Homeostatic regulation of body temperature

Question 1

what are ectotherms ?

Answer 1

• animals classified as cold blooded
• depend on external environment to survive
• e.g. reptiles

Question 2

what are endotherms ?

Answer 2

• animals that use thermoregulation to manatin constant internal temperature, even when external temparature changes
• it is crucial for life
• e.g. humans

Question 2

what are endotherms ?

Answer 2

• animals that use thermoregulation to manatin constant internal temperature, even when external temparature changes
• it is crucial for life
• e.g. humans

Question 3

Why is temperature regulation important?

Answer 3

• for metabolic processes to occur
• these metabolic processes are responsible for energy production

Question 4

what happens when someone has hypothermia ?

Answer 4

• decrease vital signs (lower heart rate, respiratory rate)
• drowsy (not feeling cold anymore, just sleepy)
• Coma (loosing consciouness)
• death

Question 5

what is a Hypothalamus and what does it do ?

Answer 5

• Part of the brain
• Control centre for temeperaure regulation
• Ajjutonomic nervous system to stimulate various organs such as the skeletal muscle to generate heat

Question 6

What is the range of normal body temperature ?

Answer 6

35.6 - 37.8 degrees

Question 7

Homeostatic control – temperature regulation in cold environment

Answer 7

• Blood temperature drops
• a signal is sent to the hypothalamus
• signal stimulates skeletal muscles to shiver and constriction of BV in skin

Question 8

How does skeletal muscle generate heat?

Answer 8

• muscle activity generates heat as a by product
• ATP is used to power muscle contraction - (75% of the energy used for the contraction escapes as heat)
• skeletal muscle is mist abundant muscle tissue in the body so it is responsible for the generation of most heat

Question 9

How does skeletal muscle generate heat?

Answer 9

• muscle activity generates heat as a by product
• ATP is used to power muscle contraction - (75% of the energy used for the contraction escapes as heat)
• skeletal muscle is mist abundant muscle tissue in the body so it is responsible for the generation of most heat

Question 10

How does the liver generate heat ?

Answer 10

• the liver is the primary site of metabolism
• Heat generated can be transferred to the rest of the body
• This happens because Liver has high blood supply which warms up by liver by conduction method.
• The warm blood then circulates round the rest of the body
  *

Question 11

how does adrenalin generate heat ?

Answer 11

• produced by the adrenal gland
• Increased production of adrenaline increases the metabolic rate in different target tissues = increased heat !!!

Question 11

how does adrenalin generate heat ?

Answer 11

• produced by the adrenal gland
• Increased production of adrenaline increases the metabolic rate in different target tissues = increased heat !!!

Question 12

how do thyroid glands affect body temeparure ?

Answer 12

• internal temperature regulation
• When issues arise,perception may be altered – so person may feel cold/hot when they are not.

Question 12

how do thyroid glands affect body temeparure ?

Answer 12

• internal temperature regulation
• When issues arise,perception may be altered – so person may feel cold/hot when they are not.

Question 13

thyroid gland and the sympathetic nervous system when exposed to cold

Answer 13

• Glucose uptake by skeletal muscle is increased
• Glucogenesis by the liver is increased
• Thermogenesis occurs in Brown Adipose Tissue (brown fat)
• Lipolysis occurs in white adipose tissue (white fat)

And core body temperature is raised.

Question 14

Other factors effecting Thyroids regulation of body temperature

Answer 14

1. Low levels of seratonin and dopamine
2. Low serotonin can lead to low TSH and low body temperature.

Question 15

what are the stages that one can go through when they have hyperthermiab (heatstroke) ?

Answer 15

1. Excessive heating caused by hot environment or intensive exercise
2. Patient feels confused, has red skin, headache and is dizzy
3. Patient can loose consciousness if not treated
4. Can result in Death

Question 16

Heat loss mechanisms

Answer 16

• Most heat loss occurs in the skin in 2 ways :
• radiation= when the body temeperature increases past the set point.
• evaporation = sweating

Question 16

Heat loss mechanisms

Answer 16

• Most heat loss occurs in the skin in 2 ways :
• radiation= when the body temeperature increases past the set point.
• evaporation = sweating

Question 17

why does fever occur ?

Answer 17

• infection
• cancer
• allergic reactions
• central nervous system injuries

therefore

Macrophages, white blood cells and injures tissue cells release PYROGENS.

Question 18

what is the effect of pyrogens ?

Answer 18

• act on the hypothalamus to raise the set point (so body temperature can rise above 37 degrees)
• This causes blood vessels in skin to constrict (makes skin feel cold,clammy)
• new thermostatic “fever” setting - maintained until the natural body defences neutralise the threat or you are treated with a drug.

Question 19

Why is mild/short term fever useful ?

Answer 19

• trigger the immune system
• Some immunological and biochemical pathways work more efficiently at slightly raised temperatures

Question 20

how does aginig affect homeostasis / body temperature ?

Answer 20

• slower metabolic rate
• those above 65 tend to have lower baseline temperatures

Question 21

name thigs that can affect body temepraure

Answer 21

• aging
• stress
• feeding
• smoking
• drugs
• Menopausal hot flashes