undirectional tension and is found in tendons, ligaments and facisa. irregular - bundles of collegen fibers in an irregular arrangement. provides resistance to tension forces from numerous directions and us found in dermis of the skin. elastic - contains large amount of elastic fibers that allow stretch and recoil

Question 15

name membranes

Answer 15

synovial - lines internal joint cavities
mucous - lines body cavities open to exterior of body
cutaneous - covers body surface skin
serous - lines closed or internal body cavities.

Question 16

muscle tissue

Answer 16

produces movment and generates heat in the body. stablisizes and gives posture. composed of muscle cells that include excitability - abilty to receive and repsond to stimulus and generate electrical signals. contractibility - abilty to shorten in response to stimulation. elasticity - abilty to recoil and regain resting length after being stretched. estensitibility - abilty to stretch when not cntracting.

Question 17

types of muscle tissue

Answer 17

skeletal muslce - formed skeletal muscle organs which mostly attach to bones and move the Skelton. stabilises joints maintians posture
cardiac muscle - forms the bulk of the heart wall and moves blood through the heart and blood vessels network. smooth muscle - forms part of the hollow organ wall and moves substances through those organs

Question 18

smooth muscle cells

Answer 18

short with tapered ends. two layers of smooth muscle cells are longitudial layer and circular layer. contratcion of smooth muscle cells are regulated by nerve signals, hormones and pacemaker cells.

Question 19

explain tissue repair

Answer 19

1 - inflamation - release of inflamatory chemicals, increased capillary permability, WBC arrive, bleeding and blood clotting. redness swelling and heat and pain
2 - organisation - blod clot replaced by granulation. new capillaries restablish blood supply. collegan fibers produced to gap fill. macrophages remove damaged tissue.
3- regeneration/fibrosis - regenerastion of new cells to replace those lost, fibrosis tissue may remain as scar tissue