Pharmacy and Research, Tathawade, Pune Dr. G.B.Jadhav, Associate professor in Pharmacology , M.V.P.’s College of Pharmacy, Nashik

anatomy and physiology is the study of various systems that compose the human body.

• Anatomy deals with the structure of different body parts, such as organs, tissues, and cells, and their relationships with one another.
• Physiology explains how these body parts function to maintain life and health. For example, the bones of the skull join tightly to protect the brain.
• Pathophysiology studies what happens when normal body functions are disturbed by diseases and helps us understand the causes and effects of illnesses. To understand the human body and its parts, it is essential to study anatomy and physiology together. The structure of a part of the body is so closely related to its functions. For example, the bones of the skull join tightly to form a rigid case that protects the brain. By studying anatomy, physiology, and pathophysiology, students learn how the body maintains balance (homeostasis), how diseases disturb this balance, and how medicines help restore it. Thus, anatomy, physiology, and pathophysiology provide the basic scientific knowledge needed to understand diseases, their treatment, and the safe and effective use of medicines. 1.1 Definition and scope of anatomy, physiology and pathophysiology Anatomy ( ana- up; tomy - process of cutting) is the science of body structures and the relationships among them. Physiology ( physio- nature; logy- study of) is the science of body functions —how the body parts work. Pathophysiology ( pathos - suffering; physis - nature, origin; logy- study of) is the study of abnormal changes in body functions in the presence of disease processes. Several branches of anatomy and physiology: Branches of Anatomy
• Gross anatomy : It is the study of Structures that can be examined without a microscope.
• Histology ( hist - tissue) : It is the study of Microscopic structure of tissues.
• Cell biology : Study of Cellular structure and functions.
• Embryology ( embry - embryo; logy- study of) : study of the first eight weeks of development after fertilization of a human egg.
• Pathological anatomy ( path - disease): Structural changes (gross to microscopic) associated with disease. Branches of Physiology
• Neurophysiology ( neuro - nerve) : study of Functional properties of nerve cells
• Cardiovascular physiology ( cardi - heart; vascular -blood vessels): study of Functions of the heart and blood vessels
• Endocrinology ( endo - _ within; crin _ secretion): study of Hormones (chemical regulators in the blood and how they control body functions.
• Cardiovascular physiology ( cardi - heart; vascular -blood vessels): study of functions of the heart and blood vessels.
• Immunology ( immun - not susceptible): study of the body’s defenses against disease-causing agents.
• Renal physiology ( ren - kidney): Functions of the kidneys.
• Respiratory physiology ( respira - _ to breathe): Functions of the air passageways and lungs. Branches of Pathophysiology
• General Pathophysiology: It is the study of basic disease processes that affect all body systems, regardless of the specific organ.
• Systemic Pathophysiology: Study of specific organ systems and how disease affects their function.
• Molecular and Cellular Pathophysiology : Focuses on the cellular and molecular mechanisms behind disease.
• Comparative Pathophysiology: Compares how diseases develop and progress across different species (e.g., humans vs. animals).
• Clinical Pathophysiology: How to apply knowledge of disease to understand patient symptoms and treatment.
• Epidemiologic Pathophysiology: Explores how disease mechanisms interact with environmental, genetic, and social factors in populations. 1.2 Levels of structural organization and body systems From the smallest to the largest, six levels of structural organization of human body are the chemical, cellular, tissue, organ, system, and organismal levels of organization 1. Chemical level : This is basic level includes atoms , the smallest units of matter that participate in chemical reactions, and molecules , two or more atoms joined together. Certain atoms, such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), calcium (Ca), and sulfur (S), are essential for maintaining life. Two familiar molecules found in the body are deoxyribonucleic acid (DNA), the genetic material passed from one generation to the next, and glucose, commonly known as blood sugar. 2. Cellular level : Molecules combine to form cells , the basic structural and functional units of an organism that are composed of chemicals. Much kind of cells present in human body are muscle cells, nerve cells, and epithelial cells. 3. Tissue level : Tissues are groups of cells and the materials surrounding them that work together to perform a particular function. There are four basic types of tissues in human body: epithelial tissue, connective tissue, muscular tissue, and nervous tissue . Epithelial tissue covers body surfaces, lines hollow organs and cavities, and forms glands. Connective tissue connects, supports, and protects body organs while distributing blood vessels to other tissues. Muscular tissue contracts to make body parts move and generates heat. Nervous tissue carries information from one part of the body to another through nerve impulses. 4. Organ level : At the organ level different types of tissues are joined together. Organs are structures that are composed of two or more different types of tissues; they have specific functions and usually have recognizable shapes. Examples of organs are the stomach, skin, bones, heart, liver, lungs, and brain. 5. System level : A system consists of related organs with a common function. An example of the system level, also called the organ system level, is the digestive system, which breaks down and absorbs food. Its organs include the mouth, salivary glands, pharynx (throat), esophagus (food tube), stomach, small intestine, large intestine, liver, gall bladder, and pancreas. 6. Organismal level : An organism any living individual. All the parts of the human body functioning together constitute the total organism. Figure 1: Levels of structural organization in the human body 1.3 The Eleven Systems of the Human Body “Table 1: lists the components of the human body with their general functions” SYSTEMS COMPONENTS FUNCTIONS INTEGUMENTARY SYSTEM Skin and associated structures, such as hair, fingernails and toenails, sweat glands, and oil glands. Protects body; helps regulate body temperature; eliminates some wastes; helps make vitamin D; detects sensations such as touch, pain, warmth, and cold; stores fat andprovides insulation. SKELETAL SYSTEM Bones and joints of the body and their associated cartilages. Supports and protects body; provides surface area for muscle attachments; aids body movements; houses cells that produce blood cells; stores minerals and lipids (fats). MUSCULAR SYSTEM Specifically, skeletal muscle tissue—muscle usually attached to bones (other muscle tissues include smooth and cardiac). Participates in body movements, such as walking; maintains posture; produces heat. NERVOUS SYSTEM Brain, spinal cord, nerves, and special sense organs, such as eyes and ears. Generates action potentials (nerve impulses) to regulate body activities; detects changes in body’s internal and external environments, interprets changes, and responds by causing muscular contractions or glandular secretions. ENDOCRINE SYSTEM Hormone-producing glands (pineal gland, hypothalamus, pituitary gland, thymus, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries, and testes) and hormone-producing cells in several other organs. Regulates body activities by releasing hormones (chemical messengers transported in blood from endocrine gland or tissue to target organ). CARDIOVASCULAR SYSTEM Blood, heart, and blood vessels. Heart pumps blood through blood vessels; blood carries oxygen and nutrients to cells and carbon dioxide and wastes away from cells and helps regulate acid–base balance, temperature, and water content of body fluids; blood components help defend against disease and repair damaged blood vessels. LYMPHATIC SYSTEM AND IMMUNITY lymph nodes, and tonsils; cells that carry out immune responses (B cells, T cells, and Lymphatic fluid and vessels; spleen, thymus, others). Returns proteins and fluid to blood; carries lipids from gastrointestinal tract to blood; contains sites of maturation and proliferation of B cells and T cells that protect against disease-causing microbes. RESPIRATORY SYSTEM Lungs and air passageways such as the pharynx (throat), larynx (voice box), trachea (windpipe), and bronchial tubes leading into and out of lungs. Transfers oxygen from inhaled air to blood and carbon dioxide from blood to exhaled air; helps regulate acid–base balance of body fluids; air flowing out of lungs through vocal cords produces sounds. DIGESTIVE SYSTEM Organs of gastrointestinal tract, a long tube that includes the mouth, pharynx (throat), esophagus (food tube), stomach, small and large intestines, and anus; also includes accessory organs that assist in digestive processes, such as salivary glands, liver, gallbladder, and pancreas. Achieves physical and chemical breakdown of food; absorbs nutrients; eliminates solid wastes. URINARY SYSTEM Kidneys, ureters, urinary bladder, and urethra. Produces, stores, and eliminates urine; eliminates wastes and regulates volume and chemical composition of blood; helps maintain the acid–base balance of body fluids; maintains body’s mineral balance; helps regulate production of red blood cells. 1.4 Homeostasis A person who is in good health may be said to be in a state of homeostasis. An important characteristic of homeostasis is maintaining the volume and composition of body fluids, dilute, watery solutions containing dissolved chemicals that are found inside cells as well as surrounding them. The fluid within cells is intracellular fluid (ICF). The fluid outside body cells is extracellular fluid (ECF). The ECF that fills the narrow spaces between cells of tissues is known as interstitial fluid. The proper functioning of body cells depends on precise regulation of the composition of the interstitial fluid surrounding them. Because of this, interstitial fluid is often called the body’s internal environment. The composition of interstitial fluid changes as substances move back and forth between it and blood plasma. Such exchange of materials occurs across the thin walls of the smallest blood vessels in the body, the blood capillaries. This movement in both directions across capillary walls provides needed materials, such as glucose, oxygen, ions, and so on, to tissue cells. It also removes wastes, such as carbon dioxide, from interstitial fluid. Definition: Homeostasis is the condition in which the body’s internal environment remains constant within physiological limits. The human body responses to the changing conditions eg. Change in surrounding environment i.e. temperature etc. change in sleep cycle. All tissues, organs and system of body help maintaining these constant conditions. An organism is in homeostatic condition when: 1. The internal environment contains optimum level of gases, nutrients, ions and water. 2. The temperature is within standard range 3. The extracellular and intracellular volume should be at optimum level. Control of Homeostasis REPRODUCTIVE SYSTEMS Gonads (testes in males and ovaries in females) and associated organs (uterine tubes or fallopian tubes , uterus, vagina, and mammary glands in females and epididymis, ductus or vas deferens, seminal vesicles, prostate, and penis in males). Gonads produce gametes (sperm or oocytes) that unite to form a new organism; gonads also release hormones that regulate reproduction and other body processes; associated organs transport and store gametes; mammary glands produce milk. Homeostasis in the human body is continually being disturbed. Some disruptions come from the external environment such as intense temperature, lack of oxygen etc) or internal environment, such as a decrease in blood glucose level after starvation. Human body has many regulating systems that maintain balance of internal environment. The nervous system and the endocrine system working together or independently, provide the required changes to maintain homeostasis. The nervous system regulates homeostasis by sending electrical signals known as nerve impulses (action potentials) to organs that can counteract changes from the balanced state. The endocrine system includes many glands that secrete messenger molecules called hormones into the blood. And these harmones then act to attain equilibrium. Both nervous and endocrine system work through negative feedback systems. Feedback Systems The body can regulate its internal environment through many feedback systems. A feedback system is a cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated, and so on. Each monitored variable, such as body temperature, blood pressure, or blood glucose level, is termed a controlled condition . Any disruption that changes a controlled condition is called a stimulus . Figure 2: Feedback Systems" A feedback system includes three basic components: 1. A receptor 2. A control center 3. An effectors 1. A receptor : A receptor is a macromolecule that monitors changes in a controlled condition and sends input to a control center. This pathway is called an afferent pathway , since the information flows toward the control center. Typically, the input is in the form of nerve impulses or chemical signals. For example, certain nerve endings in the skin sense temperature and can detect changes, such as a dramatic drop in temperature. 2. A control center in the body, for example, the brain, sets the range of values within which a controlled condition should be maintained (set point), evaluates the input it receives from receptors, and generates output commands when they are needed. Output from the control center typically occurs as nerve impulses, or hormones or other chemical signals. This pathway is called an efferent pathway , since the information flows away from the control center. E.g. Change in skin temperature example, the brain acts as the control center, receiving nerve impulses from the skin receptors and generating nerve impulses as output. 3. An effector is a body structure that receives output from the control center and produces a response or effect that changes the controlled condition. All organ or tissue in the body can behave as an effector. When body temperature fall sharply, brain (control center) sends nerve impulses (output) to skeletal muscles (effectors). The result is shivering, which generates heat and raises body temperature. Two types of feedback systems are 1. Negative Feedback Systems: This system reverses a change in a controlled condition. Eg. Regulation of heart rate and blood pressure. When the heart beats faster or harder, BP increases. If some internal or external stimulus causes increase in blood pressure (controlled condition), then following sequence of events occurs (Fig.). Baroreceptors (the receptors), detect the higher blood pressure. The baroreceptors send nerve impulses (input) to the brain (control center), which interprets the impulses and responds by sending nerve impulses (output) to the heart and blood vessels (the effectors). Heart rate decreases and blood vessels dilate (widen), which cause BP to decrease (response). This sequence of events quickly returns the controlled condition means blood pressure to normal and homeostasis is restored. Effector causes BP to fall, a result that negates the original stimulus (an increase in BP). Therefore it is called a negative feedback system. Figure 3: Homeostatic regulation of blood pressure by a negative feedback system 2. Positive Feedback Systems: This system tends to strengthen or reinforce a change in one of the body’s controlled conditions. Eg. Process of platlet plug formation during blood clotting, release of oxytocin harmone and contractions of uterine muscles during normal childbirth. In this system the effector produces a physiological response that adds to or reinforces the initial change in the controlled condition. “Figure 4: Positive feedback control of labor contractions during birth of a baby” Homeostatic Imbalances Homeostasis defined as a condition in which the body’s internal environment remains relatively stable. The physiological processes responsible for maintaining homeostasis are responsible for good health. As long as all of the body’s controlled conditions remain within certain narrow limits, body cells function efficiently, homeostasis is maintained, and the body stays healthy. Disturbances in the homeostatic balance results in illness. If the homeostatic imbalance is moderate, a disorder or disease may occur; if it is severe, death may result. 1.5 Basic anatomical terminology and anatomical positions Body Positions: When describing relative locations, the body is always assumed to be in anatomic position : standing upright with the head facing forward, arms at the sides with palms forward, and the feet together on the floor. If the body is lying facedown, it is in the prone position. If the body is lying faceup, it is in the supine position. The terms of location are listed in Table “Table 2: Terms of location and Position” Term Definition Example Superior ( cephalic or cranial) Structure near the head, or the upper part of a structure. The heart is superior to the liver Inferior ( caudal ) Structure away from the head, or the lower part of a structure. The stomach is inferior to the lungs. Anterior ( ventral ) Nearer to or at the front of the body. The chest is on the anterior side of the body Posterior ( dorsal ) Nearer to or at the back of the body. The esophagus (food tube) is posterior to the trachea (windpipe). Medial Nearer or towards the midline The heart is medial to the lungs. Lateral Away from the midline. The shoulders are lateral to the neck. Proximal Nearer to the attachment of a limb to the trunk; nearer to the origination of a structure. The humerus (arm bone) is proximal to the radius. Distal Away from the point of attachment of a limb to the trunk; away from the origination of a structure. The phalanges (finger bones) are distal to the carpals (wrist bones). Superficial (e xternal) Toward or on the surface of the body. The ribs are superficial to the lungs. Deep (Internal) Away from the surface of the body. The ribs are deep to the skin of the chest and back. Central the main part The brain is part of the central nervous system. Peripheral extending from the main part Nerves in the arm are part of the peripheral nervous system. Parietal pertaining to the wall of a cavity The parietal pleura lines the chest cavity Visceral pertaining to the organs within a cavity The visceral pleura covers the lungs. 1.6 Planes and Sections Planes are imaginary flat surfaces that pass through the body parts. 1. Sagittal plane : a vertical plane that divides the body or an organ into right and left sides. 2. Midsagittal plane or a median plane : a plane passes through the midline of the body or an organ and divides it into equal right and left sides. 3. Midline : is an imaginary vertical line that divides the body into equal left and right sides. 4. Parasagittal plane : If the sagittal plane does not pass through the midline but instead divides the body or an organ into unequal right and left sides. 5. Frontal or coronal plane : divides the body or an organ into anterior (front) and posterior (back) portions. 6. Transverse plane : divides the body or an organ into superior (upper) and inferior (lower) portions. 7. Cross-sectional or horizontal plane : Sagittal, frontal, and transverse planes are all at right angles to one another. 8. Oblique plane : passes through the body or an organ at an oblique angle (any angle other than a 90-degree angle. Section is a cut of the body or one of its organs made along one of the planes. 1. Frontal (coronal) section : a plane from side to side separates the body into front and back portions. 2. Sagittal section : a plane from front to back separatesthe body into right and left portions. A midsagittal section creates equal right and left halves. 3. Transverse section : a horizontal plane separates the body into upper and lower portions. 4. Cross-section : a plane perpendicular to the long axis of an organ. A cross-section of the small intestine (which is a tube) would look like a circle with the cavity of the intestine in the center. 5. Longitudinal section : a plane along the long axis of an organ. 1.7 Body Cavities and their membranes The space in the basic framework of the body is called as cavity. Bones, muscles, ligaments, and other structures separate the various body cavities from one another. The body has two major cavities: the dorsal cavity (posterior) and the ventral cavity (anterior). Each of these cavities has further subdivisions, which are shown in Fig. Figure 5: Body cavities Dorsal Cavity: The dorsal cavity contains the central nervous system. Subdivisions of dorsal cavity 1. Cranial cavity : It is formed by the skull and contains the brain. 2. Vertebral or spinal cavity : It is formed by the backbone (spine) and contains the spinal cord. The membranes that line these cavities and cover the brain and spinal cord are called the meninges . Ventral Cavity: The ventral cavity consists of two compartments. Subdivisions of Ventral cavity 1. Thoracic cavity : Chest cavity; It contains pleural and pericardial cavities and the mediastinum. The organs in the thoracic cavity include the heart and lungs.
• Pleural cavity: a potential space between the layers of the pleura that surrounds a lung. The membranes of the thoracic cavity are serous membranes called the pleural membranes .
• Pericardial cavity : a potential space between the layers of the pericardium that surrounds the heart. The heart has its own set of serous membranes called the pericardial membranes .
• Mediastinum: Central portion of thoracic cavity between the lungs; extends from sternum to vertebral column and from first rib to diaphragm; contains heart, thymus, esophagus, trachea, and several large blood vessels. 2. Abdominal cavity : Organs in the abdominal cavity include the liver, stomach, and intestines. The membranes of the abdominal cavity are also serous membranes called the peritoneum and mesentery. 3. Pelvic cavity : The pelvic cavity is inferior to the abdominal cavity. Within the pelvic cavity are the urinary bladder and reproductive organs such as the uterus in women and the prostate gland in men. 1.8 Conclusion: Anatomy, physiology, and pathophysiology together provide a complete understanding of the human body. Anatomy explains the structure of different body parts, physiology describes how these parts function, and pathophysiology helps us understand what happens when normal functions are disturbed by disease. Together, they form the scientific foundation for studying health and illness. By understanding these basic concepts, students can better relate the structure and function of the human body to the effects of drugs and diseases. References: 1. Tortora, G. J., & Grabowski, S. R. (2006). Principles of anatomy and physiology . New York, NY: Harper Collins College Publishers. 2. Waugh, A., & Grant, A. (2006). Ross and Wilson’s anatomy and physiology in health and illness [E-book]. London, England: Churchill Livingstone. 3. Upasani, C. D., & Undale, V. (2018). Human anatomy and physiology . Pune, India: Tech-Max Publications. 4. Phate, R. P. (2006). Anatomy, physiology and health education . Pune, India: Career Publications. 5. Mahajan, M. S., Upaganlawar, A. B., & Upasani, C. D. (2021). Human anatomy and physiology–I . Pune, India: TechKnowledge Publications.