The Human Body: An Orientation Chapter 1 The Human Body: An Orientation Health & Anatomy Mrs. Gunderson

Overview of Anatomy and Physiology Anatomy – the study of the structure of body parts and their relationships to one another Gross or macroscopic = large & easily observable Microscopic = very small Derived from the Greek words = cut (tomy) apart (ana) Physiology – the study of the function of the body and its parts

Levels of Structural Organization Chemical – atoms combined to form molecules (simplest level) Cellular – cells are made of molecules and are the smallest units of all living things Tissue – consists of similar types of cells Organ – made up of 2 or more tissue types Organ system – consists of different organs that work closely together Organismal – made up of the organ systems (highest level)

Figure 1.1

Necessary Life Functions I Maintaining boundaries – the internal environment remains distinct from the external Cellular level – accomplished by plasma membranes Organismal level – accomplished by the skin Movement – locomotion, propulsion (peristalsis), and contractility Responsiveness – ability to sense changes in the environment and respond to them Digestion – breakdown of ingested foods

Necessary Life Functions II Metabolism – all the chemical reactions that occur in the body Excretion – removal of wastes from the body Reproduction – cellular and organismal levels Cellular – an original cell divides and produces two identical daughter cells Organismal – sperm and egg unite to make a whole new person Growth – increase in size of a body part or of the organism

Survival Needs Nutrients – chemical substances used for energy and cell building Oxygen – needed for metabolic reactions Water – provides the necessary environment for chemical reactions Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates Atmospheric pressure – required for proper breathing and gas exchange in the lungs

Homeostasis Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world The internal environment of the body is in a dynamic state of equilibrium Chemical, thermal, and neural factors interact to maintain homeostasis

Body Systems: Integumentary System- Function: Waterproof, external covering, protection, cushions, excretes salts, regulates body temp. Parts: external coverings (skin), including nails & hair. Skeletal System- Function: Provides framework that muscles use for movement, supports the body & stores minerals. Parts: bones, cartilage, ligaments and joints.

Nervous System- Function: Fastest Acting System- respond to stimuli, irritants. Detect these changes and send messages. Parts: Brain, spinal cord, nerves and sensory receptors. Endocrine System- Function: Produce chemicals molecules called hormones and release into the blood. To target organs Parts: Glands located throughout the body.

Cardiovascular System- Function: Carries oxygen, hormones & nutrients. Parts: Heart and blood vessels. Lymphatic System- Function: complement the Cardio. Helps circulates fluids leaked from the blood. Parts: Lymphatic Vessels, nodes, spleen and tonsils.

Respiratory System- Function: Keep body supplied with oxygen and to remove carbon dioxide. Parts: nasal passages, pharynx, larynx, trachea, bronchi, and lungs. Digestive System- Function: Break down food and deliver products to the blood for dispersal to body cells. Parts: oral cavity, esophagus, stomach, small & Large Intestines, & rectum.

Urinary System- Function: removes nitrogenous waste from blood and flushes them from the body. Parts: kidneys, ureters, bladder and urethra. Muscular System – Function: Contract, movement occurs. Parts: Cardiac, smooth and skeletal muscles.

Stop Day 1 NOTES! Reproductive System- Function: produce offspring and supply the cell responsible for reproduction. Parts: Testes, ovaries, vas deferens, fallopian tubes, uterus, urethra, etc. Stop Day 1 NOTES!

Anatomical Position Body erect, feet slightly apart, palms facing forward, thumbs point away from the body Figure 1.7a

Directional Terms Superior and inferior – toward and away from the head. Anterior and posterior – toward the front and back of the body Medial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure

Directional Terms Proximal and distal – closer to and farther from the origin of the body Superficial and deep – toward and away from the body surface

Directional Terms Table 1.1

Directional Terms Table 1.1 (continued)

Directional Terms Table 1.1 (continued)

Body Planes Sagittal or medial – divides the body into right and left parts Frontal or coronal – divides the body into anterior and posterior parts Transverse or horizontal (cross section) – divides the body into superior and inferior parts Oblique section – cuts made diagonally

Body Cavities Dorsal cavity protects the nervous system, and is divided into two subdivisions Cranial cavity is within the skull and encases the brain Vertebral cavity runs within the vertebral column and encases the spinal cord Ventral cavity houses the internal organs (viscera), and is divided into two subdivisions: thoracic and abdominopelvic

Thoracic cavity is subdivided into pleural cavities, the mediastinum, and the pericardial cavity Pleural cavities – each houses a lung Mediastinum – contains the pericardial cavity, and surrounds the remaining thoracic organs Pericardial – encloses the heart Body Cavities

The Abdominopelvic cavity is separated from the superior thoracic cavity by the dome-shaped diaphragm It is composed of two subdivisions Abdominal cavity – contains the stomach, intestines, spleen, liver, & other organs Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs and rectum Body Cavities

Ventral Body Cavity Membranes Parietal serosa covering the body walls Visceral serosa covering the internal organs Serous fluid separates the serosae Figure 1.10

Abdominopelvic Regions Umbilical Epigastric Hypogastric Right and left iliac or inguinal Right and left lumbar Right and left hypochondriac Figure 1.11a

Abdominopelvic Regions Question: The LIVER lies (mostly) in which 2 regions? (Answer) R hypochondriac region & Epigastric region Figure 1.11b

Abdominopelvic Quadrants Right upper Left upper Right lower Left lower Figure 1.12