4 Lining, Muscle and connective tissue Flashcards
Name the four types of tissue.
- epithelial
- connective
- muscle
- nervous
What is histology?
the anatomy at cellular level
Name four features of epithelial tissue:
- found in every organ
- line every organ of the body
- lines cavities and tubes
- can from gland
Characteristics of epithelial cells:
- good at regeneration
- polarity (apical and basal membranes)
- avascular
- attached to a basement membrane
Basic structure of epithelial tissue:
closely packed and all attached to a basement membrane like a lego board
How do we classify epithelial tissue?
number of layers
shape of cells
What do we call epithelial tissue with several layers of cells vs 1 layer?
several layers = stratified
1 layer = simple
What are the shapes of epithelial cells?
- cuboidal
- columnar
- squamous
Describe the structure of a squamous epithelial cell.
long thin and flat (squashed) with nucleus stretched in same direction as cell
Describe the structure of a columnar epithelial cell
-rectangular shape - basally located nucleus
Describe the feature of a cuboidal epithelial cell
elongated nucleus in the middle and square
How do we name the tissue (shapely) if its stratified epithelial?
By the most superficial layer
Name 3 types of squamous epithelial tissue and where they are found
- Simple
- Keratinised stratified
- Non keratinised stratified
Where are simple squamous epithelial tissues found?
alveoli and blood vessels - for gas an nutrient exchange
Keratinised stratified squamous epithelial tissues are found in…
…gums and skin because the keratin provides some protection and waterproofing
non-keratinised stratified squamous epithelial tissue is found…
…oral cavity (cheek) and oesophagus - mainly for protection and a barrier
Where would you find simple cuboidal epithelium and what is it for?
Found in the kidney tubes and gland and is used for secretion and absorbtion
Where would you find simple columnar epithelium and what is it for?
Digestive tract coz they contain microvilli and are used for absorption and secretion
Where would you find simple pseudo stratified columnar epithelium with goblet cells and what is it for?
trachea - acts as a mucociliary escalator
-appear stratified as some cells don’t reach the free surface though all are attached to basement membrane
Which type of tissue lines the oesophagus (specific)?
pseudo stratified columnar epithelial tissue with goblet cells
What is an intercellular junction?
Specialised areas of a cell membrane that bind a cell together
4 examples of intercellular junctions
- tight
- demosome
- hemidemosome
- gap junctions
explain a tight junction
where?
found near the apical membrane, bind cells together tightly though interlocking proteins which don’t allow anything imbetween the cells
digestive tract
explain a demosome
loos like a wire cage holding cells together - found near the basement membrane and tightly holds cell together stopping them from splaying (lego board analogy) - resists twisting and streching
contain dense plates
explain a hemidemosome
found on the basement membrane - securely attaches the cell onto the underlying tissue
explain a gap junction
where?
interlocking membrane proteins (connexions) hold two cells together but have a central pore that small molecules can pass through
cardiac muscle
Connective tissue is made up of
few cells in an abundance of extracellular matrix
What makes up the extracellular matrix in connective tissue?
-ground substances
-extracellular (tissue) fluid
-fibres
collagen, reticular and elastic
What types of connective tissue are there?
Specialised: -Blood , lymph, bone, collagen Proper: -Loose (alveolar) -Dense regular -Dense irregular
What is in loose alveolar CT and where is it found?
-ground substances +++
-a few fibres
-adipocytes
-macrophages (transient)
-fibroblasts
found under epithelium lining and covering organs
What is in dense connective tissue?
-few ground substances
lots of fibres (mainly collagen)
fibroblasts
What are the differences between the two dens CT’s?
-regular - the collagen bundles are parallel -tendons and ligaments
Irregular - haphazardly arranged collagen bundles - resists excessive stretching and distension - dermis
What cells are present in connective tissue?
- mast cells
- adipocytes
- macrophages
- FIBROBLASTS
What are the different types of muscle?
- smooth
- skeletal
- cardiac
Skeletal muscle functions:
- skeletal movement and support
- forming sphyncters
- involved in respiration
Skeletal muscle structure:
- long thin cylindrical cells
- striated
- multinucleated
- somatic nervous system
Cardiac muscle structure:
- long branched muscle cells
- intercalated discs
- 1/2 centrally located nuclei
- striated
- autonomic
Smooth muscle function:
- found in organ walls and airways and vessels
- constriction of airways and vessels
- digestion
Smooth muscle structure:
- short fusiform cells
- single central nucleus
- non striated
- autonomic
Functions of connective tissue:
- protection of organs
- protection of body from microbes
- provides a structural framework for the body
- transport of dissolved substance
- connects different tissue types
- stores energy reserves
All muscle cells have: (3)
- -cell elongation parallel to direction of contraction
- -contractile elements
- -many mitochondria
