Midterm 1 Flashcards
what is physiology?
- the study of normal mechanisms and their interactions that work within a living system
- focuses on how organisms, organ systems, organs, cells, and biomolecules carry out the chemical or physical functions that exist in a living system
natural selection:
- matting for traits that are best suited to the environment
what is the scientific approach/ hypothetico-deductive?
- ask a question
- propose various hypotheses to explain it
- design experiments or observations
- conduct experiments
- use outcome of experiments to refine the question
- repeat the process to build reproducible outcomes that falsify all alternative hypotheses
- elevate hypothesis to a theory
what is the vertical approach to studying physiology?
hierarchical nature of physiology= atoms, molecules, cells, tissues, organs, organ systems, organisms
what is the horizontal approach to studying physiology?
studying the interactions of all systems together, functional organism
what is the comparative approach of studying physiology?
comparing the mechanisms and processes used by major invertebrates and vertebrates
- universal functions and principles
- unique adaptations
how did the physiology of organisms come to be how it is today?
through evolution of other ancestral processes and mechanisms
-complexity increased
what does the proximate/mechanistic approach to physiology ask?
how the process/function works
what does the evolutionary/ultimate approach to physiology ask?
how the organism got to be that way
what does the meteleological approach to physiology ask?
what the function or purpose of something is
-sometimes things evolve in a way that isn’t logical from an ancestor
how does a theory form?
- when a hypothesis is supported over and over
- a theory is a very strong statement
what is the smallest unit capable of carrying out the processes of life independently
a cell
what are the 4 basic functions of a cell?
- self-organization: using resources in the environment to create the cell
- obtain energy
- preform chemical reactions
- eliminate waste products from metabolic processes
- synthesize things that are needed
- metabolism - self-regulation
- sense and response to environment
- control exchange of material between cell and environment
- repair damage
- homeostasis - self-support and movement
- self-replication
what does it mean when a cell has a specialized function?
it has an elaboration or modification to its basic function in order to be better suited for its role in the environment its in
what are the 4 types of tissue?
- epithelial: sheets of cells that cover surfaces (skin, ducts, passageways, glands)
- connective: very diverse tissues, few cells, many fibres (proteins) and ground substance (to hold tissue together)
- collagen, bone, cartilage, blood, lymph, tissue fluid - muscular: muscle fibres for locomotion
- can be striated (skeletal, cardiac) or non-striated (smooth muscle) - nervous: neurons for cell communication
- used to measure or sense internal and external environments
- decide if change must be made
- initiates process to bring change
why does the surface area to volume ratio matter for organisms?
the larger the organism the smaller the SA: volume ratio which matters for diffusion rates
- its a disadvantage when diffusion is the only way of transport, without bulk transport or distribution system
- but an advantage is it involved retention of heat
what is the basis of Ficks law?
-factors affecting rate of diffusion
what does Ficks law state?
- distance: the further a substance has to diffuse, the slower the diffusion
- concentration gradient: increase in conc gradient leads to faster diffusion
- surface area: more SA, more diffusion
- size of molecule: increase in size (molecule weight), decrease in diffusion
- permeability of barrier: increased permeability leads to increased diffusion
- neuron and muscle cells can chance permeability when needed
what ways can larger organisms overcome the limits to diffusion in multicellular organism?
- bulk transport
- increased SA
- final step (diffusion into the cell) will still rely on diffusion though
what are the rates for O2 over different distance that are relevant to diffusion-based processes?
1 micrometer: 240 microseconds
10 micrometers: 24 ms
100 micrometers: 2.4 ms
what is homeostasis?
maintenance of a desired state (in a narrow range) in face of disturbances
-body condition maintained within limits necessary to preserve life (equilibrium)
what is the private environment that body cells are contained in?
the extracellular fluid (cells exchange nutrients and wastes with it)
-in vertebrates its made up of plasma and interstitial fluid
what factors are regulated by homeostasis?
- energy: concentration of energy rich molecules- fuel
- conc of O2 and CO2:important for pH regulation, carbonic acid-bicarbonate buffer system
- pH: affects nerve and enzyme function, important for optimal effieciency
- waste products: toxicity issues
- water and electrolytes: controls volume and osmolarity of intra and extracellular fluid
- blood volume and pressure: maintain plasma volume for effective bulk transport of nutrients and wastes
- temperature: maintain optimal cellular functions
- social parameters: regulating living conditions and populations levels (important for insects like termites)
how is a compensatory response achieved for homeostasis?
-usually through negative feedback (a change in a controlled variable triggers a response that opposes the change which then moves the variable in opposite direction of initial change)
to maintain homeostasis, compensatory responses are required, how are most of these responses achieved?
- negative feedback mechanisms: a change in a controlled variable triggers a response that opposes the change and moves the variable in the opposite direction of the initial change
- can be simple (unreferenced) or complex (references to a specific condition)
what two things could a response effector to homeostasis be?
- antagonistic: works against the variable
- behavioural: getting away from the variable
what are the steps of a negative feedback loop?
- a deviation in a controlled variable occurs
- gets detected by a sensor
- the sensor informs an integrator
- instructions are sent from integrator to an effector
- the effector brings about a compensatory response
- the response results in the controlled variable restoring to normal
- system responsible for response is shut off by negative feedback
what problems can occur from negative feedback and how are the resolved?
- delayed response: anticipation
- overshooting: feed-forward system
what is acclimatization in homeostasis?
- systems alter existing feedback to a new situation over time period
- includes up regulation and down regulation
how does anticipation/feed-forward happen?
- oncoming disturbance
- sensor detects this
- anticipator activates the corrective response before the variable
- integrator response
- effector brings about the response
what is acclimation in regard to homeostasis?
- acclimitization that takes place in a controlled situation
- usually not the external environment
- 1 to 2 controlled or defined variables are usually involved
what is adaptation in regard to homeostasis?
- acclimation or acclimation to new situation on longer term
- apdated to new set of conditions or environment
there are other change processes aside from negative feedback to maintain homeostasis?
- dormancy: maintaining homeostasis in broader sense, slowing down normal function over a period of time
- voluntary or on-demand: locomotion, growth, development, muscle and gland activity
- reset systems: change the set point of negative feedback system (night time body temp, sexual maturity)
- positive feedback: mechanisms to create rapid change when conditions demand it (birth, blood clots, immune system reactions)
what resets the negative feedback set point?
higher regulators, change set point which effectors the integrators timing of response
ex. sexual maturity, hibernation, mating behaviours, fever (temp control)
how does positive feedback work?
- a deviation in the controlled variable occurs
- sensor may be used to signal integrator or regulatory process
- output (effector) released
- change is enhanced by the output
positive feedback (bird of mammal) example:
- signal from mature fetus
- uterus begins contractions
- stretch sensors
- mothers hypothalamus is triggered
- pituitary gland is told to secrete oxytocin
- contractions are enhanced by to oxytocin and the signal repeats
what systems affect the whole body?
- nervous system: fast responses, CNS and PNS, reflexes
- endocrine systems: hormonal, duration over speed