negative feedback control of core body temp.

Question 1

what are the 3 components of a negative feedback system

Answer 1

sensors, control centre and effector(s)

Question 2

what are the components of this negative feedback system

Answer 2

sensors = central(abdomen) and peripheral(skin) thermoreceptors
control centre = in hypothalamus
effectors = skeletal muscles, skin arterioles and sweat glands

Question 3

describe the role of the hypothalamus in this negative feedback system

Answer 3

has a variety of neural inputs, including those from thermoreceptors, acts as body’s thermostat

Question 4

describe the effector response if the hypothalamus detects cold

Answer 4

vasoconstriction of skin arterioles(decreased heat loss), increased muscle tone, shivering(increase heat production)

Question 5

describe the effector response if the hypothalamus detects warmth

Answer 5

vasodilation of skin arterioles, sweating(increased heat loss), decreased muscle tone, decreased voluntary movement(decreased heat production)

Question 6

describe the effect fever has on the hypothalamus and how it effects the negative feedback system

Answer 6

chemicals released from WBC’s in response to infection cause reset of thermostat at a higher temp., hypothalamus initiates mechanisms to heat body so temp. increases to new set point causing fever

Question 7

describe what is meant by hyperthermia

Answer 7

extreme uncontrolled increase in body temp., elevation of temp. above accepted range due to failure of regulatory mechanisms, above 40

Question 8

describe what is meant by hypothermia

Answer 8

drop in body temp. below that required for cell metabolism and function, below 35