Chapter 1.7 Flashcards
Describe Metabolism
All Chemical reactions of the body
Describe Catabolism
Energy Releasing (exergonic) decomposition reactions:
- breaks covalent bonds
- produces smaller molecules
- releases useful energy
Describe Anabolism
Energy Storing (endergonic) synthesis reactions:
- requires energy input
- production of protein or fat
- driven by energy that catabolism releases
inseparably linked to catabolism
What is Oxidation?
Any chemical reaction in which a molecule gives up electrons and releases energy.
Molecule is Oxidized in this process
Electron acceptor molecule is the oxidizing agent
What is Reduction?
Any chemical reaction in which a molecule gains electrons and energy
Molecule is reduced when it accepts electron
Molecule that donates electrons is the reducing agent
What happens in an Oxidation-Reduction reaction?
AKA Redox reaction
Oxidation of one molecule is always accompanied by the reduction of another
Electrons are often transferred as hydrogen atoms
Define Homeostasis
The body’s ability to detect change, activate mechanisms that oppose it and thereby maintain relatively stable internal conditions.
**loss of homeostatic control causes illness or death
Coined by Walter Cannon
What is a Negative Feedback Loop?
Body sense a change and activates mechanisms to reverse it - dynamic equilibrium
Think of thermostat example, heat is turned on when too cold and turned off when too hot.
How does thermoregulation work?
Brain senses change in blood temperature. If too warm, vessels dilate (vasodilatation) in the skin and sweating begins, thus losing heat.
if too cold, vessels constrict (vasoconstriction) and shivering begins, thus gaining heat
Describe Negative feedback control of Blood Pressure
Sitting up in bed causes a drop in blood pressure in the head and upper thorax.
Baroreceptors in the arteries near the heart alert the cardiac center in the brainstem
Cardiac center send nerve signals that increase the heart rate and return the blood pressure to normal
What does a receptor do in relation to feedback control?
Sense change in the body
What does the Integrating (control) center do?
control center that processes the sensory information and “makes a decision” and directs the response
What does an Effector do in feedback control?
Carries out the final corrective action to restore homeostasis
What makes up a Positive Feedback Loop?
Self-amplifying cycle: greater change in the same direction, feedback loop is repeated and change produces more change
Normal way of producing rapid changes: occurs with childbirth, blood clotting, protein digestion, fever and generation of nerve signals
