Rising from a lying or sitting position to a standing one quickly, the blood in your carotid arteries wants to stay where it is and not follow your head up. Since this would momentarily deprive your brain of blood, which is obviously detrimental to your studying of physiology, your body tries to prevent this. Detail the control system that is designed to prevent these momentary losses of blood to the head...people who have a sluggish one of these will often faint (syncope) upon rapid rising. Be sure to identify all of the control system elements e.g. sensor etc. For full credit you will need to include effector responses from three different effectors in your answer including changes at the intracellular level that account for the effector response. Diagnostic problem: A patient comes to you complaining of dizziness and fainting upon getting out of bed or standing up. Her heart rate is 100beats/min supine, and is 110bpm upon sitting and 105 bpm when standing. Her blood pressure is 120/74mmHg supine. 115/70mmHg sitting and standing. Heart and lung sounds are normal. What's this patient's problem? List all of the possible points of pathology. Administration of Atropine a (muscarinic receptor antagonist) caused no changes in heart rate or blood pressure. Administration of adrenaline in the blood caused an increase in blood pressure, and a 20% increase in heart rate. Similarly, stimulation of post-ganglionic sympathetic nerves innervating blood vessels caused an increase in blood pressure. Can you further pinpoint this patient's problem?