Thermoregulatory System🌡 Flashcards
What is a pigs normal body temperature?
38.7-38.9 Degrees Celsius
What a humans normal body temperature?
36.1-37.2 Degrees Celsius
What is a dogs normal body temperature?
37.9-39.9 degrees celsius
What is a chickens normal body temperature?
40.6-43 degrees celsius
What are the three components within the feedback loop?
- Receptor- (group of cells which detect stimuli)
- Control centre- (receive and processes information from receptors)
- Effectors- (bring about responses to restore optimum levels)
Define endotherms
- Species that regulate their own constant body temperature are known as endothermic species
Define negative feedback loop
- Each species has their own set temperature which needs to be maintained constant
How do negative feedback loops control temperature?
- Thermoreceptor- (detect body temperature changes)
- Thermoregulatory centre- (hypothalamus receives and processes information from the receptors)
- Effectors- (different mechanisms being about changes to bring body back to set temperature
What is the hypothalamus (control centre for homeostasis) responsible for?
- Thermoregulation
- Osmoregulation
- The release of hormones from the pituitary gland
When an animal gets too hot what centre is activated within the hypothalamus?
- Heat loss centre
When an animal gets too cold what centre is activated within the hypothalamus?
- Heat gain centre
What is thermoregulation?
- To maintain its core internal temperature
What happens within vasoconstriction?
- In colder temperatures, the muscular wall of the arterioles constrict so less blood flows to the capillaries in the surface of skin; retaining heat
What happens within vasodilation?
In warmer temperatures the muscular wall of the arterioles dilate so more blood flows to the surface of the skin, increasing vascular its and aiding heat loss through convection
What is the structure and function of the pilli erector muscles?
- Structure- tiny muscle that attaches to the base of a hair follicle
- Function- to generate heat, the arrector pilli muscles contract
Define endotherm
- When body temperature is regulated by internal sources
Define ectotherm
- When body temperature is regulated by external sources
Define convection
- Heat is transferred through fluid movement
Define radiation
- Heat is transmitted through electromagnetic waves
Define conduction
- Objects touch and share heat
Define evaporation
- Liquids vaporise into gasses and heat is lost
What are the three types of adaptations?
- Physiological (body processes)
- Anatomical (animal shape and structure)
- Behavioural (behaviour for survival strategy)
What are the three selection pressures?
- Stabilising selection pressure (most common trait genes are passed on)
- Directional selection pressure (new advantageous traits to appear)
- Diversifying selection pressure (extreme traits become more common)
What are the two types of variations?
- Advantageous variation
- Speciation
What happens during pilorelaxation?
- Erector muscles relax and the hairs/feathers lower to the skin
What happens within piloerection?
- Pilli erector muscles in the skin cause hairs or feathers to stand on end
What are the three evaporative mechanisms?
- Sweating- glands secrete sweat onto skin where it evaporates and takes heat from body
- Panting- increases heat loss through evaporation from the nasal passages, mouth, lungs and air sacs
- Gular fluttering- birds can rapidly flap membranes in their throat to increase evaporation through the mouth
What is piklotherm?
- Body temperature that fluctuates within the environment
What is homeotherm?
- Body temperature that remains the same
What is metabolic rate
- The time it takes to convert food into energy
What is thermoregulation?
- The control of body temperature
Explain the effect of vasodilation?
- Blood vessels dilate, blood flow increases due to decrease in vascular resistance
- More warm blood at skin surface this leads to increased heat loss/reduced body temperature
- Greater volume of blood at surface leads to sweating
What are two symptoms of hypothermia?
- Shivering
- Cold
What are two symptoms of hyperthermia?
- Sweating
- Panting
Explain how endothermic animals maintain their normal body temperature?
- Sweating/panting leads to evaporative Cooling- this reduces higher body temperature
- Shivering increases metabolic rate- produces heat that raises body temperature
- Pilorection- traps in hairs-furs which insulates preventing heat loss
State two ways animals lose body heat
- Sweat production/sweating through paws
- Panting
- Gular fluttering
Explain how temperature is controlled as part of homeostasis
- The body detects changes and responds to correct them to a ‘set point’ by negative feedback
State the body temperatures of:
- Human: 36.1-37.2
- Dog: 37.9-39.9
Pig: 38.7-37.8
Chicken: 40.6-43.0
Name the parts of the brain that are stimulated when the animal gets:
- Too hot- heat loss centre is activated in the hypothalamus
- Too cold- heat gain centre of the hypothalamus
Describe the effect of vasoconstriction
- Arterioles constrict so less blood flows to the skin which reduces heat
What behavioural mechanisms are used by endotherms in high temperature?
- Stretching out of the body- allows a larger surface area for heat loss
- Seeking shade- and moving less to reduce heat gain
What behavioural mechanisms are used by endotherms in low temperatures?
- Curling up- results in smaller surface area to prevent heat loss
- Moving to warmer areas and increased movement to increase heat gain
Explain three ways endotherms maintain a constant body temperature at low temperatures
- Piloerection- raises hairs or feathers to trap a layer of insulating air to reduce heat loss
- Shivering muscles contract rapidly to produce heat
- Brown adipose tissue found in greater quantities in neonates and hibernating animals uses lipids to generate heat
Discuss how counter-current blood flow functions
- Countercurrent heat exchange is an alternative to insulation on the limbs
(Limbs are very thin and have a large surface area -prone to heat loss) - Arterial blood is warm as it originates from the core of an animal
- Venous blood in the limbs will be cold as it is returning from areas away from the core
- When arteries and veins pass the heat from the arterial blood passes to the venous blood
- Arterial blood entering the peripherals progressively cools down as it moves down the limbs
- The heat is carried back towards the core/heart via the venous blood
- Less heat is lost by the animal
(Meaning that less energy will be required to maintain the core body temperature)
