Tissues of the Body Flashcards
Define Tissue
A collection of cells specialised to perform a specific function
4 types of tissue
Epithelial, connective, muscle, nervous
Define biopsy
Remove piece of tissue from organ/body part, for microscopic examination
What type of biopsy for cervical cancer?
smear
Biopsy for endometrial lining?
Curettage
Biopsy for brain
Needle
Biopsy for heart
Transvascular
Biopsy for skin?
Direct incision
Biopsy for gut
Endoscope
Why fix tissues before using microscope?
Preserves structure (by forming cross links), prevents autolysis. Use formaldehyde, may have artefacts
Under a microscope, mucus in goblet cells is visible as a magenta colour.
Which stain was used?
Periodic-Acid-Schiff
Which two stains are used to visualise elastic fibres?
Weigert’s Elastin and Elastic van Gieson
H&E stain, what stains what?
Haemotoxylin - Acidic components such as nucleolus and DNA purple/blue
Eosin - Basic components such as ECM pink
Whats the point of phase contrast and differential interference contrast microscopy?
Can visualise living cells
Confocal microscopes use…
Fluorescent probes
Types of simple ‘Epithelia’
simple squamous - kera: skin, non-kera: vagina
simple cuboidal - pancreatic duct, thyroid follicles
simple columnar - gall bladder, crypts of Lieberkuhn
pseudostratified - epididymis, trachea
Types of stratified epithelia
Squa, cub, colum, transitional
What is epithelia?
Sheets of contiguous cells with varied embryonic origins. Covers external surfaces and internal linings.
Example of epithelia derived from ectoderm
Corneal epithelium, skin
Example of epithelia derived from mesoderm
Endothelium and mesothelium, i.e. blood vessels, lymph vessels, pleura, genitourinary tract
Example of epithelia derived from endoderm
Respiratory tract, gastrointestinal tract, liver, glands
Define basement membrane and describe its structure
Thin, flexible, acellular layer between epithelial cells and connective tissue.
Epithelial cells lay down basal lamina, and the subtending connective tissue lays down the reticular fibres, hence can vary thickness of basement membrane.
The epiglottis is an interesting structure in terms of its epithelia. What is so special about it?
One side is stratified squamous cells, the other is pseudostratified cells
Where do we find umbrella-like cells that stretch and recoil?
Urothelium, and also blood vessels with connective tissue
Rate of renewal of epidermis
28 days
Rate of renewal of intestinal cells
4-6 days
What is Marfan Syndrome?
A genetic disorder (Auto dom) in the fibrillin gene. Fibrillin is a glycoprotein found in microfibrils of extracellular matrix found in connective tissue. This makes the connective tissue of affected individuals abnormal, resulting in a number of peculiar symptoms: Tall, thin stature, flexible joints, scoliosis, and risk of aortic tear.
List 4 types of connective tissue
Proper, adipose, bone, blood
What are three features common to all connective tissue?
1) Originate from mesenchymal cells
2) Have different degrees of blood flow
3) Mostly extra-cellular matrix (non-living)
What is ground substance?
Amorphous gel-like substance, with proteoglycans. These have protruding glycosaminoglycans that together form a structure that somewhat resembles a brush with bristles, and traps water.
Most common loose connective tissue and where it is found
Areolar. (Has few fibroblasts, with a little elastic/collagen fibres here and there).
Superficial fascia
Reticular connective tissue
Like areolar but with reticular fibres (instead of elastin/collagen). Found in stroma of organs.
Dense connective tissue types
1) Regular - collagen in parallel, tendons, ligaments and aponeurosis
2) Irregular - collagen in random arrangement, dermis of skin and deep fascia
3) Dense elastic - Increased elasticity vs rigidity. Vertebrae joints.
Types of cartilage
Hyaline, Elastic, Fibro
Nose, Ears, Vertebrae
