TITTLE: TEMPERATURE REGULATION IN
VERTEBRATES:
GOVT, GIRLS, DEGREE
COLLEGE NUSHKI
SUBMITTED BY: SANIA MENGAL
SUBMITTED TO: MAAM MAHZAIB
SUBJECT: ANIMAL FORM AND
FUNCATION II
SEMESTER: 4TH
DEPARTMENT: ZOOLOGY
SUBMISSION DATE: 30 - SEP-2024
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SERIAL NO: CONTENTS PAGE NO:
1. INTRODUCTION 3
2. DEFINATION 3
3. THERMOREGULATION IN FISHES 3
4. THERMOREGULATION IN AMPHIBIAN 4
5. THERMOREGULATION IN REPTILES 4
6. THERMOREGULATION IN BIRDS 5
7. THERMOREGULATION IN MAMMALS 6
8. CONCLUSION 7
9. REFERANCE 8
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INTRODUCTION:
Body temperature is one of the most important factors influencing animal function. Vertebrate
animals generally regulate their body temperatures within quite narrow limits, but use different
mechanisms to achieve this stability. In some circumstances, maintaining a high stable body
temperature is not possible and several vertebrate groups have involved adaptive responses, such as
torpor and hibernation, to overcome these problems.
DEFINATION::
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries,
even when the surrounding temperature is very different
On the basis of heat that influences their body temperature, animals can be classified into:
ECTOTHERMS: they rely primarily on external environment to regulate their body temperature.
They have low metabolic rate. E.g. Reptiles, fish, amphibians (poikilotherms)
ENDOTHERMS: can regulate their body temperature by producing heat within their body. They
have high metabolic rate E.g. Mammals, Birds (Homeotherms)
thermoregulation in
THERMOREGULATION IN FISHES:
cold blooded, core body temperature is close to environment.two types of thermoregulation:
Behavioural thermoregulation and physiological thermoregulation.
Behavioural thermoregulation:
As ectotherms, fish exclusively rely on behavioural strategies for thermoregulation.It occurs when
fish actively seeks out areas of higher or lower temperature.The movement may occur from surface to
the downward or vice versa. Like other vertebrates, fish sense water temperature using
thermoreceptors in trigeminal and dorsal root ganglia neurons that innervate the skin.Sockeye Salmon
(Oncorhynchus nerka)crepuscular feeders, meaning they hunt for food – and therefore feed only at
dawn(after that they move 11m deep, 15°C temp.) and dusk(after that they retreats to 30m depth ,5°C
temperature). During the full day and the full night they rest.
Physiological thermoregulation:
fish controls its core body temperature by means of internal physiological and metabolic activities. It
is rare in fish, occurs in only a few species – all of which are marine and swim constantly. Heat
exchange takes place at rete mirabile(network of capillaries b/w swimming red muscles).Heat from
red swimming muscles transported to blood. Warm blood in veins transfers the heat to blood in
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arteries. The blood in both vessels flow in opposite direction due to which the process becomes
efficient. No body heat is lost. Body temp. Rise from 5-14°C to environment. Occurs in sharks and
tuna.
THERMOREGULATION IN AMPHIBIANS:
assumes the temp. Of the water when submerged. On land-the body temperature can differ from that
of the environment.Temp. Lowers due to evaporative loss across the thin skin and temperature rises
because of radiations from the sun and from the warm surfaces. To prevent overheating-many
amphibians are nocturnal and will hide in shady areas.Ectotherms and have difficulty in controlling
body heat as they produce less of it metabolically and rapidly lose most of it.
■ However behavioural adaptations enable them to maintain their body temp. Within a
homeostatic range most of the time.
■ Exchange oxygen and carbon dioxide across their skin surface and this moisture layer act as a
natural evaporative system.
■ The problem of heat loss through evaporation limits the habitats and activities of amphibians
to warm, moist areas
■ Bull frogs can vary the amount of mucus they secret from their body surface, a physiological
response that helps regulate evaporative cooling.
■ Change their colour darker in cooling environment and lighter in warmer environment.
THERMOREGULATION IN REPTILES:
The most noticeable process in a reptile affected by thermoregulation is their behaviour.
■ Reptiles need to thermoregulate because they cannot maintain their body temperature by
producing metabolic heat.
they rely on external conditions to regulate the temperature of their bodies
■ This can be done directly by basking in the sun or indirectly by soaking up the heat from a hot
surface such as a rock. When a reptile needs to cool down, they can retreat into the shade.
■ A snake can control how much heat it absorbs from the sun by coiling or straightening its
body. A stretched-out snake has more surface area to absorb heat while a coiled snake will
have less surface area exposed.
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■ some species of snake are coiled around their eggs, they shiver to raise the temperature of the
eggs.
Tortoises and turtles can cool themselves through salivating and frothing at the mouth.
■ Reptiles also thermoregulation via heat production in response to hormones-Thyroxine and
epinephrine.
■ Many reptiles endure cold temperature by hibernating in large groups as the temperature Is
too cold for them to function properly so they retreat to a warm area To keep their body
temperature Up until the temperature rise again.
THERMOREGULATION IN BIRDS:
They are endotherms and have special mechanism of increasing their body temperature by heat
generation within their tissues.
■ Don’t have sweat gland and they lose heat from gular pouches in throat.
■ Birds can behaviourally thermoregulation to some extent to reduce heat loss. The most
conspicuous behaviour is migration to a warmer climate.
■ In cold environments some birds “hunch down” and/or reduce surface area heat loss by
tucking the head(grebes) under the wing or body feathers.
In many species feathers provide insulation
■ Some birds have the ability to allow their body temperatures to drop-become torpid under
certain circumstances.
■ Aquatic species have rete mirabile in legs and feet which transfer heat from the outgoing (hot)
blood in the arteries to the incoming (cold) blood in the veins.
■ As temperature fluctuates they either expose themselves in the sun or seek shades.
THERMOREGULATION IN MAMMALS:
Endothermic, Depending on the mammal, there are a few ways to regulate body temperature:
Goosebumps – this slows the airflow over the skin and reduces the amount of heat loss.
Thick skin or blubber – this gives the animal an extra layer of protection in harsh conditions, such as
polar bears.
Shivering: this generates heat to keep the body warm
Sweating – this allows for evaporative cooling to bring down the body temperature.
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Panting –an animal breathes rapidly and shallowly with its mouth open to increase evaporation from
the surfaces of the mouth.
■ Opening capillaries – the capillaries of the skin can open up and allow heat to escape,
cooling off the body
Adjusting fur – animals with fur can either flatten or puff it up to allow more or less air to
get trapped within it.
■ Some mammals, especially hibernators and baby animals, have lots of brown fat which
contains many mitochondria with special proteins that let them release energy.
■ in tails and flippers, blubber is absent, counter-current system Helps In conservation of heat
lose by allowing heat to be transferred From blood vessels containing warmer blood to those
containing cooler blood.
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CONCLUSION:
Finally it can be concluded thatVertebrate thermoregulatory systems are similar in overall
organization. All vertebrates appear to sense surface and core temperatures, compare: these
temperatures with a neuronally mediated reference temperature, and effect appropriate behavioral and
autonomic output responses. Certain differences exist.
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REFERANCE:
https://onlinelibrary.wiley.com/doi/abs/10.1038/npg.els.0001824
https://www.google.com/search?q=temperature+regulation+in+vertebrates&rlz=1C1CHBF_enPK880
PK880&oq=temperature+regulation+in+vertebrates&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCjQ
yMTYxajBqMTWoAgiwAgE&sourceid=chrome&ie=UTF-
8#:~:text=Temperature%20regulation%20in%20vertebrates.
https://academic.oup.com/icb/article-pdf/24/3/791/431875/24-3-791.
https://pubmed.ncbi.nlm.nih.gov/19717669/
https://byjus.com/biology/thermoregulation/
https://www.sciencedirect.com/science/article/abs/pii/S1095643306003047
https://academic.oup.com/icb/article-pdf/24/3/791/431875/24-3-791.pdf
