tissues Flashcards
what are cell junctions?
gap junctions
tight junctions
desmosome
what are tight junctions?
they are tight so they do not allow movement between cells
ex: intestine, blood brain barrier, kidney
what is a gap junction?
have gaps allows the movement of ions
- transmission of charge
eg. heart, gut - parasympathetic and sympathetic wave like contraction in the gut moving through a gap junction
what is a desmosomes?
- prevent the pulling apart of tissues
- if we get a lot of mechanical stress on tissue then we get a desmosomes
- strong attachment
eg. skin, uterus, heart
heart contracts and fills there is stress on the heart
gap junctions and desmosos.
what is the definitions of tissues and what are the 4 types?
cells with similar structure and function
4 types:
- epithelial
-connective tissue
-nerve
-muscle
what is epithelial tissue?
every organ has a epithelial lining
eg. thoracic cavity wall, gut wall , skin
- inside and outside
glands:
exocrine: secrete into a duct , sweat glands, digestive enzymes
endocrine glands: specific to secreting hormones right into the blood
what is the meaning of stratified and simple squamous, and simple cuboidal, or stratified columnar?
stratified squamous- many layers
simple- one layer
squamous-squished cell, not round but squished
-lung tissue
simple cuboidal- one layer but more cubed
-found in gut
stratified columnar- the top stands taller and columns
what is the functions of the epithelial tissue?
protection - toxins, melanin, uv
absorption, secretion
ion transport, diffusion
filtration
forms slippery surfaces- esophagus to bring down food
what is simple squamous epithelium?
- put where we do not have a lot of wear and tear
- adapted for diffusion and filtration
eg. lung alveoli and bowmans capsule
what is stratified squamous epithelium
look at outer most layer to get the characteristic
-protects areas of wear and tear
-outer layer of skin, lining of mouth, vagina
what is transitional epithelium?
- contains cells can change shape
- in areas subject to stretching
eg. urinary bladder
what are the different specialized epithelial cells?
exocrine glands: secrete substances into ducts
e.g sweat glands, gut mucuses glands
endocrine glands : they are ductless
-secretes hormones into blood
-have more widespread effect
eg. thyroid
paracrine glands:
-secretes over short distances
-not go into blood but have a local affect
what is the unicellular exocrine glands or the goblet cell?
- goblet cells produce mucin
mucin+water-> mucus
we need mucus everywhere internal body always most time excretes mucus
(protects and lubricates) - goblet cell is a single cell
secrete out mucin which then makes the mucus
what are the different shapes of duct classifications?
simple vs compound
simple: comes out and has a coil tube
compound: has lots of branching
what are the main classes of connective tissue?
most abundant tissue
main classes:
cartilage
bone tissue
blood
fat
connective tissue
what is the connective tissue functions?
binds together, supports and strengthens
-protects and insulates internal organs
what are the two different connective tissue proteins?
- collagen- stiff protein, not very strechy
eg. tendon - elastin- strechy, eg. lung
what is the fibroblasts and ground substance?
fibroblasts are cells that secrete matrix proteins
-free macrophage
ground substance: os the matrix of loose connective tissue