Human Biology Lecture 1

Introduction to Biology

• Biology studies life from various aspects, focusing on both living organisms and their environments.
• Includes specialized fields like morphology, physiology, anatomy, and behavior.

Branches of Biology

• Anatomy: Studies the structure of organisms and their parts.
• Histology: Focuses on the microscopic structure of tissues.
• Cytology: Examines cellular structure and function.
• Physiology: Investigates normal functions of living organisms and their systems.
• Embryology: Studies the development and growth of embryos.
• Genetics: Analyzes inherited characteristics and variations.
• Molecular Biology: Studies biological molecules such as DNA and RNA.
• Biochemistry: Investigates chemical processes and reactions in organisms.
• Zoology: Scientific study of animals' behavior, structure, and classification.
• Botany: Focuses on the study of plants.
• Microbiology: Examines microorganisms.
• Evolution: Studies the development of species over time.
• Ecology: Investigates relationships between organisms and their environments.
• Entomology: Studies insects.

Human Biology

• Examines human anatomy and activities including growth, nutrition, reproduction, and respiration.
• Focuses on anatomy, physiology, histology, and embryology.
• Physiological study emphasizes organs and systems functioning together to maintain homeostasis.

Organization of the Human Body

• Human body organization ranges from cells to the entire organism, indicating increasing complexity.
• Key elements: hydrogen, oxygen, carbon, calcium, and phosphorus compose trillions of cells.
• Major electrolytes: sodium and chloride in body water, potassium in cells.

Cells

• Cells are the fundamental units of structure and function, essential for survival.
• Specialized cells, like nerve and muscle cells, perform distinct roles, such as transmitting messages and providing energy for movement.

Tissues

• Tissues are groups of similar cells serving specific functions.
• Four basic tissue types in the human body:
  • Epithelial: Protects (e.g., skin).
  • Connective: Supports (e.g., bones).
  • Muscular: Facilitates movement (e.g., skeletal muscle).
  • Nervous: Enables communication (e.g., brain).

Organs and Organ Systems

• Organs are comprised of different tissue types, e.g., brain, heart, lungs.
• Organ systems consist of groups of organs working together for complex functions.

Major Organ Systems

• Cardiovascular System: Heart and blood vessels transport oxygen and nutrients.
• Lymphatic System: Lymph nodes and vessels defend against disease.
• Digestive System: Involves esophagus and intestines for food digestion and nutrient absorption.
• Endocrine System: Glands produce hormones for cellular communication.
• Integumentary System: Skin, hair, and nails protect against injury and infection.
• Muscular System: Involved in movement and heat generation.
• Nervous System: Processes information, involving the brain and nerves.
• Reproductive System: Produces gametes and hormones for reproduction.
• Respiratory System: Trachea and lungs facilitate gas exchange.
• Skeletal System: Provides support and protection, and produces blood cells.