A 54-year-old female with symptoms of persistent fatigue and impaired cognitive function was examined by her physician.  During the exam, the patient expressed concern over increased body fat and, under questioning, reported having suffered a concussion during a soccer match in college.  Based upon the patient's symptoms and responses to questions, the physician ordered a panel of tests.A concussion is a mild traumatic brain injury (TBI) that results from impact to the skull.  TBI occurs most frequently in male patients, typically due to accidents; however, there is growing appreciation that TBI also occurs in male and female athletes during sporting events.  In addition, previously unrecognized chronic responses to TBI (eg, hormonal deficiencies) are now better understood.As part of the examination, the patient underwent a test to evaluate growth hormone (GH) secretion.  The brain participates in regulating GH secretion, and roughly half of the GH secreted into the blood is bound to a binding protein that increases the half-life of GH by inhibiting its urinary elimination.  Furthermore, lipid-soluble sex hormones, such as estradiol, augment GH secretion.During the GH secretion test, GH-releasing hormone (GHRH) was administered to the patient along with arginine.  GHRH is an endogenous stimulator of GH secretion, and arginine inhibits secretion of somatostatin, an endogenous inhibitor of GH secretion.  When administered together in healthy individuals, GHRH and arginine strongly stimulate GH secretion into the blood.  However, this patient exhibited an abnormally small response to GHRH and arginine, leading the physician to start the patient on GH therapy.  After a year, the patient's symptoms had improved, and body composition testing showed that her lean body mass had increased. Question 38Based on the passage, GH is bound to a binding protein, which most likely influences responses to activation of the GH axis by:A.decreasing the availability of GH for binding to its intracellular receptor.B.increasing the availability of GH for binding to its intracellular receptor.C.decreasing the effect duration of GH.D.increasing the effect duration of GH.

Who can determine if a student-athlete might have sustained a concussion during practice or competition? A coach A physician All answers are correct A licensed health care professional

A traumatic brain injury (TBI) is a form of brain injury caused by an external physical force.  In addition to direct injury at the site of an impact, the rapid acceleration-deceleration of the head may cause the brain to move within the skull and result in injury to the part of the brain opposite the impact site.  This is known as a contrecoup injury.If an impact to the head also results in a skull fracture, the injury is classified as an open TBI.  If there is no skull fracture, the injury is classified as a closed TBI.  The type of TBI can be predicted from the collision duration and the average acceleration of the head.  The thresholds for open and closed TBI are shown in Figure 1.Figure 1  Thresholds for open and closed TBIIn an experiment to study head collisions with projectiles, researchers equipped the head of a crash test dummy with sensors that measured acceleration on multiple axes.  The crash test dummy was stationary before its head was subjected to controlled collisions with incoming projectiles of varying mass and impact velocity.  The linear acceleration of the crash test dummy's head was recorded during and after the impact.  The results for a trial in which the impact lasted for 10 ms are shown in Figure 2.Figure 2  The acceleration of the head during and after a 10-ms collision Question 4A baseball traveling at 20 m/s strikes a player running at 5 m/s.  The relative speed of the ball with respect to the player depends on the direction of travel of the ball relative to the player's direction of travel.  What is the difference between the minimum and maximum possible speeds of the ball relative to the player?A.10 m/sB.15 m/sC.20 m/sD.25 m/s

What is the main idea of this text?Concussions are a serious problem for young people playing sports, and coaches and teams are adjusting policies to better protect players.NFL players Andrew Luck and Rob Gronkowski both quit football before the age of 30 because they were concerned about concussions.Concussions can cause a variety of symptoms, including headaches, memory loss, dizziness, and vision difficulties.Traumatic brain injury is a serious problem for athletes, but doctors don’t know enough about it to correctly diagnose it.

What factors are associated with recovery in pediatric patients with mild traumatic brain injury or concussion?

Which of the following statements about concussion is true? aA concussion is a type of traumatic brain injury. bIt is safe for a person who may have a concussion to immediately resume whatever activity they were doing when the injury occurred. cA person must have to be hit with a great deal of force to sustain a concussion. dA person with a concussion will always lose consciousness briefly.