1 Flashcards
What is the definition of a tissue?
aggregates of cells organized to perform specific functions, through a distinctive pattern of organization.
What are the 4 major types of tissues?
Epithelial
connective
skeletal
nervous
think ?nose” mais le o is for C
Which tissues are classified based on their morphology?
Epithelial
Connective
think the two in nose that are not next to each other. or think CE morphologie
Which tissues are classified based on their function?
skeletal
nervous
What are epithelial tissues derived from?
Endoderm, ectoderm, mesoderm,
What is glandular metaplasia? and give an example
Change in the nature of a tissue where irritated tissue converts to a glandular form
squamous epithelial cells –> glandular epithelial cells
roles of epithelium
Protection (Skin)
Absorption (small and large intestine)
Material transport at the surface by cilia in the RT
Gas exchange (lung alveolus and capillaries)
Excretion (kidneys tubules)
Secretions (glands releasing enzymes in GIT)
Gliding between surfaces (mesothelium)
PAM GEG
What is the mesothelium
simple squamous epithelia that lines the pleura, peritoneum and pericardium
What are the histological features of epithelial cells
1) Closely packed cells join by junctions.
2) They have a free surface as they cover body surfaces and cavities
3) They are avascular (nutrients are delivered by diffusion)
4) They are innervated
5) They are supported by a basement membrane (basal lamina + connective tissue= basement membrane), a non-cellular, protein-polysaccharide rich layer.
epithelial cells are described in terms of their morpholohgy. that is further divided into
- layer of cells (simple: one layer thick) or striated: multiple layers of cells)
- shape of the cells
squamous
cuboidal
columnar
Where can you find pseudo stratified epithelium
in the RT
What are some special categories of cells and where are they found
pseudo stratified epithelium in trachea in RT
transitional epithelium or urothelium in urinary bladder in UT
Where can you find simple squamous epithelia
kidneys, endothelium…
What are epithelioid cells and give examples
Glandular epithelial cells that lack a free surface.
Ex: lutein cells of the ovaries, Leydig cells in the testes
What is the endothelium
simple squamous epithelial lining of blood vessels
What is the endocardium
simple squamous epithelial lining of the ventricles and atria of the heart
State what 3 different junctions exist between cells and rank them in order of strength
Tight junctions: seals adjacent cells together Ex: Zonula occludens
Anchoring junctions: Structural support of adjacemt cells Ex: zonula adherens, hemidesmosomes.
Gap junctions: create communication contacts between adjacent cells.
Strength of junctions Tight –> anchoring –> Gap
What are three examples of apical domain structures and where are they commonly found
Stereocilia: inner ear and epididimis
microvili: intestine
cilia: trachea
What is one difference and one similarity between microvilli and stereocilia
stereocilia is immotile
microvilli is has passive motility
cilia it depends
stereocili and microvilli are both supported by actin filaments
cilia is supported by microtubules.
What are the different types of cilia that exist
- Motile cilia: Can move using ATP
- Primary cilia: Immotile cilia found in almost every cell. No active movement but can passively bend
- Nodal cilia: found in the embryo
What is the BM made of
Laminin and fibronectin (distinct proteins of the ECM) associate with collagens, proteoglycans + other proteins
what are the two components of the BM
- Basal lamina: sheet-like ECM in direct contact with epithelial cells (self-assembly of laminin with Collagen IV, entactin and proteoglycans).
- Reticular lamina: supports the BL and is continuous with connective tissue (collagen fibres).
What is the function of the BM
Covers the surface of muscle cells and contributes to maintaining the integrity of skeletal muscle fibers during contraction. (disruption to basal lamina-cell relationship –> muscular dystrophies)
Structural attachment of epithelial cells to underlying tissue in the kidney to perform filtration
Compartmentalization, tissue scaffolding during regeneration, regulation and signaling
What is glandular epithelium
Epithelial tissue structures originated from invaginated epithelial cells.
It makes up the parenchyma of glandular organs (thyroid)
So glandular epithelium is a type of parenchymal cell
Give and example of a stromal cell and an example of a parenchymal cell with identification of localisation its eh body
stromal cell: fibroblasts and pericytes in CT
parenchymal cells: glandular epithelium in the lungs
If an exocrine gland secretes via 1 duct it is called a…
Simple exocrine gland
If an exocrine gland secretes via 2 (+) duct it is called a…
Compound exocrine gland in a branched duct system
What are the 5 types of simple exocrine glands
simple tubular simple coiled tubular simple branched tubular simple alveolar (acinar) simple branched alveolar
What are the three types of compound exocrine glands
Compound tubular
compound alveolar (acinar)
compound tubnuloalveolar
what type of cells are sweat glands
stratified cuboidal
What are exocrine glands
product secretion onto the surface directly or through epithelial ducts that are connected to the surface.
What are endocrine glands
Lack a duct system. Products (hormones) are secreted into the connective tissue from where they enter the bloodstream.
What are the 3 different types of secretions. explain
- Merocrine/Eccrine secretion: product is delivered through exocytosis
- Apocrine secretion: product is secreted via partial loss of the cell apical portion
- Holocrine secretion: product is secreted through apoptosis.
What are the two types of exocrine glands
–Unicellular glands: secretion by a single cell, i.e. goblet cell (mucus secreting cells in small intestine and RT).
–Multicellular glands: more than one cells and can assume different structural organization.
