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81 Cards in this Set
- Front
- Back
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What are the 3 ways endocrine glands can be stimulated to release hormones |
Humoral Stimulation Neural Stimulation Hormonal Stimulation |
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Compare Humoral, Neural, and Hormonal Stimulation |
Humoral: triggered by changes in body fluid composition Neural: triggered by nerves Hormonal: Hypothalamus release hormones trigger Anterior Pituitary to secrete hormones, which stimulate other endocrine organs |
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Describe the relationship between the Hypothalamus and Anterior Pituitary |
The Hypothalamus sends release hormones via a port system to the anterior pituitary, which then secretes other hormones. |
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Describe the structure & function of the Posterior Pituitary |
A bundle of nerves fused to the Anterior Pituitary, which releases 2 hormones (Oxytocin & Vasopressin). These hormones are synthesized directly in the Hypothalamus. |
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Describe Short Feedback Loops of Hypothalamic-AP hormones. |
The hormone secreted by the anterior pituitary causes negative feedback on the hypothalamus, influencing the secretion of hypothalamic release hormones. |
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Describe Long Feedback Loops of Hypothalamic-AP hormones. |
The last hormone secreted in the reflex pathway influences secretion of upstream/trophic hormones from both the Hypothalamus & the Anterior Pituitary. |
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Describe Primary Hypersecretion |
When the last endocrine gland in the reflex is producing excess hormone |
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Describe Secondary Hypersecretion |
When dysfunction occurs in one of the tissues producing trophic hormones. |
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Location & function of Oligodendrocytes |
Location: Central Nervous System (CNS), around neuron axons Function: Create mylen sheaths around 1 or more axons, providing insulation. |
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Location & Function of Schwann Cells |
Location: Peripheral Nervous System (PNS), around neuron axons Function: Create mylen sheaths around an axon, providing insulation. |
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Location & Function of Ependymal Cells |
Location: Central Nervous System (CNS), Cerebral Spinal Fluid Function: Create barriers between compartments |
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Location & Function of Astrocytes |
Location: Central Nervous System (CNS) Function: Form blood brain barrier & ATP substrates |
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Location & Function of Microglia |
Location: Central Nervous System (CNS) Function: Act as modified macrophages (scavengers) |
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Define Membrane Potential & the relative ion concentrations between ICF & ECF |
The difference in electrical charge across the cell membrane, established mostly by Na+/K+ pumps. ICF has more K+ ions, and the ECF has more Na+, Cl-, and Ca2+ ions. The ICF has a net negative charge. |
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Why do Graded Potentials slow down and decrease in strength? |
Due to current leak of K+ to the ECF and Cytoplasmic Resistance. |
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Why don't Action Potentials slow down or decrease in strength? |
Myelin sheaths insulate the axons, preventing ion leaks, and establish nodes of ranvier, allowing for Saltatory Conduction |
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What are the two gates of the Na+ channels? |
Activation gate & Inactivation Gate |
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Describe the function and speed of the Activation Gate of Na+ Channels |
Depolarizing stimulus opens the fast & voltage-gated activation gate, and allow the inflow of Na+ into the ICF. |
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Describe the function and speed of the Inactivation Gate of Na+ Channels |
The inactivation gate is activated the same as the activation gate, but responds 0.5msec slower. The inactivation gate prevents further inflow of Na+ ions, causing the max membrane potential to be +30mV. |
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Define the Absolute Refractory Period |
When both Na+ gates are resetting: Activation gate is still open, and Inactivation gates are still closed.
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Define the Relative Refractory Period |
After the absolute refractory period, some Na+ channels are reset and ready, but K+ channels are still open, requiring a stronger depolarization from a stimulus to reactive the AP. |
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How does axon myelination and diameter contribute to Action Potential speed? |
Larger Diameter = faster due to less resistance Myelination prevents ion leakage Nodes of Ranvier: Saltatory Conduction |
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What are Nodes of Ranvier? |
The gaps between myelin sheaths on the axon. They prevent ion leakage and facilitate signal jumping (saltatory conduction) for increased speed and maintained amplification of a signal. |
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What is Physiology? |
The study of the normal functioning of a living organism and its component parts. |
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Why is the Cell the key unit of life? |
It is the smallest structural unit capable of carrying out all life processes |
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Define Homeostasis and explain why it is the Focus of Physiology? |
Maintains internal stability and constancy of the ECF, by facilitating disequilibrium/homeostasis. Physiology is the study of normal functioning, which necessitates homeostasis. |
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Explain the difference between Negative and Positive Feedback
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Negative Feedback stabilizes the regulated variable & is homeostatic: moving closer to the set point Positive Feedback reinforces the stimulus & is not homeostatic: moving further away from the set point. |
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What are the 4 Main Biomolecules, and their respective monomers? What is the most abundant and important? |
Lipids: Fatty Acids Carbohydrates: Monosaccharides Proteins: Amino Acids (Abundant/Important) Nucleic Acids: Nucelotides |
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List and describe/defin the 3 types of Chemical Bonds w/an example for each. |
Covalent Bond: 2 atoms sharing an e- pair (C-H) Ionic Bond: 1 atom takes e- (Na+Cl-) Hydrogen Bond: Attraction of H to O,N, or F (H20) |
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Describe pH |
Power of hydrogen (-log of H+ activity) |
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Describe Acid & Bases |
Acid=proton donor: contributes to H+ concentration Base=proton acceptor: decreases H+ concentration |
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Describe a buffer |
Weak acid or base that moderates changes in pH |
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Describe "denature" |
Unfolding of proteins via non-covalent bond cleavage |
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What are the 4 primary tissue types? |
Epithelial Tissue
Connective Tissue Muscle Tissue Neural Tissue |
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Describe Epithelial Tissue |
Covers external/internal surfaces and lines lumen. Regulates exchange from ICF & ECF |
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Describe Connective Tissue |
"Filler" tissue that provides support, protection & storage Ex: Tendons & ligaments |
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Describe Muscle Tissue |
Excitable tissue that produces force and heat |
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Describe Neural Tissue |
Excitable tissue that carries electrical and chemical information |
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List, describe, and give examples for the 3 types of cell to cell junctions |
Gap Junction: Channel between cells for electrical or chemical messages Ex: Cardiac Muscle Cells Tight Junction: Prevents passage between cells, forcing passage thru the cell Ex: Intestinal Cells Desmosome: Strongest junction, anchors cells via proteins & cytoskeleton Ex: Epidermis |
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Describe a Gap Junction |
Channel between cells for electrical or chemical messages Ex: Cardiac Muscle Cells |
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Describe Tight Junctions |
prevents passage between cells, forcing passage thru the cell.
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Describe Desmosomes |
Strongest cell junction that anchors cells via proteins & cytoskeleton Ex: Epidermis |
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What happens to a cell placed in a Hypotonic solution |
Net water movement into cell - Swelling & possible lysis |
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What happens to a cell placed in Hypertonic solution? |
Net water movement out of cell - Shrinking (crenation) |
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Describe Facilitated Diffusion |
Passive transport of a molecule/ion down its concentration gradient. Does not require ATP, and may utilize either channel-type or carrier-type proteins. Ex: Aquaporins or Ion Channels |
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Describe Primary Active Transport |
Utilizes carrier-type proteins and requires direct use of ATP to move molecules/ions against their concentration gradient
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Describe Secondary Active Transport |
Utilizes carrier proteins to transport a molecule against its concentration gradient. This is facilitated by another molecule/ion moving down its concentration gradient, providing enough energy for the other molecule to move against its concentration gradient |
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Describe Channel Proteins |
-Passive Transport -Somewhat Selection (size/charge) -Opened or Gated (chemically/voltage/mechanically) -Oppositely charged to molecules/ions being tranported. |
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Describe Carrier Proteins |
Passive or Active Transport - Facilitated Diffusion or Primary/Secondary Transport Slower & More specific than channels Uniport, Symport, or Antiport May become saturated |
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Why is Na+ so important in the body |
High Na+ concentrations in the ECF are maintained to facilitate Na+ dependent secondary tranporters, which make up the bulk of the transporters of that type. |
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List the 3 types of Local Communication |
Gap Junctions Contact Dependent Diffuse to Nearby Target |
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Describe Gap Junctions (local communication) |
Direction communication/connection between cells via a protein "tunnel" that links the cytoplasm and allows for rapid but non-specific signaling Ex: Muscle cells 'act as one' |
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Describe Contact Dependent (local communication) |
a mobile cell comes into contact with another cell, allowing for ligand/receptor binding Ex: Growing Neurons in development |
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Describe Diffuse-To-Nearby Target (local communication) |
Paracrine & Autocrine signals diffuse through interstitial fluid, resulting in a very short range due to distance being a limiting factor in diffusion Ex: Histamine |
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Define Neurocrine |
Signals released by neurons |
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Define Neurotransmitters |
Diffuse across a small gap (synapse) to a target cell Ex: Acetylcholine |
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Define Neurohormones |
Released into the blood/plasma for action at distant targets, which must ahve the appropriate receptor. |
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Define Neuromodulators |
Neural signal that diffuses through large areas of the nervous system, effecting multiple neurons, and influencing the effect of other neurotransmitters. They are slow acting and behave in a paracrine fashion. |
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Define Intracellular Receptors (location, type of ligand that binds, and speed of response) |
Location: Cytosol or Nucleus Type of ligand: Usually steroids (lipophilic) Speed: Slow, involving the synthesis of proteins |
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Define Membrane Receptors (location, type of ligand that binds, and speed of response) |
Location: Cellular Membrane Type of ligand: Ions, Glucose, Protein/Peptide hormones, amino acids, nucleotides, or neurotransmitters. Speed: Fast, involving modification of proteins |
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Describe Signal Transduction
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Converts one form of a signal into a different form. Is used to relay information from a signal into the cell. Ex: Electrical-Chemical |
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Describe Signal Cascade |
series of events that initiated after the first inactive enzyme or molecule is activated by R:L binding. |
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Describe Amplification |
allows a small amount of a signal to have a big effect, by amplifying one ligand into many intracellular molecules via a 2nd messenger. |
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Describe Specificity as it relates to Protein binding |
The ability of particular ligands/receptors to bind to one another and not to others. |
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Describe Competition as it relates to Protein binding |
When two or more signal molecules have the ability to bind to the same receptor, causing them to "compete" for the mutual receptor |
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Describe Saturation |
The inability of receptors to bind to multiple ligands. |
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Describe Down-Regulation |
the decrease in number of receptors when under sustained high numbers of ligands. This process is slower than desensitization and is a mechanism of drug addiction |
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Describe Up-Regulation |
The insertion of more receptors in the cell membrane under sustained low number of ligands |
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Describe Desensitization |
The easily reversed process of temporarily modifying the receptors affinity to a ligand |
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Explain Tonic Reflex control |
The regulation of parameters up and down; the signal is always present but changes in intensity Ex: Norepinephrine on blood vessel dilation |
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Explain Antagonistic Reflex control |
Uses different signals to send a parameter in opposite direction Ex: Insulin/Glucagon hormones on blood sugar concentration |
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List and describe the 7 components of the Reflex Response Loop |
1. Stimulus: Change in regulated variable 2. Sensor/Receptor: Sensing/monitoring variable 3. Input Signal: How the signal is delivered 4. Integrating Center: Compares input signal to setpoint 5. Output Signal: electrical or chemical signal sent to target 6. Target: carries out response to bring variable back into range 7. Response: the negative feedback to decrease stimulus. |
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What are the 6 hormones released from the Hypothalamus? |
1. Prolactin (milk) [ONLY non-trophic] 2. Growth Hormone 3. Thyroid Stimulating Hormone 4. Adreno cortico trophic (ACTH) hormone (adrenal cortex - Cortisol) 5. Leutenizing Hormone (reproduction) 6. Follicle Stimulating Hormone (reproduction) |
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What are the three types of neurons |
Sensory Neurons: a. Somatic (body) PNS (w/schwann) b. Special Sensory: close to CNS (w/o schwann) Interneurons: highly branched & in CNS Efferent Neurons: typical & myelinated |
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What are the 4 types of Glial cells |
Ependymal Astrocytes Microglia Oligodendroytes |
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What is the neuron resting energy potential? |
-70mV |
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What is depolarization? |
ICF temporarily becomes more positive due to influx of Na+ |
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What is repolarization? |
Occurs after depolarization to bring membrane back to resting membrane potential due to efflux of K+ |
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What is hyperpolarization? |
ICF becomes MORE negative than -70mV due to influx of Cl- or additional efflux of K+ |
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What are the 9 steps of an Action Potential? |
1. Resting membrane potential at -70mV 2. Depolarizing stimulus 3. Membrane depolarizes to threshold: Voltage gated Na+ and K+ channels begin to open 4. Rapid Na+ entry depolarizes cell 5. Na+ channels close and slower K+ channels open 6. K+ moves from cell to ECF 7. K+ channels remaind open and additional K+ leaves cell, hyperpolarizing it 8. Voltage-gated K+ channels close 9. Cell returns to resting ion permeability and resting membrane potential |
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What is the threshold membrane potential to initiate an Action Potential? |
-55mV (difference of 15mV) |
