Tissues Flashcards
What are some functions of epithelial tissue?
Covers surfaces, connects cells, separates compartments, forms glands
What defines the structure and function of connective tissue?
The extracellular matric and fluid it is composed of
Where is the contractile apparatus in muscle tissue?
Cytoplasm
What are some of the functions of nervous tissue?
Communication, receives, generates and transmits electrical signals and integrates info
How do epithelial tissues maintain coverage of surfaces?
No contact inhibition, cell-cell junctions and cell-ECM junctions
What are some cell-cell junctions in epithelial tissue?
Desmosomes, tight junctions, gap junctions
What are desmosomes function?
Firm anchorage, maintain integrity of epithelial layer
What is the function of a tight junction?
Seal intercellular spaces
What is the function of a gap junction?
Cell to cell communication
What two layers make up the basement membrane?
Basal lamina and reticular lamina
What is an example of a cell-ECM junction?
Hemidesmosomes
What are the secondary roles of thick and thin epithelium?
Thick = wear and tear Thin = diffusion
What are cilia and where can they be found?
Finger like projections from apical surface to help with movement, can be found in trachea
What are microvilli and what do they do?
Finger like projections from apical surface, help in absorption
What are the different classification of epithelia?
Square: squamous, cuboidal, columnar
Layers: simple, stratified or pseudostratified
Where can transitional epithelium be found?
Urinary system: bladder, urethra, ureters
What are glands?
Collections of secretory epithlial cells (single-celled or multicellular)
What are the two types of glands?
Exocrine and endocrine
How do exocrine glands form?
Differentiates into specialised epithelial cells
How do endocrine glands form?
Detach from epithelium and attach to nearest blood cells
What are the different shapes of exocrine glands?
Simple: tubular and acinar
Compound: tubuloacinar
What are types of exocrine glands?
Mucous glands, serous glands
What do mucous glands secrete and where can they be found?
Mucus rich in proteoglycans with water - found in gut and trachea
What do serous glands secrete and where can they be found?
Protein rich secretion - found in exocrine pancreas
What is the role of myoepithelial cells?
They contract to secrete the contents of the gland
What are examples of endocrine glands?
Pancreatic islets which secrete proteins into blood vessels, steroid glands e.g. Adrenal cortex which secretes steroid hormones on demand
What is the liver parenchyma?
Hepatocytes arranged in rows between blood vessels
What is one of the roles of hepatocytes?
Secretion of glucose and biles
What do the support epithelial cells of the liver do?
Line blood vessels and bile ducts
How are the epithelial cells in the kidneys organised?
Into nephrons
What do the nephrons do?
Filtration of blood, partial absorption of filtrate, overall to release urine from kidneys
What do the support epithelial cells of the kidneys do?
Line blood vessels and renal pelvis (receives toxic urine)
What are some of the abnormal functions of epithelial cells?
Over- and under-proliferation, over- and under-secretion, loss of cilia/ciliary beat
What is an example of over- or under-secretion?
Growth hormone in pituitary gland - can result in gigantism or dwarfism
What makes up extracellular matrix (ECM)?
Fibres, ground substance, tissue fluid
What makes up the fibres in ECM?
Collagen and elastin
What makes collagen?
Fibroblasts
What percentage of body weight is collagen?
About 30%
What makes up the ground substance of ECM?
Proteoglycans, hyaluronic acid, glycoproteins
What cells are found in loose connective tissue?
Fibroblasts, macrophages, adipocytes, mast cells, undifferentiated mesenchyme cells
What is a transient cell type found in loose connective tissue?
White blood cells
What is an example of dense irregular CT?
Sebaceous gland in the skin
What are some abnormal functions of CT?
Leukaemia (overproduction of WBCs), osteoporosis, cartilage tear
