Tissues Flashcards
How are tissues held together?
By secreted ECM molecules
How are cells kept in place?
By cell-cell adhesion
What are the four basic body tissues?
Nervous, muscle, epithelial, and connective
What does neural tissue do?
Conduct nerve impulses in brain, spinal cord, nerves
What does muscle tissue do?
Contract to move skeleton, pump blood, propel food
What does epithelial tissue do?
Cellular sheets to line organs (barrier)
What does connective tissue do?
Secrete ECM to support body and connect parts (bone, blood, etc.)
What is the form of muscle tissue?
Elongated
What do fibroblasts do?
Generate fibers
What do macrophages do?
Consume dead cells
How are epithelial cells and nervous tissue similar?
They are both elongated and participate in conduction
What is an example of an organ with all types of tissue?
Intestine
What tissues does the intestine have?
- Epithelial cells for boundary
- Connective tissue (fibroblasts) to join layers through ECM
- Smooth muscle cells for perastalsis
- Neural tissue
How dense is ECM?
Cells are sparse
What is the majority of ECM and why?
Collagen, because it bears most of mechanical stress
What is the structure of ECM?
Lots of fluid, and few cells
How can ECM be different?
It is hard/rigid in bone, firm in cartilage, fibrous in facia, flexible/tough/strong in skin, and fluid in blood
What is ground substance?
The fluid gel in ECM that shapes amorphous surrounding tissues
How do the properties of the ECM arise?
From hydrophilic proteoglycans and glycoproteins interacting with electrolytes
What provides elasticity in the ECM?
Elastin molecules
What is important to generate elasticity for biopolymers?
Crosslinking
What happens in rheumatoid arthritis?
Collagen is degraded
What happens in athereosclerosis?
Too much collagen is secreted, so it accumulates with fats in walls of vessels
What are reticular fibers?
Mesh-like internal structure that has collagen fibrils to support basement membrane of epithelia and vascular endothelial
