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Category: Medical

Topic: Cellular Physiology

Level: Paramedic

Next Unit: Cell Communication

7 minute read

Cellular Components

Each cell is made up of certain components and each of these has a specific job.

  • The cell membrane is the outermost wall of the cell, made up of fats (lipids) and proteins that surround the cytoplasm of the cell. The cell membrane acts as a barrier to protect the cytoplasm and also facilitates movement of particles into and out of the cell.
  • Cytoplasm is the material inside the cell (excluding the nucleus). It is made up of cytosol, which makes up over half of the cell volume. The cytoplasm surrounds the nucleus and its chromosomes within the cell and contains all the organelles such as mitochondria, lysosomes, Golgi apparatus, ribosomes, and the endoplasmic reticulum.
  • Mitochondria: considered the "powerhouse of the cell," they are spherical or elongated organelles in the cytoplasm containing the genetic material and enzymes important for cellular metabolism, including those responsible for converting food to usable energy using ATP.

Mitochondria are also involved with other tasks such as signaling, cellular differentiation, pre-programmed cell death ("apoptosis"), and maintaining control of the cell cycle and cell growth.

  • Lysosomes are spherical vesicles found within the cytoplasm of human cells that are made up of a specifically acidic composition and include many enzymes that act as the waste disposal system of the cell by aiding in polymer breakdown. They also act in other tasks of secretion, plasma membrane repair, cell signaling, and energy metabolism.
  • Endoplasmic reticulum: where the enzymes of the lysosomes are created. It is a huge (if it were unfolded) organelle made up of the smooth endoplasmic reticulum and the rough endoplasmic reticulum. The enzymes produced are imported into the lysosomes from the Golgi apparatus. The rough endoplasmic reticulum is studded with protein-manufacturing ribosomes (complex molecules that link amino acids together in the order specified by messenger RNA) that are constantly being bound to and released from its membrane.


Cellular Differentiation

Cellular differentiation is defined as the process by which a less specialized cell becomes a more specialized cell type.

Cellular maturation is defined as the process by which a cell matures over time. Cells either perform one specific function or act in concert with other cells to perform a more complex task.


An Excellent Metaphor:

The easiest way to think of cellular anatomy as described here is to imagine them as a factory creating energy.

  • The mitochondria is comparable to a dining facility for employees, feeding the cell.
  • The lysosomes are comparable to janitorial or waste disposal staff, ridding the cell of the waste product by using products produced at the factory.
  • Ribosomes would be the incoming and outgoing energy product being used at the assembly line (rough endoplasmic reticulum) and the
  • Golgi apparatus packages and sends the assembled product to the lysosomes for use.
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