tissues Flashcards
exocrine gland
Secretions through ducts onto epithelial surfaces (Outside)
endocrine
Hormones, no ducts, Into blood & interstitial fluid (inside)
serous glands
Watery, serous solutions
–Often protein-rich
- mucous glands
–Thick, viscous, carbohydrate-rich
–Gel-like mucin glycoproteins
sebaceous gland
sebum – oily, waxy secretions
mixed glands
- both serous & mucous
Merocrine secretion
cell stays intact
ex: salivary gland
secretion from the bottom of epitheliam upward
Apocrine secretion
apex (top) breaks off and becomes part of the secretion
ex: maMMARY glands
Holocrine secretion
whole cell reptures
cells grow and divide at the base and cells at the top die and release secretion
ex: sebaceous gland of hair follicle
Connective tissue function
provides support & structure for
epithelial tissue
diverse and specialized
Extracellular Matrix is made of what
extracellular proteins and fluid like ground substance
Types of Extracellular Matrix (ECM)
Fibers
collagen
* reticular fibers– special type & arrangement of collagen
* elastic fibers
Ground Substance
Fluid & gel-like (except
bone & cartilage)
* Composition varies between tissues
* Often includes:
–glycosaminoglycans
–proteoglycans
–glycoproteins
*
“glyco-”: relating to
sugar
mesenchyme cell
Embryonic tissue
* Type of stem cell
* Loosely connected
& migrate
Stem Cells
- Stem cells can develop into
other types of cells - Stem cells can regenerate &
produce more stem cells
Differentiation
process by which stem cells
become specialized cells
– Stem cells “choose” certain
genes to develop into
specialized cells
Fibroblasts
Most abundant connective tissue cell type
* Secrete all types of ECM protein fibers
* Easily divide & regenerate
* Can develop into mature fibrocytes
blast”
“immature”
embryonic form of a cell
* Can divide to make more cells
cyte”
If a “-cyte” has a “-blast” form,
“-cyte” is the “mature” form
Fibroblasts
Most abundant cell type in Connective tissue proper Secrete proteins(e.g. collagen & elastin
-lots of protein synthesis
Fibrocyte
-2nd most abdundant
-Maintain fibers
-limited protein synthesis
Melanocytes
cell that produces and
stores melanin
melanin
class of brown/black or red
pigments
Adipocytes
-fat cells
-Store triglycerides & cholesterol
Macrophages
Eat pathogens, damaged cells, debris
* May be stationary
or mobile
Neutrophils (microphages)
eat debris & pathogens thru phagoccytosis
Granulocytes
Promote inflammation
* Impede & destroy pathogens
Loose connective tissue
“Packing materials” of the body
Areolar
Least specialized
* Open area of fiber framework
–Elastic fibers
–Thick ground substance fills the
gaps
* Holds nerves, ducts, & vessels in place
Reticular Tissue
reticulum – “network”
* Provides support
* Complex, three dimensional network
* Supportive fibers (stroma)
–Support functional cells (parenchyma)
Adipose Tissue
Contains many adipocytes (fat
cells)
* Adipocytes in adults do not divide
–Mesenchymal cells can become
adipocytes
–Store excess energy
–Metabolize fats for energy
types of adipose tissue
white, brown and beige
Dense Connective Tissues
Less fluid ground substance; more
densely packed fibers
Dense Regular Connective Tissue
Tightly packed, parallel
collagen fibers
Tendons
attach muscles to bones
ligaments
attach bones to bones
–or stabilize organs
aponeuroses
sheets attached to flat muscles
dense irregular
interwoven networks of collagen(fibers going in multiple directions)
-Layered in skin
-Wraps around cartilage
(perichondrium) & bones
(periosteum)
-Form capsules around some
organs
Elastic Tissue
plasma
extracellular matrix of blood
mast cells
release histomine and help with allergies
lymphocyte
immature cells that defend against pathogens
white adipose
more common, fat and lipid storage
brown adipose
has a lot more mitochondia, infants have a lot
mucous membrane
Tissue membrane that is covered by protective thick secretions and lines tissue exposed to the outside environment
fibrocartilage
Toughest form of cartilage, made of thick bundles of collagen fibers embedded in chondroitin sulfate ground substance
hayline cartilage
Most common type of cartilage, smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance
basement membrane
In epithelial tissue, a thin layer of fibrous material that anchors the epithelial tissue to the underlying connective tissue; made up of the basal lamina and reticular lamina
spot desmosome
________ is a type of junction between cells that provides a strong connection between cells that resists stretching and twisting.
mesenchyme
Embryonic tissue from which connective tissue cells derive
