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102 Cards in this Set

  • Front
  • Back
Types of Physiological Subdiciplines
Cellular and Molecular Phys
-genetics, metabolism, organelles
Systems Phys
-function of organs
Organismal Phys
-whole animal
Ecological Phys
-animal and it's environment
Integrative Phys
-multiple levels of organization
Levels of Study in Physiology
Reductionism
Emergence
Reductionism
understanding a system by studying the function of it's parts
Emergence
The whole is more than the sum of its parts
Homeostasis
maintenance of internal consistency
Genotype
genetic makeup
Phenotype
morphology, physiology, and behavior
Allometric Scaling
Body size influences physiological pattern
metabolic rate over body mass
line of unity between the two
Strategies for coping with changing conditions
Conformers
Regulators
Conformer
allows internal conditions to change with external conditions
Types of Physiological Subdiciplines
Cellular and Molecular Phys
-genetics, metabolism, organelles
Systems Phys
-function of organs
Organismal Phys
-whole animal
Ecological Phys
-animal and it's environment
Integrative Phys
-multiple levels of organization
Levels of Study in Physiology
Reductionism
Emergence
Reductionism
understanding a system by studying the function of it's parts
Emergence
The whole is more than the sum of its parts
Homeostasis
maintenance of internal consistency
involves continuous maintenance
nervous system and endocrine systems accomplish the communication via nerve impulse and hormones
Strategies for Coping with Changing Conditions
Conformers
Regulators
Conformers
Allow internal conditions to change with external conditions
Regulators
Maintain relatively constant internal condition regardless of external condition
Homeostatic Control Mechanisms
Nervous-- quick
Endocrine-- slow
Components of Control Mechanism
Receptor (sensor)
Control Center
Effector
Receptor
Monitors the environment
Responds to Stimuli (changes in controlled variables
Receptor--Afferent Pathway--Control Center
Control Center
Determines the set point at which the variable is maintained
Receives input from receptor
Determines appropriate response
Control Center-- Effernet pathway-- Effector
Effector
Receives output form control center
Provides the means to respond
Response acts to reduce or enhance the stimulus (feedback)
Involved after control center is elicited by afferen signal sent to control center to effernt signal which elicites the effector which wich effects feedback and returns the variable to homeostatic level
Negative Feedback Loop
Response reduces or shuts off the original stimulus
eg stress hormones (endocrine system)
regulation of body temp
regulation of blood volume by ADH (also endocrine system response)
Negative Feedback Loop Examples
Stim of risen body temp-- receptors in the skin-- to the afferent pathway-- to control center-- to effernt pathway-- sweat glads triggered-- body temp is reduced-- stim ends

Body temp is lowered-- efferent pathway sends stim to control center-- afferent pathway sends signal to skin-- triggers shakes or goose bups-- body temp is risen-- end of stim
Positive Feedback Loop
Response enhances or exaggerates the original stim
May exhibit a cascade or amplifying effect
Usually controls: enhancement of labor contractions via oxcytocin or platlet plug formation and blood clotting
Phenotypic Plasticity
single genotype generates more than one phenotype DEPENDING upon environmental stimulus
*PHENOTYPE is a product of genotype and its interaction with the environment
eg Daphnia
look at figure 1.1
can be reversible or irreversible
Irreversible Phenotypic Plasticity
Polyophenism-- developmental plasticity
Reversible Phenotypic Plasticity
Acclimation-- under laboratory conditions
Acclimatization-- under natural environment
Natural Coping Under Phentoypic Plasticity
Diversity in anatomic and physiological strategies animals use to cope with their environment
2 Types of questions : Proximate Cause and Ultimate Cause
eg: giraffe heart size and log neck apposed to desert rodent renal tubule size
Proximate Cause
How did certain phenotypes develop?
eg for Daphnia-- to protect them from predator
Ultimate Cause
Why are these changes helpful?
eg for Daphnia-- to become immune to predator via phenotypic changes
Basis for Evolution and Natural Selection
Darwin did not discover evolution
he came up with notion of a mechanism for evolution (natural selection)
Alfred Russel Wallace and Darwin came up with the idea..
BASIC IDEA:There is evolution; traits in population change in time
~ change can occur enough for speciation (new formed species)
Fundamental Principles of Evolution
Traits are heritable
Variation among individuals for specific traits (They are heritable)
Some versions of those traits are more adaptive (more fitness) than others
eg Giraffe hearts
Combine these three pieces together and you get changes in populations; changes in frequency of traits
-Add to random changes int riats (i.e. genteic mutations) and you get large changes in traits of a population
--Environmental changes, thus adaptive traits might no longer be adaptive over time
Genetic Drift
Not all differences are adaptable
RANDOM changes in the frequency of genotypes over time
Independent of adaptive evolution
Most common in SMALL populations
--eg forest fires resulting in founder effect
This can cause a founder effect
Founder Effect
Survival without genetic or evolutionary dominance, they just happened through genetic drift
Evolutionary Relationships
Common evolutionary ancestor
Despite diversity in animal form and function, there are similarities
The more closely related, the more shared featrues
Understanding evolution is necessary to understand physiological diversity
Cellular Physiology
Modern phys is much about the interactions of molecules and cells as it is about the interactions of organs in organisms
Necessary to understand the structure and characteristics of cells to be able to understand organs, organ systems, and organisms
Cellular Physiology Functions
Cell is the smallest structural functioning living unit
Organismal functions depend on individual and collective cell functions
Biochem activities of cells are dictated by their specific subcellular structures
--structure dictates function
Cellular Physiology Cell Functions
Cells for task s essential to survival to maintain homeostasis based on INTRACELLULAR functions
Cells need to generate energy from nutrient molecules to sustain life
Energy is generated intracellularly via the cytosol and mitochondria
Cellular Physiology Cell Organelles
Organelles and cytoskeleton participate in many tasks contributing to homeostasis
Understand the function of plasma membrane
--membrane transport and membrane potential-- vital to maintaining homeostasis in various cell types
Disturbances causes issues-- eg K abnormalities in cardiac cells
How do adaptations on a cellular level allow organs to perform tasks
--emphasize protein synthesis modification and trafficking
Cells
2 MAJOR TYPES
Prokaryotes
-bacteria, cyanobacterial
-small 1-10 microns
-primitive, simple structure
Eukaryotes
-fungi, plants, animals
- larger, 10X larger than prokaryotes
-complicated structure
- lots of intracellular compartments
Eukaryotic Cells
Plasma membrane
-- phospholipid bilayer
-- outer boundary
Cytosol/Cytoplasm
-- inside of cells
-- filled with protein fillaments
-- filled with organells
Nucleus
-- control center
Intracellular membranes form distinct compartments, like rooms in a house, concentrate specific characteristic set of proteins with biochem funtion, segregate biochem reactions that could be hazardous to one another.
--- allows cells to be bigger, and accomplish a wide range of functions
Generalized Cell
All cells have common structures and functions
LOOK AT
Life of a Cell: http://multimedia.mcb.harvard.edu/
Cytosol
space between membrane and orgnanells
50% of cell volume
site of protein synthesis, much of intermediary metabolism
Gelatinous(high concentration of soluble filamentous proteins
Small molecules diffuse easily
EG of cytosolic proteins
enzymes required for glycolysis: glucose-6-phosphate dehydrogenase
Synthesis of cytosolic protein... peptide chain completed and released!
Mitochondria
Site of ATP sythesis
-- oxidative phosphorylation
2 compartments
-- matrix
-- inter-membrane space
some proteins synthesized here on their own ribosomes
It has it's own genomes b/c evolved from bacterium
Endoplasmic Reticulum
Extensive membrane network
Defines a continuous internal space (ER lumen)
Rough ER
Smooth ER
Most proteins translocated to ER get glycosylated
Rough Endoplasmic Reticulum
ribosomes associated on surface
major function: biosythesis of membrane and secreted proteins
close to nucleus
Smooth Endoplasmic Reticulum
no associated ribosomes
major function: lipid biosythesis
most cells have very small SER
Liver cells ahve a lot: site of drug detoxification and glycogen breakdown
--eg cytochrome P450 enzyme
Protein Glycosylation in ER
1.Carbohydrate (sugar) molecules are linked to amino acid in protein
2. Carried out by enzymes that reside in ER
FUNCTION of glycosylation
Increase resistance to proteases
some protein-protein interactions are dependent
After translocation into the ER all proteins move on to the Golgi
Golgi Apparatus
series of distinct compartments
disk-like shaped
ER-- to Golgi-- Cis Golgi-- Medial Golgi-- Trans Golgi-- Plasma Membrane
FUNCTION of GOLGI
protein maturation and sorting
it packages protein for movement
Some proteins are removed/ added
Each reaction occurs in specific compartment... cis, medial, trans so glycosylation can be used to determine the progress of proteins through ER/ Golgi
-- some enzymes subclasses get unique modifications
---eg: protein that function in lysosome (only) get manno-6-phosphate
In Golgi there are enzymes that chop proteins
Protein Maturation in Golgi: II Proteolytic Processing
Some proteins are sythesized as inactive precursor proteins, that need to be proteolytically cleaved to become mature (active) cleavage can occur in Golgi
EG: peptide hormones: including insulin, and some growth factors
In accordance to diabetes:
Insulin is a protein secreted to decrease or regulate blood glucose levels and golgi stores it away for later use
Probly also in Golgi-- if insulin is not broken down, glucose levels go through the roof and casue damage to blood vessels
Protein Sorting in Golgi
Golgi is like a clearing house; proteins with differnt destinations are segregated and sent to final location
Sorting is accomplished via special sorting sequences
Possible destinations:
1. Golgi Retenation: Golgi-resident proteins (proteases, glycosylation enzymes) have a Golgi Retention Signal
eg: some stay in Cis, some move to Medial, some move to Trans
Other possible destinations: 2. Plasma Membranes/ Constitutive Secretion-- default pathway. no special sorting info requiredother than signal peptide. Soluble proteins get secreted, integral membrane proteins go to plasma membrane
3. Specialized Secretory Vesicles (i.e. regulated secretion or exocytosis) Only occurs in some cells (neurons). Proteins have undefined signal. They get sorted, concentrated, sroted in specialized secretory vesicles. When cell is stimulated, vesicles fuse with dock protiens on plasma membrane and get released.
4. Lysosome: proteins that receive mannose-6-phosphatein Golgi go to the Lysosome.
Lysosome
Small membrane-bounded vesicles
Contain hydrolytic enzymes to digest macromolecules (i.e. proteases, nuclease, lipases, phosphotases, ect)
FUNCTION: to breakdown macromolecules and recycle components to use in the cell.
Inside of lysosome is acidic!! pH approx. 5.0 due to ion pump that hydrolyzes ATP and pumps H into lysosome
Macromolecules get delivered to Lysosome via endocytosis.
Lysosomal Enzyme Sorting form Golgi to Lysosome
*Lysosomal proteins receive specific modification: Mannose-6-phosphate
1. In Golgi, proteins containing mannose-6-phosphate get packaged into clathrin-coated vesicles
---- cathrin forms a basket-like coat on surface of Trans-Golgi membrane and promotes vesicle formation. Coat also contains adaptins (look at figure p 19)
2. Mannose-6-phosphate receptor binds lysosomal protein in Golgi and binds clathrin coat via adaptation. This allows (mannose-6-phosphate-protein-receptor-clathrin) complex to accumulate in a bud and pinch off into a vesicle
3. Coat comes off vesicle and fuses with endosome and delivers content
--- endosome is preexisting compartment with low pH like the lysosome
4. Low pH in endosome casues mannose-6-phosphate& receptor complex to fall apart. phosphate on protein is removed by phosphatase in Lysosome
5. Mannose-6-phosphate receptor is recycled back to Golgi via transport vesicle
6. Sorted protein stays in endosome, endosome matures to become a Lysosome
Lysosomal Storage Disease
1.Disruption of lysosome sorting can occur in several ways
--Drug tunicamycin blocks addition of N-linked sugars to newly synthesized proteins, preventing attachment of mannos-6-phosphate recognition marker
-- Compounds that elevate pH prevent enzymes from dissociating from receptor and block recycling back to TGN so proteins pass through TGN unrecognized
2. Tay-Sachs
results from mutated gene that encodes lysosomal enzyme (HEX A); unable to degrade substance that contains certain specific sugar linkages. Overcrowding of these sugar linkages causes cell death.
Cell Signaling and Endocrine Regulation
-Nucleus & Plasma Membrane
-Membrane Transport
- Cellular Communication
- Endocrine Regulation
Membrane Structure
Phospholipid Bilayer
Within the bilayer, there are integral proteins, peripheral proteins, cholesterol, glycoproteins (with sugar that is connected/ resides on them), and channel proteins
Membrane Transport
Cells have to transport molecules across the membrane
3 types:
Passive Diffusion
Facilitated Diffusion
Active Transport
Distinguished by direction of transport, nature of carriers and role of energy
Cellular Communication
communication between cells
Signaling cell sends a signal (usually a chemical) and target cell receives the signal and responds to it
Types of Cell Signaling
DIRECT
Signaling cell and target cell connected by gap jusnctions
Signal passed directly from one cell to another
INDIRECT
signaling cell releases chemical messenger
chemical messenger carried in extracellular fluid (some secreted into environment)
chemical messenger binds to a receptor on the target cell
activation of signal transduction pathway
response in target cell
Indirect Signaling over Short Distances
Paracrine
Chemical messenger diffuses to nearby cell
Autocrine
Chemical messenger diffuses back to signaling cell
--eg of Autocrine is a T-cell. this is also a part of a positive-feedback loop

memorize at table 3.1
Indirect Signaling over Long Distances
Endocrine System
Chemical messenger (hormone) transported by circulatory system
Nervous System
Electrical signal travels along neuron and chemical messenger (NT) released

memorize at table 3.1
Direct Signaling
Gap Junctions
Specialized protein complexes creates an aqueous pore between adjacent cells
Movement of ions between cells
Changes in membrane potential (via electrical signal)(eg heart block-- block in electrical signal between cells)
Chemicla messenger can travel through the gap junction (eg cAMP)
Opening and closing of gap junction can be regulated
Steps Involved in Indirect Signaling
3 Steps:
--Release of chemical messenger from signaling cell (gland)
--Transport messenger through extracellular environment to target cell
--Communication of signal to target cell
Systems for indirect signaling have similarities and differences
Glands
Exocrine Gland
-- excrete substance into center of gland (into environment)
Endocrine Gland
-- secretory cells release hormone into blood stream and the hormone only binds to target cell
Chemical Messengers
6 Classes of Chemical Messengers:
-Peptides
-Steroids
-Amines
-Lipids
-Purines
-Gasses
Structure of chemical messenger (especially hydrophilic vs hydrophobic) affects signaling mechanism

memorize table 3.2
Peptide/Protein Hormones
2-200 amino acids long
Synthesized in RER
--often larger preprohormones
Stored in vesicles
--prohormones
Secretes by exocytosis
--hormones
Hydrophilic
--soluble in aqueous solutions
-- travel to target cell dissolved in extracellular fluid
Binds to transmembrane receptor
--signal transduction
RAPID EFFECT ON TARGET CELL
eg insulin
Transmembrane Receptor
eg: G-protein
stretches across cell membrane
the ligand binding domain is in the extracellular fluid. The transmembrane domain is in the phospholipid bilayer. The inracellular domain is contained in the cytoplasm
Steroid Hormones Types
Derived from cholesterol
Synthesized in SER or Mitochondria
Steroids are a 4 ring structure
3 Classes of Hormones
Mineralocorticoids
-- Electrolyte Balance
Glucocorticoides
--Stress Hormones (eg: chortosol)
Reproductive Hormones
--Regulate sex-specific characteristics (eg: testosterone, estrogen, oxcytocin
Steroid Hormones
Hydrophobic
Can diffuse through plasma membrane so they ONLY bind inside of cell
No carrier protein is needed but if bound, must dissociate before entering cell
Cannot be stored in the cell
Must be synthesized on demand
Tranported to target cell by carrier proteins
-eg. albumin
Bind to intracellular or transmembrane receptors
Slow effect on target cell (gene transcription)
---- stress hormone cortisol has rapid non-genomic effects
Amine Hormones
Chemical possessing amine group (NH2)
-- eg: ACh, Catecholamines(dopamine, norepinephrine, epinephrine) serotonin, melatonin, histamine thyroid hormones
-- sometimes called biogenic amines
Some true hormones, some NT, some both
Most hydrophilic
-- thyroid hormones are hydrophobic
Diverse effects
Other Chemical Messengers
Eicosanoids
-most act as paracrines
-hydrophobic
-often involved in inflammation and pain.
eg: arachidonic acid
these need a protein for transport
Other examples
1st Prosaglandin-- inflammation
2nd Prostocycline-- thins blood
3rd Thromboxanes-- promotes clotting
COX inhibitors
Cycloogenase exists in 2 forms (COX-1 and COX-2)
Aspirin irreversibly inhibits COX-1
-- know the downstream effect
COX Inhibitors (COX-1 and COX-2 Effects)
Cycloogenase Exists in 2 forms- COX-1 and COX-2
Aspirin irreversibly Inhibits COX-1 and weakens COX-2
- Reduces Prostaglandis (anti-inflammatory) via COX-2
-Reduces Thromboxanes (less platelet aggregation= thinned blood) via COX-1
-Reduces Prostacyclins (removes inhibition of clotting= increased bleeding) via COX-1
--normally inhibits platelet plug formation( notice homeostatic antagonism between TX and PG)
--can lead to GI bleeding after chronic ingenstion
NSAIDS such as aspirin, acetaminophen, ibuprofen- directly target cycloogenase
SO drug companies now generate a compound that ONLY inhibits COX-2 (anti-inflammatory)
*celecoxib (Celebrex)
*rofecoxib (Vioxx)-- but was withdrawn in 2004 by Merck after cardiovascular risks found associated with it
Gases are Chemical Messengers
Most act as paracrines (nearby cells)
eg: nitirc oxide (NO) and carbon monoxide (CO)
Purines are Chemical Messengers
Function as neuromodulators and paracrines
eg: adenosine, AMP, ATP, GTP
Communication to the Target Cell (Overview)
Hormones made from plentiful precursors wit easy synthesis
When possible, one generates many diff hormones with similar starting product
-steriodal ring makes <1,000 diff major and minor steroid hormones
--- progesterone, major, gives rise to minor ones with anti-anxiety effects
Endocrine glands conserve resources so require fancy receptor that can differentiate among similar hormones
------ imagine estrogen receptor mistaking it for testosterone
Receptors on Target Cell (Communication to the Target Cell)
Hydrophilic messengers bind to transmembrane receptor
Hydrophobic messengers bind to intracellular receptor
Ligands to Target Cell (Communication to the Target Cell)
chemical messenger can bind to specific receptor
receptor changes shape when ligand binds
Ligand-Receptor Interactions
Very specific
Only correctly shapes ligand can bind to receptor
Ligand mimics
-Agonist- Active receptor
-Antagonist- block receptor
-Many ligand mimics act as drug or poisons (beta blockers, Ca++ channel blockers, ect)
Ligand-Receptor Binding
L+R=LR
Formation of LR causes response
More free L or R will increase the response
--- Law of Mass Action
Receptors are saturated at high L
-- response is maximal
[L][R]/[LR]=KD
KD tells you how likely binding is to occur
smaller the KD, steeper slope, more affinity to bind (shown in Skatchard graph)
BUT HIS SLIDES show it as %of receptors bound over the concentration of messenger (Ligand?)
Changes in Number of Receptors
Number if receptors affects L-R complexes
-More receptors= more LR complexes= higher response
Target cells alter respons numbers
-DOWN Regulation
-- target cell decreases the number of receptors
--often due to high concentration ligand
UP Regulation
--target cell increases the number of receptors
Inactivation of Ligand-Receptor Complexes
Diffusion
Endocytosis
Enzyme Digestion
-eg ACh esterase is an enzyme that digests extracellular ACh in synapse
Signal Transduction Pathway
When hormone binds to receptor they cause a variety of changes within the cell
-Chenges mediated by intracellular signal transduction pathway
Interaction Among Transduction Pathways
Cells have receptors for different ligands
Diff Ligands activate diff transduction pathways
Response of the cell depends upon the complex interaction of signaling pathways
--often involving a negative-feedback loop
Endocrine System
Endocrine System- cells, tissues, organs- secrete and respond to circulating chemical messenger molecules
Controls FUNCTIONS
-salt and water balance
-bp
-stress response
-cellular metabolism
-growth and development
-sexual maturation and desire
Organ System of Endocrine System
Pineal Gland
Hypothalamus
Pituitary Gland
Thyroid Gland
Parathyroid Gland (on dorsal aspect of thyroid)
Thymus
Adrenal Gland
Pancreas
Ovary/ Testis
Several Ways the Brain Controls Endocrine System
Anterior Pituitary hormone system
Posterior Pituitary hormone system
Autonomic nervous system
Posterior Pituitary-Hypothalamus Relationship
It's a downgrowth of hypothalamic tissue
Neurohormones are produced in cell body of hypothal and sent down axons to the post pituitary gland.
-Following AP in neuron, hormone is released form axon terminal in posterior pituitary into the blood
FIGURE page 19
Anterior Pituitary- Hypothalamus Relationship
Aka Hypophyseal portal system (ant pit called hypophysis)
When stimulated, hypothal releases homones into primary capillary plexus from axon
Hypothalamis hormones travel through the portal veins into ant pit and stimulate or inhibit the release of hormones from the ant pit
Ant pit hormones are secreted into secondary capillary plexus
Anterior Pit releases tropic hormones (eg. ACh) that cause the release of another hormone
Third order endocrine pathway
FIGURE page 20
ANS control of Endocrine System
ANS can also control the release of hormones
EG: Sympathetic NS controls the release of epinephrine from the adrenal gland
Regulation of Blood Glucose
Precisely controlled
-blood glucose too high=osmotic balance of blood disturbed
-blood glucose too low= brain cannot function properly
Hormones
-Insulin lowers blood glucose levels
-Glucagon raises blood glucose levels
Insulin and glucagon are secreted by pancreas
--direct feedback loop
--pancreas also receives neural and hormonal signals
FIGURE 3.33 page 22
Additivity
When hormones cause same response in target cell
Hormones do not use the same signaling pathway
--EG: glucagon, epinephrine, and cortisol all raise blood glucose levels by different mechanisms
Response of target cell to combos of these hormones is ADDITIVE
Synergism
When hormones enhance the effect of other hormones
Response of target cell to combos of these hormones is more than additive
Evolution of Cell Signaling
Chemical messengers, receptors, and cell signaling mechanisms of animals share many similarities
*Suggest a common ancestor
Vertebrate Hormones
Evolutionary change in the way tissues respond to hormones, rather than a change in the hormone molecule
Some hormones have same effect in diff animals
-EG: HGH increases growth rate in fish; estrogen from pregnant mares can be used in post menopausal women
Some hormones have diff effet in diff animals
-EG: prolactin- stim milk production in mammals, inhibits metamophosis and promotes growth in amphibians, and regulates water balance in fish
Stress Response
adaptive and maladaptive components to stress response
Homeostatic Control Mechanisms
Involve continuos monitoring and regulation of many factors
Nervous and Endocrine system accomplish communication
Stress is a short-term physical stressor that disturbs homeostasis
What is Stress?
stimulus (stressor) that is recognized by the brain (stress perception) which activates fight/flight response (stress response)
Acute Stress: minutes to hours
Chronic Stress: weeks/months/years
Fight-or-Flight Response
Mobilization of energy
Increased cardiovascular tone
Suppression of digestion
Sharpening of cognition
HPA Axis
Hypothalamus--releases factor to-- Anterior Pituitary-- releases ACTH through blood-- to Adrenal Gland--- releases cortisol