Introduction to A&P

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

2. 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.

3. Levels of Organization

4. 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

5. 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

6. 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.

7. 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.

8. +/- 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.

9. +/- 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.

10. Planes of the Body • sagittal – lengthwise plane running from front to back, it divides the body into right and left sides • transverse – refers to a cut that divides the body into superior and inferior portions • Coronal (frontal) – lengthwise plane running from side to side, it divides the body into front (anterior) and back (posterior) portions

11. Body Cavities

12. Body Cavities • The human is divided into an axial portion (head, neck and trunk) and an appendicular portion (upper and lower limbs) • The axial portion has 2 major cavities: a dorsal and a ventral cavity

13. 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

14. 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 Body Cavities