Tissues Flashcards
What does Histology and Pathology mean?
Histology: histo = tissue; ology = study
* Histology: microscopic study of tissues
* Pathologist: physician that examines tissue to help other physicians
What is the Difference between Epithelial and Connective tissue?
Epithelial tissue
Has cells tightly packed together
Has little or no ECM
Connective tissue
Has a few scattered cells
Cells are surrounded by large
amount of ECM
What is Surface (Proper) ET?
- Forms surface layers and
- Avascular: does not have its own
blood supply - Provides coverings of skin and some
internal organs - Forms linings of vessels, ducts, and
body cavities - Body cavities such as:
interior of respiratory, digestive, urinary, and reproductive systems
What are the Classifications of Surface ET: number of cell layers?
- Simple ET (uni-laminar = one layer)
- Very thin -allows diffusion, osmosis and filtration and absorption to pass through
- Oxygen and carbon dioxide diffuse through simple ET in lungs
- Can function with absorption: absorption of fluids and other substances
- Stratified (two or more layers)
- More layers = more protection, etc.
- Appears where there is considerable wear and tear.
- Pseudostratified:
- Looks like more than one layer, but it’s not.
What are the Classifications of surface ET: cell shape?
Squamish cells:
* Think “thin” rapid passage of
substances through them
Cuboidal cells:
* Cube shaped secretion or absorption
Columnar cells:
* Taller than wide (like columns)
* protect underlying tissues (shock
absorbers) / absorption: have microvilli =
increase surface area for absorption
What are Transitional (Urothelium) cells?
Transitional (Urothelium) cells:
* Change shape: relaxed = Cuboidal / stretched = Squamish
* Example urinary bladder: cells can stretch to large size and collapse to smaller size
What is Glandular ET?
Glandular ET
Primary function is secretion
* Glands either endocrine or exocrine
*epithelium tissue that secretes substances (via ducts) onto either:
* A surface (exocrine)
* Into blood (endocrine)
What does all connective tissue have in common?
- Develop from same cell (Mesenchyme)
- They have different degrees of vascularity
- Connective tissues are mostly composed of non-living material (ECM)
What is ECM made up of?
EM (Jell-O) made up of two components:
1. Ground substance and
2. Fibers
All connective tissue cells (marshmallows) have
two phases. What are they?
- Immature phase
* Cells called “Blasts” (means forming)
* secrete ground substance and fibers
* Creates unique extracellular matrix - Mature phase
* Blasts mature into “cytes”
* Cytes maintain matrix health
What are the Connective tissues functions?
- Binds things together
- Supports and strengthens
- Protects
- Compartmentalizes structure
- Adipose tissue (a connective tissue type) = primary location of stored
energy reserves - Blood (a connective tissue type) = transport system to service cells
What is Ground substance?
Ground substance:
* Component between cells and fibers
* Supports cells, binds them together
* Provides medium for exchange between blood and cells
* role in tissues development/ functions
* Contains water and large organic molecules (polysaccharides and proteins) collectively known as GAG’s
* GAG’s trap water and make ground substance more jelly-like
What are the three types of ECM fibers?
Three types of ECM fibers
1. Collagen fibers
* Protein fibers: strongest and most abundant fibers (stronger than steel
of same size)
* Resist pulling or stretching
2. Elastic fibers
* Contain protein elastin
* Strong but can be stretched up to 150% then return to normal length
* Plentiful in skin
3. Reticular fibers
* Made of collagen arranged in bundles with a coating of glycoproteins
* Provide support for walls of blood vessels and form a supporting
framework around many “soft” organs (spleen, lymph nodes).
Connective tissue cells vary according to type of what?
Fibroblasts:
-Secretes fibers and ground substance
-Most common cell in connective tissue
Macrophages:
-Develop from monocytes (WBC) and destroy bacteria by phagocytosis
Plasma cells
-Part of Adaptive Immune System
Mast cells:
-Involved in triggering inflammatory responses (innate immune system)
White blood cells
-Not found in significant numbers in normal connective tissue
-Respond to infection/pathogens
Examples:
-neutrophils (gather at sites of infection)
-eosinophils (migrate to parasitic invasions)
-Adipocytes:
-Fat cells
-Store triglycerides
Three types of Mature Connective tissue are?
A. Connective Tissue Proper
* Tendons and ligaments
* Flexible / ground substance has abundant fiber
B. Supporting Connective Tissue
* Cartilage and bone
* network of collagen and elastic fibers
* High tensile strength
C. Liquid Connective Tissue
* Blood plasma
What are membranes and the types?
Membranes = flat sheets of pliable tissue
* Cover/line body parts
Two types of membranes
* A: Epithelial Membranes
* B: Synovial Membranes
What are Epithelial Membranes?
Epithelial Membranes
* Majority of membranes
* Consist of epithelial layer attached to
underlying connective tissue
* Three types of epithelial membranes:
1. Mucous membranes (or mucosa) line
body cavities that open to exterior/
secrete mucus
2. Serous membranes (serosa)
* Line cavities that don’t open to exterior
* Lines inner walls of body cavities and
secretes lubricating fluid to reduce
friction between opposing surface
3. Cutaneous membranes: covers surface of body (skin)
What are Synovial Membranes?
Synovial Membranes (syn = together)
Used when two bones articulate
* Do not open to exterior
* Lack epithelium thus they are not epithelial membranes
* Composed of synoviocytes cells which secrete some component of
synovial fluid
* Synovial fluid lubricates and nourishes cartilage covering bones and joints
* Synovial fluid contains macrophages
What are the types of Muscular Tissue?
Skeletal Muscle
-Consists of long, cylindrical, striated fibers
-Multicellular with nuclei located at cells periphery
-Controlled voluntarily
-Usually attached to bones by tendon
Cardiac Muscle
-branched striated fibers and only a single centrally located nucleus
-Attached end to end by intercalated discs
-gap junctions
-Involuntary control
Smooth Muscle
-Lack striations (hence term “smooth”)
-Spindle shaped cells
-Cells have single central nucleus
-Gap junctions
-Involuntary control
What is Nervous Tissue?
- Nervous tissue consists of neurons and neuroglia
- Dendrites and axons project from main neuron body
- 98% of nervous tissue located in CNS
- Highly excitable: generate action potentials
