module 6 Flashcards
Basic Cellular Functions
-Growth
-Repoduction
-Metabolism
Requirements for Cellular Function
-Bring in nutrients and expel wastes
-Create cellular energy
-Synthesize new proteins
-Respond to external signals
-Transport materials throughout the cell body
Epithelial Cells
-Form protective barriers in tissues and may be specialized to absorb or secrete specific compounds
-Line cavities and surfaces of organs
Muscle Cells
-Responsible for movement of skeleton, heart, and many internal organs (stomach)
-Have specialized structures and proteins that allow them to generate motion
Nervous tissue
-Conduct electrical signals to carry info
-Differences in ion concentrations across membrane create electrical potential
-composed of nerve cells and glial cells (ex.schwann cells)
Bone Cells
-Form bones and skeleton system that give strength and support to the body
-These cells include osteoclast cells that degrade bone and osteoblast cells that create new bone
Secretory Cells
-Form glands and, as their name implies, secrete substances (e.g., mucous, hormones, enzymes, etc.)
Adipose Cells
-Located throughout the body to store fat
-This fat is in the form of triglycerides which are released when the body is in a period of fasting
Red Blood Cells
-Formed primarily in the bone marrow and released into the circulation where they move and deliver oxygen throughout the body
-NO nuclei or mitochondria
-limited lifespans, must continuously be replaced
Cell Junctions
-Membrane proteins
-Faciliate cell-to-cell attachments (for communication)
What kind of cells require junction complexes (adhesion proteins)
-Endothelial Cells
-Epithelial Cells
Endothelial Cells
Line inside of blood vessels
What are the proteins in the junctional complex
-tight junctions
-adherens junctions
-desmosomes
Tight Junctions
Divide plasma membrane into 2 domains:
* The apical (top) surface of the cell
* The basal (bottom) surface of the cell
Regulate paracellular transport
Phospholipids cant move across it
Adherens Junctions
Use transmembrane receptors proteins called cadherins that bind to other cadherins on neighbouring cells
amount of overlap –> proportional to bond strngth
found in neural synapses and cardiac muscles
Desmosomes
“Provide structural integrity to cell, ““snap”” cytoskeleton of cell together
In cells that are exposed to physical stress”
What does 1/2 of the desmosome complex consist of?
Hemidesmosomes, tether to basement membrane of epithelial cells, attachign them to extracellular matrix ECM
Gap Junctions Structure & Function
-Built in 2 halves to connect intercellular gap
-Use channel gating to move ions, sugars, nucleotides and other molecules from one cell to another
-important for cardiac muscle contractions
Extracellular Matrix
Proteins in matrix provide structure and support
Special matrix: basement membrane
Basement Membrane
-Matrix found below epithelial cells and outside tissues
-Contains special collagen sheet the provides structure and barrier for epithelial cells
Types of proteins in the ECM
-collagen
-gibronectin
-elastin
-laminins
-proteoglycans
Collagen
Most common protein in the body
-Main structural protein in the ECM
-Exists as a triple helix –> crosslinks to form fibrils –> form collagen fibers.
-Body makes multiple types of collagen
Fibronectin
-Glycoproteins that connect cells to collagen matrices, functioning in cell adhesion
-Expressed as dimers, and bind to integrins
-Interactions with cytoskeleton causes fibronectin dimers to straighten and associate with other fibronectins –> fibrils @ cell surface
Elastin
-Responsible for giving elasticity to tissues, allowing them to return to their original shape after being distorted
-Has hydrophobic and hydrophilic regions that return to og shape