1. pressure is low and blood may pool

2. muscular compression and respiration are impaired, leading to a decline in cardiac output- blood supply to brain is reduced and fainting can occur

3. Venous return is achieved by a system of one-way valves in veins – when skeletal muscles contract, they squeeze veins, producing pressure and moving blood back toward the heart. Also, during normal breathing, pressure changes within the chest cavity affects similar pressure changes in the vena cava, the major vein entering the heart from the systemic circulation. (muscular compression and respiratory pump)

4. i.e. brachial artery: external pressure applied to cut off artery and then is slowly deflated; when turbulent flow resumes, that is systolic pressure; when the sound stops and flow is smooth, that is diastolic pressure

5. see and study picture in notes; The pancreas has beta-cells which secrete insulin in response to increased blood sugar – insulin stimulates several tissues to take up sugar for storage. Meanwhile, a decrease in blood sugar stimulates pancreatic alpha-cells to secrete glucagon – this hormone primarily stimulates the liver to release glucose into the blood for immediate use. These two peptide hormones help maintain blood glucose within tolerable limits.

6. a chemical messenger that carries a signal from one location to another, often through the blood

– affect the synthesis of other hormones: ?
- metabolic effects: ?