first lecture Flashcards
(22 cards)
what is physio
physiology is the study of the normal function of a living organism and its component parts.
Includes all its chemical and physical processes
Physiology involves the integration of function across many levels of organization.
To integrate means to bring varied elements together to create a unified whole
physio organization
Physiology includes multiple levels, from molecular and cellular biology to the ecological physiology of populations
The Cell is the smallest unit of structure capable of carrying out all life processes.
Collections of cells that carry out related functions are called tissues.
Tissues form structural and functional units known as organs.
Groups of organs integrate their functions to create organ systems.
organ systems
use picture on powerpoint
mapping
visual representation of physio processes.
two types:a structure/funciton maps; b. process maps or flow charts.
Function and Mechanism:
Teleological vs Mechanistic
Approach to Science
Physiologists are careful to distinguish between function and mechanism.
Function – the “why” of a system
Mechanism – the “how” of a system
Teleological Approach:
- What is the purpose or function?
- Why does something exist?
- Why does it need to be done?
Mechanistic Approach:
What are the processes involved?
How does something work?
how to distinguish external vs. internal
nothing is internal until it crosses some sort of epithelial cells. or some sort of membrane
flow charts show what
physio process as ti proceeds through time. also called process maps.
Themes in Physiology
4
Structure and Function are closely related
Living organisms need energy
Information flow coordinates body function
Homeostasis maintains internal stability
structure and funciton
Function always reflects structure
What a structure can do depends on its specific form
is divided in two categories:
1. Molecular Interactions (Lecture 2)
The ability of individual molecules to bind or react with other molecules is essential for biological function.
Interactions between proteins, water, and other molecules influence cell structure and the mechanical properties of cells and tissues.
2. Compartmentation (Lecture 3)
The division of space into separate compartments.
Compartments allow a cell, tissue, or an organ to specialize and isolate function.
organisms need energy
All living processes (growth, reproduction, movement, etc.) require the continuous input of energy.
Where does this energy come from?
How is this energy stored?
How is this energy used to do work?
Lecture 4 – Will describe some of the ways that energy in the body is used for building and breaking down molecules.
- Information Flow Coordinates Body Function
The flow of information in living systems ranges from transfer of information stored in DNA from generation to generation, to the flow of information within the body of a single organism.
Cellular level: (Lecture 5)
DNA-RNA-PROTEIN
Proteins are responsible for cell structure and function as well as the many forms of cell-to-cell communication that coordinate the functioning of a complex organism.
Organismal level: (Lectures 6 and 7)
Information flow between cells takes the form of either chemical signals or electrical signals
Local communication or long-distance communication
homeostasis
Homeostasis - Regulation of the body’s internal environment
Keeping the internal environment stable
The body monitors its internal state and takes action to correct disruptions that threaten its normal function
When the body fails to maintain homeostasis and normal function is disrupted, a diseased state, or pathological condition may result.
The cells in your body work best if they have the proper:
Temperature
pH
Water & Nutrient levels
Ion concentrations
Glucose concentrations
Balance of oxygen & carbon dioxide
Your body works to maintain the cells in a constant environment.
homeostasis:internal environment
The body’s internal environment is the watery internal environment that surrounds the cells, called the extracellular fluid (ECF)
The ECF serves as the transition between an organism’s external environment and the intracellular fluid (ICF) inside cells.
Physiological process have evolved over time to keep the ECF composition relatively stable. If the composition falls outside normal range, compensatory mechanisms activate to try to return the ECF to the normal state.
homeostasis: law of mass balance
The Human Body is an open system that exchanges heat and materials with the outside environment.
To maintain homeostasis, the body must maintain mass balance.
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.
The amount of a substance in the body is also called the body’s load (ie. sodium load, sugar load)
Materials enter the body primarily by ingestion or breathing or may be produced through metabolism
Materials leave the body by excretion or by metabolism
homeostatic reflex pathways
To maintain homeostasis, the human body monitors certain key functions, such as blood pressure and blood glucose concentrations.
These important regulated variables are kept within their normal range by physiological control mechanisms.
These control mechanisms kick in if the variable ever strays too far from its setpoint, or optimum value.
2 Basic Patterns of control mechanisms
Local Control
Long-Distance Reflex Control
local congrol homeostatsis
restrictued to the cells or tissue invovled. ex local control can be obesred when oxygen concentration tin a tissue decreases
long-distance reflex control homeostasis
chagnes that are widespread through thebody, or systemic in nautre, require more complex control systems ot maintain homeostasis. ex maintaiing blood pressure
homeostasis reflex control
Any long-distance pathway that uses the nervous system, endocrine system or both is referred to as Reflex Control.
A physiological reflex can be broken down into two parts: a response loop and a feedback loop.
A response loop has 3 primary components
an input signal
an integrating center
and an output signal
These 3 components can be expanded into the following seven steps (shown on the left) to form a pattern that is found with slight variations in all reflex pathways.
response loop
The input side of the response loop starts with a stimulus – the change that occurs when the regulated variable moves out of its desirable range.
A specialized sensor monitors the variable
If the sensor is activated by the stimulus, it sends an input signal to the integrating center.
The center evaluates the information coming from the sensor and initiates an output signal.
The output signal directs a target to carry out a response.
If successful, the response brings the regulated variable back into the desired range.
In mammals, integrating centers are usually part of the nervous system or endocrine system.
Output signals may be chemical signals, electrical signals, or a combination of both.
The targets (also referred to as effectors) activated by output signals can be any cell of the body.
feedback loop
In the aquarium example, once the response starts, what keeps the heater from sending the temperature beyond the setpoint?
Answer: A Feedback Loop, where the response “feeds back” to influence the input portion of the pathway.
In the aquarium example, the sensor (thermometer) continuously monitors the temperature and sends the information to the control box. When the temperature warms up to the setpoint, the control box shuts off the heater, thus ending the reflex response.
negative feedback loop
A pathway in which the response opposes or removes the signal is known as Negative Feedback.
Negative feedback loops stabilize the regulated variable and thus aid the system in maintaining homeostasis.
Negative feedback loops can restore the normal state and are homeostatic.
positive feedback loop
In a Positive Feedback Loop, the response reinforces the stimulus rather than decreasing or removing it.
The response sends the regulated variable even farther from its normal value which initiates a cycle of ever-increasing response and sends the system temporarily out of control.
Requires some intervention or event outside the loop to stop the response.
example:
Hormonal control of uterine contractions during childbirth
This cycle continues until finally the baby is delivered, releasing the stretch on the cervix and stopping the positive feedback loop.
no homeostatic
