tissues Flashcards
define tissue
A group of cells (that usually have a common origin in an
embryo) that function together to carry out specialised activities
define histology
the study of tissues
what is a pathologist
examines tissues for changes that may indicate
disease
what is a biopsy
the removal of a sample of living tissues for microscopic
examination. They are key for the diagnosis of cancer and
unexplained inflammation
what are the 4 types of tissues
- epithelial
- connective
- muscular
-nervous
what is the role of epithelial tissues
covers the body surfaces and lines hollow organs - also forms glands
what is the role of connective tissue
protects and supports organs. they can also store energy (adipose) and act as a route for the immune cells to travel through
what is the role of muscular tissue
made of cells specialised for contractions and generation of force - they also generate heat in the process
what is the role of nervous tissue
they detect changes in a variety of conditions in and outside the body and responds by generating electrical impulses
does epithelial tissue have a lot or a little extra cellular matrix
very little or none
what is the function of epithelial tissues
1- selective barriers that limit or aid the transfer of substances in and out of the body
2-secretory surfaces that release products of cells on to their free surface
3- protective surfaces that resist the abrasive influences of the environment
what is the structure of epithelial tissue
- basement membrane: a thin fibrous extracellular layer that separates the lining of an internal or external body surface from underlying connective tissues (made of collagen)
- the reticular lamina which contains macromolecules made by connective tissue layers
- hemidesmosomes that connect the basement layer membrane to the epithelial and connective tissues
what are the 2 main subtypes of epithelial tissue
1- covering and lining epithelium - forms outwards covering the skin and internal organs
2- glandular epithelium - makes up secreting parts of glands such as thyroid and sweat glands
where can stratified squamous epithelial tissue be found in the body
cheek lining
where can stratified cuboid epithelial tissue be found in the body
the skin
where can simple squamous epithelial tissue be found in the body
lining of the lungs
where can simple cuboid epithelial tissue be found in the body
the kidney
where can simple columnar epithelial tissue be found in the body
intestines
where can pseudostratified columnar epithelial tissue be found in the body
ovaries
what are the two types of secretory structures in glands
tubular and alveolar
what is an example of simple tubular
intestinal glands
what is an example of simple branched tubular
stomach glands
what is an example of simple alveolar
n/a in humans
what is an example of simple branched alveolar
sebaceous (oil)glands
what is an example of compound tubular glands
duodenal glands of the small intestine
what is an example of compound alveolar glands
mammary glands
what is an example of compound tubuloalveolar glands
salivary glands
what are exocrine glands and give an example
glands that produce and secrete substances onto an epithelial surface by way of a duct such as sweat, salivary or mucous
what are endocrine glands and give an example
secrete their products (hormones) directly into the blood rather than through a duct
what is diabetic kidney disease
also known as diabetic neuropathy
- most common cause of end-stage kidney disease
- commonly caused by the the basement membrane thickening, due to hyperglycemia induced signalling causing more collagen and other macromolecules to shut off filtration and stop kidney function
what is the function of connective tissues
- they connect support and bind other tissues and organs
- they protect and insulate organs
- they serve as a major transport system (blood)
- primary reserve of stored energy (fat in adipose tissue )
what are the components of connective tissue
cells such as fibroblasts, and extra cellular components (including; fibers, proteoglycans, glycoproteins, basement membranes and tissue fluid )
what are ground substances
- they can be fluid, semi-fluid, gelatinous or calcified
- it supports cells, binds them together and stores water
- also provides an active role in tissue development, migration and metabolic activity
what types of fibres are in connective tissues
collagen -
elastic fibres - smaller in diameter and branch more, large capacity to stretch; this is highly important in the skin and the lungs.
reticular fibres - collagen in fine bundles with a coating of glycoproteins. they provide support in blood vessel walls and form networks around cells in some tissues (such as fat and nervous tissue)
what are the types of connective tissue cells
mesenchymal cells
macrophages
mast cells
adipocytes
fibroblasts
what is the role of a masenchymal cell
they’re stem cells which raise the number of cells
what is the role of macrophages
they ingest and remove foreign material or damaged cells
what is the role of mast cells
trigger inflammation
what is the role of adipocytes
they store fat
what is the role of fibroblasts
they secrete the fibres and ground substance of the extra cellular matrix
where is cartilage found
between bones
what is cartilage made up of
chondrocytes
how do chondrocytes get their nutrients as cartilage had no blood vessels
the nutrients diffuse through a dense connective tissue surrounding the cartilage
what are osteoblasts
they’re bone forming cells.
they make a protein mixture known as osteoid, primarily composed of type 1 collagen, which mineralises the bone.
- new bone is built by building around itself
what are osteocytes
they originate from osteoblasts that have migrated into and become trapped in the bone matrix
- the spaces they occupy are know as lacunae
what are osteoclasts
large multinucleate cells that are responsible for the breakdown of bones - by the process of bone reabsorbtion
what is osteoporosis caused by
when bone reabsorbtion by osteoclasts occurs at a faster rate than the production of bone by osteoblasts
what are the 3 types of muscle tissue
skeletal, cardiac and smooth
what are the main features of skeletal muscles
- fibres - striated, tubular and multinucleated
- voluntary
- usually attached to skeleton
what are the main features of smooth muscle
fibres - non striated, spindle shaped and uninucleated
-involuntary
- usually covering wall of internal organs
what are the main features of cardiac muscles
fibres - striated, branched and uninucleated
- involuntary
- only covering walls of the heart
what are neuroglia
they assist with the propagation of the nerve impulse as well as provide nutrients to the neurons
what are glial cells
theyre non nuronal cells in the CNS and the PNS that do not produce electrical impulses
- they maintain homeostasis from myelin and provide support and protection for neurons
what are the main types of glial cells in the CNS
microglial cells
astrocytes
oligodendrocytes
ependymal cells
what is the role of microglial cells
Microglia are macrophage cells that make up the primary immune system for the CNS.
They are the smallest neuroglial cell that produce cytokines and other factors. They also receptors for
hormones and sex steroids
what is the role of Astrocytes
Star-shaped macroglial cells with many processes found in the CNS. They are the most abundant cell type in the brain, and are intrinsic to a healthy CNS
what is the role of oligodendrocytes
CNS cells with very few processes. They form myelin
sheaths on the axons of a neuron, which are lipid-based insulation that increases the speed at which the action potential, can travel down the axon
what is the role of ependymal cells
It is involved in the
production of cerebrospinal fluid (CSF), and is shown to serve as a reservoir for neuroregeneration. They
are lining the central canal of the spinal cord
