Organ systems working Organ systems working together to maintain together to maintain homeostasishomeostasis

Body’s Mechanisms to maintain Body’s Mechanisms to maintain homeostasis against the change in homeostasis against the change in environmental factorsenvironmental factors

Regulation Of Regulation Of Temperature Temperature

Cold Blooded Cold Blooded OrganismsOrganisms When it’s too When it’s too

coldcold– Bask in sunBask in sun– Blood vessel Blood vessel

constrictionconstriction– Less activityLess activity

When it’s too hotWhen it’s too hot– Stay in cooler Stay in cooler

placesplaces– Dilation of blood Dilation of blood

vesselsvessels

Thermoregulation in Thermoregulation in warm blooded warm blooded vertebratesvertebratesToo coldToo cold ShiverShiver More metabolic activitiesMore metabolic activities Goose bumpsGoose bumps Vaso constriction (blood vessels Vaso constriction (blood vessels

constricting)constricting)Too hotToo hot Sweating and Evaporative coolingSweating and Evaporative cooling Vaso dilation blood vessels expanding Vaso dilation blood vessels expanding Panting in dogsPanting in dogs

Cold

•the brain senses the low temperature and sends message to skeletal and muscular system to shiver and form goose bumps

•it also sends message to circulatory system to constrict its blood vessels

Organ systems work together to maintain temperature

homeostasis

Organ systems work together to maintain

temperature homeostasisHot

Brain sends message to integumentary system to produce more sweat

It sends message to circulatory system for vasodilation

In both cases after body temperature comes back to normal, the signals are stopped being transmitted from the brain to other systems (negative feed back)

Maintaining the water Maintaining the water balancebalance

When there is too much water…When there is too much water…

Brain senses an increase in blood volumeBrain senses an increase in blood volume It sends message to kidneys to remove more It sends message to kidneys to remove more

water from blood and organism urinate morewater from blood and organism urinate more After the blood volume is restored this signal After the blood volume is restored this signal

would stop (negative feed back)would stop (negative feed back) Here nervous and excretory system work Here nervous and excretory system work

together to maintain homeostasistogether to maintain homeostasis

When there is less water in When there is less water in blood / blood volume is lowblood / blood volume is low

Brain sends message to pituatary gland to Brain sends message to pituatary gland to produce anti diuretic hormoneproduce anti diuretic hormone

ADH gives message to kidneys to take less ADH gives message to kidneys to take less water from blood and organism urinate water from blood and organism urinate less less

Brain signals for thirstBrain signals for thirst When blood volume is restores both these When blood volume is restores both these

signals would stop( negative fed back)signals would stop( negative fed back) Here nervous system works with endocrine Here nervous system works with endocrine

system and circulatory system system and circulatory system

How pH of blood is How pH of blood is maintainedmaintained Blood pH is close to neutral ( Blood pH is close to neutral ( pH of 7-pH of 7-

8 8 )) It can become acidic because of It can become acidic because of

increase in carbon dioxide level in increase in carbon dioxide level in bloodblood

Carbon dioxide and water in blood Carbon dioxide and water in blood forms carbonic acidforms carbonic acid

This low pH is sensed by brainThis low pH is sensed by brain

How pH of blood is How pH of blood is maintainedmaintained It gives message to lungs to work It gives message to lungs to work

more to expel carbon dioxide and more to expel carbon dioxide and bring in more oxygenbring in more oxygen

When the carbon dioxide level When the carbon dioxide level decreases and pH is maintained the decreases and pH is maintained the signal stopssignal stops

Here nervous system works with Here nervous system works with circulatory and respiratory systems to circulatory and respiratory systems to maintain homeostasis of body pH.maintain homeostasis of body pH.

The Metabolic ActivityThe Metabolic Activity

Can be affected by pH Can be affected by pH Can be affected by temperatureCan be affected by temperature

They first increase and then decreasesThey first increase and then decreases

The Metabolic ActivityThe Metabolic Activity

Can be affected by Can be affected by light light ((photosynthesisphotosynthesis))

Can be affected by Can be affected by radiation (radiation (CancerCancer))

Can be affected by Can be affected by toxic substances toxic substances ((DrugsDrugs))