Tissues Flashcards
What are the 4 types of tissue?
Nerve
Epithelial
Connective
Muscle
What are nerve tissues used for?
Projecting electrical signals across the body for communication
What do muscle tissues do?
Contract and generate a force
What is the purpose of epithelial tissue?
Covers surfaces and seperates compartments
How does epithelial tissue stick and cover surfaces?
Through the use of junctions giving minimal contact inhibition
What type of junction is a desmosome?
Its an adhering junction that gives strong links, but isn’t water tight
What type of junction is a tight junction?
Two cell membranes sticking together forming a water tight seal. Not very strong
Can tight junctions be used with desmosomes? If yes why?
Yes, to form strong water tight seals/junctions
What is a gap junction?
Like a tight junction - two cell membranes stick and form a seal, but this one is permeable to allow channels between two cells
What do all epithelial cells sit on?
A basement membrane
What is the basement membrane made of?
Basal lamina and Reticular lamina
What is a hemi-desmisome?
A junction in contact with the basal lamina and the extracellular matrix rather than between two cells
What does the function of epithelial cells depend on?
The cell itself and not the ECM
What is the function of the cilla?
Movement due to finger like tublin projections
What is the function of microvilli?
Absorption via finger like projections made from actin
What are the three types of simple epithelial structures?
How many cells thick are they?
Squamous - very thin, good for diffusion
Cuboidal - thicker cells with a lining of nephrons, good for secretion, absorption/pumping
Columnar - similar to cuboidal but higher, lines digestive tract and when cillated, moves mucas
What is a stratified epithelium?
Same types as simple but with multiple layers of cells
What is a pseudostratified epithelium?
Cells look layered, but isn’t as every cell makes contact with the BL, in a tetris sort of structure
What are the epithelial components of the liver?
Hepatocytes
Arranged in rows between blood vessels
Multiple functions - secretion
Supporting epithelial cells line the blood vessels and bile ducts
What are the epithelial components of the kidney?
Epithelial cells are arranged into nephrons
Multiple functions - filtration of blood, partial absorption of filtrate
Support epithelial cells line blood vessels and renal pelvis which receives toxic urine
How are endo/exocrine glands develped?
Difference between exo and endo?
Cell proliferates inwards past the BL and underlining connective tissue into the cell.
Exo froms a tube to secrete outwards - e.g sweat
Endo just spreads hormones inside the body via blood
What are the two simple exocrine glands?
Tubular - long thin, straight invagination into cell. Secretes watery things
Acinar - round grape like shape, secretes thicker substances like mucas
What is the compound exocrine gland?
Tubuloacinar - mix of two simple and has a varied function
Example of an exocrine gland?
Serous gland - secretes water solutions that are protein rich
Mucous glands - secrete mucus rich in proteoglycans
What do endocrine glands tend to secrete?
Steroids and proteins into bloodstream
Describe a outcome of abnormal function of glands
over/under proliferation or loss of cillary beat
Example of abnormal gland function
Pituitary gland - releases growth hormones so over proliferation causes pituitary gigantism and under causes pituitary dwarfism
What does fibrous CT do? What is it made of and what makes it elastic? Colour?
Gives support
Made of collagen, is flexible with very high tensile strength
Elastic fibers have protein elastin, microfibrils and an amorphous component. Has a yellow colour
What is ground substance CT?
Jelly substance made of;
- Proteoglycans - consists of GAGS and a protein core.
- Hyaluronic Acid
- Glycoproteins - signaling molecules telling body what part is what
Makes up the ECM
What is Loose CT?
Fixed cells - fibroblasts, macrophages, adipocytes, mast cells
Transient cells - blood cells
What is dense CT?
Thick, lines up and very regular - tendons
What is tissue fluid?
Fluid in ECM
Consequences of abnormal CT?
Blood/Bone Marrow - overproliferation of WBC causes Leukaemia
Loose/Dense - Loss/abnormal fibres
Cartilage - Tears
Bone - Osteoporosis
