Introduction to A&P Levels of Organization, Homeostasis, Body Cavities

Terminology Anatomy – the study of internal and external structures of the body, and the physical relationships among body parts. Ex. Studying the parts of the kidney. Physiology – the study of how living organisms perform their vital functions. Ex. Studying the mechanisms by which the kidneys produce urine.

Definitions What 2 languages form the basis for most anatomical and physiological words? Biology Embrology Pathology Histology Cytology

Homeostasis Definition: state of balance in which the body’s internal environment remains in the normal range. Our body is said to be in homeostasis when the needs of its cells are met and its activities are occurring smoothly. Occurs with a balance of positive and negative feedback.

Metabolism Definition: sum total of all chemical processes occurring in the body ◦catabolism – breakdown of organic matter, usually with the release of energy ◦anabolism – buildup of organic matter, usually requiring the input of energy ◦Example: A catabolic process would be the breakdown of a Carbohydrate for a release of energy to the body. An anabolic reaction would occur when that energy is captured and then used (or required) for something else.

+/- Feedback negative feedback – when the information decreases the system’s output to bring the system back to its set point ◦Example: The level of glucose rises after a meal, glucose stimulates the release of insulin, and insulin encourages the passage of glucose in the cells and therefore reduces the glucose level.

+/- Feedback positive feedback – the information returned to the system increase the deviation from the set point ◦Example: Stimulating a nerve cell causes sodium ions to flow across the membrane into the cell; the sodium flow increases the membrane’s passageways to encourage more sodium ions to flow inward. The result is a nerve impulse.

Anatomical Terms Anterior/ ventral – Posterior / Dorsal – Superior Inferior Medial Lateral Proximal Distal

Body and Dissection Terms: Superficial – At, near or close to the surface Deep – Farther from the body surface Ex. - The thalamus is located deep within the brain.

Planes of the Body sagittal – lengthwise plane running from front to back, it divides the body into ______ _____ ______sides transverse – refers to a cut that divides the body into _________ ____ ______ portions Coronal (frontal) – lengthwise plane running from side to side, it divides the body into front _________ _____ ___________ portions

Body Cavities

The human is divided into an _____ portion (head, neck and trunk) and an _____________ portion (upper and lower limbs) The _____ portion has 2 major cavities: a ______ and a ventral cavity

Body Cavities ◦dorsal – subdivided into the cranial (brain) and spinal (vertebrae and spinal cord) cavities ◦ventral (divided by the diaphragm) – subdivided into the thoracic (heart, lungs, esophagus) and abdominopelvic ( stomach, intestines, spleen, liver, etc) cavities

Body Cavities thoracic – the mediastinum separates the thoracic cavity into 2 compartments, the left and right lungs. The mediastinum includes the heart, esophagus, trachea, and thymus gland abdominopelvic cavity includes the upper abdomen and the lower pelvic areas. The abdominal region is subdivided into nine regions  right hypochondriac  epigastric  left hypochondriac  right lumbar  umbilical  left lumbar  right iliac  hypogastric  left iliac region

Levels of Organization

chemical level – lowest – chemicals essential for maintaining life- atoms to molecules to macromolecules to organelles cellular- basic structural and functional unit; ex. Muscle and nerve cells tissue- similar cells with same function; ex. Connective tissue, epithelial tissue

Levels of Organization organ- structures of definite form and function composed of 2 or more tissues; ex. Heart, liver system- association of organs with common function ex. Digestive, nervous organism – all parts of the body functioning with one another