Chapter One Introduction to Human Anatomy and Physiology
Understanding the Human Body Our earliest ancestors were interested in the way their bodies worked.
Through time and changes in human activity, ideas about health and the body evolved. People began asking questions that set the stage for modern medical science.
Modern Medical Knowledge Techniques for making accurate observations and performing experiments improved and knowledge expanded. This new knowledge required a specialized language. These terms,derived primarily from Greek and Latin, formed the basis for the language of anatomy and physiology.
Anatomy and Physiology Anatomy involves the study of the structures of the body parts (morphology). Physiology considers the function of these body parts, what they do and how they do it. Both anatomy and physiology rely on each other. Form follows function and function leads to form.
The Human Organism It is difficult to separate anatomy and physiology because structure makes possible function.
Anatomy and physiology are ongoing as well as ancient fields. Research at the molecular level and new findings help in understanding the human organism.
Characteristics of Animal Life Movement Responsiveness Growth Reproduction Respiration Digestion Absorption Circulation Assimilation Excretion
Requirements of Life Water - required for metabolism, transport, regulation Food - substances that provide nutrients Oxygen - used in the release of energy Heat - a form of energy which helps control metabolic reactions Pressure - application of force on an object
Homeostasis The internal environment of the body protects cells. The body’s maintenance of a stable internal environment is called homeostasis. Homeostasis is often maintained by a mechanism called negative feedback.
Examples of Homeostasis Regulation of glucose in the blood Regulation of blood pressure Regulation of body temperature
Negative feedback Homeostasis is the consequence of a self-regulating control system that operates by a mechanism called negative feedback. Such a system receives signals about changes in the internal environment and then causes responses that reverse these changes back to the set point.
Homeostasis in Medicine Homeostasis mechanisms maintain a relatively constant internal environment, but physiological values vary in an individual. Normal values for an individual and the idea of a normal range for the population are clinically important.
Levels of Organization Atoms- tiny particles that make up matter Molecules- atoms bound together Macromolecules- large molecules, polymers Organelles- activity specific structures
Cells- basic unit of structure and function Tissues- groups of cells Organs- structures with specialized function Organ systems- groups of organs that perform a function Organism- the sum of the organ systems Levels of Organization cont.
Serous Membranes Parietal layer lines the wall. Visceral layer lines the organs. Thoracic membranes line the chest.
Serous Membranes Pleural membranes surround the lungs. Pericardial membranes surround the heart. Peritoneal membranes line the abdominopelvic cavity.
Organ Systems Integumentary Skeletal Muscular Nervous Endocrine Cardiovascular Lymphatic Digestive Respiratory Urinary Reproductive
Integumentary System Skin, hair, sweat glands, sebaceous glands Protects underlying tissues Site of sensory receptors Regulates body temperature Synthesis of biochemicals Needed by the body
Skeletal System Bones, ligaments, cartilage, joints Body framework Protection of vital organs Attachment for muscles Blood cell production Storage of inorganic salts
Muscular System Muscles Body movement Body posture Generation of body heat
Nervous System Brain, spinal cord, nerves, sense organs Detect changes in the internal and external environment Receive and interpret sensory information Stimulate muscles and glands
Endocrine System Glands that secrete hormones, chemical messengers that travel in the blood or other body fluids Hormones alter metabolism in target cells
Transport Systems Cardiovascular system –heart, arteries, capillaries, veins, blood –transport of gases, nutrients, hormones, wastes Lymphatic system –lymphatic vessels, fluid, nodes, thymus, spleen, lymphocytes
Digestive System Mouth, tongue, teeth, salivary glands, pharynx, esophagus, stomach, liver, gallbladder, pancreas, small and large intestine Ingestion of food Breakdown of food molecules Absorption of nutrients
Respiratory System Nasal cavity, pharynx, larynx, trachea, bronchi, lungs Movement and exchange of respiratory gases, oxygen and carbon dioxide between air and blood
Urinary System Kidneys, ureters, urinary bladder, urethra Remove wastes from blood Maintain body water and electrolyte balance Transport urine
Reproductive System Produces gametes, support development of embryo
Lifespan Changes Aging is the passage of time and accompanying bodily changes, from the whole-body level to the microscopic level.
Lifespan Changes Changes at the tissue, cell, and molecular levels explain the familiar signs of aging. A clearer understanding of the precise steps will emerge as we understand the role of genes in this process.
Anatomical Terminology Superior/Inferior: above or below a body Anterior/Posterior: in front of or behind Medial/Lateral: towards the middle or side
Anatomical Terminology cont. Proximal: close to a body part Distal: far from a body part Superficial/Deep: on the surface or lying beneath
Planes through the Body Sagittal: lengthwise cut dividing body into right and left portions.
Planes through the Body Transverse (horizontal): cut that divides the body into superior and inferior portions.
Planes through the Body Coronal (frontal): section that divides the body into anterior and posterior sections.