Human Body Orientation Chapter 1 Human Body Orientation

Anatomy Study of structure Types Gross Anatomy: the study of large body structures visible to the naked eye such as the heart or lungs Microscopic Anatomy: the study of structures too small to be seen without a microscope such as tissues and cells Developmental Anatomy: the study of structural changes that occur in the body throughout the lifespan

Physiology The study of the function of the body Types Renal Physiology: kidney function and urine production Neurophysiology: nervous system Cardiovascular Physiology: heart and blood vessels

Structure determines Function How a cell looks determines what the cell does. (ex. Long dendrites on a nerve cell allows it to send signals quickly) How an organ looks determines how well it functions.

Levels of Structural Organization 1. chemical level (atoms & molecules) 2. cellular level (cells & organelles) 3. tissue level (groups of similar cells that have a common function) 4. organ level (discrete structures composed of at least two tissue types) 5. organ system (organs work together to accomplish a common purpose) 6. organismal level (the sum total of all structural levels)

Necessary Life Functions 1. maintaining boundaries: internal boundaries remain distinct from external environment 2. movement: activities of the muscular system, etc. 3. responsiveness: the ability to sense changes (stimuli) and respond to them 4. digestion: breaking down food to simple molecules 5. metabolism: chemical reactions in the body 6. excretion: removing wastes 7. reproduction: cellular or organismal 8. growth: increase in the size of cells, body parts, or the organism itself

Survival Needs 1. nutrients: contain the chemical substances used for energy and cell building 2. oxygen: allows cellular respiration to occur 3. water: accounts for 60-80% of body weight, needed for chemical reactions 4. normal body temperature: maintains metabolic reactions 5. atmospheric pressure: needed for proper breathing and gas exchange in the lungs

Homeostasis The ability to maintain a stable internal environment Every organ system plays a role in maintaining the constancy of the internal environment

Negative Feedback The output shuts off the original stimulus or reduces its intensity (prevents sudden severe changes in the body) These mechanisms cause the variable to change in a direction opposite to that of the initial change Ex. Body temperature and blood volume

Positive Feedback The response enhances the original stimulus so that the activity is accelerated The change that occurs is in the same direction as the initial disturbance Ex. Oxytocin: intensifies labor contractions

Response to Environment Nervous system – electrochemical Afferent pathway – (arriving) receptor stimuli to control center Efferent pathway – (exiting) control center Ex. hot stove and hand Endocrine system – hormones Ex. insulin and glucose

Orientation and Direction Cranial Caudal Ventral Dorsal Superior Inferior Medial Lateral Proximal Distal

Body Planes and Sections Sagittal: divides body into right and left Median: sagittal along the midline Frontal (coronal): divides body into anterior and posterior Transverse: horizontal; divides body into superior and inferior parts

Body Cavities Dorsal Ventral Cranial & vertebral Thoracic Abdominal Pleural cavities – houses lungs Mediastinum – houses heart, trachea, esophagus Abdominal -- Pelvic

Membranes of Body Cavities Serous membranes Covering on organs Parietal serosa: lines the cavity walls Visceral serosa: covers the organs Serous fluid: lubricating fluid Peritonitis- inflammation of the membrane lining of the abdominal cavity

Abdominopelvic Quadrants

Other Body Cavities 1. oral and digestive 2. nasal 3. orbital 4. middle ear 5. synovial

11 Systems Cardiovascular Skeletal Integumentary Lymphatic Urinary Muscular Digestive Respiratory Reproductive Nervous Endocrine