Histology Pracs Flashcards
Layers of the GIT from inside out?
Lumen, mucosa, submucosa, muscularis propria or externa, adventitia (outer layer merges with surrounding tissues) or serosa (covered by mesothelium in peritoneal cavity)
X= goblet cells
Y = regenerating stem cells
Z = muscularis mucosae
What type of collagen is the main componet of basement membranes
collagen IV
What does desmoplastic stroma do to the malignant tumour?
Fibroblast infliration due to TGF-B -> increased firmness of lesion
In a metastatic malignant epthelial cells are these up or down regulated?
E-cadherin expression
Surface integrins
metalloprotenases
VEGF factor
E-cadherin expression - down regulation
metalloprotenases - increased
VEGF factor - increased
Surface integrins - upregulated
Biochem level main regulator of cell cycle?
Phosphorylation
Gefitinib and Erlontinib are targeted therapies for selected cases of non-small cell lung carcinoma. What type of receptor do they target?
Receptor Tyrosine Kinase
What substances are tissues first placed in to presevre them for histological sections? how does it work?
Formalin
Formalin (formaldehyde) preserves tissue by cross-linking amino groups in proteins with nearby nitrogen atoms in protein or DNA.
Label:
mucosa
submucosa
muscularis propria. This layer is sometimes called the muscularis externa
serosa
yellow: mucosa
green: submucosa
blue: muscularis propria. This layer is sometimes called the muscularis externa
purple: serosa
Label: surface epithelium, glands (glandular epithelium), lamina propria, muscularis mucosae
green: surface epithelium
blue: glands (glandular epithelium) yellow: lamina propria
purple: muscularis mucosae
Which is basement membrane and which is muscularis mucosae? Blue or Black?
Basement membranes lie at the base of epithelia (black). The blue line here is located along the muscularis mucosae.
What type of cells are present in the epithelial layer of the mucosa of the small and large intestines?
Goblet cells, Enterocytes (absorptive cells in large intestine), Enteroendocrine (neuroendocrine) cells, stem cells and lymphocytes
Immune Cells in normal lamina propria?
eosinophils
plasma cells
dendrictic cells
Mast cells
Fibroblasts
Macrophages
Lymphocytes
Endothelial cells
Difference between serosa and adventitia of the GIT?
Serosa is connective tissue covered by a layer of simple squamous cells (known as mesothelial cells) which lines a cavity while adventitia is connective tissue which merges with surrounding tissues.
Which parts are normal mucosa?
muscularis propria?
region of tumour?
metastatic tumour in lymph and pericolonic adipose tissue?
yellow: normal mucosa
blue: normal muscularis propria
green: tumour
purple: lymph node containing metastatic tumour in the pericolonic adipose tissue
Factors relevant for determining Grade of a tumour?
Freq of mitotic figures in tumour cells
similarity of tumour cells to their normal counterparts
degree of variability of nuclear shape and size
What factors are relvant to the stage of a cancer?
metastases in lymph nodes
metastases in distant organs
size and depth of primary tumour
Besides stage and grade what else are factors determining prognosis and subsequent treatment of a tumour?
- The presence of microvascular invasion
- Specific tumour type
- The completeness of surgical excision
- Likelihood of response (via detecting presence of specific mutations) to relevant targeted therapies
- The pattern of the local inflammatory response
What type of mineral definciy can colon cancers present with and how is it caused?
Iron deficiency
Gradual unrecognised loss of red blood cells via the ulcerated surface
What structures are labelled with the black arrows? What type of carcinoma are they common in?
keratin curls
Squamous cell carcinoma
Gas exchange occurs across the alveolar air blood barrier composed of what layers?
Epithelium -> basement membrane -> endothelium
What type of cells are in the alveolar walls?
Type 2 pneumocytes
Elastin
Fibroblasts
Pores of Kohn
Endothelium
What type of epithilium are the trachea and bronchi lined by?
Pseudostratified ciliated columnar epithilium with goblet cells.
aka respiratory epithelium
What is present in the bronchi mut not the large bronchioles? What do they both have?
Seromuccous glands and Cartilage.
They both have:
Goblet cells and cilia (disappear over length)
Smooth muscle
basement membrane
What is in the walls of the large bronchioles but not the terminal or respiratory bronchioles?
Goblet cells and Cilia
What is the key feature of chronic diffuse interstitial lung dieaeses and chronic obstructive pulmonary disease?
Fibrosis of inter-alveolar septae
Label:
Goblet cell
region of basement membrane
region of cilia
region of lamina propria
yellow: Goblet cells
green: basement membrane
blue: cilia
red: lamina propria
Nuclei appear basophilic as haematoxylin binds to what?
Phosphate groups of nucleic acids
Which epithelial subtype is best adapted to withstand mechanical abrasion?
Stratified squamous
What type of collagen is the main compenetn of basemement membranes?
Type IV aka four
Identify the three structure?
Blue arrows?
Black arrows?
Yellow squares?
Blue: Cytoplasm
Black: Nucleolus
Yellow: nucleus
What are the four basic tissue types?
epithelium, connective tissue, neural tissue and muscle
Why the dermis appears eosinophilic on low power?
The dermis is predominantly composed of collagen which is protein so stains pink with eosin.
What other cells besides besides fibroblast would be in the ECM of skin?
include mast cells, macrophages, dendritic cells and lymphocytes. All are present such thay are able to initiate inflammatory and immune responses in case of penetration of the epidermis by antigens.
Lable columnar epithelium, simple squamous and smooth muscle in image?
Purple = smooth muscle
Yellow = columnar
Green = simple squamous
Several types of collagens where are they mainly?
Type 1
Type 2
Type 3
Type 4
Type 5
Type 7?
ype 1: found in bone
Type 2: found in elastic and hyaline cartilage
Type 3: found in reticulin fibers
Type 4: found in basement membranes
Type 5: found in a variety of connective tissues such as tendons
Type 7: found in anchoring fibrils of epithelial basement membrane
What happens in G1, S, G2 and M Phase?
G1 phase: the cell synthesizes RNA, regulatory proteins, and enzymes which will provide for cell growth through synthesis of new cellular components.
S phase: the cell duplicates its genome with formation of new DNA to comprise twice the amount of DNA (in autosomal cells) in a resting cell.
G2 phase: DNA is repaired and the cell produces RNA and proteins needed for division.
M phase: the cell undergoes mitosis and divides in half.
Four phases of mitosis?
Prophase, Metaphse, Anaphase, Telophase
Types of Epithelium? Five major types (one of them has two components.
- Stratified squamous epithelium (keratinsing (skin) and non-keratinising (cervix)
- Columnar epithelium (Surface lining colon)
- Pseudostratified columnar epithelium (bronchus - respiratory epithelium)
- Transitional Epithelium (ureter: strong but allows stretching)
- Cuboidal Epithelium (lines ducts and draining glands)
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Difference between exocrine and endocrine glands?
Exocine glands secret into a duct which drains to a lumen or a surface while endocrine glands drain directly into bloodstream (product is a hormone).
Describe the series of attachments from the epithelial cells to the basement membrane.
Integrins in the epithelial cells extend into the basement membrane and attach to laminin which in turn attaches to type 4 collagen and to fibronectin in the portion of the basement membrane known as the basal lamina. There are anchoring fibrils of type 7 collagen.
Types of Junctional Complexes? Basic Description?
Tight Junctions (zonula occludens) form impenatrable barrier between cells.
Zonula adherens - extracellular cadherins join cytoskeletal elements through transmembrane proteins
Desmosomes: have attachment proteins that link to intermediate filaments of cytokeratin.
Gap junctions : tselective communication by passage of small molecules between cells.
