Ch. 1 Organization & General Plan of the Body

Introduction Anatomy – study of body structure Physiology – study of body function

Levels of Organization Fig. 1-1 Chemicals Inorganic – simple molecules made of one or 2 elements other than carbon (usually) water, oxygen, carbon dioxide, iron, calcium, sodium Organic – very complex molecules containing carbon and hydrogen carbohydrates, fats, proteins, nucleic acids

Levels of Organization Cells – smallest living units of structure & function Tissues – group of cells with similar structure & function Epithelial – cover or line body surfaces Connective – connect and support body parts Muscle – bringing about movement Nerve – generate & transmit impulses that regulate body functions

Levels of Organization Organ – group of tissues that perform specific functions Organ systems – group of organs that perform a specific function Table 1-1, Fig. 1-2

Metabolism & Homeostasis Metabolism – all the chemical reactions (rxns) & physical processes within the body Homeostasis – maintaining a relatively stable metabolism and functioning normally despite constant changes

Terms of Location & Position Table 1-2, Table 1-3 Anatomic position – standing up, facing forward, arms at sides, palms forward, feet apart

Body Cavities & Their Membranes 2 major cavities Dorsal (posterior) Ventral (anterior) Each of these has further subdivisions (Fig. 1-5)

Dorsal Cavity Contains central nervous system (CNS) Brain & spinal cord (CNS) Cranial cavity & spinal cavity Meninges - membranes lining cavities & covering CNS

Ventral Cavity Consists of 2 compartments separated by the diaphragm Thoracic cavity Abdominal cavity *Pelvic cavity may be considered a subdivision of the abdominal cavity or as a separate cavity

Ventral Cavity Thoracic cavity includes the heart, lungs Pleural membranes Parietal pleura – lines chest wall Visceral pleura – covers lungs Pericardial membranes – for heart Parietal pericardium – lines pericardial sac Visceral pericardium – covers heart

Ventral Cavity Abdominal cavity liver, stomach, intestines Membranes Peritoneum – lines entire abdominal wall Mesentery – continuation of peritoneum; folds around, covers outer surfaces of abdominal organs Pelvic cavity – inferior to abdominal cavity bladder, reproductive organs

Planes & Sections Plane – imaginary flat surface separating 2 portions of the body or an organ (Fig. 1-6)

Planes & Sections Section – a cut to make structures easily visible (Fig. 1-6) Types of sections Frontal (coronal) – separates body into front & back Sagittal – separates body into right & left; midsagittal creates equal right/left halves Transverse- separates body into upper & lower portions

Planes & Sections Cross-section – plane perpendicular to the long axis of an organ Longitudinal section – plane along the long axis of an organ See Fig. 1-6

Areas of the Abdomen Quadrants –transverse plane and midsagittal plane that cross at the umbilicus; divide the abdomen into 4 quadrants Used most frequently Nine areas – 2 transverse planes and 2 sagittal planes divide abdomen into 9 areas Fig. 1-7