Human Circulatory System: Heart, Blood Flow, and Pressure
Introduction
The basic function of the circulatory system is to transport nutrients and oxygen to cells and remove metabolic waste. The heart, a muscular pump, propels blood throughout the body. The circulatory system is divided into two main circuits: pulmonary circulation (heart-lungs-heart) and systemic circulation (heart-body-heart). Arteries carry blood away from the heart, and veins carry blood back to the heart, regardless of oxygen content.
Heart
The heart, located in the mediastinum, is protected
Read MoreCellular Biology: Exploring Organelles and Cell Cycle
Chloroplasts
Chloroplasts are cellular organelles found in eukaryotic photosynthetic organisms. They are essential for photosynthesis. Enclosed by a double membrane, chloroplasts contain thylakoids, vesicles where pigments and other molecules convert light energy into chemical energy. Chlorophyll, the primary pigment, is mainly located within chloroplasts. Key Features: Responsible for the light and dark phases of photosynthesis. Involved in the biosynthesis of fatty acids from carbohydrates and
Read MoreUnderstanding Mitosis and Meiosis
MITOSIS: CONCEPT AND HISTORY
Mitosis is the process of splitting the nucleus and the main function of the S phase is to duplicate the mother cell’s chromosomes into two identical groups. This creates new cells with the same genetic information as the mother cell. This division, called replication, results in newly divided cells with the same chromosomes as the previous one. This is a universal division. This complex phase is classified into four sub-phases to facilitate research: prophase, metaphase,
The Human Nervous System: Structure, Function, and Organization
The Nervous System
Introduction
The nervous system, a complex network of specialized tissue, allows for communication and coordination within the body. It responds to internal and external environmental changes, integrating activities across different body parts. This system emerges around the third week of embryonic development, originating from the ectoderm.
Divisions of the Nervous System
The nervous system is divided for educational purposes into several categories based on anatomical, embryological,
Read MoreDNA, Genes, and Biotechnology: A Deep Dive
Protein Synthesis
Protein synthesis takes place in the cytoplasmic ribosomes. A ribosome has two sites for tRNA entry.
- The ribosome binds to the mRNA. The initiator codon occupies the P site, and the following codon occupies the A site. The first codon then joins its complementary anticodon on the tRNA.
- The tRNA carrying the anticodon complementary to the codon in the A site moves into the A site.
- Once both tRNAs are in position, a ribosomal enzyme joins the two amino acids.
- The tRNA in the P site, now
Animal & Plant Tissues: Structure and Function
Animal Tissues
Epithelial Tissue
Formed by closely packed flat, cubic, or cylindrical cells with short lifespans. Two main types:
- Covering Epithelium: Forms a sheet covering body surfaces, cavities, and organ openings. Rests on a basement membrane. Three types:
- Monostratified: Single layer of cells.
- Squamous: e.g., alveoli lining.
- Cuboidal: e.g., ovary wall lining.
- Columnar: e.g., small intestine lining (with microvilli for absorption).
- Pluristratified: Two or more cell layers.
- Cuboidal: e.g., conjunctiva.
- Monostratified: Single layer of cells.