Tissue level organisation

Question 1

cell junctions. definition and function

Answer 1

points of contact between adjacent cell plasma membranes

• form fluid tight seals
• anchor cells together or to extracellular material
• act as channels, which allow ions and molecules to pass from cell to cell

Question 2

list 5 cell junction types

Answer 2

tight junctions 
adherent junctions 
desmosome 
hemidesmosomes 
gap junction

Question 3

Tight junctions

• structure
• function
• location

Answer 3

plasma membranes fused with strap of transmembrane proteins

watertight seal between seals

common between cells that line GIT and bladder

Question 4

Adherens junctions

• structure
• function
• location

Answer 4

dense layer of proteins (plaque) insdide cell membrane attaches to membrane proteins (catherine) and microfilaments (actin)

holds epithelial cells together

common between cells that line GI

Question 5

Gap junctions

• structure
• function
• location

Answer 5

cells are separated by fluid filled tunnels called connexons

cell communication, diffusion of ions and small molecules, transfer fo nutrients

heart and smooth muscle of gut; muscle and nerve impulses spread from cell to cell

Question 6

Desmosomes

• structure
• function
• location

Answer 6

contains plaque and catherine and attaches to intermediate filaments (keratin)

cell to cell stability

skin and cardiac muscle

Question 7

Hemidesmosomes

• structure
• function
• location

Answer 7

half desmosome; same structure ad desmosome but it connects cell to underlying basement membrane d extracellular material using membrane proteins (integrin)

cell to membrane stability

any cell attached to basest membrane

Question 8

Types of tissues.
definition
4 principle types (ecmn)

Answer 8

tissue is a group of similar cells that are specialised for a particular function

epithelial tissues

connective

muscle tissue

nervous

Question 9

Epithelial tissue

structure

Answer 9

• closely packed epithelial cells that always have a free (apical) surface and a basal surface
• little extracellular material between cells
• many cell junctions
• cells sit on basement membrane
  basal lamina
  reticular lamina
• avascular (no blood supply)
• good nerve supply
• rapid cell division (high mitotic rate)

Question 10

Epithelial tissue

general functions

Answer 10

• selective barrier
  helps transfer substance in / out of body

-secretory surface
release molecules into free surface

-protective surface
resist any abrasive influence of environment

Question 11

What two types is epithelial tissue is there?

Answer 11

covering and lining epithelium

glandular epithelium

Question 12

classification of covering and lining epithelium

name 3 arrangement of cells

Answer 12

simple (one layer)
stratified (two or more)
pseudostratified (located at multi levels - lots multilayered)

Question 13

classification of covering and lining epithelium

name 4 shapes of cells

Answer 13

squamous (flat)
cubodial (cube shaped)
columnar (tall column)
transitional (shape varies with tissue stretching)

Question 14

simple squamous epithelium
structure
function
location

Answer 14

single layer. flat scale like cells. nuclei centrally located

diffusion, secretion, filtration

lining of blood vessels (endothelium), serous membranes (mesothelium), kidneys, lungs

Question 15

simple cuboidal epithelium
structure
function
location

Answer 15

single layer of cube shaped cells. nuclei round and centrally located

secretion and absorption

lines kidney tubules, makes up secreting portion of glands

Question 16

simple columnar epithelium

non-ciliated & ciliated
structure
function
location

Answer 16

non ciliated

• single layer of column like cells
• no cilia but microvilli and goblet cells present
• oval nuclei near base of cell

secretion, absorption and protection

lines GIT, ducts of glands

Ciliated

• single layer of column like cells
• cilia present
• oval nuclear near base of cell

motility

lines bronchioles, uterine tubes, uterus, ventricles of brain

Question 17

Pseudostratified columnar epithelium

ciliated and non ciliated
structure
function
location

Answer 17

non ciliated

• single layer - appears to have several
• nuclei at various levels
• no cilia, lacks goblet cells

absorption and protection

large ducts of glands, male urethra

Ciliated
single layer - appears to have several
nuclei at various levels
cilia and goblet cells present

secretion (mucous) motility

lines airways

Question 18

stratified squamous epithelium

keratinised and non.
structure
function
location

Answer 18

keratinised

• several layers of cells. apical layer flat. deeper layers vary from cuboidal to columnar
• tough layer of keratin in apical layer
• protection
• superficial layer of skin

non keratinised
- several layers. apical is flat. deeper vary from cuboidal to columnar
- does not contain large amounts of keratin
constantly moistened by mucous
lines mouth, oesophagus, pharynx, vagina

Question 19

stratified cuboidal epithelium
structure
function
location

Answer 19

2 or more layers of cells where apical cater is cube shaped
fairly rare

protection
limited secretion and absorption

ducts of sweat glands, male urethra

Question 20

stratified columnar epithelium
structure
function
location

Answer 20

2 or more layers where apical layer is columnar and lower layers and irregular in shape
uncommon

protection and secretion

lines large, excretory ducts f some glands, part of urethra and in conjunctiva of eye

Question 21

transitional epithelium
structure
function
location

Answer 21

multiple layers. variable appearance
apical surface contains large rounded cells
cells change shape as tissue stretches from cuboidal to squamous

protection

lines urinary bladder, ureters, urethra

Question 22

Glandular epithelium

list the two types and a general description

Answer 22

gland is a single cell or a mass of epithelium cells adapted for secretion

endocrine glands

exocrine glands

Question 23

Endocrine glands 
structure 
function 
location

Answer 23

ductless
secrete product (hormones) into interstitial fluid and then into blood stream 

secrete hormones that maintain homeostasis

brain, thyroid, adrenal, pancreas, reproductive organs

Question 24

exocrine glands
structure
function
location

Answer 24

contains ducts
secrete product into ducts that empty onto surface of a covering an lining epithelium (skin)

secrete substances such as sweat, oil, saliva, digestive enzymes

salivary, sudorifero and ceruminous glands, pancreas

Question 25

exocrine glands

structural classification

Answer 25

uni cellular
- single cell (goblet)

multicellular
- composed of many cells
different complexities based on branching patterns (simple/compound) and shape of secreting portion (tubular/acinar) (salivary gland)

Question 26

exocrine glands

3 types of functional classification. based on how secretions are released

Answer 26

Merocrine glands
- form secretory products and discharge by exocytosis (saliva, digestive enzymes and watery sweat)

apocrine glands
- accumulate secretory products at the apical surface, portion pinches off from rest of cell to form secretion (smelly sweat)

holocrine glands
- accumulate secretory profits into cytosol; cell dies and product discharged (oil glands)

Question 27

Connective tissue

structure

Answer 27

abundant and widely distributed

two basic elements
cells & ecm

highly vascular (except cartilage and tendons)
good nerve supply (except cartilage)

Question 28

connective tissue general functions

Answer 28

binds structures together

supports and strengthens other tissues

protects and insulates internal organs

provides elasticity

transport system

stores energy

immune response

Question 29

two basic elements of connective tissue.

describe cells & ecm

Answer 29

cells

• immature (blast)
• mature (cyte)
• widely spaced, few in numbers

ecm
- material located between cells
secreted by cells
consistency varies(liquid, gel, solid) in large amount

Question 30

connective tissue cells
FAW MPM
name 6 and brief function

Answer 30

fibroblasts - secrete ECM

adipocytes (fat cells) store energy in form of fat

white blood cells (leukocytes) immunity and defence

Macrophages
develop from monocytes and engulf bacteria and debris by phagocytosis