Thermoregulation

Question 1

define Thermoregulation

Answer 1

maintenance of a constant body temperature through balancing heat production (thermogenesis) and heat loss (thermolysis)

Question 2

Optimum temperature and why?

Answer 2

37 degrees for optimal enzyme function

Question 3

How is heat produced (1) and how is it lost (4)

Answer 3

heat produced through cellular respiration and lost through radiation (warm body to the cooler environment), conduction (heat goes from hotter to colder), convection (warm heat air rises and is replaced by colder air) and evaporation (heat used to turn water to water vapor)

Question 4

What affects the rate of evaporation(3)

Answer 4

temperature- higher temp= more heat for water to water vapor
air movement- disperse water vapor and increase rate of evaporation
low humidity- higher concentration gradient- increased evaporation (sweating)

Question 5

Skin Diagram (3 Layers)
(10+ functions)

Answer 5

Epidermis-hair shaft and erector muscle (not functional as humans have less)
sebaceous gland to waxy lubricate skin
Meissner’s corpuscle- small vibrations
malphigian layer- prevent water loss

dermis- sweat gland, pore, duct- allow for water vapor to leave the body and cool
Thermoreceptors- krause detects decreased temp and Ruffini detects an increase
Pacinian detects pressure and high vibrations
blood vessels- vasoconstriction/ dilation

subcutaneous fat layer- doesn’t conduct heat but insulates heat from escaping through conduction and radiation

Question 6

What are thermoreceptors needed for?

Answer 6

allow to adapt to environmental temperature changes

Question 7

Explain vasoconstriction

Answer 7

the hypothalamus is stimulated (receptor) by a decrease in blood temp and Krause sends impulse
hypothalamus sends impulses to the blood vessels and constricts circular muscles (effectors) and this pushes blood through the relaxed sphincter and shunt vessels in the subcutaneous layer to prevent heat loss through radiation and conduction. less evaporation as heat from blood doesn’t go to the sweat gland- this keeps heat in the body and returns to setpoint

Question 8

Hypothermia?

Answer 8

body temp below 35 due to prolonged cold- to prevent enzymes from working- and impaired brain function which leads to cardiac arrest amd coma

Question 9

Vasoconstriction diagram

Answer 9

capillaries are small and circular muscles constricted- high blood flow
blood flows through relaxed shunt vessels in the subcutaneous layer
decreased heat loss

Question 10

How is heat maintained on a cold day?

Answer 10

decreased heart rate to allow warm blood to flow for longer
shallow breathing to allow less cold air in the lungs
adipose tissue after vasoconstriction insulates blood heat from leaving the body

Question 11

Explain Vasodilation

Answer 11

the hypothalamus is stimulated by increased blood temp and Ruffini corpuscle impulses
hypothalamus send impulses to inhibit impulses to stop constriction of the circular muscles which allows blood to flow to capilaries
sphincter muscle and shunt vessel constricted allowing blood to epidermis- more heat lost to radiation and conduction and blood heat used by sweat glands to turn water into water vapour to cool the body

Question 12

Explain Hyperthermia

Answer 12

prolonged heat exposure- the thermoregulatory system doesn’t function- sunstroke

Question 13

Vasodialation diagram?

Answer 13

capillaries dilated and circular muscles relaxed- low blood flow
blood flow through constricted shunt vessel in the subcutaneous layer
increased heat loss