Physiology 2 Exam 2 Thermoregulation

yulokuko's version from 2016-05-10 10:14



Where are the thermoreceptors locatedperipherally in the skin and centrally in the anterior hypothalamus. Anterior hypothalamus activated by heat. Posterior Hypothalamus activated by cold
What is the sequence of events for thermoregulation (think vague)Sensors monitor skin temp and core temp, send info to the thermoregulatory center, hypothalamus compares input signals with desired set point, coordinates response and either raises or lowers core temp.
How is heat gained/lost?dilation of blood vessels in the skin (loss), Shiver and nonshivering thermogenesis (gain)
What are sweat glands made of?transporting epithelium
How is sweat production regulate?cholinergic sympathetic neurons.
What are the two categories for heat production?(1) unregulated heat production from voluntary muscle contractions and normal metabolic path ways (2) regulated heat production
What is shivering thermogenesis?creation of heat through shivers.
How does shivering thermogenesis work?Signals from the hypothalamic thermoregulatory center initiate skeletal muscle tremors.
How does nonshivering thermogeneis work?Mitochondrial uncoupling in brown fat cells.
How does mitochondrial uncoupling work?Energy flowing through the electron transport system is released as heat rather than being trapped in ATP.
How is mitochondrial uncoupling initiated?cold triggers response in thyroid hormones and increases sympathetic activity.
Where is brown fat located?intrascapular area between shoulder blades.
How do hot flashes occur?decrease in estrogen decrease set point making room temperature feel too hot leading to sweating and flushing of skin.
How does a fever reset the temp set point?toxins from bacteria trigger endogenous pyrogens, pyrogens are fever-producing cytokines, increase hypothalmic set point. Body responds via hypothermia mechanisms.
What is Heat exhaustion?fluid loss; individual cannot maintain adequate sweat rate or circulation
What is Heat Stroke?cessation of sweating and increased core temperature (>41°C; 106°F)
What is Malignant Hyperthermia?body temp becomes too elevated, genetically linked. A defective Ca++ channel in skeletal muscle releases too much Ca++ into cytoplasm causing cell transporters to overwork moving Ca++ back into the mitochondria and sarcoplasmic reticulum. The heat released from ATP hydrolysis substantially raises body temp.
What is Hypothermia? lethal if body temperature drops between 23°C and 25°C