Planes and Sections of the Body
• Sagittal Plane: Extends lengthwise, divides body into right and left portions.
• Frontal Plane: Extends lengthwise and divides body into anterior and posterior portions.
• Transverse: Runs crosswise to separate body into horizontal sections.
Body Cavities and Membranes
• Posterior (Dorsal) Body Cavity- – Cranial Cavity: Contains the brain.– Vertebral Canal: Contains the spinal cord.– Lined by three membranous layers called
meninges.• Meningitis = Infection of these membranes.
Body Cavities and Membranes
• Anterior (Ventral) Body Cavity-– Thoracic Cavity– Abdominopelvic Cavity– Separated by Diaphragm– Lined by Serous membranes.
• Secrete fluid similar to serum• Reduces friction between organs.
Thoracic Cavity
• Enclosed by rib cage and has three portions.– Mediastinum: Located in the middle and holds
the heart, thymus, trachea and others.
– Right and left portions hold the lungs
– Pleural and Pericardial spaces surround the lungs and heart to provide protection.
Abdominopelvic Cavity
• Abdominal Cavity is superior: Contains most of the digestive organs.
• Pelvic Cavity is inferior: Contains the rectum, bladder and some parts of the large intestines.
• The organs (viscera) in the cavity are covered by membranes and the cavity is lined by a membrane.
• Peritoneal fluid fills the space between.
Abdominopelvic Cavity Cont.
• Broken down into four quadrants.
Organ Systems
• Support, Movement and Protection:– Integumentary– Skeletal– Muscular: Muscles
• Reproduction and Development:– Reproductive system.
• Integration and Coordination:– Nervous– Endocrine
• Maintenance of Body:– Cardiovascular– Lymphatic– Respiratory– Digestive– Urinary
“Balance” in the Body
• Homeostasis: This is the relative constancy of the body’s internal environment.
• Outside environment may change lots, the inside stays very steady.– pH of blood, blood sugar levels, body temp.
Negative Feedback
• Keeps a variable close to a partciular value.
• Three components:– Sensor– Regulatory center– Effector
• Ex. Home heating system, blood pressure, body temperature.
Positive Feedback
• Brings about an ever greater change in the same direction.
Positive Feedback
• Brings about an ever increasing change in the same direction.
• Examples: Blood Clotting, Digestion of proteins in the stomach, muscle contractions during child birth.