connective tissue Flashcards
what is c.t.?
tissue that holds other tissues together to give the body its form and has a supportive function
what is c.t. composed of?
cells called fibroblasts, fibers produced by these cells, and ground substance or extracellular matrix
what are the four basic types of c.t.?
Connective tissue proper
Blood
Bone
Cartilage
what are the two categories of c.t. proper?
dense c.t.
loose c.t.
what is loose c.t.?
- loose filmy to gelatinous material that is present in tissues.
- mostly irregular with random distribution of fibroblasts and loosely packed fibers weaving in and out of the c.t.
what is dense c.t.?
tougher and is found as protective sheaths, and also makes up ligaments and tendons.
what is dense regular c.t. and examples
fibers are packed tightly together and have the same orientation
ex. tendons and ligaments
what is dense irregular c.t. and examples?
random fibers and cells, but they are packed tightly together giving it a thick fabric-like appearance.
ex. Tough connective tissue sheaths and capsules of organs
what is the predominant cell type of c.t.?
fibroblasts
describe the appearance of fibroblasts
fusiform with an elongated nucleus
what do fibroblasts produce?
collagen fibers
what type of cell is predominant in embryonic tissue, are stellate, and are pluripotent?
mesenchymal cell
what are reticular cells
present in organs and provide a framework or scaffold for certain cells
give an example of where reticular cells are present and what they produce
lymph nodes, where they produce reticular fibers and provide a scaffold for lymphocytes to populate the lymph node
where are adipocytes found and why?
found in loose connective tissue and in adipose tissue that serves as a padding under the skin or around organs
which cell type has a signet ring?
adipocytes
list the inflammatory cells that migrate to c.t.
histiocytes, mast cells, lymphocytes, eosinophils, macrophages and plasma cells
describe type I collagen
- most predominant, 90% of c.t.
- coarse fibers: produced by fibroblasts but also smooth muscle cells and osteoblasts
describe type II collagen (fine collagen)
- found in cartilage, nucleus of pulposus of intervertebral disc, and vitreous humor of eye
- can’t see it
describe type III collagen (reticular fibers)
- produced by reticular cells, fibroblasts, smooth muscle cells
- found in lymphoid organs and skin
- visualized with silver strain
describe type IV collagen (lattice fibers)
- forms lattice on which epithelial cells rest
- makes up basement membrane for epithelial surfaces
where are elastic fibers found?
bvs and elastic cartilage
what are elastic fibers synthesized by?
fibroblasts, smooth muscle cells, and chondroblasts
what are ground substances made of?
glycosaminoglycans (GAGs) and proteoglycans
what is the purpose of ground substance?
- retain water and help with nutrient transfer
- important for tissue repair and regeneration
true or false: you can’t see ground substance in a stain
true
true or false: muscle is a type of c.t.
false
muscle account for what percentage of body mass?
70%
what are the 3 basic types of muscle?
- skeletal
- smooth
- cardiac
what is the purpose of skeletal muscle?
- making the body move
- provides shape
- plays important role in physiological function like metabolism, thermogenesis, and maintaining electrolyte balance
what is the purpose of smooth muscle?
- forms protective covering for internal organs and helps in their motility
- helps with storing body fluid and ingesta, digestion and respiration
- helps maintain blood pressure
- facilitates movement of blood throughout body
what is cardiac muscle responsible for?
supplying blood to and from different parts of body
what is the most abundant type of muscle in body?
skeletal
Each muscle is made up of individual muscle cells or ________
myofibers
Each muscle cell or myofiber is made up of numerous _________
myofibrils
Each myofibril is made up of ___________ stacked on top of each other
sarcomeres
Each sarcomere is made up of myofilaments, what are myofilaments composed of?
actin, myosin, troponin, tropomyosin
what gives muscle its striated appearance?
actin and myosin filament arrangement within the sarcomere
The nuclei of the myofibers are always located in the ____________
periphery
what can skeletal muscle be identified by?
- striations
- peripherally located nuclei
true or false: skeletal muscle is placed under involuntary control
false: voluntary
describe the muscle fiber of smooth muscle
short, fusiform, tightly packed
why is the smooth muscle in the gut arranged as an inner circular and outer longitudinal layer?
helps peristalsis
why are striations not visible in smooth muscle?
myofilaments are oriented along the axis of the cell
why are there gap junctions between cells of smooth muscle?
to facilitate quick and coordinated contraction
how can smooth muscle be identified?
Lack of striations
Short length
Centrally placed nuclei
why is cardiac muscle unique?
it is not only under autonomic control, but has its own rhythm of contraction
how can cardiac muscle be identified?
- striations
- centrally placed nuclei
- branched
- intercalated discs
