EXAM 1 Flashcards
To prove I'm not stupid
Greek: Physis
Nature
Greek Logia
“study of”
Physiology Definition:
The study of how animals work
What does it do?
Function
How does it do it?
Mechanism
Physiology is based on_____
physics & chemistry
Phenotypes are influenced by______
genetics & the environment
Physiological processes are usually _______
regulated
Hierarchy of Integration
atoms>molecules>cells>tissues>organs>organ systems> organisms > populations
3 characteristics of Phenotypes
- morphology (structure/anatomy)
- physiology (function)
- behavior
what is phenotypic plasticity?
ability of a phenotype to change in response to environmental conditions
- same genotype may result in multiple phenotypes
- can be reversible or irreversible
- NOT adaptation (no genomic changes)
epigenetics
non DNA changes
homeostasis
you know what homeostasis is you dumb lunk
2 strategies for physiological regulation (facing external conditions) [graph!!]
- Conformer
- allow internal environment to match external environment
- Regulator
- changes to to a set point, maintain zone of stability
- particular to a specific environmental factor
4 types of Regulatory Mechanisms
- Negative feedback
- Positive feedback
- Feed-Forward Action
- Acclimatization
Negative Feedback
Response opposes stimulus
e. g.:
- Increase in body temp: blood vessels dilate, sweat
- Decrease in body temp: blood vessels constrict, no sweating
Antagonistic control
two functions that work in the opposite directions to maintain set point (homeostasis)
e.g.: Blood glucose
Positive Feedback
response amplifies stimulus (until an END POINT)
e.g. childbirth: as muscles in uterine wall contract, contraction leads to further distortion of uterus which is detected by stretch receptors, affects brain, releases oxytocin to cause further contractions.
Feed-Forward (anticipatory) mechanism
anticipation of stimulus
e.g.: stomach growling at lunch time (a.k.a. Pizza Time)
Acclimatization
adjusting physiological function in response to changes in the environment
Typically reversible
e.g.: jet lag, elevation change
Acclimation
laboratory phenomenon - response to change in only one factor
Emergent Properties
a property that complex systems have that the individual members do not
Basic Cell structure
- Nucleus: DNA > gene expression
- Cytoplasm (cytosol)
- Plasma membrane
- mitochondria: makes majority of ATP
Membrane proteins
On the plasma membrane
- Polar heads (hydrophilic)
- Non-polar lipid tails (hydrophobic)
- Small, non-polar molecules can pass through PM
- Large and/or polar/charged molecules can not cross bilayer
Plasma Membrane
- maintain composition of intra and extracellular fluids
- forms framework for protein components
- desmosomes - no transfer of molecules
- tight junctions - some molecular transfer
Types of membrane transport
- simple diffusion
- Facilitated Diffusion
- Active Transport
- Bulk Transport
Characteristics of Simple diffusion
- Movement from a region of high to low concentration
- Powered by random thermal motion
- no ATP required
- FLUX: measure of diffusion rate
Direction and magnitude of net flux depends on_______
- Permeability
- Concentration gradient
- Temperature
- Surface Area
- Size of molecule
- Distance
Facilitated diffusion
Transmembrane proteins facilitate diffusion of some polar or charged molecules
With Facilitated diffusion, molecules move _______ their concentration/electrochemical gradient
Down
ATP is _____ required for facilitated diffusion
NOT
Channel proteins
- Provide corridor for polar or charged molecules to pass through membrane
Channel protein specificity depends on______ and _____
charge & size
Two types of ion channels
Selective (Na+, K+, Cl-)
&
Non-selective (Na+,K+,Li+)
Aquaporins
Facilitated diffusion for water
high concentration of water to low concentration of water
Osmolarity
Total concentration of solutes in a solution
Measured in OSMOLES
1 Osmole =
1 mole of solute/L
Osmolarity depends on______
Total number of molecules NOT individual type
3 ways to compare osmolarity of two solutions
Isomotic: same solute concentration
Hyperosmotic: higher solute concentration
Hyposmotic: lower solute concentration
Isomotic
same solute concentration
Hyperosmotic
higher solute concentration
Hyposmotic
Lower solute concentration
Water moves from ___tonic side to ____tonic side
Hypotonic side to hypertonic side
Osmotic Pressure
Pressure generated by movement of water by osmosis.
No net flux is reached when hydrostatic (gravity) pressure is equal to osmotic pressure
3 different classifications of channel proteins
- Constitutive channels
- Gated Channels
- Special gated channels
Constitutive channels
Always open
- e.g.: Aquaporins
Gated channels
- ligand gated channels
- Voltage-gated channels
- Mechanically gated channels
Ligand gated channels
- signal molecule binds to receptor to open/close channel
- e.g.: acetylcholine regulates entry of Na+ into muscle cells
Voltage-gated channels
- regulated by the electrical state of the cell
- activated by change in voltage across membrane
Mechanically-gated channels
Regulated by a physical change
e.g. touching your skin leading to a sense of touch
Special gated channel
gap junctions
Gap Junctions
- aqueous pore between two adjacent cells
- made of connexin
- allows cell signals (chemical messenger) to be transferred directly between two cells
- not always open
Gap junctions are gated by ________
pH, voltage, other
Carrier Proteins
Permease: binds the substrate, undergoes a conformational change, and releases substrate on the other side
Active Transport
Transported molecules must bind to the transporters
- metabolic energy is required
- primary active transport - directly
- secondary active transport - indirectly
Primary Active Transport
ATP bonds break, energy is released
- maintains electrochemical gradient
e. g.: Ca2+ ATPase
e. g.: Na+/K+ ATPase
- ATP binding Phosphate to transport protein, K triggers Phosphate to detach
Secondary Active Transport
the generated electrochemical gradients use “Coupled Transport”
Two Secondary Active Transport transporters
Antiporters & Symporters
Antiporter
Two ions going in opposite directions (K in, Na out)
Symporter
two ions coupled going in same direction (Na bringing glucose in with it)
Bulk Transport
Simultaneous movement of many large molecules that cannot be transported by carriers
Two types of bulk transport
Exocytosis & Endocytosis
Exocytosis
bulk transport out of the cell
- fusion of the membrane-bound vesicles that contain cellular products with the plasma membrane
Endocytosis
bulk transport into the cell
- specific molecules can be taken into the cell because of the interaction of the molecule and a protein receptor
Ions with greater concentration inside the cell:
K+, Organic Anions
Examples of Organic Anions
Phosphate, nucleic acid
Ions with greater concentration outside of the cell:
Na+, Cl-
Nernst Equation at STP
58log([outside]/[inside])
The difference between an ion’s equilibrium potential and RMP is called_______
Driving force
Any extension off of a cell body is called a _____
process
Signals are received at the _______
dendrites
Signal integration happens at the _________
axon hillock
The axon hillock is also known as the ______
trigger zone
A signal is conducted along the _____
axon
Signal ends at the ______
axon terminal
Gap between the axon terminal and the receptor ____
synapse
Transient changes that occur locally
Graded potential
characteristics of Graded potentials
- short distance
varied in magnitude and duration
occur in dendrites and cell bodies
Graded potentials can stack over ____ & _____
Space & Time
EPSP
Excitatory Post-Synaptic Potential
EPSPs move Vm ______
closer to threshold for AP
IPSP
Inhibitory Post-Synaptic Potential
IPSPs move Vm ______
farther from threshold
Depolarization is caused by ___ ions flowing ___
Na+, into the cell
Repolarization is caused by ____ ions flowing ___
K+, out of the cell
A strong driving force is caused by _____
a large difference in RMP and an ion’s equilibrium potential
The period where absolutely NO Action Potential can occur
Absolute Refractory Period
The period where a large enough stimulus could trigger a new Action Potential
Relative refractory period
3 types of neurons
- Multipolar
- Bipolar
- Unipolar
Characteristics of multipolar neurons
- many processes (dendrites and axon)
- Many in the brain
- Spinal cord
Characteristics of bipolar neurons
- only 2 processes off the cell body
- single dendrite
- single axon
- involved in special senses
- vision
- olfaction
- hearing
Characteristics of unipolar neurons
- off of the cell body only one extension (process)
- then it branches
- idk, they’re weird
What receptors mediate detection of chemicals?
Chemoreceptors
Two types of chemoreceptors
- Exteroreceptors
- Interoceptors
Exteroreceptors are involved in which senses?
- Olfaction (smell)
- Gustatory (taste)
- Nociception (pain)
Interoceptors are involved in what senses?
Internal senses
- Blood pH
- Chemosensors in stomach
What are neurons involved in smell called?
Oderant Receptor Neurons (ORNs) (bipolar)
What is the pathway for Oderant Receptors?
- Chemical is ligated to receptor
- Gprotein (Golf) is activated, which activates adenylate cyclase.
- Acycl converts ATP into cAMP
- cAMP opens cAMP gated ion channels (allow Ca2+ and Na+ into cell) (non-specific channels)
- Ca2+ opens Ca2+ gated Cl- channels, Cl- flows out, further increasing depolarization, leads to AP
what chemical does the olfaction Action Potential release?
Glutamate
What is the sweet G-protein?
Gustducin
Gustducin pathway
Activates Acycl to make cAMP
- Closes K+ channels (depolarization)
- this activates Ca2+ channels (enter cell) causes NT release (glutamate)
What is the bitter G-protein?
Transducin
Transducin Pathway
- Activates PLC (not Acycl) acts on secondary messenger IP3
- Releases calcium from internal stores (NOT DEPOLARIZED)
Ca2+ activates NT release (glutamate)
Salty pathway
Na+ enters directly
- causes depolarization
- opens Ca2+ channels
- Release NT (serotonin)
Sour pathway
H+ from sour foods block K+ channel
- K+ can’t leave, depolarization, Ca2+ opens, release NT
Vertebrates use _____ potential
Receptor
Invertebrates use ______ potential
generator
Mechanoreception is used in what senses?
- Touch/pressure
- Proprioception
- Equilibrium/Balance
- Hearing
- Baroreception
Epithelial Sodium Channel
- Large extracellular link
- Intracellular link from mebrane to cytoskeleton, activated with pressure, allows Na+ in
Transient Receptor Potential (TRP) channel
non-selective cation channels
Two channels activated with mechanoreception:
- Epithelial Sodium Channel (EnaC)
- Transient Receptor Potential (TRP) channel
Somatosensation
touch receptors
Two types of accessory Structures
- Tonic Receptors
- Phasic receptors
Tonic receptors
- activated with light pressure
- e.g.: merkels disks
- responding for duration of stimulus
Phasic receptors
- activated with deep pressure
- respond only to changes in pressure
- e.g. Pacinian corpuscle
Proprioceptors:
Monitor the position of the body in space
Mechanoreceptors for equilibrium example
Lobster
- statocyst
- statolith (stony particles)
- as porganism moves, statoliths roll around, which ever neurons are contacted, detected as mech. force
Hair cell mechanoreceptor
- responsible for hearing and balance
- sterocillia movement
- intrinsic excitability
- bathed in endolymph
- high external K+, low internal
What happens with a move toward longer stereocillia?
- more channel opening
- depolarization
- frequency of APs
What happens with a move toward shorter stereocillia?
- more closure of Ca2+ channels
- hyperpolarization
Vestibular apparatus
maintains stereocillia mechanism in inner ear
otoliths
rocks on gelatenous layer in vestibular apparatus
