Exam – Science 2026 |
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, lymphatic system -picks up fluid leaked from blood vessels and returns it to blood.
-disposes of debris in the lymphatic stream.
-houses white blood cells (lyphocytes) involved in immunity.
-the immune response mounts the attack against foreign substances within the
body.
nervous system responds to internal and external changes by activating appropriate muscles and
glands.
digestive system breaks down food into absorbable units that enter the blood for distribution to body
cells.
cardiovascular system blood vessels transport blood which carries oxygen, carbon dioxide, nutrients,
water, etc.
respiratory system keeps blood constantly supplied with oxygen and removes carbon dioxide.
urinary system -eliminates nitrogenous wastes from the body.
-regulates water,electrolyte and acid-base balance of the blood
endocrine system glands secrete hormones that regulate processes such a growth, reproduction, and
nutrient use (metabolism) by body cells.
what are the 3 parts of homeostatic regulation? 1. the receptor- receives info that something in the environment is changing.
2. the control center- receives and processes information from the receptor.
3. the effector- responds to the commands of the control center by either opposing
or enhancing the stimulus.
what is homeostasis? the bodys attempt to maintain a constant internal enviroment.
what is negative feedback? a reaction in which the system responds in such a way as to reverse the direction of
change
examples of negative feedback: - thermoregulation
-home heating system
-blood glucose level
what is positive feedback? a response is to amplify the change in the variable. this has a destabilizing effect, so
does not result in homeostasis. positive feedback is less common.
examples of positive feedback: -blood clotting
-child birth
pathways that can alter homeostasis: nutrition, toxins, psychological, physical digestion.