MEC322: Tissues Flashcards
Define tissue
groups of cells with similar structure and function
What are the four primary types of tissue?
Epithelial tissue (epithelium) (cover) Connective tissue (compose) Muscle tissue (contract) Nervous tissue (call (signal))
Where can you find epithelial tissue?
Body coverings
Body linings
Glandular tissue
What are the main functions of epithelial tissue?
Protection
Absorption
Filtration
Secretion
What are the characteristics of epithelial tissue?
Cells fit closely together and often form sheets
The apical surface is the free surface of the tissue
The lower surface of the epithelium rests on a basement membrane
Avascular (no blood supply)
Regenerate easily if well nourished
Where is connective tissue found in the body?
everywhere
What are the main functions of connective tissue?
Provides protection
Binds body tissues together
Supports the body
What are the characteristics of connective tissue?
Variations in blood supply
Some tissue types are well vascularized
Some have a poor blood supply or are avascular
Extracellular matrix:
Nonliving material that surrounds living cells
What are the two main elements of an extracellular matrix?
ground substance - mostly water along with adhesion proteins and polysaccharide molecules
fibres: collagen, elastin, reticular (produced by cells)
What are the three major types of connective tissue?
connective tissue proper
fluid connective tissue
supporting connective tissue
What is areolar tissue?
Loose connective tissue
- most widely distributed connective tissue
- soft, pliable tissue (like cobwebs)
- functions as a universal packing tissue and glue to hold organs in place
layer of areolar tissue called lamina propria underlies all membranes
All fiber types form a loose network
Can soak up excess fluid (causes edema)
What is adipose tissue?
Loose connective tissue
- Matrix is an areolar tissue in which fat globules predominate
- many cells contain large lipid deposits with nucleus to one side (signet ring cells)
What are the functions of adipose tissue?
- insulates body
- protects some organs
- serves as a site of fuel storage
What is reticular tissue?
Loose connective tissue
delicate network of interwoven fibers with reticular cells (like fibroblasts)
Where are reticular tissues found?
forms stroma (internal framework) of organs, such as these lymphoid organ:
- lymph nodes
- spleen
- bone marrow
What is dense connective tissue?
dense fibrous tissue
- main matrix element is collagen fibre
- fibroblasts are cells that make fibres
Where is dense connective tissue found?
- tendons: attach skeletal muscle to bone
- ligaments: attach bone to bone joints and are more elastic than tendons
- dermis- lower layers of skin
What are the three types of loose connective tissue proper?
Areolar tissue
Adipose tissue
Reticular
What is a type of fluid connective tissue?
blood (vascular tissue)
- blood cells surrounded by fluid matrix known as blood plasma
- soluble fibres are visible only during clotting
Vascular tissue functions as a transport vehicle for the cardiovascular system, it carries…
nutrients
wastes
respiratory gases
What is supporting osseous tissue?
supporting connective tissue bone (osseous tissue) is composed of - large numbers of collagen fibres - hard matrix of calcium salts - osteocytes (bone cells) within lacunae (cavities)
What is the function of osseous tissue?
protect and support the body $
What is cartilage?
supporting connective tissue
Describe cartilage
- less hard and more flexible than bone
- found in only a few places in the body
- chondrocyte (cartilage cell) is the major cell type
What is hyaline?
(supporting connective tissue)
most widespread type of cartilage
- composed of abundant collagen fibres and a rubbery matrix
- more flexible skeletal element than bone
Where is hyaline found?
larynx, epiphyseal plates
entire fetal skeleton
Describe elastic cartilage
- Supporting connective tissue
- provides elasticity
- supports the external ear
describe fibrocatilage
- highly compressible
- forms cushion-like discs between vertebrae of the spinal column
What is the function of muscle tissue?
contract, or shorten, to produce movement
What are the three types of muscle tissue?
skeletal
cardiac
smooth
Describe skeletal muscle?
- voluntarily (consciously) controlled
- attached to the skeleton and pull on bones or skin
- produces gross body movements or facial expressions
What are some characteristics of skeletal muscles?
- striations (stripes)
- multinucleate (more than on nucleus)
- long, cylindrical shape
Describe cardiac muscle
- involuntarily controlled
- found only in the heart
- pumps blood through blood vessels
What are the characteristics of cardiac muscle?
- striations
- uninucleate, short, branching cells
- intercalated discs contain gap junctions to connect cells together
Describe visceral muscle (smooth)
- involuntarily controlled
- found in walls of hollow organs such as stomach, uterus, and blood vessels
- peristalsis, a wavelike activity, is a typical activity
What are the characteristics of visceral muscle?
- No visible striations
- Uninucleate
- Spindle-shaped cells
Describe nervous tissue
Composed of neurons and nerve support cells
Function is to receive and conduct electrochemical impulses to and from body parts
Irritability
Conductivity
Support cells called neuroglia insulate, protect, and support neurons
