lecture notes block 2

8 Block 2: APES (add histology L1 notes)
Histology L2:
4 main types of animal tissue: epithelial, muscle, connective, nervous


Epithelial tissues: classification based on number of cell layers.
 Occurs as sheets of cells
 Covers the outside of the body and lines the organs and cavities within the
body
 They contain cells that are closely packed with tight junctions, function as:
 Barriers against mechanical injury, pathogens and fluid loss
 Interface with the environment
 Are categorized based on the cell
shapes and number of cell layers
 3 types: squamous, cuboidal &
 Adapted for diffusion
columnar
 Lining of glands, guts,
 Simple epithelial tissuesingle layered
pipes
 Stratified epithelial tissuemulti
 Adapted for protection
layered


Types pf epithelium (NB* shape, Location, Function)
 Simple squamous
 Simple cuboidal
 Simple columnar
 Stratified squamous
 Stratified cuboidal
 Pseudostratified columnar
 Transitional
Polarity of epithelia:


2 different sides

Apical surface: Basal surface:
Faces the lumen/cavity or outside the Non-cellular membranous layer
organ
Exposed to fluid/air Protein
Usually covered with specialized Structural support
projections e.g.) microvilli
Point of attachment


General functions of epithelial tissues:
1. Protection
2. Secretion
3. Selective absorption
NB*

, 4. Excretion
5. Trans-cellular transport
6. Sense organ




Type of Position shape location function
epithelium of nuclei
(insert
micrographs of
each)
Simple squamous Horizontall Irregular, Lungs, blood DiffusionExc
y flattened platelike, vessels(endotheliu hange of
and thin, leaky m), nutrients
elliptical heart(mesothelium)
, major cavities
Simple cuboidal Centre, Dice or Epithelium of Secretion
spherical cube exocrine glands,
Kidney tubules,
germinal cells
Simple columnar Oval, Tall, Lining of stomach Specialized-
towards narrow, & intestines sensory
base of goblet- receptors nose,
cells brick- ears & taste
shaped buds), secrete
digestive juices
& absorb
nutrients
Stratified Multi- Urothelium Specialised
squamous layered (bladder, ureter & keratinised,
urethra), outer transitional,
skin, linings of i.e. stretchy
mouth, vagina & tissues,
anus withstand
damage,
waterproofing
Stratified cuboidal Armpit
Stratified Testes
columnar


Epithelium Diseases and Disorders:
 Acne
 Dermatitis 9 various types)inflammation of skin
 Impetigo (bacterial skin infection)
 Psoriasis (marked by red, itchy, scaly patches on skin)
 Sunburn (what really causes sunburn?)
 Sweating disorders
 Yeast infections of the mucous membranes

, Histology L3:
Connective tissue:
 Found throughout the body
Functions:
 Connect parts of the body DO NOT NEED TO
 Support softer organs of the body MEMORISE
 Provides structure, elasticity &
transport
 Produce blood cells
 Store fat
Connective tissue = cells + fibres + *ground Extracellular matrix
substance (ECM)
(The type of CT is dependent on the dominant component)
FIBRES:
CELLS:
Collagens reticular Elastic
 Fibroblasts
 Adipocytes Extracellular Matrix:
 Macrophages
 Leukocytes
e.g. mast cells
Collagens Proteoglyca
Non-collagens n
glycoproteins aggregates
 Strengt
h

Types of C.T.: Due to high portions of
1. Ordinary/Proper/Fibrous collagenous fibres, dense,
2. Specialized C.T. irregular CT provides
strength making the skin
resistant to tearing by
stretching forces from
 Loose different directions
 dense