KIN105: Unit 1
1. Define the term “organ system”. Describe three of the eleven organ
systems in the body by describing their main function and the organs
that they consist of. (4 marks)
>Organ System: a group of organs classified as a unit b/c of a common function or set
>>Skeletal System: provides protection and support, allows body movements, produces
blood cells, and stores minerals and fat. Consists of bones, associated cartilages,
ligaments, and joints.
>>Muscular System: produces movements, maintains posture, and produces body heat.
Consists of muscles attached to the skeleton by tendons.
>>Respiratory System: Exchanges oxygen and carbon dioxide between the blood and
air and regulates blood pH. Consists of the lungs and respiratory passages.
2. Describe the concept of homeostasis. Why is it important? What type of
feedback is utilized to maintain homeostasis? (3 marks)
>Homeostasis: the existence and maintenance of a relatively constant environment
within the body. Most body cells depend on the maintenance of the cells’ fluid
environment within a narrow range of conditions, including temperature, volume, and
chemical content. Negative feedback helps maintain homeostasis.
3. Define negative feedback and positive feedback. Describe an example of
each, to clarify the meaning of these physiological concepts. (3 marks)
>Negative Feedback: mechanism by which any deviation from an ideal normal value or
set point is resisted or negated; returns a parameter to its normal range and thereby
>ex: blood pressure control; 3 components: receptor that monitors the value of a
variable, a control centre that establishes the set point around which the variable is
maintained, and an effector that changes the variable. Receptors can detect a change
in blood pressure and send the information to the control center in the brain. The control
center causes the heart rate to increase/decrease and the blood vessels to
dilate/constrict in order to have the blood pressure maintained in a normal range.
>Positive Feedback: mechanism by which any deviation from an ideal normal value or
set point is made greater.
>ex: inadequate delivery of blood to cardiac muscle. Contraction of cardiac
muscle generates blood pressure and moves blood through the blood vessels to the
tissues. In effect, the heart pumps blood to itself. Following extreme blood loss, blood
pressure decreases to the point that the delivery of blood to cardiac muscle is
inadequate. Cardiac muscle homeostasis is disrupted and the heart pumps less blood,
which leads to a decrease in blood pressure, and continues to decrease until the heart
stops beating and death results.
4. The human body consists of many different types of elements.
Interactions among these elements allow the formation of ions and
molecules that are essential for the physiological function of the human body. Describe the terms “ion” and “molecule” and provide two
examples of each. (4 marks)
>Ion: atom or group of atoms carrying an electrical charge because of a loss or gain of
one or more electrons.
>ex: Sodium (Na) atom
>Molecule: two or more atoms chemically combined to form a structure that behaves as
an independent unit
>ex: covalent bond between two hydrogen atoms forming a hydrogen molecule
5. Describe the three classifications of chemical reactions. Include a
specific example of each type. (6 marks)
>Synthesis Reactions: when two or more reactants combine to form a larger, more
>ex: A + B --> AB
>Decomposition Reactions: when reactants are broken down into smaller, less complex
products. (Reverse of a Synthesis Reaction)
>ex: AB --> A + B
>Exchange Reactions: is a combination of a decomposition and synthesis reaction
>ex: AB + CD --> AC + BD
6. a. Maintaining a constant level of hydrogen ions in body fluids is
important for the nervous system to function properly. The reversible
reaction involving carbon dioxide and water plays an important role in
maintaining this balance. Define the terms “reversible reaction” and
“equilibrium” (2 marks).