Medical Biology Lecture Notes PDF

Medical biology Lec 1 MSC.Marwa Naeem What is biology scince? The Seven Characteristics of Living Things living things : All animals , plants, bacterium, protist, fungus are living things. If something is living it will carry out all of the seven activities Non-living things: Sand...

Medical biology Lec 1 MSC.Marwa Naeem What is biology scince? The Seven Characteristics of Living Things living things : All animals , plants, bacterium, protist, fungus are living things. If something is living it will carry out all of the seven activities Non-living things: Sand, wood and glass are all non-living things. 1-Feeding All living organisms need to take substances from their environment to obtain energy, to grow and to stay healthy. 2-Movement All living organisms show movement of one kind or another. All living organisms have internal movement, which means that they have the ability of moving substances from one part of their body to another. Some living organisms show external movement as well - they can move from place to place by walking, flying or swimming. 3-Breathing or Respiration All living things exchange gases with their environment. Animals take in oxygen and breathe out carbon dioxide.  4-Excretion Excretion is the removal of waste from the body. If this waste was allowed to remain in the body it could be poisonous. Humans produce a liquid waste called urine. We also excrete waste when we breathe out. All living things need to remove waste from their bodies. 5-Growth When living things feed they gain energy. Some of this energy is used in growth. Living things become larger and more complicated as they grow 6-Sensitivity Living things react to changes around them. We react to touch, light, heat, cold and sound, as do other living things. 7-Reproduction All living things produce young. Humans make babies, cats produce kittens and pigeons lay eggs. Plants also reproduce. Many make seeds which can germinate and grow into new plants. Branches of Biology: Biology can be divided into two major fields: zoology and botany. Zoology deals with animals, while botany deals with plants. Each of these major fields includes different life sciences such as: Morphology: A branch of biology that deals with form and structure of animals and plants. Such study on the cellular level is known as Cytology. On tissue level, it is known as Histology Embryology: The study of formation and development of embryo Anatomy: study of the animal form, particularly human body Biotechnology: science that is concerned with biological systems, living organisms, or derivatives to make or modify products or processes for specific use Cell biology : the study of cells at the microscopic or at the molecular level. It includes studying the cells’ physiological properties, structures, organelles, interactions with their environment, life cycle, division and apoptosis Ecology: the scientific study of the relationships between plants, animals, and their environment  Immunobiology: a study of the structure and function of the immune system, innate and acquired immunity, and laboratory techniques involving the interaction of antigens with specific antibodies Microbiology: the branch of biology that deals with microorganisms and their effects on other living organisms Molecular Biology: the branch of biology that deals with the formation, structure, and function of macromolecules essential to life, such as nucleic acids and proteins, and especially with their role in cell replication and the transmission of genetic information Mycology: the study of fungi Parasitology: the study of parasites and parasitism Pathology : the study of the nature of disease and its causes, processes, development, and consequences Pharmacology :the study of preparation and use of drugs and synthetic medicines Species are arranged in a hierarchical system in which genera are grouped into families, families into orders, orders into classes, classes into phylum (alternatively called division in plants, fungi and bacteria), phyla into kingdoms, kingdom into domain. The following figure shows the hierarchical system used in classifying organisms The earliest classification system recognized only two kingdoms (plants and animals).As biologists discovered microorganisms and learned more about other organisms, the number of kingdoms increased. Biologists now use their, six-kingdom system, which included two of prokaryotes and four kingdoms of eukaryotes. Prokaryotes: are organisms without a cell nucleus or any other membrane-bound organelles. Most are unicellular, but some prokaryotes are multicellular. Eukaryotes: are organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. The most characteristic membrane bound structure is the nucleus.