1. Cells (Part 2)
Karen Malt, MSN, RN

2. Cells (Part 2) Relationship of Cell Structure and Function
Every Human Cell Performs Specific Functions
Some Maintain Cell Survival
Some Maintain the Body’s survival
Examples:
Heart Muscle must contain large numbers of mitochondria due to the amount of energy needed to support constant contraction of the heart muscle.
Sperm Cells flagellum propels the cell to increase the chance of successful fertilization.

3. Cells (Part 2)
Movement of Substances through Cell Membranes
Two Types of Transport Processes
Passive Transport (does not require energy) to move substances from a high concentration to a low level of concentration.
Active Transport (requires energy) to move substances from a low concentration to a high concentration.

4. Cell Part 2
Passive Transport – (down a concentration gradient) substances in passive systems move from a region of high concentration to a region of low concentration until they reach equal portions on both sides of the membrane.
Diffusion
Osmosis
Dialysis
Filtration

5. Cells (Part 2)
Diffusion- Movement of particles from an area of high concentration to an area of low concentration.
Experiment: Gently lower a teaspoon of sugar to the bottom of a cup of coffee. Wait a few minutes and taste the coffee. The coffee will taste sweet because some of the sugar molecules will have “diffused” from an area of high concentration (the mound of sugar at the bottom of the cup) to an area of low concentration (the top of the cup).
Examples: Movement of sodium ions into nerve cells as they conduct an impulse.

6. Cells (Part 2)
Osmosis – type of passive movement of water through a semipermeable membrane.
Osmotic Balance- the fluids outside the cell is the same chemical make up as inside the cell.
Isotonic- equal amounts; same osmotic pressure (cell does not change in shape).
Hypertonic- A solution contains a higher level of salt than than inside the cell ( The cell crenates, or scallops)
Hypotonic- A solution has a lower level of salt than inside the cell (the cell swells).

7. Cells (Part 2)
Dialysis – some solutes move across a selectively permeable membrane and others do not.
A procedure in which blood is pumped through membranous tubing bathed in a solution that mimics normal body fluid. The small waste molecules which would normally be removed by the kidney now diffuse into the bath solution.
Note: Peritoneal Dialysis; pump the bath solution into the space of the abdominopelvic cavity to accept the body’s waste by dialysis.

8. Cells (Part 2)
Filtration – the movement of water and solutes through a membrane as a result of a pushing force that is greater one side of the membrane than the other side. This force is called “hydrostatic pressure.”
EXAMPLE: The force or weight pushing against a surface (blood pressure.)
Note: Filtration is one of the processes, which produces urine. Wastes are filtered out of the blood into the kidney tubules because of a difference in hydrostatic pressure.

9. Cells (Part 2)
Active Transport – uphill movement of a substance, or moving from an area of lower concentration to a higher concentration.
Ion Pump
Phagocytosis
Pinocytosis

10. Cells (Part 2)
Ion Pump- Movement of particles from an area of high concentration to low concentration.
Example:
Sodium-Potassium Pump; “coupled” together, pumps sodium out of cell while it pumps potassium into the cell.

11. Cells (Part 2)
Phagocytosis- permits a cell to engulf or “eat” large particles.
Example: White Blood Cells (WBC’s) can use phagocytosis to destroy some types of bacteria.
Pinocytosis – Used to “trap” substances inside a pocket of the plasma membrane that pinches off inside the cell.

12. Cells (Part 2) Cell Growth and Reproduction
Cell Growth; in order for human life to be maintained, the cell must continually produce diverse structural and functional proteins.
DNA & RNA both play crucial roles in directing this protein synthesis.
DNA: the genetic code contained in the DNA are called genes, which determines the structure and function of the cell. This information can be transmitted to generations of cells and eventually to offspring.

13. Cells (Part 2) Cell Growth (continued)
Protein Synthesis- A transfer of genetic information from the nucleus into the cytoplasm, where proteins are produced.
Two Forms;
Transcription-
Translation-

14. Cells (Part 2) Cell Reproduction Cell Life Cycle
Cell reproduction involves division of the nucleus; a process called “mitosis.” The following video will explain the process of cellular division in details including the various phases of mitosis.

15. Cells (Part 2)
Note: During various stages of development, the addition of cells help tissues and organs grow in size. During such periods of various body growth, mitosis allows for some cells to “differentiate,” or develop into different tissues.
If the body loses its ability to control the cell life cycle (cell growth, reproduction, differentiation, and death) an abnormal mass of cell develops. This mass is called a “neoplasm.”
Neoplasms
Benign- Non- Cancerous
Malignant- Cancerous

16. References
Patton, K., Thibodeau, G. (2016). Structure and function of the body (15th ed.). St. Louis, Missouri: Elsevier