Cellular Division and Human Biological Processes
Cellular Division
- Cellular Division: A mother cell produces two daughter cells.
- Cellular Interphase: The time period between the end of cell division and the beginning of the next.
- Cell Division Stages: Meiosis, mitosis, and cytokinesis.
- Meiosis: A process where the nucleus divides through two successive stages, resulting in four cells with half the chromosomes of the original cell. This process is used to form eggs and sperm.
- Cytokinesis: The division of the cytoplasm and organelles.
Mitosis Phases
- Prophase: Centrioles duplicate and move toward the poles of the cell; mitotic spindle fibers appear.
- Metaphase: Chromosomes align at the equatorial plate, attached to spindle fibers.
- Anaphase: Spindle fibers shorten, pulling chromosomes toward the cell poles.
- Telophase: Two sets of chromosomes reach the poles, and nuclear envelopes reform. Cytokinesis follows, narrowing the cytoplasm until two separate cells are obtained.
Biological Organization
Cells group together to form tissues, which organize into organs, systems, and appliances, ultimately constituting multicellular organisms.
Human Digestive Process
- Chewing: Food is broken down by teeth.
- Insalivation: Food mixes with saliva secreted by salivary glands.
- Food Bolus: The resulting pasty mass of food.
- Swallowing: The bolus moves from the mouth to the stomach through the pharynx and esophagus.
- Cardia: A muscle ring that regulates the passage of substances from the esophagus to the stomach.
- Stomach Digestion: Stomach movements and gastric juice secretion transform the food bolus into chyme.
- Intestinal Digestion: Chyme passes through the pylorus into the small intestine, where digestive juices transform it into chyle.
- Elimination: Remaining food waste is compacted into stool and removed via the anus during defecation.
Respiratory Process
- Air Filtration: Air enters through the nostrils, where particles are retained by mucus.
- Warming: Air contacts the mucosa covering the nasal cavity walls.
- Gas Exchange: Occurs in the alveoli, where oxygen passes through thin walls into blood vessels to be distributed to cells.
Inspiration and Expiration
- Inspiration: The diaphragm and intercostal muscles contract, increasing the volume of the ribcage.
- Expiration: The diaphragm and muscles relax, reducing the volume of the thorax.