1. 5 Coordination and regulation: endocrine systems

2. Death at sea

3. 2207 people left the UK, 1502 people died in a freezing ocean

4. If a body deviates too far from the normal steady state of a variable, death can occur. Tissue fluid and plasma form the internal environment of body cells. The internal environment is relatively stable. Fluids located outside cells are termed extracellular. Fluid located within cells is intracellular. Exchange of substances occurs between the various fluids of the body.

5. !!! Plasma- special form of ECF surrounding RBCs in vascular system BODY cell Intracellular fluid- cytosol Extracellular fluid cell

7. What variables are subject to homeostasis? nutrients blood volume temperature blood pressure water ions, such as Na+, Ca+, Cl− carbon dioxide pH (hydrogen ion concentration) red blood cells. oxygen Read pages 137/8.

8. Homeostasis is the condition of a relatively stable internal environment. Homeostasis is essential for cell functioning. Homeostasis can be disrupted by agents such as disease and trauma. Most body systems play various roles in homeostasis. The hormone and nervous systems are the two systems that coordinate all other systems of the body. Do QC. 1-8

9. Homeostasis: hormones in action

10. All negative feedback systems involve sensors that monitor the state of a particular variable and compare that state with optimal levels. All negative feedback systems involve effectors that respond to messages from sensors and act to maintain a variable within its optimal limits. Although the majority of hormone systems operate by negative feedback, positive feedback systems do exist. Read. pp139/44 QC 9-12

11. Hormones as cell communicators