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 Ex. Heart beating Ex. Nerve sending electrical impulse

Anatomy—Levels of Study Gross anatomy Large structures Easily observable Microscopic Anatomy Very small structures Can only be viewed with a microscope Figure 14.1

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 1. Integumentary System (skin) Functions: Forms the external body covering Protects deeper tissue from injury Helps regulate body temperature Location of cutaneous nerve receptors Figure 1.2a

Organ System Overview 2. Skeletal System Functions: Protects and supports body organs Provides muscle attachment for movement Site of blood cell formation Stores minerals Figure 1.2b

Organ System Overview 3. Muscular Functions: Produces movement Maintains posture Produces heat Figure 1.2c

Organ System Overview 4. Nervous Fast-acting control system Functions: Responds to internal and external changes Activates muscles and glands Figure 1.2d

Organ System Overview 5. Endocrine Secretes hormones Functions: Regulation of Growth Reproduction Metabolism Figure 1.2e

Organ System Overview 6. Cardiovascular Function: Transports materials in body via blood pumped by heart Oxygen Carbon dioxide Nutrients Wastes Figure 1.2f

Organ System Overview 7. Lymphatic Functions: Returns fluid to blood vessels Cleanses the blood Involved in immunity Figure 1.2g

Organ System Overview 8. Respiratory Functions: Keeps blood supplied with oxygen Removes carbon dioxide Figure 1.2h

Organ System Overview 9. Digestive Functions: Breaks down food Allows for nutrient absorption into blood Eliminates indigestible material (feces) Figure 1.2i

Organ System Overview 10. Urinary Functions: Eliminates nitrogenous wastes (ex. Urea) Maintains acid-base balance Regulates water and electrolytes Figure 1.2j

Organ System Overview 11. Reproductive Function: Produce offspring Males - produce sperm in testes Females - produce eggs in ovaries - serve as site of fertilization & fetal development Figure 1.2k–l

Necessary Life Functions Maintain boundaries Separation of internal from external environment Movement Locomotion Movement of substances Responsiveness Ability to sense changes and react Digestion Break-down and absorption of nutrients

Necessary Life Functions (con’t) Metabolism chemical reactions within the body Produces energy Makes body structures 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 Makes up 20% of the air we breathe

Survival Needs Water 60–80% of body weight Necessary for metabolic reactions Stable body temperature 37 degrees C or 98 degrees F Atmospheric pressure Must be appropriate level to allow for gas exchange

Interrelationships Among Body Systems Figure 1.3

Homeostasis Homeostasis: maintenance of a stable internal environment despite continuous changes dynamic equilibrium necessary for normal body functioning and to sustain life Homeostatic imbalance A disturbance in homeostasis resulting in disease or illness

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

Maintaining Homeostasis Homeostatic Control Mechanisms neural and hormonal control systems (Nervous & Endocrine Systems) Receptor Responds to changes in the environment (stimuli) Sends information to control center

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

Feedback Mechanisms Negative feedback Can shut off the original stimulus or reduce its intensity as well as turn on or increase its intensity Ex. a household thermostat, most hormones

Feedback Mechanisms Positive feedback Can ONLY increase the original stimulus to push the variable farther Ex. blood clotting and childbirth

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

Directional Terms

Directional Terms (con’t)

Directional Terms (con’t) Table 1.1 (3 of 3)

Regional Terms: Anterior View Figure 1.5a

Regional Terms: Anterior View Scan and insert Answer Key that corresponds to blank sheet Figure 1.5a

Regional Terms: Posterior View Figure 1.5b

Regional Terms: Posterior View Scan and insert Answer Key that corresponds to blank sheet Figure 1.5b

Body Planes and Sections A sagittal or parasagittal 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, or coronal section divides the body (or organ) into anterior (front) and posterior (back) parts A transverse, or cross, section divides the body (or organ) into superior (upper) and inferior (lower) parts An oblique section divides the body (or organ) diagonally

Body Planes and Sections Figure 1.6

Body Cavities Dorsal body cavity Cranial cavity- brain Spinal cavity- spinal cord Ventral body cavity Thoracic cavity- heart & lungs Abdominal cavity- most digestive organs Pelvic cavity- most urinary system organs

Abdominopelvic Quadrants Abdominopelvic Regions Figure 1.8a Figure 1.8b