Introduction to Anatomy PDF

Introduction to Anatomy Levels of Organization The Chemical (or Molecular) Level Atoms are the smallest chemical units. Essential atoms for life include carbon (C), hydrogen (H+), oxygen (O2), nitrogen (N), phosphorus (P), calcium (Ca2+), and sulfur Molecules are a group of atoms working toge...

Introduction to Anatomy Levels of Organization The Chemical (or Molecular) Level Atoms are the smallest chemical units. Essential atoms for life include carbon (C), hydrogen (H+), oxygen (O2), nitrogen (N), phosphorus (P), calcium (Ca2+), and sulfur Molecules are a group of atoms working together. The Cellular Level = Cells are a group of atoms, molecules and organelles working together. Muscle cells, nerve cells, epithelial cells The Tissue Level = Tissues are a group of similar cells working together. Four basic types of tissues: Epithelial, Connective, Muscular, Nervous The Organ Level = An organ is a group of different tissues working together. Cardiac muscle tissue and connective tissue form wall of the heart. The System Level = Organs interact in organ systems. Heart, blood and blood vessels form cardiovascular system. The Organism Level = Human ☺ Summary Human body has 11 Organ systems Integumentary system functions Skeletal system functions Muscular system functions Nervous system functions Endocrine system functions Cardiovascular system functions Lymphatic system functions Respiratory system functions Digestive system functions Urinary system functions Reproductive system functions The study of the human body Study of human body: Surface anatomy – studies surface markings of body Gross anatomy – examines structures that can be seen with unaided eye Microscopic anatomy – studies structures that can only be seen with aid of a microscope; include: Histology (study of tissues) and Cytology (study of cells) Physiology has subfields classified by organ or organ system being studied; examples include: Neurophysiology – studies brain and nerves Cardiovascular physiology – studies heart and blood vessels Anatomical Position Anatomical position – common frame of reference from which all body parts and regions are described: Body is standing upright; feet are shoulder width apart, with upper limbs at sides of trunk and head and palms facing forward Body is always referred to as if it were in anatomical position, even when it’s in another position “Right” and “left” always refers to right and left sides of body being described, not our own Male in anatomical position: The penis in the anatomical position is described in its erect position = it lies against the abdomen. The dorsal surface of the penis is actually anterior when the penis is flaccid. Directional terms Directional terms, another means of ensuring accurate communication, describes relative location of body parts and markings; some of more common paired terms include Anterior refers to front, in humans while posterior refers to back; can refer to either body as a whole or to a body part Superior means toward head while inferior refers to closer to the feet; terms are used to refer to positions only on head, neck, and trunk Note: In humans, ventral and anterior are interchangeable; dorsal and posterior are interchangeable because we walk upright Directional terms Directional terms (continued): Proximal refers to something being closer to point of origin; distal refers to being more distant or further away from same point of origin The body’s midline is an imaginary line that runs down middle of the body; medial refers to a position that is closer to midline; lateral refers to a position that is further away Superficial refers to structures that are closer to surface of the body while deep refers to those further away Directional terms Planes of section Three primary planes of section provide a means of studying form and function of a body region by dividing body or a body part up for examination: Sagittal plane divides body or body part into right and left sections; includes following two variations Midsagittal plane = divides body or body part into equal left and right sections Parasagittal plane divides body or body part into unequal right and left sections Planes of Section Frontal plane =coronal plane = divides body or body part into anterior and posterior sections Transverse plane (horizontal plane) = divides body or body part into superior and inferior sections or proximal and distal sections when describing structures of appendicular region Oblique plane, a less standardized plane, is taken at an angle; useful for examining structures that are difficult to examine using only three primary planes of section Body Cavities Dorsal Body Cavity – largely located on posterior side of body; subdivided into two cavities Cranial cavity – within skull; protects brain Vertebral (spinal) cavity – within vertebral column; protects spinal cord Body Cavities Ventral Body Cavity = separated into two divisions by diaphragm: Thoracic cavity and its subdivisions are superior to diaphragm Abdominopelvic cavity and its subdivisions are inferior to diaphragm Body Cavities Ventral Body Cavity (continued): Thoracic cavity – divided into three smaller cavities: Pleural cavities – each surround either left or right lung Mediastinum – between pleural cavities; houses heart, great vessels = pulmonary trunk and aorta, trachea, and esophagus Pericardial cavity – within mediastinum; within serous membrane that surrounds heart Body Cavities Ventral Body Cavity (continued): Abdominopelvic cavity – subdivided into superior abdominal cavity = spans from diaphragm to bony pelvis and pelvic cavity = area within bony pelvis Contains organs from several systems = digestive, lymphatic, reproductive, and urinary Body Cavities Body has three serous body cavities formed by three main serous membranes: Pleural membranes Consist of outer parietal pleura (follow contours of thoracic wall) and inner visceral pleura (runs along surface of lungs) Thin space enclosed by pleural membranes forms pleural cavities Body Cavities Body has three serous body cavities (continued): Pericardial membranes Consist of outer parietal pericardium = separates heart from mediastinum and inner visceral pericardium Space created by pericardial membranes forms pericardial cavity Body Cavities Body has three serous body cavities (continued): Peritoneal membranes = surrounds some of abdominal organs Consist of outer parietal peritoneum and inner visceral peritoneum Space between these layers forms peritoneal cavity Doesn’t cover every organ; kidneys lie outside of and behind parietal peritoneum and are thus called retroperitoneal organs Homeostasis Physiological Processes Operate to Maintain Body’s Homeostasis = maintain balance = functioning healthy Homeostatic imbalances – disturbances in homeostasis can lead to disease or death if uncorrected Misconception: Maintaining homeostasis means body’s internal environment is static or unchanging Maintenance of “set points” or “normal/functioning ranges” does NOT mean body’s internal environment is unchanging Misconception: Regulatory mechanisms and feedback loops are either “on” or “off,” like a switch Since body’s internal environment is a dynamic place, feedback loops are constantly engaged in some degree of activity Positive feedback Positive feedback loops = less common than negative feedback loops; effector activity increases and reinforces initial stimulus; shuts off when conditions return to the normal range. Child birth and blood clotting Negative feedback Negative feedback loops = maintain homeostasis When a change in status of a regulated variable is detected, a series of events is triggered to return variable to its normal value Each regulated variable has a set point or an established baseline value Negative feedback A matching exercise The System that regulates the body’s responses to internal and A) Circulatory System external stimuli B) Digestive System The System that differentiates self from non-self and neutralizes C) Endocrine System potentially pathogenic organisms or substances D) Immune System The System consisting of the skin and its associated structures, E) Integumentary System such as the hair, nails, sweat glands, and sebaceous glands F) Lymphatic System The System involved in reproduction G) Muscular System The System of organs that produce, collect, and eliminate urine H) Nervous System The framework of the body, consisting of bones and other I) Reproductive System connective tissues, which protects and supports the body tissues J) Respiratory System and internal organs K) Skeletal System The System of endocrine glands that chemically controls the various L) Urinary System functions of cells, tissues, and organs through the secretion of hormones The System of organs and glands responsible for the ingestion, digestion, and absorption of food The System that circulates blood and lymph through the body; distributes nutrients, wastes, oxygen and carbon dioxide The System of organs involved in the intake and exchange of oxygen and carbon dioxide between the body and the environment The System that is composed of skeletal, smooth, and cardiac muscle tissue and functions in movement of the body or of materials through the body, maintenance of posture, and heat production Part of the immune System; the System which circulates lymph; also water homeostasis Review o Describe the anatomic position and its importance in the study of anatomy. o Describe the anatomic sections and planes through the body. o Define the different anatomic directional terms. o Identify the major regions of the body, using proper anatomic terminology. o Describe the body cavities and their subdivisions. o Explain the role of serous membranes in the ventral cavities.