Cell Biology Mitosis Overview

Mitosis

• Mitosis is a type of cell division producing two identical daughter cells.
• Essential for growth, repair, and asexual reproduction.
• Phases include prophase, metaphase, anaphase, and telophase.
• Prophase: Chromosomes condense, the nuclear envelope breaks down, and spindle fibers form.
• Metaphase: Chromosomes align at the metaphase plate.
• Anaphase: Sister chromatids separate and move to opposite poles.
• Telophase: Chromosomes decondense, nuclear envelopes reform, and the cell divides.
• Cytokinesis divides the cytoplasm, completing the process.
• Critical for organismal growth, tissue repair, cell replacement, and asexual reproduction.

Eyes

• The human eye is a complex sensory organ for vision.
• Light enters through the cornea, which refracts the light.
• The iris adjusts the amount of light entering the eye.
• The lens further refracts light, focusing it onto the retina.
• The retina contains photoreceptor cells (rods and cones) converting light to electrical signals.
• Rods enable low-light and peripheral vision.
• Cones are for color vision and high-resolution vision.
• The optic nerve transmits electrical signals from the retina to the brain.

Nervous System

• The nervous system is the body's communication network.
• Composed of the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS includes the brain and spinal cord.
• The PNS consists of nerves branching from the CNS, connecting to the body.
• Neurons are the nervous system's functional units.
• Neurons transmit information via electrical and chemical signals.
• Neurotransmitters carry signals across synapses (gaps between neurons).
• Sensory neurons carry signals from the environment to the CNS.
• Motor neurons carry signals from the CNS to muscles and glands.
• Interneurons connect sensory and motor neurons within the CNS.

Structure of the Brain

• The brain is the body's control center.
• It receives, processes, and sends information throughout the body.
• Key structures include the cerebrum, cerebellum, and brainstem.
• Cerebrum: Higher-level functions like thought, memory, and language. Divided into two hemispheres connected by the corpus callosum.
• Cerebellum: Coordinates movement and balance.
• Brainstem: Controls essential life functions like breathing and heart rate.
• Different brain regions have specialized roles.

Ethical Issues Surrounding the Use of Stem Cells

• Stem cells are undifferentiated cells, becoming various cell types.
• Embryonic stem cells come from embryos.
• Adult stem cells are found in various body tissues.
• Ethical concerns surround embryonic stem cell research, especially extraction methods and using human embryos.
• Potential for treating diseases, especially regenerative medicine.
• Religious and moral views can oppose embryonic stem cell research.
• Potential for misuse and irresponsible practices in stem cell research.
• Importance of informed consent for stem cell research.
• Debate about allocating resources to stem cell research relative to other medical needs.