Regulation of the Internal Regulation of the Internal EnvironmentEnvironment

By:By: Tony Chung, Kani Cheung, Tony Chung, Kani Cheung, Keng Lam, and Rebecca YangKeng Lam, and Rebecca Yang

Don’t panic! It’s gonna be fun!!!Don’t panic! It’s gonna be fun!!!

What? Homeostasis?What? Homeostasis?

Homeostasis is defined as the Homeostasis is defined as the internal balance condition of the internal balance condition of the body.body.

Regulators: they use internal Regulators: they use internal mechanisms to regulate the mechanisms to regulate the temperaturetemperature

Conformers: their internal condition Conformers: their internal condition varies with the outside temperaturevaries with the outside temperature

Mechanisms of HomeostasisMechanisms of Homeostasis

ReceptorReceptor

Control Center Control Center

EffectorsEffectors

Ok, what about Ok, what about thermoregulation?thermoregulation?

Thermoregulation is the process by Thermoregulation is the process by which the animals maintain the internal which the animals maintain the internal temperature within a set of range.temperature within a set of range.

Endotherms and EctothermsEndotherms and Ectotherms

Animals can be classified by their Animals can be classified by their use of metabolic heat. Some animals use of metabolic heat. Some animals are endotherms and others are are endotherms and others are ectotherms.ectotherms.

Endotherms use metabolism to Endotherms use metabolism to generate heat and regulate their generate heat and regulate their body temperature. Endotherms have body temperature. Endotherms have higher metabolic rates.higher metabolic rates.

Ectotherms do not rely on Ectotherms do not rely on metabolism for heat, instead they metabolism for heat, instead they gain most of their heat from their gain most of their heat from their environment. Ectotherms can environment. Ectotherms can survive greater temperature survive greater temperature variations.variations.

Four Physical Processes of Heat Four Physical Processes of Heat ExchangeExchange

All organisms exchange heat by All organisms exchange heat by four physical processes: four physical processes: Conduction, convection, Conduction, convection, radiation, and evaporation.radiation, and evaporation.

Conduction is the direct transfer Conduction is the direct transfer of heat between objects in direct of heat between objects in direct contact with each other.contact with each other.

Convection is the transfer of Convection is the transfer of heat by the movement of air or heat by the movement of air or liquid.liquid.

Radiation is the transfer of heat Radiation is the transfer of heat between objects that are not in between objects that are not in direct contactdirect contact

Evaporation removes heat from Evaporation removes heat from the surface of a liquid that is the surface of a liquid that is losing its molecules as gas.losing its molecules as gas.

Balancing Heat loss and GainBalancing Heat loss and Gain

The goal of thermoregulation is to balance the rate The goal of thermoregulation is to balance the rate of heat gain and heat loss. All endotherms and of heat gain and heat loss. All endotherms and some ectotherms thermoregulate. If the heat some ectotherms thermoregulate. If the heat management is unbalanced, the animal becomes management is unbalanced, the animal becomes too hot or too cold. too hot or too cold.

To prevent this, animals have five general To prevent this, animals have five general categories of thermoregulation adaptations: categories of thermoregulation adaptations: Insulation, Circulatory Adaptations, Cooling by Insulation, Circulatory Adaptations, Cooling by Evaporative Heat Loss, Behavioral Responses, and Evaporative Heat Loss, Behavioral Responses, and Adjusting Metabolic Heat Production.Adjusting Metabolic Heat Production.

InsulationInsulation

Insulation is a very energy Insulation is a very energy efficient and dependable efficient and dependable adaptation in mammals and birds adaptation in mammals and birds that reduce the flow of heat that reduce the flow of heat between the animals and the between the animals and the environment. Some examples of environment. Some examples of insulation are feathers, hair, and insulation are feathers, hair, and fat layers. fat layers.

Mammals that live in the water Mammals that live in the water rely on fat layers and don’t have rely on fat layers and don’t have fur or feathers because fur and fur or feathers because fur and feathers loses a lot of its feathers loses a lot of its insulating powers when wet.insulating powers when wet.

Circulatory AdaptationsCirculatory Adaptations Circulatory adaptations allows animals to Circulatory adaptations allows animals to

alter the amount of blood flowing between alter the amount of blood flowing between the body core and the skin. Circulatory the body core and the skin. Circulatory adaptations are present in many endotherms adaptations are present in many endotherms and some ectothermsand some ectotherms

One type of circulatory adaptation is the use One type of circulatory adaptation is the use of vasodilation and vasoconstriction. of vasodilation and vasoconstriction. Vasodilation is the increase of the diameter Vasodilation is the increase of the diameter of blood vessels to allow more blood flow. of blood vessels to allow more blood flow. Vasoconstriction is the decrease of the Vasoconstriction is the decrease of the diameter of blood vessels to reduce blood diameter of blood vessels to reduce blood flow.flow.

This aids in heat exchange because colder This aids in heat exchange because colder blood can be kept away from the body core blood can be kept away from the body core and warmer blood can be kept away from and warmer blood can be kept away from the skin and near the body core.the skin and near the body core.

Circulatory AdaptationsCirculatory Adaptations

Another type of circulatory Another type of circulatory adaptation is the arrangement of adaptation is the arrangement of blood vessels called a blood vessels called a countercurrent heat exchanger. A countercurrent heat exchanger. A countercurrent heat exchanger is countercurrent heat exchanger is important for the reduction of heat important for the reduction of heat loss in many marine mammals loss in many marine mammals and birds. and birds.

Blood can either go through the Blood can either go through the heat exchanger or bypass it by heat exchanger or bypass it by going through other blood going through other blood vessels. Many large, powerful vessels. Many large, powerful swimmers need this adaptation swimmers need this adaptation for sustained swimming.for sustained swimming.

Cooling by Evaporative Heat LossCooling by Evaporative Heat Loss

When the environment is warmer When the environment is warmer than body temperature, animals than body temperature, animals gain heat from the environment in gain heat from the environment in addition to their own heat addition to their own heat generated by metabolism. If generated by metabolism. If nothing regulates this, the body nothing regulates this, the body temperature would rise too temperature would rise too rapidly, one way to counter this is rapidly, one way to counter this is evaporative heat loss. evaporative heat loss.

Animals have various adaptations Animals have various adaptations to this including sweating, to this including sweating, panting, and bathing. When water panting, and bathing. When water evaporates, it carries a significant evaporates, it carries a significant amount of heat with it.amount of heat with it.

Behavioral ResponsesBehavioral Responses

Both endotherms and Both endotherms and ectotherms use behavioral ectotherms use behavioral responses to control body responses to control body temperature. Ectotherms temperature. Ectotherms control body temperature control body temperature mainly by behavioral mainly by behavioral responses, i.e. moving into responses, i.e. moving into shade when hot and into sun shade when hot and into sun when cold.when cold.

More extreme behavioral More extreme behavioral responses include hibernation responses include hibernation or migration.or migration.

Adjusting Metabolic Heat Adjusting Metabolic Heat ProductionProduction

ShiveringShivering Nonshivering Thermogenesis: mitochondriaNonshivering Thermogenesis: mitochondria Brown FatBrown Fat

Adjusting Metabolic Heat ProductionAdjusting Metabolic Heat Production

Endotherms usually have a warmer body Endotherms usually have a warmer body temperature than their environment, so they temperature than their environment, so they must be able to counteract the constant amount must be able to counteract the constant amount of heat loss from radiation. Animals cannot of heat loss from radiation. Animals cannot decrease their rate of metabolism so their only decrease their rate of metabolism so their only option is to produce more heat as they lose option is to produce more heat as they lose more heat.more heat.

In some mammals, a hormone can cause In some mammals, a hormone can cause mitochondria in cells to produce heat instead of mitochondria in cells to produce heat instead of ATP, this is called nonshivering thermogenesis ATP, this is called nonshivering thermogenesis (NST). (NST).

Some mammals have a tissue called “brown fat” Some mammals have a tissue called “brown fat” in the neck and between the shoulders for rapid in the neck and between the shoulders for rapid heat production.heat production.

Animals can also shiver and perform NST to Animals can also shiver and perform NST to increase heat production by as much as 5-10 increase heat production by as much as 5-10 times than normal.times than normal.

Temperature Temperature Regulation of Your Regulation of Your

BodyBody

How to face the changing How to face the changing temperature?temperature?

It is all about the physiological It is all about the physiological response acclimatization!!!response acclimatization!!!

Hibernation and EstivationHibernation and Estivation

                                                                             

Common diseases and disorders Common diseases and disorders involving thermoregulationinvolving thermoregulation

FeverFever—Increase in body core temperature. Fever is not an —Increase in body core temperature. Fever is not an illness but a natural reaction to a number of illnesses. illness but a natural reaction to a number of illnesses.

HyperthermiaHyperthermia—Overheating of the body caused only by an —Overheating of the body caused only by an external factor, as for example a hot environment, or a hot bath. external factor, as for example a hot environment, or a hot bath.

HypothermiaHypothermia—A low body temperature, as caused by exposure —A low body temperature, as caused by exposure to cold weather or a state of low temperature of the body to cold weather or a state of low temperature of the body induced by decreased induced by decreased metabolismmetabolism. .

HypothyroidismHypothyroidism—Hypothyroidism refers to a condition in which —Hypothyroidism refers to a condition in which the amount of thyroid hormones in the body is below normal. the amount of thyroid hormones in the body is below normal. Since the thyroid hormones are important in thermoregulation, Since the thyroid hormones are important in thermoregulation, hypothyroidism affects the body's capacity to control hypothyroidism affects the body's capacity to control temperature. temperature.

Source from E-notes.com Incorporation

Human Temperatures Variation Human Temperatures Variation ChartChart

37°C (98.6°F)37°C (98.6°F) - Normal body temperature (which varies between about 36-37.5°C (96.8-99.5°F) - Normal body temperature (which varies between about 36-37.5°C (96.8-99.5°F) 35°C (95.0°F)35°C (95.0°F) - (Hypothermia) is less than 35°C (95.0°F) - Intense shivering, numbness and - (Hypothermia) is less than 35°C (95.0°F) - Intense shivering, numbness and

blueish/greyness of the skin. There is the possibility of heart irritability. blueish/greyness of the skin. There is the possibility of heart irritability. 33°C (91.4°F)33°C (91.4°F) - Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of - Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of

shivering, slow heart beat, shallow breathing. Shivering may stop. Subject may be unresponsive to shivering, slow heart beat, shallow breathing. Shivering may stop. Subject may be unresponsive to certain stimuli. certain stimuli.

becoming comatose. Shivering is absent (subject may even think they are hot). Reflex may be becoming comatose. Shivering is absent (subject may even think they are hot). Reflex may be absent or very slight. absent or very slight.

31°C (87.8°F)31°C (87.8°F) - Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and - Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems. slow heart rate. Possibility of serious heart rhythm problems.

28°C (82.4°F)28°C (82.4°F) - Severe heart rhythm disturbances are likely and breathing may stop at any time. - Severe heart rhythm disturbances are likely and breathing may stop at any time. Patient may appear to be dead. Patient may appear to be dead.

24-26°C (75.2-78.8°F) or less24-26°C (75.2-78.8°F) or less - Death usually occurs due to irregular heart beat or respiratory arrest; - Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have to been known to survive with body temperatures as low as 14°C however, some patients have to been known to survive with body temperatures as low as 14°C (57.2°F) (57.2°F)

39°C (102.2°F)39°C (102.2°F) (Pyrexia) - Severe sweating, flushed and very red. Fast heart rate and (Pyrexia) - Severe sweating, flushed and very red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and epileptics may be very breathlessness. There may be exhaustion accompanying this. Children and epileptics may be very likely to get convulsions at this point. likely to get convulsions at this point.

41°C (105.8°F)41°C (105.8°F) - (Medical emergency) - Fainting, vomiting, severe headache, dizziness, confusion, - (Medical emergency) - Fainting, vomiting, severe headache, dizziness, confusion, hallucinations, delirium and drowsiness can occur. There may also be palpitations and hallucinations, delirium and drowsiness can occur. There may also be palpitations and breathlessness. breathlessness.

43°C (109.4°F)43°C (109.4°F) - Normally death, or there may be serious brain damage, continuous convulsions and - Normally death, or there may be serious brain damage, continuous convulsions and shock. Cardio-respiratory collapse will occur. shock. Cardio-respiratory collapse will occur.

44°C (111.2°F) or more44°C (111.2°F) or more - Almost certainly death will occur; however, patients have been know to - Almost certainly death will occur; however, patients have been know to survive up to 46°C (114.8°F). survive up to 46°C (114.8°F).

Source from BookRags.com Incorporation

Thank you for paying attention!!!Thank you for paying attention!!!

Now let’s talk about the Osmoregulation…Now let’s talk about the Osmoregulation…

Organisms balance the gain and Organisms balance the gain and loss of water and regulate solute loss of water and regulate solute

concentrationsconcentrations

The main function of Osmoregulation is to maintain the form The main function of Osmoregulation is to maintain the form of cellular cytoplasmof cellular cytoplasm

Transport epithelium are layers of specialized epithelial cells Transport epithelium are layers of specialized epithelial cells that regulate solute movements they move specific solutes in that regulate solute movements they move specific solutes in controlled amounts in specific directions. controlled amounts in specific directions.

Drinking seawater brings a lot of salt into the body, birds for Drinking seawater brings a lot of salt into the body, birds for example, achieve a net gain of water example, achieve a net gain of water

Seagulls deal with a high salt diet by secreting salt through Seagulls deal with a high salt diet by secreting salt through their nostrils a way of getting rid of high sodium chloride their their nostrils a way of getting rid of high sodium chloride their nasal salt glands secrete fluid much more saltier than the ocean.nasal salt glands secrete fluid much more saltier than the ocean.

Transport epithelia in excretory organs have a dual function of Transport epithelia in excretory organs have a dual function of maintaining water balance and disposing metabolic wastesmaintaining water balance and disposing metabolic wastes

Waste produced by animals effect the water quality Waste produced by animals effect the water quality and balance depending on type and qauntity and balance depending on type and qauntity

The most important waste products are nitrogenous The most important waste products are nitrogenous breakdown products of proteins and nucleic acids. breakdown products of proteins and nucleic acids.

The amount of waste and type of waste can create an The amount of waste and type of waste can create an animal’s living condition and habitat. Although some animal’s living condition and habitat. Although some animals can change their form of nitrogenous waste animals can change their form of nitrogenous waste depending on their adaptation to a new environment. depending on their adaptation to a new environment.

There are different types of waste secreted from There are different types of waste secreted from animals Urea, Ammonia, and Uric acid. animals Urea, Ammonia, and Uric acid.

Filtration – The extracting of water & small solutes Filtration – The extracting of water & small solutes (Metabolic wastes from body fluids into the excretory (Metabolic wastes from body fluids into the excretory system). system).

Reabsorption – Essential small molecules are Reabsorption – Essential small molecules are recovered from the filtrate and returned to the body recovered from the filtrate and returned to the body fluids as it flushes out waste. fluids as it flushes out waste.

Secretion – The discharge of wastes from the body Secretion – The discharge of wastes from the body fluid into the filtrate. fluid into the filtrate.

Excretion – The disposal of nitrogen – containing Excretion – The disposal of nitrogen – containing waste products of metabolism. waste products of metabolism.

The mammalian kidney uses its ability to The mammalian kidney uses its ability to adjust to both the volume and osmolarity of adjust to both the volume and osmolarity of Urine. The kidney contains blood flow which Urine. The kidney contains blood flow which contains nutrients that can be absorbed and contains nutrients that can be absorbed and circle in the circulatory system. circle in the circulatory system.

The mammalian excretory systemThe mammalian excretory system

(a) Excretory organs and major associated blood vessels

The mammalian excretory systemThe mammalian excretory system

(b) Kidney structures

The mammalian excretory systemThe mammalian excretory system

(c) Nephron

The mammalian excretory systemThe mammalian excretory system

(d) Filtrate and blood flow

Three feedback mechanismsThree feedback mechanisms

(1)(1) Antidiuretic Hormone (ADH)Antidiuretic Hormone (ADH)

A hormone produced in the hypothalamus and release from the posterior A hormone produced in the hypothalamus and release from the posterior pituitary. It promotes water retention by the kidneys as part of an elaborate pituitary. It promotes water retention by the kidneys as part of an elaborate feedback scheme that helps regulate the osmolarity of the blood.feedback scheme that helps regulate the osmolarity of the blood.

(2)(2) Renin-angiotensin-aldosterone system (RAAS)Renin-angiotensin-aldosterone system (RAAS)

A part of a complex feedback circuit that helps regulate blood pressure and A part of a complex feedback circuit that helps regulate blood pressure and blood volume.blood volume.

(3)(3) Atrial natriuretic factor (ANF)Atrial natriuretic factor (ANF)

A peptide hormone that opposes the Renin-angiotensin-aldosterone system A peptide hormone that opposes the Renin-angiotensin-aldosterone system (RAAS).(RAAS).

The nephron and collecting duct: regional The nephron and collecting duct: regional functions of the transport epitheliumfunctions of the transport epithelium

The numbered regions in this diagram are keyed to the circled numbers in the

text discussion of kidney function.

From Blood Filtrate to UrineFrom Blood Filtrate to Urine

(1)(1) Proximal tubuleProximal tubule

(2)(2) Descending limb of the loop of HenleDescending limb of the loop of Henle

(3)(3) Ascending limb of the loop of HenleAscending limb of the loop of Henle

(4)(4) Distal tubuleDistal tubule

(5)(5) Collecting ductCollecting duct

How the human kidney concentrates urine: the two-solute How the human kidney concentrates urine: the two-solute model.model.

Two solutes contribute to the osmolarity of the interstitial fluid: NaCl and urea. The loop of Henle maintains the interstitial gradient of NaCl, which increase in the descending limb and decrease in the ascending limb. Urea diffuses into the interstitial fluid of the medulla from the collecting duct. The filtrate makes three trips between the cortex and medulla. As the filtrate flows in the collecting duct past interstitial fluid of increasing osmolarity, more water moves out the duct by osmosis, thereby concentrating the solutes, including urea, that are left behind in the filtrate.

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