Lecture 1 Human Biology PDF

Lecture th (1) Nov. 17 , 2024 Introduction to Human Biology Prof. Dr. Sami R. Al-Zubaydi College of pharmacy University of Duhok Biology Biology: The study of life. Greek origin: Bio: Life Logos: Study of Is the science that studies the life from all its aspects....

Lecture th (1) Nov. 17 , 2024 Introduction to Human Biology Prof. Dr. Sami R. Al-Zubaydi College of pharmacy University of Duhok Biology Biology: The study of life. Greek origin: Bio: Life Logos: Study of Is the science that studies the life from all its aspects. It is including the study of living and non-living parts in life. Studying living organisms divided into many specialized fields covering their morphology, physiology, anatomy, behaviour, origin, and distribution. Biology includes many branches, such as: 1. Anatomy: is the study of the basic structure of the body of the organisms and their parts. Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures (which known as histology), and also in the study of cells. 2. Histology: is the study of the microscopic structure of tissues. 3. Cytology: is the branch of biology that studies the structure and function of cells. 4. Physiology: is the branch of biology that studies the normal functions of living organisms and their parts. It studies the function of each structure in the body and the chemical reactions occur inside the body. 5. Embryology: is the branch of biology and medicine concerned with the study of generation and the growth of embryos and their development. 6. Genetics: the branch of biology that studies the inherited characteristics of the organisms. It is also studying the variation of inherited characteristics. 7. Molecular Biology: is the study of biology at the molecular level, e.g.: studying biological molecules like DNA and RNA. 8. Biochemistry: is the study of chemical nature and sequence of biochemical reactions in organisms. 9. Zoology: is the scientific study of the behaviour, structure, physiology, classification and distribution of animals. 10. Botany: is the branch that studies the plants. 11. Microbiology: is the science that studies the microorganisms. 12. Evolution: The study that deals with the development of highly organized species from lowly organized species by a gradual change. 13. Ecology: the branch of biology that deals with the relations of organisms one to another and to their physical surroundings. 14. Entomology: The study of Insects. Human Biology Is the study of the anatomy and all the human activities such as growth, nutrition, reproduction, respiration, digestion, excretion, secretion ….etc. Studying the human body involves the study of the anatomy, physiology, histology and embryology. Physiological study focuses on the systems and organs of the human body and their functions. Many systems and mechanisms interact in order to maintain the homeostasis with safe levels of substances such as sugar and oxygen in the blood. In order to begin the study of human biology in which we will learn how human body works & how human beings relate to other living things, it is appropriate to take a look at who humans are & how they fit into the world of living things. The certain characteristics of human beings shared by all other living things are: (1) Organization (2) Acquiring materials & energy (Take materials & energy from the environment) (3) Reproduction (4) Growing & Developing (5) Being homeostatic (6) Responding to stimuli (7) Evolution (1) Organization Atom, the smallest unit of an element composed of: - Electrons - Protons - Neutrons Two or more atoms of the same or different elements joined together to form the molecules that make up a cell. ↓ A cell is the smallest and functional unit of an organism. (Some organisms are single cells. Human beings are multicellular because they are composed of many different types of cells). ↓ A group of cells with common structure & function forming the tissue ↓ Several types of tissues make up an organ ↓ Each organ belongs to an organ system (organ system composed of several organs working together) Levels of Biological Organization: Molecule ▪ Atoms are units of matter (anything that takes up space and mass) that cannot be broken down into simpler substances by ordinary chemical means. ▪ An element is a pure form of matter containing only one kind of atoms. A molecule is two or more atoms bonded together. - Example: water (H2O) The organization of the human body begin at the very small and basic and come together to form the complete body whose different parts work in unison. This can be seen as a kind of ladder going from the basic to the very complex. At the simplest level, the body is comprised of atoms. Organization of the Human Body The human body is organized at different levels, starting with the cell and ending with the entire organism (see the figure). At each higher level of organization, there is a greater degree of complexity. The brain works with the spinal cord to sent commands to body parts by a way of nerves. ↓ Collection of an organ system make up the organism The levels of biological organization extend beyond the individual ↓ All the members of one species (group of inter breeding organism) in a particular area belong to a population ↓ The interacting populations make up a community ↓ The community of population interact with the physical environment to form an ecosystem ↓ Finally, all the Earth’s ecosystems make up the biosphere Levels of Biological Organization ▪ Population: All individuals of the same species in an area. - Example: Humans living in Duhok ▪ Community: All the species in an ecosystem that can interact. - Example: All the species including plants and animals ▪ Ecosystem: A community and its physical environment - Example: All the species in Duhok , including the water, soil, sunlight, etc. ▪ Biosphere: The part of the earth that supports life. Levels of Biological Organization: Review Levels of Biological Organization: Review Cells Cells are the basic units of structure and function in the human body, as they are in all living things. Each cell carries out basic life processes that allow the body to survive. Many human cells specialized in form and function. Each type of these specialized cells plays a specific role. For example, the nerve cells have long projections that help them in carrying the electrical messages to other cells. Muscle cells have many mitochondria that provide the energy they need to move the body. Levels of Biological Organization: Organelle ▪ An organelle is a membrane-bound internal compartment in cells for specialized functions. - Example: Mitochondrion Source: Qiagen Characteristics of life 2. They are composed of cells - Cells are the smallest unit of life - Some organisms are composed of only one cell (unicellular) - Others are composed of more than one (multicellular)  Cells - “Fundamental Unit of Life” Prokaryotes Eukaryotes - single celled - single or multicellular - no nucleus - nucleus & nuclear - no organelles membrane - DNA is a single, - organelles present circular molecule - DNA packaged into - e.g., bacteria chromosomes - e.g., protozoans, plants, animals Tissues The tissue is the next level of organization in the human body. A tissue is a group of connected cells that have a similar function. There are four basic types of human tissues: epithelial, muscular, nervous, and connective tissues. These four tissue types make up all the organs of the human body. Connective tissue is made up of cells that form the body’s structure, such as the bone and cartilage. Epithelial tissue is made up of cells that line inner and outer body surfaces, such as the skin and the lining of the digestive tract. Epithelial tissue protects the body and its internal organs, secretes substances such as hormones, and absorbs substances such as nutrients.  Muscular tissue is made up of cells that have a unique ability to contract or become shorter. Muscles attached to bones enable the body to move. Nervous tissue is made up of neurons (or nerve cells) that carry electrical messages. Nervous tissue makes up the brain and the nerves that connects the brain to all the body parts. Levels of Biological Organization: Organ ▪ An organ is a structure with two or more tissues working together to perform a function. Organs and Organ Systems Organs are the next level of organization of the human body. An organ is a structure that consists of two or more types of tissues that work together to do the same job. Examples of human organs include the brain, heart, lungs, skin and kidneys. Human organs are organized into organ systems, many of which are shown in the following figure. An organ system is a group of organs that work together to carry out a complex overall function. Each organ in the system does part of the larger job. Your organ systems do not work alone in your body. They must all be able to work together. For example, one of the most important functions of organ systems is to provide cells with O2 and nutrients and to remove toxic waste products such as CO2. A number of organ systems, including the cardiovascular and respiratory systems, all work together to do this. Organ Systems Taxonomy ▪ Biologists like to classify things and put them in categories. ▪ One way to divide them is into domains. Domains ▪ There are three domains: 1. Domain Bacteria: Unicellular, prokaryotic organisms (lack a nucleus) 2. Domain Archaea: Unicellular, prokaryotic organisms. Most live in extreme environments. 3. Domain Eukarya: Eukaryotic cells (contain nucleus) that contain a membrane bound nucleus and internal compartments. Domain Eukarya ▪ There are four kingdoms in Domain Eukarya. 1. Protista (unicellular organisms with a nucleus) - Examples: Protozoans, algae, diatoms 2. Fungi - Examples: Mushrooms and molds 3. Plants - Examples: Mosses, ferns, seed plants 4. Animals - Examples: Invertebrates and vertebrates (animals with a nerve cord protected by a backbone) Domains: Review Linnaeus coined the binomial name Homo sapiens ( Homo meaning “man”, & sapiens meaning “ knowing or wise”) to describe the human species. Modern biologist have kept the basic Linnaeus classification although they have added a subspecies name, Homo sapiens sapiens to distinguish modern humans from earlier humans who appeared approximately 250,000 years ago. Two word naming system for all organisms on the planet. (Name in Latin) Rules: 1. First word is the genus name and the second is the species. 2. First word is capitalized and second is lower case. 3. Scientific names need to be underlined or italicized.  Evolution & Classification of humans BYA/MYA Classification Category Characteristics 2 BYA Domain: Eukarya Membrane- bound nucleus 600 MYA Kingdom: Animalia Multicellular, motile, heterotrophic 540 MYA Phylum: Chordata Sometime in life history: Dorsal tubular nerve cord, notochord, pharyngeal pouches. 120 MYA Class : Mammalia Vertebrates with hair, mammary glands. 60 MYA Order: Primates Well – developed brain, adapted to lives in trees 7 MYA Family: Hominidae Adapted to upright stance & bipedal locomotion 3 MYA Genus: Homo Most developed brain, made & used tools 0.1 MYA Species: sapiens Modern humans; speech centers of brain well developed BYA = Billions of years ago MYA = Millions of years ago (2) Acquiring materials & energy (Take materials & energy from the environment) Human beings cannot maintain their organization or carry on life’s activities without an outside source of materials & energy. Food provides nutrient molecules, used as building blocks or for energy. It takes energy to maintain the organization of the cell and of the organism. Some nutrient molecules are broken down completely to provide the necessary energy to convert other nutrient molecules into the parts & products of cells. Most living things can also convert energy into motion. (3) Reproduction Reproduction is a fundamental characteristic of life. (It is mean to produce a new individual of the same types). Cells come into being only from preexisting cells, & all living things have parents. When living things reproduce, they create a copy of themselves & ensure the continuance of their own kind. The presence of genes, in the form of DNA molecules, allows cells & organisms to make more of themselves. DNA contains the hereditary information that directs the structure of each cell and its metabolism ( all the chemical reactions in the cells). Before reproduction occurs, DNA is replicated so that exact copies of genes are passed on to offspring. When human reproduce, a sperm carries genes contributed by a male into the egg, which contains genes contributed by a female. The genes direct development so that the organism resembles the parents. For example humans only produce humans. (4) Growing & Developing Growing: Increase in the size & often the number of cells. Growing is a part of development. Development include all the changes that occur from the time the egg is fertilized until death and, therefore all the changes that occur during childhood, adolescence & adulthood. Development also includes the repair that take place following injury (5) Being Homeostatic Homeostatic: Maintenance of normal internal conditions in a cell or an organism by means of self regulating mechanisms. (6) Responding to stimuli: Living things respond to external stimuli, often by moving toward or a way from a stimulus, such as the sight of food. Living things used a variety of mechanisms to move, but movement in humans and other animals is dependent upon their nervous & musculoskeletal systems. Homeostatic would be impossible without the ability of the body to respond to stimuli. For example, when we startled by a loud noise, our heartbeat increases, which causes increasing in the blood pressure. If blood pressure rises too high, the brain directs blood vessels to dilate, helping to restore normal blood pressure. Characteristics of life 6. Maintain homeostasis - Homeostasis is the relatively constant and self-correcting internal environment of a living organism - For example, body temperature is 37 degrees Celsius, or 98.6 degrees Fahrenheit Characteristics of life 7. Populations of living things evolve and have adaptive traits - Natural selection: Reproducing organisms with beneficial genetic traits for the environment will survive and reproduce better than organisms that don’t possess these traits - In an environment, the organisms will have adaptive traits, or traits that would help the organisms survive and reproduce