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BIOL 1142 - Exam 1
Physiology Exam !
Question | Answer |
---|---|
physiology | study of function |
anatomy | study of structure |
levels of organization | atoms, molecules, cells, tissues, organs, organ systems, organisms, population of species, ecosystem of different species, biosphere |
10 systems of physiology | integumentary, nervous, endocrine, musculoskeletal, respiratory, urinary, reproductive, digestive, circulatory, immune |
teleologic approach | approach that is concerned with why things happen, what is the purpose of a certain function |
mechanistic approach | approach that is concerned with how things happen |
homeostasis | relative stability, regulated control within an optimal range, maintenance of a relatively stable environment tht can support life |
themes in physiology | homeostasis, biological energy systems, structure/function relationships, communication |
intracellular fluid | fluid inside of a cell |
extracellular fluid | fluid outside of a cell and in between cells |
which type of fluid is more active in maintaining homeostasis | extracellular fluid |
Cannon's postulates | 1. The nervous system has a role in maintaining fitness/homeostasis. 2. Some systems are under tonic control. 3. Some systems are under antagonistic control. 4. A single chemical signal can have different effets in different tissues. |
local control (homeostasis) | simplest type of homeostatic control, cell or tissue senses change and responds |
long distance control (homeostasis) | involves the nervous or endocrine system, involves response loops and feedback loops |
three different variations of response loops | 1. simple endocrine reflex 2. simple neural reflex (most common) 3. complex neuroendocrine reflex |
negative feedback loop | response eliminates the stimulus, homeostatic |
positive feedback loop | response increases or furthers the stimulus, not homeostatic |
independent variable | condition that the experimenter is manipulating |
dependent variable | things that change due to the manipulation of an independent variable |
law | statement of fact describing an action or set of actions; simple, universal, absolute; often expressed as a mathematical equation |
hypothesis | educated guess based on observation |
theory | explanation of a set of related observations or events based upon proven hypotheses and verified multiple times |
crossover study | same individual is studied for both experimental and control |
placebo effect | when a person has a response despite being given a drug that does not elicit any response |
nocebo effect | when a subject experiences side effects more frequently because they are informed about the side effects |
blind study | subject does not know whether they are part of the experimental or control group |
double-blind study | neither the subject nor the person administering the experiment knows whether the subject is part of the experimental or control group |
covalent bond | . |
ionic bond | . |
hydrogen bond | . |
van der Waals forces | . |
cation | positively charged ion |
anion | negatively charged ion |
polar | , |
non-polar | , |
hydrophilic | attracted to water |
hydrophobic | repels water |
pH | the concentration of hydronium ions in a solution; changes in pH can be due to changes in hydrogen bonding or van der Waals forces |
buffer | substance that moderates changes in pH and helps keep them constant |
biomolecules | carbohydrates, lipids, proteins, nucleotide |
carbohydrates | monosaccharides (glucose, fructose, galactose) and disaccharides (sucrose, lactose, maltose) |
lipids | triglycerides - glycerol + 3 fatty acids |
proteins | chains of amino acids (polypeptides) |
nucleotides | DNA and RNA |
soluble proteins | act as: enzymes, membrane transporters, signal molecules, receptors, binding proteins, regulatory proteins, immunoglobulins |
insoluble proteins | not usually involved in homeostasis, may provide structure or other non-essential actions |
ligand | any molecule that binds to another; also known as a substrate, if binding to an enzyme or membrane transporter |
agonist | ligands that bind to the same protein and activate it |
antagonists | ligands that bind to a protein and deactivate it |
specificity | ligands will bind to only one type of protein |
affinity | how strong the bonding is |
competition | tendency of a ligand to bind more easily with one molecule over another |
saturation | maximum bonding capacity |
isoforms | different forms of the same protein |
modulators | temperature, pH; competitive inhibitors; allosteric inhibitors; covalent modulators |
temperature and pH as modulators | may change shape of a protein or activate/deactivate it |
competitive inhibitor | use of another substance that has more of an affinity than the original substance |
allosteric inhibitor | substance that inhibits or activates certain receptors (ex, barbituates and GABA receptors) |
covalent modulator | alters covalent bonds and allows something to bind to a protein to modify it |
ATP | potential energy |
kinetic energy | . |
potential energy | . |
exogonic reaction | energy is released |
endergonic reaction | energy is utilized |
activation energy | amount of energy required to start a reaction |
enzyme | catalyst that lowers the energy of activation |
catabolic reactions | metabolic reactions that produce energy via breakdown of large biomolecules |
anabolic reactions | metabolic reactions that use energy to produce large biomolecules |
measurement of metabolism | heat |
metabolism | rate at which chemical reactions are taking place; focuses on how we get and manufacture ATP |
ATP vs ADP | ATP is higher energy than ADP |
ATP production from glucose | glycolysis, citric acid cycle, electron transport chain; only about 1/3 of ATP is captured, the rest is released as heat |
glycolysis | breakdown of glucose into 2 3-C molecules (pyruvate) |
citric acid cycle | requires O2, occurs in mitochondria |
electron transport chain | requires O2, yields 6 molecules of CO2, 6 molecules H2O and 32-24 molecules of ATP depending on cell type |
glycogen | storage form of glucose |
gluconeogenesis | formation of glucose when no glucose or glycogen is available |
deamination | glycolysis and the citric acid cycle are examples |
lipolysis | process where triglycerides are catalyzed and ATP is produced; requires O2, occurs in mitochondria; slow process, yeilds fewer ATP than using glucose, neurons cannot use this process |
DNA | "instruction sheet" for a cell, housed in the nucleus, double-stranded |
transcription | copy; identical information in a different form, example - RNA is a single strand copy of DNA that can leave the cell |
translation | happens in ribosomes of a cell |
RNA | "middle man" - gets DNA information to ribosomes |
gap junctions | communication junctions between cells |
tight junctions | prevents leakage between cells |
adherens junctions, desmosomes | provide strength to cells |
focal adhesions, hemidesmosomes | hold cells where they are supposed to be; functions as a break in cell division |
4 types of tissues | 1. epithelial 2. connective 3. muscle 4. nervous |
anatomical compartments | . |
functional compartments | . |
membrane | structure that lines a cavity; phospholipid bilayer that forms the outer boundary of an organelle or cell |
types of cell membranes | plasma membrane, plasmalemma, sarcolemma, neurolemma |
selective permeability | allows some things to pass through the membrane while others cannot |
permeable molecules | can cross the cell membrane |
nonpermeable molecules | cannot cross the cell membrane |
membrane structure | heads of lipids - hydrophilic tails of lipids - hydrophobic lipids provide structure proteins give added functionality carbohydrates play a role in cell recognition and immune function |
role of proteins in membrane | integral proteins - part of the membrane, peripheral proteins, lipid-anchored proteins; act as channels, carriers, docking-marker acceptors, membrane bound enzymes, receptors, cell adhesion molecules, self-recognition |
exocytosis | use of vesicles to bring materials out of a cell |
endocytosis | use of vesicles to bring materials into a cell |
need to re-do percentage of body fluids - tonicity | , |
assisted membrane transport | 1. carrier-mediated 2. vesicular transport |
carrier mediated transport | transmembrane proteins move molecules across the cell membrane |
2 types of transport proteins | 1. channel proteins 2. carrier proteins |
channel proteins | are selective for a certain substance; allow things to move through the channel created via diffusion (passive process); channels may be gated channels or leak channels; when channel is "open" molecules can pass through |
carrier proteins | specifically bind to a molecule on one side of the membrane and despot it onto the other side - usually only open to one side of the membrane at a time, slower process (5,000 molecues/sec) |
properties of carrier proteins | specificity (transports only one thing); saturation (can only transport a certain number of things); competition (some molecules bind more readily than others) |
uniport carriers | carriers that transport a single molecule in one direction |
symport carriers | carriers that transport two or more molecules in the same direction |
antiport carriers | carriers that transport two or more molecules in opposite directions |
gated channels | channel proteins can have mechanical gates, voltage gates, or chemical (ligand) gates. Type of gate tells what is needed to "open" the channel. |
leak channel | a channel that is always open and allows substances to pass through; very important for resting membrane potential |
facilitated diffusion | passive carrier-mediated transport; carriers allow lipophobic molecules to cross the membrane; does not require energy, molecules travel according to concentration gradient, high-->low |
active transport | energy dependent carrier-mediated transport; transport of molecules against their concentration gradient, low--->high |
primary active transport | involves Na+, K+, H+, Ca++; most important primary active transport is the Na+/K+ pump, nearly 50% of ATP is used for this pump. 3 Na+ out, 2 K+ in uses 1 ATP. |
secondary active transport | primary transport provides the energy needed for the secondary transport, example: sodium glucose transporter (SGLT) |
vesicular transport | includes phagocytosis, endocytosis (pinocytosis, receptor-mediated endocytosis), exocytosis |
phagocytosis | cell "eating" |
endocytosis | bringing materials into a cell |
exocytosis | removing materials from a cell, happens a lot in endocrine cells |
pinocytosis | cell "drinking" - cell gulps extracellular fluid and hopes to obtain item needed |
receptor-mediated endocytosis | receptor is specific to a certain substance, more selective than pinocytosis |
transepithelial transport | transport of molecules across epithelial tissue into other parts of the body; must cross both the apical cell membrane and the basement membrane; example: small intestine, kidneys |
transcytosis | formation of vesicles moves things across a cell |
types of epithelial transporters | apical surface transporters and basolateral surface transporters (ex, Na+/K+ ATPase) |
resting membrane potential | electrical energy difference between inside and outside the cell that has the potential to do work for the cell; the resting membrane potential of most cells at rest is ~70mV |
electricity review | the human body is electrically neutral; opposite charges attract; negative charges repel; charges move through a conductor; charges are separated by an insulator (plasma membrane); electrical potential is measured in volts (or mV, 1/1000th of a volt) |
what determines the resting membrane potential | differences in concentration of ions on either side of the cell membrane (chemical force), selective permeability of the cell membrane, separation of charges on either side of the cell membrane (electrical force), equilibrium potentials for permeable ions |
ions responsible for resting membrane potential | Na+, K+ and A- |
[Na+] outside cell/[Na+] inside cell [K+] outside cell/[K+] inside cell | ~150 mM, ~15 mM ~5 mM, ~150 mM |
plasma membrane, Na+, K+ and resting membrane potential | plasma membrane is permeable to Na+ and K+ (not equally); only a tiny portion of Na+ and K+ need to move to result in a large electrical difference, ion concentrations do not change. |
Nernst equation | used to calculate equilibrium potentials; value for K+ is -90 mV; value for Na+ is 60 mV; only calculates based on permeability of one particular ion |
equilibrium potential | the balance point between the chemical force driving something in/out of the cell and the electrical force driving something in/out of the cell |
Goldman-Hodgkin-Katz equation | modified Nernst equation that considers relative permeabilities of the ions that contribute to the resting membrane potential |
permeability of ions | ions are lipophobic; unequal permeabilities through the plasma membrane are due to more open channels for a certain type of ion; membrane potential changes when permeability to Na+, K+, Ca++ or Cl- changes. |
depolarization | change of the resting membrane potential from negative to positive |
hyperpolarization | change of resting membrane potential from positive to negative |
repolarization | return back to resting membrane potential from either a depolarized or hyperpolarized state |
insule secretion | . |
number of cells in an adult human | 10 trillion |
reasons cells need to communicate with each other | growth and development, maintenance of homeostasis, sensation/thinking/acting, immune function |
direct intercellular communication | physical contact via gap junctions or transient cell-to-cell contact |
gap junctions | allow passage of ions and small molecules; only method for direct transfer of electrical signals from one cell to another; may be open or closed; allows immediate, fast communication with the next cell; less common than indirect communication |
transient cell-to-cell contact | occurs when cells migrate throughout the body; example - T-cells; very important during development (melanocytes from the spinal cord travel to skin and not other organs); important for immune system function in adults |
indirect intercellular communication | all cells engage in indirect communication; cell makes and releases a chemical into the interstitial fluid, target cell has a receptor that binds to the messenger, target cell responds |
target cell | cell with a receptor that can receive a chemical messenger |
paracrines | travel short distances; effect exerted only on immediate neighbors; spread by simple diffusion through interstitial fluid; autocrine activity; function as growth factors, clotting factors, cytokines |
autocine | cell that releases a paracine acts on it - the cell has both signals and receptors; may be used as a negative feedback loop that shuts off the release of the paracrine |
histamine | paracrine signal that initiates inflammation (heat, swelling, redness, pain) |
neurotransmitters | short distance intercellular communication; highly localized to the synapse; released by a presynaptic neuron, diffuse across synaptic cleft, binds to postsynaptic receptors; travels by diffusion; amino acids or amines |
hormones | long distance intercellular communication; secreted into the blood by endocrine system; act on target cells; travel to all systems but not all cells have receptors for a specific hormone; some neurons release hormones instead of neurotransmitters |
neurohormones | hormones released by neurosecretory cells; act on target cells; subtype of hormone; example: hypothalamus |
amino acids as chemical messengers | all amino acids function as neurotransmitters; synthesized in cytosol, transported and stored in vesicles, all are lipophobic and can diffuse across synaptic cleft but not plasma membrane |
most common excitatory neurotransmitters | glutamate, aspartate |
most common inhibitory neurotransmitters | gamma-aminobutyric acid (GABA), glycine |
chemical messengers by functional classification | paracrines, neurotransmitters, hormones |
chemical messengers by structural classification | amino acids, amines, peptides/proteins, steroids, eicosanoids |
amines as chemical messengers | function as paracrines, neurotransmitters and hormones; contain an amine group (nitrogen); catecholamines - dopamine, norepinephrine, epinephrine (derived from tyrosine); serotonin, histamine, thyroid hormones; all EXCEPT thyroid hormone are lipophobic |
catecholamines | include dopamine, norepinephrine, epinephrine; production is sequential - tyrosine --> LDopa --> dopamine --> norepinephrin --> epinephrine; enzymes allow these conversions |
peptides/proteins as chemical messengers | most common chemical messenger, function as paracrines, neurotransmitters and hormones; syntheisized in the rough endoplasmic reticulum, modified in the golgi apparatus, stored in secretory vesicles; prepropeptide --> propetide --> peptide; lipophobic |
steroids as chemical messengers | function as hormones; derived from cholesterol; found in smooth endoplasmic reticulum; lipophilic and can cross membrane/cannot be stored; regulated by production, used immediately |
eicosanoids as chemical messengers | function as paracines; derived from arachidonic acid, a 20 C fatty acids; examples: prostaglandins, leukotrienes, thromboxanes, prostacyclins; lipophilic, cannot be stored |
transport of messengers | paracrines and neurotransmitters travel by simple diffusion over short distances; hormones are dissolved in the plasma or bound to a carrier protein |
half-life | time it takes for the concentration to drop from full concentration to 50%; lipophobic messengers have short half lives, lipophilic messengers have longer half lives; carriers give proteins longer half lives because of protection from enzymes |
how chemical signals produce responses in target cells | signal molecule (ligand) is known as the first messenger; binding to a receptor activates the target cell; receptor activates one or more intracellular signal molecules; last signal molecule exerts cellular response |
lipophobic messengers/ lipophilic messengers and receptors | lipophobic messengers bind at the cell mebrane, typically change the function of some protein, short duration; lipophilic messengers bind to cytosolic or nuclear receptors, usually turns on or off a gene |
signal transduction | how a extracellular message is converted into an intracellular message that activates a response; depends on the type of receptor that is activiated; multiple types of signal transduction pathways |
3 main cell responses to an extracellular messenger | 1. open or close a gated receptor-channel (change permeability) 2. activate a receptor enzyme (generally contained inside cell) 3. activate a second messenger pathway via a G-protein coupled receptor (inside the cell, activiates a second transduction) |
protein kinase | enzyme that phosphorylates a target protein (ie, attaches a phosphate to a target); phosphorylation is a common on/off switch |
membrane receptors | includes ligand-gated channels, receptor-enzyme, G-protein coupled receptors, integrin receptors |
amplification | one receptor may turn on multiple proteins, each of these in turn activates multple proteins, etc.; allows low concentration of hormones to produce a significant response |
ways that signal transduction pathways may be modified | receptors exhibit specificity, saturation and competition; down-regulation; up-regulation; signal termination |
down-regulation | decrease in receptor numbers; example - tolerance for drugs |
up-regulation | increase in receptor number; become more sensitive to the signal |
endocrine cells | select group of cells that can produce hormones |
hormones | secreted by a cell or group of cells; transported by the blood; binds to receptors on the target cell; exert effects at very low concentration; hormone action must be terminated |
primary endocrine organs | primary function is the secretion of hormones - hypothalamus, thyroid/parathyroid, pituitary gland, adrenal gland, pancreas, gonads, pineal gland |
secondary endocrine organs | hormone secretion is secondary to some other function |
hypothalamus | "the master gland"; with the pituitary gland, regulates almost every body system; has both non-endocrine and endocrine functions; secretes 6-7 hormones |
infundibulum | thin stalk of tissue that connects the pituitary gland to the hypothalamus |
pituitary gland | inferior to hypothalamus; originated from epithelium in roof of the mouth; two sections: anterior (adenohypophysis) and posterior (neurohypophysis); protected by the bones of the sphenoid, specifically the sella turcica |
anterior pituitary (andenohypophysis) | more vascular connections; produces, stores and releases 6 hormones; all secretions are controlled by hypothalamic neurohormones |
posterior pituitary (neurohypophysis) | extension of the neural tissue; has a stronger physical connection to the brain; stores and releases 2 hormones - vasopression (ADH - antidiuretic hormone) and oxytocin |
trophic hormone | a hormone that controls the release of another hormone; 5 of the 6 anterior pituitary hormones are trophic; hypothalamus hormones are trophic |
hypothalamic-hypophyseal portal system | specialized circulatory system that allows the hypothalamus to act trophicly; first capillary bed is in the hypothalamus, 2nd capillary bed is in the anterior pituitary; low volume portal system; allows for high conc. of hormones to pituitary gland |
TABLE with hormones | m |
feedback loops in the hypothalamic-pituitary pathway | each hormone acts as a negative feedback signal; long-loop and short-loop feedback; example - hormone produced by the pituitary gland "turns off" the homrone that was released by the hypothalamus |
adrenal glands | adrenal cortex (outer portion of the kidney)secretes: mineralocorticoids, glucocorticoids, androgens; adrenal medulla (inner portion) sercretes: epinephrine (80%) and norepinephrine (20%) via chromaffin cells |
pancreas | glandular organ, has both exocrine and endocrine functions; secretes insulin, glucagon and somatostatin |
Gonads | ovaries in females, testes in males; male hormones include testosterone and androstenedione; female hormones include estradiol and progesterone |
examples of secondary endocrine organs | Heart, Liver, Kidney, GI trct, ?Skin |
things that influence hormone action | type of receptor, signal transduction methods, hormone concentration |
things that influence hormone concentration | rate of hormone secretion, hormone transport to bound receptors, hormone metabolism |
humoral signals | signals that occur in the blood and produce changes in the blood such as stimulating hormones, responding to ions, responding to metaboli such as glucose |
neural signals | hormone release is controlled by the nervous system |
hormone insteractions | synergism, permissivenes, antagonism |
synergism | 2 hormones that produce a similar effect on their own, but if both are present the rate is more than additive. For example, epinephrine + glucagon |
permissiveness | one hormone doesn't act on its own; the secondary hormone will give response but it won't be stronger with the first hormone; thyroid and reproductive hormones fall into this category |
antagonism in the endocrine system | insulin/glucagon, parathyroid/calcitonin |