homeostasis

Question 1

homeostasis

Answer 1

-maintenance of a constant internal environment

Question 2

negative feedback

Answer 2

-the mechanism that counteracts changes in the internal environment and restores it towards the set norm

Question 3

main functions of the skin

Answer 3

-barrier to prevent entry of bacteria into the body
-separates the internal body from the environment
-thermoregulation that enables human body temperature to remain close to set point of 37ºc

Question 4

structure 1 - sweat glands

Answer 4

-secrete sweat onto surface of skin, which evaporates and removes latent heat of vaporisation, cooling the body down

Question 5

structure 2 - temperature receptors

Answer 5

-sense/ detect the temperatures of the surrounding skin, and generate nerve impulses to be sent to the nervous system

Question 6

structure 3 - blood vessels

Answer 6

-arterioles and venules located in the fatty tissue layer of the skin
-arterioles are capable of vasoconstriction and vasodilation to control the amount of blood flowing through the capillaries near the surface of the skin

Question 7

structure 4 - fat tissue

Answer 7

-provides add thermal insulation and protection against mechanical shock

Question 8

when body temperature rises above norm of 37ºc,

Answer 8

-caused by high air temperature/ exercise
-the higher temperature is detected by the hypothalamus (internal body temperature)/ thermoreceptors of skin (temperature of surroundings)
-nerve impulses are sent from the hypothalamus to a number of effectors
-vasodilation of arteriole increases blood flow per unit time to capillaries near skin surface to increase heat loss via conduction, convection and radiation
-sweat glands more active increasing sweat production, more evaporation of sweat, more heat loss via latent heat of vaporisation
-decreased metabolic activity
-body temperature falls back towards norm of 37ºc

Question 9

when body temperature falls below norm of 37ºc,

Answer 9

-caused by low air temperature/ drinking cold drinks
-the lower temperature is detected by the hypothalamus (internal body temperature)/ thermoreceptors of skin (temperature of surroundings)
-nerve impulses are sent from the hypothalamus to a number of effectors
-vasoconstriction of arteriole decreases blood flow per unit time to capillaries near skin surface to decrease heat loss via conduction, convection and radiation
-sweat glands less active decreasing sweat production, less evaporation of sweat, less heat loss via latent heat of vaporisation
-shivering releases heat
-increased metabolic activity
-contraction of hair erector muscle, resulting in hairs in skin standing on end to trap insulting pockets of air
-body temperature rises back towards norm of 37ºc