Urinary System and Homeostasis
Urinary System Functions
Excretion
Removes indigestible chemicals and waste from the blood.
pH Regulation
Removes hydrogen and adds bicarbonate ions to adjust blood pH.
Blood Pressure Regulation
Secretes renin, increasing water and salt in the blood, causing blood vessel narrowing.
Osmoregulation
Removes excess salt and water to balance body fluids.
Blood Volume and Composition
Maintains adequate blood volume and composition.
Other Homeostatic Functions
Releases erythropoietin for red blood cell production
Read MoreUnderstanding the Cell Cycle, Mitosis, and Meiosis
Cell Cycle
The cell cycle is a sequence of events in a cell’s life, leading to its division and duplication. It consists of two main stages: interphase and cell division (mitosis or meiosis).
Interphase
Interphase is the period between cell divisions, where the cell grows and prepares for division. It constitutes the majority (about 90%) of a cell’s lifespan. Interphase is divided into three periods:
- G1 (Gap 1): Cell growth and synthesis. The cell reaches a restriction point (R), after which it commits
Evolution: A Comprehensive Overview
Fixism (19th Century)
- Species are immutable, remaining unchanged over time.
- Current species are unchanged descendants of those that first appeared on Earth.
- No species evolves.
- Fossils belong to extinct species due to natural disasters. Present species are descendants of those that survived.
Creationism (20th Century)
- Earth is approximately 6,000 years old.
- Species were created by God and have remained unchanged.
Evolutionism
- Creatures have evolved throughout Earth’s history, becoming increasingly differentiated.
Microbiology and Immunology
Anthrax
Anthrax is a highly aggressive bacterial disease that can be fatal. Used as a biological weapon, it persists in the ground (reservoir), affecting sheep and other grazing animals. The bacteria form spores with a tough outer covering.
Viruses
Features
Viruses are macromolecules with a protein coat containing a single type of nucleic acid, either DNA (like adenoviruses) or RNA (like retroviruses). As obligate parasites, they use the genetic material of the cells they infect. Viruses can infect
Read MoreFlower Morphology and Anatomy: A Comprehensive Guide
Flower Morphology and Anatomy
Introduction
Flower: A specialized stem or bud where internodes are reduced and the leaves are modified into antophylls. The modification is more profound from the outside to the inside.
Parts of a Flower
Stem: The flower stem, a small stalk with a widened tip called the receptacle or thalamus.
Flower Wraps:
- Perigone (tepals or calyx)
- Perianth (calyx and corolla)
Essential Bodies:
- Androecium (stamens)
- Gynoecium (carpels)
Anatomical Structures
Peduncle: The epidermis, ground tissue,
Read MoreBone Structure and Types: A Comprehensive Guide
Bones
Types of Bones
Long Bones
Long bones are characterized by their length and consist of:
- Diaphysis: The middle or body of the bone contains a cavity called the medullary cavity. Its hollow, cylindrical shape and compact bone within this region make it well-suited for providing strong support without excessive weight.
- Epiphysis: Refers to the ends of the long bone. Its bulbous shape provides ample space near the joints for muscle attachment and joint stability.
- Articular Cartilage: A fine layer of