Interactions Among Systems Organ systems coordinate with other organ systems Examples: – Respiration: Circulatory and Respiratory systems – Vitamin D Production – Control of body temp

Vitamin D Production UV light stimulates vitamin D production – Skin absorbs UV – Blood carries inactive vitamin D – Liver converts inactive vitamin D – Kidneys convert to vitamin D – Blood transports around the body – Vitamin D used to help build bone

Thermoregulation Defined: Maintenance of body temperature – Skin: sensors provide feedback to brain – Nervous & Endocrine system: send messages to/from brain – Muscles: Start to shiver

Homeostasis disruption Sensors fail Wrong messages sent Message doesn’t reach target Serious injury Microorganism infection Short Term – Temporary discomfort (usually)

Long Term: Diabetes Normal – Insulin controls glucose level – High: cells intake more glucose – Low: pancreas creates more glucose Type 1 – Immune system destroys cells to produce insulin – Pancreas fails – Blood pH decreases (more acidic) Type 2 – Insulin production decreases – Glucose level in blood rises – Cells starve