Chapter 1 Introduction to Human Body

Definitions Anatomy – Physiology- Science of the structure of the human body, and the relationship between body parts Physiology- The science of body function, the study of the physical and chemical processes that direct activity

Approaches to A & P Systemic Regional Study all organs of a system together Regional Study all organs/structures in 1 area of the body

Physical Needs for Life Water body is 60-80% water Fluid base for reactions, secretions and excretions Ingested from foods or liquids Lost from evaporation in lungs and skin Oxygen Chemical reactions that release energy from foods requires oxygen

Physical Needs For Life Food Contains chemicals used for energy Carbohydrates – used for energy Proteins – used for structure Fat – cushion body organs Temperature Body temperature must remain fairly constant @ 98.6 F Pressure Exchange of oxygen depends on atmospheric pressure

Requirements for life Maintaining Boundaries Responsiveness Movement Inside must remain distinct from outside Ex: cell membrane, skin Responsiveness Ability to sense changes in environment and react to them Movement Growth

Requirements for life Metabolism Digestion Excretion Reproduction All chemical reactions that occur within body cells Digestion Breaking down food into smaller molecules Excretion Removal of wastes (CO2, urine, feces) Reproduction Production of offspring

Organizational Levels MOLECULAR Atoms, molecules, organelles CELLULAR Cell is basic functional unit in the body Different cells have different function TISSUE Group of cells carrying out common function ORGAN 2+ tissue types that perform a specific function SYSTEM Group of organs with similar/related functions ORGANISM Combination of all systems

Reference Terminology Anatomical Position Palms forward Body standing erect Feet slightly apart Thumbs point away from body

Directional Terms Superior – toward the head Inferior – toward the feet Anterior/ventral – front Posterior/dorsal – back Medial – toward the midline of body Lateral – away from the midline of the body Proximal – toward the core of the body Distal – away from the core of the body Superficial – toward the surface of the body Deep – further within the body Visceral- lining of organ Parietal – lining of cavity

Body Planes Sagittal Transverse Frontal Cuts body into right/left halves Transverse Cuts body into top and bottom Frontal Cuts body into front and back

Body Cavities Dorsal body cavity Ventral body cavity Cranial Spinal Thoracic Pleural Pericardial (mediastinum) Abdominopelvic Abdominal pelvic

Homeostasis The maintenance of a constant internal environment despite a changing external environment

Negative Feedback Loop Maintains constant internal environment Reaction is opposite to stimuli input Three parts Sensors Integrating center Effector

Examples of negative feedback House thermostat Body thermostat Balance Heart rate

Positive Feedback Loop Effectors increase stimuli input Does not allow fine control Example: childbirth