Chapter 15 Homeostasis Flashcards
What conditions internally may the human body need to regulate?
Concentration of chemicals like Na ions and glucose.
pH of blood.
Water balance of bodily fluids.
Core temperature of the body.
What is homeostasis?
Homeostasis is where the body uses chemical and electrical systems to monitor any changes, to which it takes action to maintain a steady state of the body.
What is a feedback system
A feedback system maintains a relatively steady state around a narrow range of conditions.
What is a negative feedback system?
A negative feedback system is when a small change is detected by sensory receptors. As a result, effectors work to reverse the change and restore conditions to base level.
Give an example of a negative feedback system.
An example of negative feedback is the regulation of blood sugar levels, involving insulin and glucagon. Other examples include temperature control and water balance.
What is a positive feedback system?
A positive feedback system is where a change in the internal environment of the body is detected by sensory receptors, and effectors are stimulated t reinforce this change and increase the response.
Give examples of positive feedback systems.
Blood clotting cascade- When a blood vessel is damaged, platelets stick to the damaged area and release factors that initiates clotting and attracts more platelets.
Childbirth- The head of the baby presses against the cervix, and this stimulates the production of the hormone oxytocin. Oxytocin stimulates the uterus to contract, pushing the head of the baby even harder against the cervix, and triggering the release of more oxytocin.
Organisms are constantly heating up and cooling down. These changes are dependent on a number of factors. What are some of these factors?
> Exothermic chemical reactions.
Latent heat of evaporation- objects cool down when water evaporated from their surface.
Radiation- Transmission of electromagnetic waves from the air, water or ground.
Convection- Heating and cooling by current or air or water, warm air or warm water rises and cooler air or water sinks setting up convections around an organism,
Conduction- Heating as a result of collision of molecules. Air is not a good conductor of heat but the ground and water.
What are ectotherms?
Ectotherms are animals that heavily depends on the environment to maintain and regulate a core body temperature.
Give examples of ectotherms.
Ectotherms include all invertebrate animals, as well as fish, amphibians and reptiles (these are vertebrates).
