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Aristotle, Galileo, Galen, and William Harvey details
- Aristotle – all problems solved by thinking, no experiments.
- Galileo – first true scientist, performed ball experiment.
- Galen – developed physiology based on 4 humors (black bile, yellow bile, phlegm, and blood).
- William Harvey – discovered blood circulation
Steps in the scientific method
Problem, hypothesis, experiment, data, conclusion, report
How does a negative feedback loop work?
Sensor detects deviation from set point, sends information to an integrating center which controls effectors that correct the deviation
How does a positive feedback loop work?
Response of effectors moves the variable farther away from the set point
Relationship of variables to diffusion: concentration gradient, temperature, mass, surface area, distance, medium
- Concentration gradient - direct
- temperature - direct
- mass - inverse
- surface area - direct
- distance – inverse
Carbohydrates: basic formula? Polarity? Types w/ examples?
- CnH2nOn. Polar.
- Monosaccharide (glucose, galactose, fructose)
- Disaccharide (sucrose [glucose + fructose], maltose [glucose + glucose])
- Polysaccharide (glycogen, starch)
Lipids: polarity? Types w/ example?
- Triglycerides (fats and oils)
- Phospholipids (phospholipids bilayer)
- Steroids (cholesterol [precursor for steroid hormones], corticosteroids [produced by adrenal glands], sex steroids [produced by gonads])
Proteins: polarity? Levels of structure, held by? Functions?
- Mostly polar but can contain nonpolar sections.
- Primary – sequence of amino acids (peptide bonds)
- Secondary – alpha-helix or beta-pleated sheet shape (H+ bonds, electrostatic interactions)
- Tertiary – twisting/folding of a peptide chain (chem. Interactions involving R groups)
- Quaternary – interaction of multiple peptide chains (chem. Interactions involving R groups).
- Structural functions, hormones, enzymes, receptors
Amino Acid structure?
Central C connected to Amino group (NH2), H atom, Carboxyl group (COOH), and R-group
Transcription vs. translation?
- Transcription – DNA -> RNA
- Translation – RNA -> protein
Double membrane. Inner membrane (cristae) surrounds matrix.
Rough ER function
Synthesizes proteins for cell membranes, lysosomes, and export from cell
Smooth ER function
Lipid synthesis, Ca2+ storage, metabolize various molecules
Golgi body function
Posttranslational modifications, sort/direct finished products to destination
How is apoptosis completed?
Caspaces (enzymes) fragment DNA and disassemble organelles
Aerobic Respiration steps and ATP released
- Glycolysis – glucose breakdown (2 ATP)
- Krebs Cycle (2 ATP)
- Oxidative phosphorylation (26-28 ATP)
- 30-32 ATP total per glucose molecule
Anaerobic Respiration alternate name? Used by? ATP released?
- Lactic acid fermentation.
- Used by quick skeletal muscle fibers and RBCs.
- 2 ATP per glucose.
What does brain use to get energy?
Aerobic respiration of blood glucose ONLY
Types of tissue w/ function?
- Muscle (movement, heat production)
- nerve (communication)
- epithelial (barriers, secretion/absorption)
- connective (structure/support)
Muscle tissue types. Striation? Shape? Voluntary? Location?
- Skeletal – striated, very long, multinucleated, involuntary.
- Smooth – small, fusiform, not striated, involuntary.
- Cardiac – heart only, striated, involuntary
Epithelial tissue types. Function? Classification?
- Covering – thin sheets that cover all body surfaces, linked via basement membrane. Classified by cell depth (Simple [1 cell thick], stratified [2+ cells thick]) and cell shape (squamous- flat, cuboidal- cube, columnar- rectangular).
- Glands – clusters of epithelial cells that secrete materials. Classified by Exocrine (w/ ducts, outside of body), endocrine (no ducts, hormones into blood)
Connective tissue classification? Examples?
- Classified by extracellular matrix (ground substance + fibers) and cells.
- Tendons, dermis, adipose, cartilage, bone, blood
Bulk transport: description? Examples? Active?
- Large # of molecules can be exchanged w/ extracellular fluid simultaneously.
- Phagocytosis, endocytosis, exocytosis. Active transport
Vesicle vs. vacuole
Vesicle – small, vacuole – large
Phagocytosis: description? What uses phagocytosis?
- Cell extends pseudopods around particle which merge to form a vacuole.
- Neutrophils, monocytes (macrophages)
Endocytosis: description? Examples
- Invagination of plasma membrane to import materials ALSO removes material from plasma membrane.
- Pinocytosis (cell invaginates and fuses over interstitial fluid)
- Receptor-mediated endocytosis – binding to receptor proteins induces membrane invaginations and substances on receptors are pulled into the vesicle
Fusion of vesicle with plasma membrane, contents released into extracellular fluid ALSO adds material to plasma membrane
Simple diffusion vs. facilitated diffusion and who uses what?
- Simple diffusion – across membrane without carrier protein (directly across membrane – nonpolar molecules [O2, CO2, steroid hormones], through channel proteins – polar molecules [water, Na+, K+]).
- Facilitated diffusion – across membrane with carrier protein (glucose)
Blood plasma osmotic pressure? NaCl isotonic value? Glucose isotonic value?
- 300 mOsm or .3 Osm.
- 9g/L (.9% m/v) NaCl.
- 50g/L (5% m/v) glucose
Aquaporins produced/inserted by? Function?
Produced in ER, inserted by Golgi (via exocytosis). Change membrane’s H2O permeability.
Carrier mediated transport description? Active vs. passive?
- Both – bind to substance on one side, change shape to release substance on other side, have a maximum rate of transport (can become saturated), highly specific.
- Passive (facilitated diffusion) effected by diffusion variables.
- Active (pumps) act against concentration gradient
Active transport examples, details?
- Ca2+ pumps – Ca2+ binds to carrier protein in cytosol, carrier protein is phosphorylated by ATP -> ADP + Pi, carrier protein changes shape moving Ca2+ out of cell (where concentration is greater).
- Na+/K+ ATPase – pumps 3 Na+ out of cell and 2 K+ into cell simultaneously to generate gradients for electrical impulses in nerves and muscles AND drive co-transport of other substances across the membrane (glucose)
Tracts vs. nuclei vs. nerves vs. ganglia
- Tracts (axons, CNS).
- Nuclei (cell bodies, CNS).
- Nerves (axons, PNS).
- Ganglia (cell bodies, PNS)
Axon hillock vs. axon terminal
- Axon hillock – where action potential originates, base of axon near cell body.
- Axon terminal – where neurotransmitters are released (presynaptic terminal).
Types of neurons (functional)? Cell body/axon location? (_polar)? Afferent/Efferent? Function?
- Sensory – afferent, cell body in PNS, axon in CNS, relays stimuli from tissue to CNS, dendrites/sensory receptors, unipolar.
- Motor – efferent, cell body in CNS, axon in PNS, carries signals from CNS to effector (muscle/gland), multipolar. Somatic motor – skeletal muscles. Autonomic motor – smooth and cardiac muscle, glands. Autonomic divided into sympathetic (fight or flight) and parasympathetic (rest and digest).
- Association – interneurons, cell body and axon in CNS, receive from/send to other neurons, analyze/modulate/modify/integrate signals, responsible for cognition/memory, 99% of neurons, multipolar
Types of neurons (structural)? Location? Shape?
- Multipolar – many dendrites with a single axon, most common (motor/association).
- Pseudounipolar – single short process that branches like a T (sensory).
- Bipolar – two processes, one dendrite one axon, rare (sensory in eyes, ears, nose)
PNS neuroglial cells w/ function?
- Schwann’s cells – forms myelin sheath (single axon), helps regenerate damaged axons.
- Satellite cells – surrounds cell bodies in ganglia
CNS neuroglial cells w/ function?
- Oligodendrocytes – forms myelin sheath (multiple axons).
- Astrocytes – controls permeability of blood-brain barrier, supports neuron activity.
- Microglia – act as macrophages.
- Ependymal cells – lines brain/spinal cord cavities creating CSF
Major insulator in myelin sheath?
Multiple plasma membranes
What is standard resting membrane potential? What 3 channels contribute to maintains this potential?
- -70 mV.
- K+ leak channels, Na+ voltage gated channels, and Na+/K+ ATPase
Depolarization vs. hyperpolarization
- Depolarization – stimulation, more positive than RMP.
- Hyperpolarization – inhibition, more negative than RMP
Major channel types in neurons w/ description? Location?
- Ligand-gated – binding of a chemical signal (neurotransmitter) causes channel to open, found on dendrites and cell body and synapses.
- Voltage-gated – depolarization causes channel to open (must reach threshold potential), found on axons (Ca2+, K+, Na+)
What are the possible states for a voltage-gated Na+ channel w/ description?
- Closed – RMP, can be triggered by depolarization.
- Open – threshold (-55mV), Na+ flows into cell.
- Inactive – (+30mV), activation gate closes and is not able to be triggered
Action potential description/information
- Begin at axon hillock,
- travel length of axon,
- rapid change driven by opening of voltage-gated Na+ and K+ channels,
- self propagating,
- all or none response [threshold potential (-55mV) must be met]
- cannot summate, must run toward axon terminal
Events during an action potential – depolarization?
- event causes membrane to depolarize,
- if threshold potential is met voltage gated Na+ channels open causing Na+ to rapidly flow into the cell causing depolarization,
- when membrane potential reaches +30mV Na+ channels are inactivated which stops Na+ movement into the cell,
- at this time K+ channels are fully opened
Events during an action potential – repolarization?
- K+ flows out of the cell, bringing potential back to RMP,
- when the potential is hyperpolarized beyond RMP both K+ and Na+ channels close (Na+ no longer inactive).
- Na+ and K+ gradients are restored by Na+/K+ ATPase
What effect does a stronger stimulus have on a signal?
Signal strength remains identical (all or none) but frequency is increased
Types of refractory period w/ description and timing
- Absolute refractory period – cannot respond to a 2nd stimulus, Na+ channels are either open or inactive.
- Relative refractory period – AP may be produced but stronger stimulus is required, Na+ channels closed but K+ still flowing out of the cell at a high rate
Compound APs vs. individual APs?
Compound APs can vary in amplitude and threshold because many or few axons can be stimulated in a nerve (bundle of axons)
How are neurotransmitters propagated to leave the axon terminal? Where do they go? What effect does a stronger stimulus have on this process?
- Voltage-gated Ca2+ channels on axon terminal open in response to AP, Ca2+ rushes into cell and induces exocytosis of neurotransmitter.
- Neurotransmitter diffuses across synaptic cleft and binds to receptors on the post-synaptic membrane.
- More frequent APs result in more neurotransmitters being released
Ionotropic receptors vs. metabotropic receptors
- Ionotropic receptors – ligand-gated ion channels bind to a neurotransmitter which causes the channel to open.
- Metabotropic receptors – G-protein linked receptors generate second messengers (cAMP, IP3, DAG) which can have a variety of postsynaptic changes
Types of synaptic potential w/ description?
- EPSP – excitatory, Na+ diffuses in, cell depolarizes, if EPSP is reaches axon hillock at threshold then AP is formed.
- IPSP – inhibitory, Cl- diffuses in, cell hyperpolarizes, makes threshold more difficult to reach
Synaptic potential characteristics
Decrease in amplitude with distance, graded responses, no refractory period, can summate
Spatial summation vs. temporal summation
- Spatial summation - summation due to multiple presynaptic neurons.
- Temporal summation – summation due to a single presynaptic neuron
Nicotinic ACh receptors: ionotropic/metabotropic? Excitatory/inhibitory? Location? Function? How is neurotransmitter removed?
- Found in specific regions of brain, skeletal muscle cells, cell bodies of autonomic motor neurons in ganglia.
- Na+ in and K+ out simultaneously.
- ACh quickly broken down by acetyl cholinesterase which is embedded in the post-synaptic cell membrane
Muscarinic ACh receptors: ionotropic/metabotropic? Excitatory/inhibitory? Location? Function? How is neurotransmitter removed?
- Excitatory in GI tract, inhibitory in the heart.
- Found in CNS neurons, smooth muscle, glands, and cardiac muscle.
- G-Protein dissociates into separate subunits that activate enzymes/ion channels.
- ACh quickly broken down by acetyl cholinesterase which is embedded in the post-synaptic cell membrane
GABA receptors: ionotropic/metabotropic? Excitatory/inhibitory? Location? Function?
- Found in CNS neurons.
- Cl- in
Monoamine receptors: ionotropic/metabotropic? Excitatory/inhibitory? Function? How is neurotransmitter removed?
- Can be inhibitory or excitatory depending on postsynaptic cell.
- G-Protein dissociates into separate subunits that activate enzymes and produce second messengers that activate addition enzymes which induce metabolic changes or change in membrane potential.
- Monoamines generally taken back up by presynaptic cell then broken down by an enzyme inside the pre-synaptic axon terminal
Examples of monoamines
- Catecholamines (dopamine, epinephrine, norepinephrine).
lysosome “eats” other organelles
long/stringy functional unit of DNA (+protein)
short/condensed DNA packaged for movement
flattened sacks of the Golgi Body
sequence of DNA containing info. for amino acid sequence to make a protein
breakdown of glycogen to create glucose
M taking into account ALL permeable solutes
Isotonic glucose solution in hospitals
difference in charge from inside of cell to outside of cell (typically negative)
node of Ranvier
segment between myelenation on an axon
APs jump from one node of Ranvier to the next increasing conduction speed (in a myelenated axon)