Download Cells (Part 2)

Cells
(Part 2)
Karen Malt, MSN, RN
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.
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.
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
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.
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).
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.
• https://www.youtube.com/watch?v=fKlY2SKi_dk
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.
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
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.
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.
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.
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-
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.
https://www.youtube.com/watch?v=WAGjRcoolds
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
https://www.youtube.com/watch?v=8LhQllh46yI
References
Patton, K., Thibodeau, G. (2016). Structure and function of the body (15th ed.). St. Louis, Missouri:
Elsevier