Joe walks from his dorm room to the woods nearby so he can begin his run. What d

Question

Joe walks from his dorm room to the woods nearby so he can begin his run. What did Joe's leg muscles use to produce ATP during this brief walk. A) Krebs cycle (tricarboxylic acid cycle). B) Glycolysis. C) Cori Cycle D) A & B E) A, B, & C Joe begins to perspire at the beginning of his run. The sweat was secreted from _____glands and results in evaporative cooling. A) sebaceous sweat B) ceruminous C) endocrine D) sweat E) Ehlers-Danlos Joes increased perspiration in response to increased body temperature is an example of feed forward. A) negative feedback B) homeopathy C) feed forward D) dysregulation E) positive feedback After running for an hour, Joe's leg muscles begin to fatigue. What causes this? A) Depletion of energy stores and elevated pH in the muscles. B) Using aerobic metabolism for an extended period of time will lower the pH in the muscles. C) Using anaerobic metabolism for an extended period of time will elevate the pH in the muscles. D) Depletion of energy stores and lowered pH in the muscles. E) Joe's leg muscles are atrophied because Red Bull gives you wings. He flies everywhere so his leg muscles aren't used. The body responds to strenuous exercise as a form of stress. After running for an hour, which of the following is occurring body? A) His pupillary dilator muscles are relaxed and the pupillary constrictor muscles are contracted B) The smooth muscle in the heart is contracting with maximum force with each heart beat C) The smooth muscle in the small arteries supplying the skeletal muscles are relaxed. D) The smooth muscle in the small arteries supplying the gastrointestinal tract muscles are relaxed. E) The smooth muscle in the small arteries supplying the skeletal muscles are contracted. After running for an hour, what is Joe's heart using to produce most of its ATP A) Krebs cycle (tricarboxylic acid cycle). B Glycolysis. C) Cori Cycle D) A&B; E) A, B, &C;

Explanation / Answer

Ans:-19 Merocrine Sweat Glands

1.Sweat helps keep people cool in hot weather or when exerting themselves and is therefore an important part of thermoregulation, the maintenance of a uniform body temperature. By moistening the skin, the liquid cools the body as it evaporates. Sweat is produced by glands in the skin as a response to temperature or other stimuli.

2.The content of sweat is mainly water, but about 0.2 to 1% of the solute is made up of minerals, lactate, and urea. In addition to being triggered by a rise in temperature, it can also be caused by nausea and stress. Cooling the body typically reduces sweating.

3.Sweat Glands in the skin are controlled by the hypothalamus in the brain, part of the autonomic nervous system. Temperature receptors in the skin affect the bodies hypothalamic, or core, temperature, which in turn sends signals to the hypothalamus. Heated skin lowers the hypothalamic set point or threshold at which sweating begins. When this set point is reached, the hypothalamus sends signals to activate the glands.

4.These glands are coiled, tubular structures in the epidermis, or skin. Each contains a special type of cell called myoepithelial cells that contract when activated. This motion squeezes the glands, excreting sweat directly onto the surface of the skin.

5.Human skin contains two types of sweat glands: merocrine and apocrine. Merocrine glands are more numerous and widespread, and shallower than apocrine glands. They are located all over the body, with the highest concentrations on the palms and soles of the feet. These glands are responsible for most of what people think of as perspiration.

6.Apocrine glands are located in the armpits, groin, and around the nipples. They secrete a more viscous, cloudy product and become active at puberty. The presence of bacteria in these glands sometimes causes a noticeable scent, which is part of why some people give off an obvious smell when they sweat. It has been hypothesized that these glands secrete pheromones, which can potentially communicate signals to others by affecting their hormonal levels.

Ans 20: Negative Feedback

1. The usual means of maintaining homeostasis is a general mechanism called a negative feedback loop. The body senses an internal change and activates mechanisms that reverse, or negate, that change.

2. Negative feedback is body temperature regulation. If blood temperature raises too high, this is sensed by specialized to neurons in the hypothalamus of the brain. They signal other nerve centers, which in turn send signals to the blood vessels of the skin. As these blood vessels dilate, more blood flows close to the body surface and excess heat radiates from the body. If this is not enough to cool the body back its set point, the brain activates sweating. Evaporation of sweat from the skin has a strong cooling effect, as we feel when we are sweaty and stand in front of a fan.

3.If the blood temperature falls too low, on the other hand, this is also sensed by the hypothalamus and signals are sent to the cutaneous arteries (those supplying the skin) to constrict them. Warm blood is then retained deeper in the body and less heat is lost from the surface. If this is inadequate, then the brain activates shivering. Each muscle tremor in shivering releases heat energy and helps warm the body back toward its 37 degrees Celsius set point.

4. In both cases, specialized neurons sense the abnormal body temperature and activate corrective negative feedback loops that return the temperature to normal. As a result, body temperature seldom goes more than0 .5 degrees Celsius above or below its set point. Other negative feedback loops regulate blood sugar concentration, water balance, pH, and countless other variables. Many such loops are regulated by the nervous system and others by the hormones of the endocrine system.

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