Human Biology Lecture Notes PDF

Human Biology Lec. 1 Introduction to Human Biology 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,...

Human Biology Lec. 1 Introduction to Human Biology 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 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. 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. Types Function Example Epithelial tissue Protection Skin Connective tissue Support Bones Muscular tissue Movement Skeletal Nervous tissue Communication Brain  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. 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 System Major Tissues and Organs Function Cardiovascular Heart; blood vessels; blood Transports oxygen, hormones, and system nutrients to the body cells. Moves wastes and carbon dioxide away from cells. Lymphatic system Lymph nodes; lymph vessels Defend against infection and disease, moves lymph between tissues and the blood stream. Digestive system Esophagus; stomach; small Digests foods and absorbs nutrients, intestine; large intestine minerals, vitamins, and water. Endocrine system Pituitary gland, hypothalamus; Produces hormones that adrenal glands; ovaries; testes communicate between cells. Integumentary Skin, hair, nails Provides protection from injury and system water loss, physical defense against infection by microorganisms, and temperature control. Muscular system Cardiac (heart) muscle; skeletal Involved in movement and heat  Nervous system Brain, spinal cord; nerves Collects, transfers, and processes information. Reproductive Female: uterus; vagina; fallopian Produces gametes (sex cells) and sex system tubes; ovaries Male: penis; testes; hormones. seminal vesicles Respiratory system Trachea, larynx, pharynx, lungs Brings air to sites where gas exchange can occur between the blood and cells (around body) or blood and air (lungs). Skeletal system Bones, cartilage; ligaments Supports and protects soft tissues of body; produces blood cells; stores minerals. Urinary system Kidneys; ureters; urinary bladder Removes extra water, salts, and waste products from blood and body; controls pH; controls water and salt balance. Immune system Bone marrow; spleen; white blood Defends against diseases. Thank you