Module 1: Basic Principles Flashcards
Physiology (formal definition vs operational definition)
Formal: The biological study of the FUNCTIONS of living organisms and their parts
Operational: The study of how cells interact with their “environment” to obtains the things required for life
Vital Substances
The things required for life
–> Water, salts, oxygen, nutrients, heat, etc.
Vital substances are obtained through…
Exchange between internal and external environments (at the organ, organismal, and cellular level)
Exchange System
Any system that allows for the exchange of material from the external and internal environments
4 major levels of organization
1) Cell
2) Tissue
3) Organ
4) System
Cellular Level (+ major cell types)
Cell = The basic structural and functional unit of life
4 general cell types:
1) Epithelial
2) Nerve
3) Muscle
4) Connective Tissue Cells
Epithelial Cells
Cells that cover/line the inside and outside of a body
Nerve Cells
Cells that are specialized for communication
Muscle Cells
Cells specialized for contraction
Connective Tissue Cells
Cells that provide structural strength and immune function
Tissue Level
Tissue = A collection of cells (with common structure and function) that work together to achieve a common purpose
Organ Level
Group/organization of different tissues to perform/carry out specific related functions
System Level
Several organs that work together to perform a certain task (major body functions)
Basic Principles of Life (5)
1) All life is aquatic
2) All life is compartmentalized
3) All life deals with the same fundamental problems
4) All life is constrained by the laws of physics and chemistry
5) All life can tolerate a limited range of conditions
“All life is aquatic” meaning
All life is water-based
Body fluids of all animals have the same general composition:
1) WATER
2) Salts
3) Biochemical substances
All life is aquatic BECAUSE…
All life evolved from aquatic organisms –> They evolved to “take the sea with them” (by creating an aquatic INTERNAL environment)
Water is ______ % of all human body molecules and _____ % of human body weight
Water =
1) 75% of human body weight
2) 99% of all human molecules
Salts make up ___% of molecules in a human body
~0.75%
Biochemical substances make up ________% of molecules in a human body
~0.25%
Compartmentation
The division of space (of the body or cell) into separate compartments so that functions + substances can be isolated
Advantages of Compartmentation
1) Compartments separate biochemical processes that might otherwise conflict with each other
2) Allows for contents of adjacent compartments to differ (differentiation of cells + bodily functions)
Disadvantage of Compartmentation
Barriers between compartments can make it difficult to move/exchange needed materials from one compartment to another
Lumen
The interior/cavity of a HOLLOW organ
(Ex: Heart, lungs, intestines)
The lumen is an extension of the…
What is the analogy for this?
EXTERNAL Environment (in some organs)
Like a hole through a bead –> The hole isn’t INSIDE of the bead, it is merely passing through it
Material in the lumen/s is NOT a part of __________ until ____________
Material in the lumen is not part of the body’s internal environment until it crosses the wall of the organ
3 functional fluid compartments:
1) Intracellular fluid
2) Extracellular fluid
a) Plasma
b) Interstitial fluid
ECF
Extracellular Fluid
Extracellular Fluid
The fluid outside of the cells (the external environment of the cell)
–> (the internal environment of the body)
“A sea within”
(Extra = Outside of)
Intracellular Fluid
Fluid within the cells (internal cellular environment)
Plasma
The fluid portion of the blood
The two main components (subcompartments) of the ECF
1) Plasma
2) Interstitial Fluid
Interstitial Fluid
Surrounds the cells and lies between the cells and the plasma
(ECF that is NOT in the circulatory system!)
Between compartments there exists an _______________________ of substances
ASYMMETRICAL DISTRIBUTION
–> Different compartments contain different substances/different concentrations of substances
Na+ Concentration INSIDE cell
ICF = LOW Na+
Na+ Concentration OUTSIDE cell
ECF = HIGH Na+
K+ Concentration INSIDE cell
ICF = HIGH K+
K+ Concentration OUTSIDE cell
ECF = LOW K+
Ca2+ Concentration INSIDE cells
ICF = VERY low Ca2+
Ca2+ Concentration OUTSIDE cells
ECF = Low Ca2+
Na+ Ion Distribution Asymmetry
Inside Cell (ICF) = LOW conc.
Outside cell (ECF) = HIGH conc.
K+ Ion Distribution Asymmetry
Inside Cell (ICF) = HIGH conc.
Outside cell (ECF) = LOW conc.
Ca2+ (free calcium) Ion Distribution Asymmetry
Inside cell (ICF) = VERY LOW conc.
Outside cell (ECF) = LOW conc.
A fundamental challenge for all organisms is…
(Hint: compartmentation)
BECAUSE…
Maintaining asymmetry between compartments
–> Cells expend a lot of energy to maintain the asymmetry BECAUSE it foes AGAINST the gradient
Life is energetically _________________/______________
What does this mean?
Life is energetically INEFFICIENT / UNFAVORABLE
–> At the very fundamental level of just maintaining asymmetries, life must expend energy
“All life deals with the same fundamental problems” MEANING
All organisms have the same basic needs
(Ex: water, food, air, etc.)
HOW we address these problems is where organisms may differ (and the specificities of the problems)
Aerobic Metabolism
Uses OXYGEN
–> Yields 38 ATP + Water (+ CO2)
Positives and Negatives of Aerobic Metabolism
(+) = LARGE YIELD (of energy) + water production
–> VERY EFFICIENT
(-) = Longer process + bigger “overhead costs”
Anaerobic Metabolism
DOES NOT use oxygen
–> Produces lactic acid + 2 ATP
Positives and Negatives of Anaerobic Metabolism
(+) = Faster process + lower “overhead” costs
(-) = LOW YIELD (of energy) + produces lactic acid
Anabolic vs Catabolic
Anabolic = Building biomass (transforming simple substances into complex molecules; storing energy)
Catabolic = Breaking down biomass (Breaks down complex substances into simpler ones; releases energy)
Metabolic Rate (MR)
Amount of energy an animal uses in a unit of time
[Energy (kcal)] / [Time]
–> Can be seen as the SUM of all biochem rxns. taking place in an organism
How is MR measured?
Through measuring OXYGEN CONSUMPTION
(Amount of oxygen taken in = Amount of oxygen going through cell resp. = Amount of ATP being produced)
BMR
Basal Metabolic Rate
= Amount of energy needed to solely carry out basic cellular functions
MR can NEVER be = to…
MR can NEVER be = to ZERO
–> MR can only ever get as low as the BMR (any lower = organism is not alive)
“All life is constrained by laws of physics and chemistry” MEANING
The physical environment governs what cells can and cannot accomplish
(Ex: Size Principle)
The Size Principle
Surface Area : Volume RATIO
–> As a cell (or anything) increases in size, the VOLUME increases faster than the surface area
–> Larger cells have LOWER SA:VOL ratios which is not ideal as the surface area available for exchange is not sufficient for the amount of activity occurring in the cellular volume
–> Smaller cells have a HIGHER SA:VOL ratio which allows for greater amount of exchange per amount of cellular activity in its volume
** LIMITS HOW BIG A CELL CAN GET**
Size principle + HEAT:
Large Animal
Large Animal = SMALLER SA:VOL
= LESS surface area for heat exchange = better at retaining heat
(Heat retention = High vs Heat loss = low)
Size principle + HEAT:
Small Animal
Small Animal = LARGER SA:VOL
= MORE surface area for heat exchange = better at heat exchange
(Heat retention = LOW vs Heat loss = HIGH)
Homeostasis
Maintenance of a relatively constant internal environment (maintenance of conditions tolerable range)
Set Point
Optimum value
To maintain homeostasis, the body has _____________ systems
CONTROL systems
Control Systems
Processes in which the body regularly monitors certain variables and kickstarts physiological control mechanisms if any variable strays too far from the set point
2 Main Parts of Control Systems:
1) Response Loop
2) Feedback Loop
Response Loop
An input signal (stimulus), integrating center (programs response), and an output signal/response (action)
Feedback Loop
The response to a stimulus “feeds back” to the input portion of the pathway to either amplify, continue, or stop a response
Components of a Response Loop
1) Sensor (takes input)
2) Integrator (processes input)
3) Effector (the response)
Sensor
Measures some aspect of the internal environment
–> What picks up on a signal/stimulus
Integrator
Compares the sensor measurement to a reference value (set point)
–> Determines if a response is needed and if it is, it coordinates the respsonse
Effector
The output of the response loop system that changes the internal environment
Negative Feedback
The effector (output) COUNTERACTS (is directly opposite to) the initial stimulus
–> Will cause system to TURN OFF the response loop once homeostasis is re-achieved
Positive Feedback
A loop in which the response to a stimulus reinforces/increases the initial stimulus –> Escalates the response + causes RAPID CHANGE
–> Requires some intervention to stop the response
Negative vs Positive Feedback
Negative Feedback = HOMEOSTATIC
Positive Feedback = NOT Homestatic!!!
