Human Biology - Lec. 1 Introduction to Human Biology PDF

Ashur University Human Biology College of Pharmacy Lec. 1 Introduction to Human Biology DR. Basma Ahmed Ratib Biology Is the science that studies the life from all its aspects. It is including the study of living and non-living parts in life. Studyi...

Ashur University Human Biology College of Pharmacy Lec. 1 Introduction to Human Biology DR. Basma Ahmed Ratib Biology 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. 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 deals with the normal functions of living organisms and their parts. 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 homeostasis with safe levels of substances such as sugar and oxygen in the blood. 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 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. The human body is composed of elements including hydrogen, oxygen, carbon, calcium and phosphorus. These elements reside in trillions of cells and non-cellular components of the body. The main electrolytes in body water outside cells are sodium and chloride, whereas within cells it is potassium and other phosphates. The most basic parts of the human body are cells, an amazing 100 trillion of them by the time the average person reaches adulthood. The human body is composed of many different types of cells that together create tissues and subsequently, organ systems. They ensure homeostasis and the viability of the human body. Generally, the human body comprises a head, neck, trunk (which includes the thorax and abdomen), arms and hands, legs and feet. 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 are specialized in form and function, as shown in the figure below. Each type of cell in the figure plays a specific role. For example, nerve cells have long projections that help them carry electrical messages to other cells. Muscle cells have many mitochondria that provide the energy they need to move the body. Tissues After the cell, 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, muscle, 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. Examples include 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. Muscular tissue is made up of cells that have the 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 connect the brain to all parts of the body. Types Function Example Epithelial tissue Protection Skin Connective tissue Support Bones Muscular tissue Movement Skeletal Nervous tissue Communication Brain Organs and Organ Systems After tissues, organs are the next level of organization of the human body. Examples of human organs include the brain, heart, lungs, skin, and kidneys. An organ system is a group of organs that work together to carry out a complex overall function.  Organ Major Tissues and Function System Organs Cardiovascular Heart; blood vessels; Transports oxygen, system blood hormones, and nutrients to the body cells. Moves wastes and carbon dioxide away from cells. Lymphatic Lymph nodes; lymph Defend against infection system vessels and disease, moves lymph between tissues and the blood stream.  Digestive Esophagus; stomach; Digests foods and absorbs system small intestine; large nutrients, minerals, intestine vitamins, and water. Endocrine Pituitary gland, Produces hormones that system hypothalamus; adrenal communicate between glands; ovaries; testes cells. Integumentary Skin, hair, nails Provides protection from system injury and water loss, physical defense against infection by microorganisms, and temperature control. Muscular Cardiac (heart) muscle; Involved in movement and system skeletal muscle; smooth heat production. muscle; tendons Nervous Brain, spinal cord; Collects, transfers, and system nerves processes information. Reproductive Female: uterus; vagina; Produces gametes (sex system fallopian tubes; ovaries cells) and sex hormones. Male: penis; testes; seminal vesicles Respiratory Trachea, larynx, Brings air to sites where system pharynx, lungs gas exchange can occur between the blood and  cells (around body) or blood and air (lungs). Skeletal Bones, cartilage; Supports and protects soft system ligaments tissues of body; produces blood cells; stores minerals. Urinary Kidneys; ureters; Removes extra water, system urinary bladder salts, and waste products from blood and body; controls pH; controls water and salt balance. Immune Bone marrow; spleen; Defends against diseases. system white blood cells