Cell Biology Functions and Communication

Specialized Cell Functions

• Muscle cells contract to enable movement
• Nerve cells generate and transmit electrical impulses.
• Metabolic Absorption: Cells intake and utilize nutrients
• Cells such as mucous glands can secrete hormones.
• Cells eliminate waste like lysosomes breaking down cellular debris.
• Cells convert oxygen into energy through ATP production.
• Cells divide to create new cells.
• Cells communicate using signals to coordinate their functions

Cell-to-Cell Adhesions

• Extracellular matrix provides structural support with collagen, elastin and proteoglycans.
• Cell adhesion molecules allow cells to adhere to one another and to the exterior matrix.
• Specialized cell junctions include:
  • Tight junctions
  • Gap junctions
  • Desmosomes
• These structures help maintain the integrity of tissues and organs.

Cellular Communication

• Cells communicate via direct contact using gap junctions.
• Cells communicate with receptors on the cell surface.
• Cells utilize signal transduction to create responses within the cell.

Types of Tissues

• Epithelial tissue protects, absorbs, and secretes substances (e.g., skin)
• Connective tissue provides structure and support (e.g., bone, blood).
• Muscle tissue enables movement, including skeletal, smooth, and cardiac muscles.
• Nervous tissue transmits electrical impulses for communication using neurons.

Genetics

• Genetics is the study of genes and inheritance.
• Human Genetics focuses on hereditary traits and human variations.
• DNA contains genetic information in a double helix structure.
• RNA assists in translating genetic code from DNA into proteins.
• DNA duplicates itself by splitting and creating a complementary strand which ensures genetic continuity.

Mutations

• Mutations occur as a change in the DNA sequence.
• Mutations can be inherited, or caused by environmental factors.
• Mutations result from errors during DNA replication or exposure to mutagens such as chemicals or radiation.

Cellular Adaptation

• Atrophy is when the cell size decreases due to disuse or lack of resources.
• Hypertrophy is when the cell size increases due to increased workload.
• Hyperplasia is when the number of cells increases, often due to increased demand or hormonal stimulation.
• Dysplasia is when abnormal cell growth and appearance occurs, which can be reversible, but can precede cancer.
• Metaplasia is when there is a reversible replacement of one cell type with another better suited to the stressor.

Cellular Injury, Stress, and Cell Death

• Cellular Injury is caused by toxic, infectious, physical, or deficit-related factors.
• Cells can adapt, recover, or die in response to the severity and duration of stress.
• Toxic Injury can be caused by harmful chemicals or metabolic errors.
• Deficit Injury happens when cells lack essential resources like oxygen or nutrients.
• Infectious Injury is caused by pathogens that disrupt cell function.
• Physical Injury can occur from thermal or mechanical forces such as trauma or radiation.