The Human Body: An Orientation

The Human Body—An Orientation Anatomy Study of the structure and shape of the body and its parts Physiology Study of how the body and its parts work or function

Anatomy—Levels of Study Gross anatomy Large structures Easily observable Figure 14.1

Anatomy—Levels of Study Microscopic Anatomy Very small structures Can only be viewed with a microscope Figure 14.4c–d

Levels of Structural Organization Smooth muscle cell Molecules Atoms Smooth muscle tissue Epithelial tissue Connective tissue Blood vessel (organ) Cardio- vascular system Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells Organ level Organs are made up of different types of tissues Organ system level Organ systems consist of different organs that work together closely Organismal level Human organisms are made up of many organ systems Chemical level Atoms combine to form molecules Figure 1.1

Organ System Overview Integumentary Forms the external body covering Protects deeper tissue from injury Helps regulate body temperature through _______ Location of cutaneous nerve receptors Figure 1.2a

Organ System Overview Skeletal Protects and supports body organs Provides muscle attachment for movement Site of blood cell formation (________) Stores minerals Figure 1.2b

Organ System Overview Muscular Produces movement Maintains posture Produces heat Figure 1.2c

Organ System Overview Nervous Fast-acting control system Responds to internal and external change Changes Sensory receptors ______ CNS effectors Activates muscles and glands (______) Figure 1.2d

Organ System Overview Endocrine – Controls body activities more ______ than nervous system. Secretes regulatory hormones Growth Reproduction Metabolism Figure 1.2e

Organ System Overview Cardiovascular – Heart+ _______ Transports materials in body via blood pumped by heart Oxygen Carbon dioxide Nutrients Wastes Figure 1.2f

Organ System Overview Lymphatic Returns fluids to blood vessels Cleanses the blood Involved in immunity Lymph vessels, nodes, tonsils and _______ Figure 1.2g

Organ System Overview Respiratory Keeps blood supplied with oxygen Removes carbon dioxide Tiny vessels called ______ transport gases to and from blood Figure 1.2h

Organ System Overview Digestive Breaks down food – begins in the mouth and continues in the ______ Allows for nutrient absorption into blood Eliminates indigestible material Liver and Pancreas too Figure 1.2i

Organ System Overview Urinary Eliminates nitrogenous wastes Maintains acid-base balance Regulates water and electrolytes Figure 1.2j

Organ System Overview Reproductive Produces offspring ______ produce eggs Figure 1.2k–l

Interrelationships Among Body Systems Figure 1.3

Life Functions Maintain boundaries Movement Locomotion Movement of substances Responsiveness Ability to sense changes and react Digestion Break-down and absorption of nutrients

Life Functions Metabolism—chemical reactions within the body Produces energy (_____) Makes body structure Excretion Eliminates waste from metabolic reactions Reproduction Produces future generation Growth Increases cell size and number of cells

Survival Needs Nutrients Chemicals for energy and cell building Includes carbohydrates, proteins, lipids, vitamins, and minerals Oxygen Required for chemical reactions _____% of the air we breathe

Survival Needs Water 60–80% of body weight Provides for metabolic reaction Stable body temperature - _____ Atmospheric pressure Must be appropriate

Homeostasis Homeostasis—maintenance of a stable internal environment A dynamic state of equilibrium Homeostasis is necessary for normal body functioning and to sustain life Homeostatic imbalance A disturbance in homeostasis resulting in disease

Maintaining Homeostasis The body communicates through neural and hormonal control systems ___________ Responds to changes in the environment (stimuli) Sends information to control center _________ pathway

Maintaining Homeostasis Control center Determines set point Analyzes information Determines appropriate response Effector Provides a means for response to the stimulus _______ pathway

Feedback Mechanisms Negative feedback Includes most homeostatic control mechanisms _______the original stimulus, or reduces its intensity Works like a household thermostat

Feedback Mechanisms Positive feedback ________ the original stimulus to push the variable farther In the body this only occurs in blood clotting and during the birth of a baby

Variable (in homeostasis) Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Receptor (sensor) Effector Change detected by receptor Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4, step 5

The Language of Anatomy Special terminology is used to prevent misunderstanding Exact terms are used for Position Direction Regions Structures

Regional Terms Anterior body landmarks Figure 1.5a

Regional Terms Posterior body landmarks Figure 1.5b

Directional Terms Table 1.1 (1 of 3)

Directional Terms Table 1.1 (2 of 3)

Directional Terms Table 1.1 (3 of 3)

Body Planes and Sections A sagittal section divides the body (or organ) into left and right parts A median, or midsagittal, section divides the body (or organ) into equal left and right parts A frontal section divides the body (or organ) into anterior and posterior parts A transverse, or cross, section divides the body (or organ) into superior and inferior parts

Body Planes and Sections Figure 1.6

Body Cavities Dorsal body cavity Cranial cavity houses the brain Spinal cavity houses the spinal cord Ventral body cavity Thoracic cavity houses heart, lungs and others Abdominopelvic cavity houses digestive system and most urinary system organs

Body Cavities Figure 1.7

Abdominopelvic Quadrants Figure 1.8a

Abdominopelvic Regions Figure 1.8b

Abdominopelvic Major Organs Figure 1.8c