Chapter 1 Flashcards
Define physiology
The study of the functions of the body
List the levels of organization from atoms to organisms.
atoms –> molecules –> organelles –> cells –> tissues –> organs –> organ systems
Name the 10 organ systems of the body and give their functions.
RIM INDUCER
- Circulatory (heart, blood vessels, blood) - Transport of materials between all cells of the body.
- Digestive (stomach, intestine, liver, pancreas) - Conversion of food into particles that can be transported into the body; elimination of some wastes.
- Endocrine (thyroid gland, adrenal gland) - Coordination of body function through synthesis and release of regulatory molecules.
- Immune (thymus, spleen, lymph nodes) - Defense against foreign invaders.
- Integumentary (skin) - Protection from external environment.
- Musculoskeletal (skeletal muscles, bone) - Support and movement.
- Nervous (brain, spinal cord) - Coordination of body function through electrical signals and release of regulatory molecules.
- Reproductive (ovaries and uterus, testes) - Perpetuation of the species.
- Respiratory (lungs, airways) - Exchange of oxygen and carbon dioxide between the internal and external environments.
- Urinary (kidneys, bladder) - Maintenance of water and solutes in the internal environment; waste removal.
List and give examples of the four major themes in physiology.
- Structure and function are related - A molecule’s function depends on its structure and shape.
- Living organisms need energy - converting nutrients into usable molecules.
- Information flow coordinates body functions - DNA –> RNA –> proteins –> control body function
- Homeostasis maintains internal stability - functions such as body temperature, heart rate, and blood pressure have a set point at which they are more stable. Our body functions and is constantly adjusting to maintain these set points in the event of change.
Define homeostasis. What happens when homeostasis fails?
The maintenance of a relatively stable internal environment (in the face of internal and external threats.) If homeostasis fails - illness, disease, possible death.
Name and describe the two major compartments of the human body.
Intracellular fluid - the fluid found within cells
Extracellular fluid - surrounds cells
Explain the law of mass balance and how it applies to the body’s load of a substance.
Law of mass balance - if the amount of a substance in the body is to remain constant, any gain must be offset by an equal loss.
Mass balance = Existing body load + intake or metabolic production - Excretion or metabolic removal
Define mass flow using mathematical units and explain how it relates to mass balance.
Mass flow is used to follow material throughout the body.
Mass flow = concentration x volume flow
(amount min.) = (amount volume) x (volume min.)
Mass flow can be used to determine the rate of intake, output, or production of a substance.
Define clearance and give an example.
The rate at which a substance disappears from the blood (usually expressed as a volume of blood cleared of substance per unit of time.
Ex: urea is a normal metabolite produced from protein metabolism. a typical value for urea clearance is 70mL plasma cleared of urea per minute, written as 70 mL/min.
Distinguish between equilibrium and steady state.
Equilibrium (aequus, equal + libra, balance) implies that the composition of the body compartments is identical and steady state refers to the body compartments being relatively stable through a process of materials, much of the time in different concentrations, moving back and forth between the two body compartments.
List the three basic components of a control system and give an example.
- input signal
- controller or integrating center
- output signal
Ex: Oxygen concentration in a tissue decreases - cells sense the lower oxygen concentration and respond by secreting a chemical signal. The signal molecule diffuses to nearby muscles in the blood vessel wall, bringing them a message to relax. Relaxation of the muscles widens the blood vessel which increases blood flow into the tissue.
Explain the relationship between a regulated variable and its setpoint.
Regulated variables are kept within their acceptable (normal) range by physiological control mechanisms that kick in if the variable ever strays too far from its setpoint, or optimum value.
Compare local control, long distance control, and reflex control.
- Local control - simplest form, restricted to the tissue or cell involved; a relatively isolated change occurs in a tissue.
- Long distance control - more complex control, changes that are widespread throughout the body, or systemic in nature.
- Reflex control - any long-distance pathway that uses the nervous system, endocrine system, or both.
Explain the relationship between a response loop and a feedback loop.
A response loop evaluates a stimulus and produces an action to bring the regulated variable back into the desired range. A feedback loop sends the response information back to influence the input portion of the pathway.
Compare negative feedback, positive feedback, and feedforward control. Give an example of each.
- Negative feedback - (homeostatic) A pathway in which the response opposes or removes the signal - It keeps the system at or near a setpoint so that the regulated variable is relatively stable.
Ex: Body Temp - Positive feedback - (not homeostatic) A pathway in which the response reinforces the stimulus rather than decreasing or removing it - sends the regulated variable even farther from its normal value.
Ex: Child birth - Feedforward control - reflexes that enable the body to predict that a change is about to occur and start the response loop in anticipation of the change.
Ex: Salivation reflex
