Human Anatomy and Physiology Lecture I PDF

**Human Anatomy and Physiology** **Lecture I.** **Human Anatomy** - Study of the structure of the body - Anatomy is the scientific discipline that investigate the structure of the body. - It means to dissect or cut apart for study. - 2 basic approaches- systemic and regional - *...

**Human Anatomy and Physiology** **Lecture I.** **Human Anatomy** - Study of the structure of the body - Anatomy is the scientific discipline that investigate the structure of the body. - It means to dissect or cut apart for study. - 2 basic approaches- systemic and regional - **Systemic anatomy** is the study of the body system like NV system - **Regional anatomy** is the study of the organization of the body areas like head, abdomen - 2 way of examining internal structures -- surface anatomy and imaging - **Surface anatomy** is the study of external features such as bony projections which serves as landmarks in locating deeper structure like sternal area or pelvic area - **Anatomical imaging** involves the use of xray ultrasound, MRI, CT Scan to create pictures of the internal structures such as to determine when a bone is broken. **Physiology** - Is the scientific discipline that deals with the process es or functions of living things - Purpose of studying is to predict the body responses to stimuli and how body maintains internal conditions within in a narrow range of values in the presence of a continually changing internal and external environments **Structural and Functional Organization of the Human Body** - Six levels of organization of the body -- chemical, cellular level, tissue level, organ level, organ system level, organism level - **Chemical level** of organization involves how atoms such as hydrogen and carbon interact and combine into molecules. Molecular structure determines its functions. Example, collagen molecules are strong rope like fibers that give the skin structural strength and flexibility. In old age where collagen changes in structure the skin now becomes fragile and easily torn. - **Cells** are the basic and structural and functional unit of organism. Molecules when combined to form organelles that comprise the cell. - **Tissue level** are groups of similar cells and the materials surrounding them. The characteristics of cells and their matrix determine the functions of the tissue. Major types are Epithelial, connective, muscular and nervous tissues. - **Organ level** is composed of 2 or more tissue types that together perform one or more common function. Examples are heart, stomach, liver and urinary. - **Organ system** level are groups of organs classified as a unit because of a common function or set of functions. Example the urinary system is composed of the kidney, ureter, urinary bladder and urethra. The coordinated activity of each organ in the system is necessary for normal function. - **Organism level** is any living thing considered as a whole whether composed of one cell such as bacterium or trillion of cells such as human. **Characteristics of life** - Human are organisms sharing characteristics with other organisms. Common to this is life. - 6 recognizable characteristics of life -- organization, metabolism, responsiveness, Growth, development and differentiation, reproduction - **Organization** refers to the specific relationship of the many individual parts of an organism from cell organelles to organs, interacting and working together. - **Metabolism i**s the ability to use energy to perform vital functions, such as growth, movement, and reproduction. - **Responsiveness** is the ability of an organism to sense changes in the environment and make adjustments that help maintain its life. Examples are movement towards food and water and away from danger or poor environmental conditions such as extreme cold or heat. - **Growth** refers to an increase in size of all parts of the organism.it is a result of an increase in the number of cells, cell size, or the amount of substance surrounding the cells - **Development** includes changes an organism undergoes through time. It involves growth and differentiation. ***Differentiation*** is change in cell structure and function from generalized to specialized. Example from fertilization cell start to differentiate to cell type. - **Reproduction** is the formation of new cells or new organism. **Homeostasis** - Is the existence and maintenance of a relatively constant environment within the body despite fluctuations in either the external or internal environment. - Most body cells are surrounded by a small amount of fluid and normal cell functions depend on the maintenance of the cells' fluid environment within a narrow range of conditions including temperature, volume and chemical content. These conditions are called variables because their values changes. - Homeostatic mechanism are mechanism made by the body to maintain average normal values or set point. Example shivering or sweating in a decrease or increase body temperature. - Most homeostatic mechanism are governed by the nervous system or the endocrine system. - Homeostatic mechanism are not able to maintain body temperature precisely at the set point but slightly around the set point producing a normal range of values. As long as the values are within the normal range, homeostasis is maintained. - **Negative Feedback Mechanism** that maintain homeostasis is when any deviation from the set point is made smaller or is resisted. It does not prevent variation but maintains variation within a normal range. - 3 component- a **Receptor**, that monitor the value of a variable, such as body temperature by detecting the stimuli; **Control center**, part of the brain that determine the set point for the variable and receive inputs from the receptor about the variable; **Effector**, such as sweat glands, can change the value when directed by the control center. - **Positive Feedback Mechanism** occur when the initial stimulus further stimulates the response. The response means that the deviation from the set point becomes greater. Example during bleeding, a chemical responsible for clot formation stimulates production of itself. However the clot formation is self limiting. Eventually the components needed to form a clot will be depleted in the damaged area and more clot material cannot be formed. - New words may be overwhelming when we study anatomy. Pay attention to the etymology of the terms which are derived from latin or Greek. Example- anterior which means to go before. - **Body positions** -- refers to person standing upright with the face directed forward, upper limbs hanging to the sides and the palms of the hands facing forward. Supine when lying face upward and prone when lying face down ward. - **Directional terms** -- describes part of the body relative to each other. Right and Left. Superior above and inferior below. Anterior front and posterior back. Ventral means belly. Dorsal means back. Proximal nearest and distal means distant. Medial towards the midline and lateral means away from the midline. Superficial is close to the surface and deep is toward the interior of the body - **Body parts and region**- central region of the body is the head, neck and trunk. The trunk is composed of thorax, abdomen and pelvis. Upper limb is the arm, forearm, wrist and hand. The lower limb thigh, leg, ankle and foot. Abdomen is divided into quadrants by 2 imaginary line that intersect in the navel and region by 4 imaginary line. - **Planes** is way of sectioning the body to look inside and observe body structure. Sagittal plane runs vertically that divide the body into right and left. Median plane is a sagittal plane divide the body into right and left. Transverse plane divide the body into superior and inferior. Frontal plane dive the body into anterior and posterior. - **Body cavities** -- the trunk contains 3 large cavities, Thoracic, abdominal and pelvic. Thoracic cavity is surrounded by rib cage and is separated from abdominal cavity by the diaphragm. In between is the mediastinum that houses the heart, thymus, trachea, esophagus and other structure. Abdominal cavity contains the stomach, liver, intestines spleen pancreas and kidneys. Pelvic cavity contains the urinary bladder, part of the large intestines and internal reproductive organs. - **Serous membranes** -- line the trunk cavities and cover the organs of these cavities. 2 parts, Visceral serous membranes that are in contact with the surface of the organ and Parietal serous membrane that the outer part. In between is filled with a thin lubricating film of serous fluid produced by the membrane. **Thoracic cavity** contains 3 serous membrane -- 2 pleural cavities and pericardial cavities. The heart is covered by the visceral pericardium and the outer layer of the sac is the parietal pericardium, in between is the pericardial fluid. **Pleural cavity** surrounds each lungs. **Abdominopelvic cavity** is lined by the peritoneal cavity. **Mesenteries** which consist of 2 layers of peritoneum fused together that connect peritoneum of some abdominopelvic organs to the parietal peritoneum on the body wall or to the visceral peritoneum of other abdominopelvic organs. It provides pathway for nerves and blood vessels.