vertical orientation
Chapter 15 1 The heart rate increases to send more blood to the muscles, and the liver releases stored glucose to fuel the muscles. 3 The effect of gravity on circulation means that it is harder to get blood up from the legs as the body takes on a vertical orientation. 5 The release of urine in extreme fear. The sympathetic system normally constricts sphincters such as that of the urethra. 7 D 9 C 11 A 13 D 15 A 17 A 19 B 21 B 23 C 25 D 27 Whereas energy is needed for running away from the threat, blood needs to be sent to the skeletal muscles for oxygen supply. The additional fuel, in the form of carbohydrates, probably wouldnt improve the ability to escape the threat as much as the diversion of oxygen-rich blood would hinder it. 29 The nerves that carry sensory information from the diaphragm enter the spinal cord in the cervical region where somatic sensory fibers from the shoulder and neck would enter. The brain superimposes this experience onto the sensory homunculus where the somatic nerves are connected. 31 Pupillary dilation and sweating, two functions lost in Horners syndrome, are caused by the sympathetic system. A tumor in the thoracic cavity may interrupt the output of the thoracic ganglia that project to the head and face. 33 Blood vessels, and therefore blood pressure, are primarily influenced by only the sympathetic system. There is no parasympathetic influence on blood pressure, so nicotine activation of autonomic ganglia will preferentially increase blood pressure. Also, cardiac muscle tissue is only modulated by autonomic inputs, so the conflicting information from both sympathetic and parasympathetic postganglionic fibers will cause arrhythmias. Both hypertension and arrhythmias are cardiac risk factors.