Physiology and Homeostasis Flashcards
Define Physiology
What does Physiology study?
What two categories of processes are studied?
the study of the
normal functioning of
a living organism and
its component parts,
including all its
chemical and physical
processes
What type of science is Physiology classified as?
What does this type of science classification mean?
What other scientific discipline is it closely related to?
Physiology is an integrative science. This means looking at everything as individual components does not provide sufficient insight therefore all components must be analyzed as a whole to provide a greater understanding.
It is closely tied to anatomy; the structure of a cell, tissue,
or organ must provide a physical base for its function.
The levels of organization that compile life on Earth range from Atoms (smallest unit) to the Biosphere (Largest unit).
What levels of organization does Physiology encompass?
Briefly describe each organization level too.
Physiology encompasses:
- Molecules such as Lipids, Proteins and Carbohydrates
- Cells: The smallest unit capable of carrying out life processes
- Tissues: Collections of cells that carry out related functions
- Organs: A formation of tissues into a structural and functional unit
- Organ Systems: Organs that are integrated together
- Organisms
- Populations of a single species
True or False?
It is common to
study each organ
system individually
because there is no integration
between many of
the organ systems.
False
Yes it is common to study each organ system individually but there IS much integration between many organ systems.
i.e. circulatory, nervous system, endocrine system
Physiologists often distinguish between functional and mechanism approaches.
What do each of these approaches focus on asking and what is the more common approach in Physiology?
Functional approaches asks “Why” something happens in the body (i.e. Why do we need oxygen)
Mechanism approaches asks “How” something happens in the body (i.e. How does RBCs transport oxygen)
Physiology focuses on the “How” Mechanism approach
Define Homeostasis. What does it maintain?
What are some examples of variables managed by Homeostasis?
Homeostasis is the ability to maintain a relatively stable internal environment despite exposure to external variability.
Some variables managed are Blood pressure, body temperature, ion/molecule concentrations
Homeostasis can be disrupted by External and internal changes.
What is the difference between the two types of changes and what can be the causes?
When these changes occur, the organism attempts to compensate. What can happen when compensation fails?
External changes are things that are not native to the body such as chemical toxicity, physical trauma and viruses.
Internal changes are native to the body such as disorders from genetics or cancer.
If a change cannot be compensated by homeostasis then disease / illness will occur.
What is the Extracellular fluid’s (ECF’s) function?
True or False?
The Extracellular fluid that surrounds cells is NOT considered apart of the body’s internal environment.
The ECF is said to be in a dynamic steady-state with the ICF and external environment. What does this mean?
The ECF surrounds cells and acts as a buffer between the external environment and cells.
False. The ECF IS considered to be a part of the body’s internal environment.
Dynamic steady state is the constant movement of materials back and forth from the ECF between the ICF and external environment.
Homeostasis depends on mass balance.
What is the law of mass balance? Why is this important for homeostasis?
The law of mass balance is “is the amount of a substance in the body is to remain constant, then any excess gain must be offset by an equal loss”.
This is important for homeostasis because if mass balance is not achieved then homeostasis cannot maintain constant levels.
Explain this quote
“The body compartments are in a dynamic steady state but are not in equilibrium but rather a stable disequilibrium”
Different compartments require differing levels of concentrations of molecules. This means equilibrium is not established
i.e. Potassium has high levels in ICF but low in ECF
i.e. Sodium and chlorine have low levels in ICF but high in ECF
Homeostasis keeps regulated variables within a normal control range by using control mechanisms.
What are the 4 general segments that form control mechanisms?
The 4 segments that form control mechanisms are
- An input signal
- Integrating center
- output signal
- response
Homeostasis uses two categories of control mechanisms to control variables.
What is the difference between the local control and reflex control mechanisms? what type of signaling pathway does Reflex use?
Which one of these has a more complex control mechanisms?
Local control only impacts a variable in a small area of the body (i.e. blood vessel dilation in arm)
Reflex control impacts a variable throughout the whole body and uses long distance signaling pathways that uses nervous, endocrine or both.
Reflex control has more complex control mechanisms.
what two parts can reflex control be broken down into?
Briefly explain them
Response loop and Feedback loop
The response loop is the pathway of stimulus causing a response
The Feedback loop senses the response of the response loop and alters the stimulus
What are the 3 types of Feedback loops?
Negative Feedback
Positive feedback
Feedforward control
Explain Negative feedback loops. How does it alter the stimulus? is it homeostatic? What can it and cannot do?
Negative feedback loops removes the stimulus signal to prevent further responses.
It is considered homeostatic (maintain a specific range / point of a variable)
it will restore the response to it’s initial state but is unable to prevent disturbances
