Tissues Flashcards
What is the function of epithelium?
Covers surfaces, fills gaps between cells, forms cell-cell and cell-ECM junctions, separates compartments, absorption and movement
What are the properties of epithelium?
Adaptive and regenerative
Where can epithelium occur?
Covering the body: cell-cell junctions
Lining internal structures: cell-ECM junctions
What type of junctions are cell-cell junctions?
Desmosomes, tight junctions, occluding junctions an gap junctions
What are desmosomes?
They are adhering junctions that provide firm anchorage
What is the function of tight and occluding junctions?
Seal IC spaces
What is the function of gap junctions?
Allow cell-cell communication
What are examples of cell-ECM junctions?
Hemidesmosomes
What allows movement in epithelium?
Cilia
What allows absorption in epithelium?
Microvilli
How is epithelium arranged in the liver?
Arranged rows of hepatocytes between BVs
What are hepatocytes?
Epithelial cells (parenchyma)
What are the functions of epithelium in liver?
Secretion and epithelial cell support via lining BVs and bile ducts
How is epithelium arranged in the kidneys?
Epithelial cells arranged into nephrons
What are the functions of epithelial cells found in the kidneys?
Blood filtration, partial absorption of filtrate and epithelial cell support via lining BVs and renal pelvis
What does epithelium lining the renal pelvis receive?
Toxic urine
What are the abnormal functions of epithelium?
Over/under proliferation and secretion and loss of ciliary beat
What are the causes of alternating proliferation?
Rapid cell reproduction
What are the 2 types of surface epithelia?
Simple and stratified
What are the 3 types of epithelia found in simple and stratified epithelium?
Squamous, cuboidal and columnar
What is the difference between squamous epithelial in simple and stratified epithelium?
Simple- thin and allows for easy diffusion e.g. alveoli and capillaries
Stratified- thick and regenerative e.g. epidermis
What is the difference between cuboidal epithelial in simple and stratified epithelium?
Simple- performs secretion and absorption e.g. lining of nephrons
Stratified- protection e.g. ducts of sweat glands
What is the difference between columnar epithelial in simple and stratified epithelium?
Simple- moves mucous when ciliated e.g. lining digestive tract
Stratified- protection and secretion e.g. pharynx
What does ciliated mean?
Contains cilia
What is a gland?
Collection of multi or single cellular secretory epithelial cells
What does glandular epithelium consist of?
Exocrine and endocrine glands
What are endocrine glands?
Steroid glands that secrete into blood
What is an example of an endocrine gland?
Adrenal cortex
What are exocrine glands?
Glands that secretes to the surface
What is an example of an exocrine gland?
Sweat glands, mucous glands and serous glands
What are mucous glands?
Secretions rich in proteoglycans e.g. in the trachea
What is mucous?
Secretion and water
What are serous glands?
Secretions rich in protein e.g. exocrine pancreas
What are the ECM components of connective tissue?
Rope-like fibres, ground substance and tissue fluid
What is a ground substance?
Proteoglycans and glycoproteins (jelly-like)
What are the fibre components of connective tissue?
Collagen and elastin
What is collagen?
It is an inelastic but flexible fibre that makes up 30% body weight. It has a high tensile strength and comes in many types
What is elastin?
Elastic fibres made of protein which contains micro fibrils which can stretch then return to its original length. It is arranged in sheets rather than fibres and is found in the aorta
What colour is elastin?
Yellow
What are the 2 types of cells found in loose connective tissue?
Permanent (fixed) cells and transient cells
What are permeant cells?
Fibroblasts, macrophages, adipocytes, mast cells and undifferentiated cells
What are transient cells?
WBCs
What are the 2 types of dense connective tissue?
Regular and irregular
Where can you find dense regular connective tissue?
Tendons
Where can you find dense irregular connective tissue?
Skin
What are the types of connective tissue found in fat?
Mesenteric fat and bone marrow
What is the abnormal functions of blood/bone marrow?
Leukaemia
What are the abnormal functions of loose/dense connective tissue?
Loss of fibres or abnormal fibres
What are the abnormal functions of cartilage?
Tear
What are the abnormal functions of bone?
Osteoporosis
