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Physio Exam 1
Week 1 Info
| Question | Answer |
|---|---|
| The function of a tissue or organ is closely linked to its... | Structure |
| What is Physiology? | The study of normal funtion in living system |
| How does an increase in the metabolic activity of a muscle lead to an increase in bloof flow to that muscle? | Increase metabolic activity, decrease oxygen and increase metabolites in organ intersitial fluid, arteries dilate in organ, and increase blood flow to organ. |
| When there is an increase in metabolic activity of a muscle... | It uses more oxygen and nutrients. |
| What is Pathophysiology? | Studying how mormal function goes wrong as in human diseases. |
| Organization and layers of the body... | Cells-tissues-organs-organ systems-organism(body) |
| What are Cells? | The simplest s tructural units into which a complex multicellular organism can be divided and still retain the characteristics of life. |
| What are the functions most common to cells? | 1. Exchange materials with their environment 2. Obtain energy from organic nutrients 3. Synthesize complex molecules 4. Duplicate themselves 5. Detect and respond to signals in their immediate environment |
| What is Cell Differentiation? | Cells specialize to perform certain functions |
| 4 types of differentiated cells | 1. Muscle Cells (myocytes; skeletal, cardiac, and smooth) 2. Neural Cells 3.. Epithelial Cells 4. Connective Tissue Cells |
| What is a Tissue? | An aggregate of differentiated cells with similar properties and functions |
| 3 Types of Muscle Cells | Smooth, cardiac, and skeletal |
| Which of the 3 muscle cells is voluntary movement? | Skeletal |
| What is a Neuron? | Initiates, integrates, and conducts electrical signals to other cells. |
| What are Epithelial Cells? | Specialized for selective secretion, absorption of ions, and organic molecules and protection. |
| What do Connective Tissues do? | Connect, anchor, and support structures of the body. |
| Extracellular matrix (ECM) | Provides a scaffold for cellular attachments and also transmits informantion. |
| Blood cells are... | Connective tissue cells |
| What is an Organ? | A collection of tissues joined in a structural unit to serve a common function. |
| What is an Organ System? | Organs that are linked together to serve an overall function. |
| If cells can perform their own fundamental activities, why are the functions of the organ systems essential for survival? | -Most of the cells are isolated from external environment -Existence of a stable internal environment made up of fluids in distinct compartments -The constant balance between these internal fluid compartments is neccessary |
| Why in a closed vascular system, are the extracellular fluids compartmentalized? | To enable exchange of nutrients and waste. |
| What % of the body is water? | 60% |
| Where do we find the water in the body? | 2/3 of it is found inside cells (intacellular fluid) and 1/3 outside of cells (extracellular fluid). |
| What is the plasma volume? | 20% of the Extracellular fluid which is inside the cardiovascular system. |
| What is the interstitial fluid volume? | 80% ECF which is located between cells. |
| What separated the intracellular fluid from the extracellular fluid compartment? | The cell/plasma membrane. |
| The composition of the ECF is... | Similar to seawater, very salty. |
| What separates the interstitial fluid from the blood plasma? | The capillary wall. |
| What do plasma proteins do? | Keep the fluid inside the cardiovascular system. |
| What is it called when there is too much interstitial fluid? | Edema |
| What is Homeostasis? | The relative constancy of the internal environment, dynamic constancy. |
| When a cell is at rest... | It is slightly negative. |
| When a cell is activated... | It reverses and for a very short time becomes positive (action potential). |
| What initiates reactions? | Whenever there is a change in the extracellular fluid composition. |
| Ways the body does homeostasis | -Ions, pH -Fluids -Blood Sugar -Body temperature |
| The core temperature of the body is continuously sensed by... | Thermoreceptors located in the body. |
| Where is the integrating sensor located? | Hypothalamus. |
| In the integrating center, the body core temperature is continuously compared to the... | Set point. |
| Effector responses... | Return the body temperature closer to its normal value. |
| Stimulus + Response= | Reflex |
| What is Negative Feedback? | Decreases the effect of the stimulus by moving the variable in the opposite direction. |
| What is a Reflex Arc? | A biological contol system that directly links a stimulus with a response. |
| What is a Stimulus? | A detectable change in the controlled variable. |
| What is a Receptor? | The sensore on which the stimulus acts. |
| The signal is then relayed from the receptor to... | The integrating center via affrent pathway. |
| The integrating center integrates the input from many receptors and sends its response to the... | Effectors via effrent pathways. |
| Negative feedback mechanisms are sometimes helped by... | Feedforward mechanisms. |
| Feedforward mechanisms... | Anticipate changes. |
| What is Positive Feedback? | Accelerated a process leading to an "explosive" system. |
| Positive feedback systems typically end with... | A major event that stops the process. |
| The communication between cells can happen using different types of messengers: | -Hormones -Neurotransmitters -Paracrine and autocrine agents |
| What is a Hormone? | A chemical messenger secreted by endocrine cells into the bloodstream. |
| What is a Neurotransmitter? | A chemical messenger released by a neuron to affect a muscle, gland, or nerve cell. |
| What is a Paracrine agent? | A chemical messenger released by a cell that acts on nearby cells. |
| What is an Autocrine agent? | A chemical messenger released into the interstitial fluid that acts upon the very cell that secreted it. |
| The characteristic that determines whether we call it a hormone, neurotransmitter, or a paracrine agent is... | Where it travels (location). |
| What is Negative balance? | Overall loss of a substance in the body. |
| What is Positive balance? | Overall gain of a substance in the body. |
| In a generic homeostatic reflex arc, what senses changes in either the internal or external environment? | Receptor. |
| What spontaneously aggregates in water to form a membrane? | Phospholipids. |
| The general structure of the membrane is called... | Fluid mosaic model. |
| What is Membrane fluidity? | There are no chemical bonds between the fatty acid chains, so there can be a lot of lateral movement within the membrane. (No chemicals hold them together) |
| What is a Selective barrier? | Regulates the passage of substances into and out of the cell. |
| What do Membrane junctions do? | Link adjacent cells together. |
| What are the functions of the plasma membrane? | -Act as a selective barrier. -Communication between cells. -Link adjacent cells together by membrane junctions. -Anchoring cells to the ECM. |
| Membrane functions are primarily carried out by... | Membrane proteins. |
| What are Integral/transmembrane membrane proteins? | Closely associated with the membrane lipids and are amphipathic. |
| What are Peripheral membrane proteins? | Located at the inner or outer membrane surface and are polar. They do not interact with phospholipid tails or span whole membrane. |
| What is a Ligand? | Any molecule that is bound to a protein. |
| Is ligand binding reversible or irreversible? | Reversible. |
| Binding of a ligand to a protein will often... | Change the conformation of the protein. |
| What is Affinity? | How strong or weak the ligand protein bind is. |
| What is Saturation? | All of the binding sites are occupied. |
| What is Competition? | More than one ligand can bind one site. |
| What is Random thermal motion (Brownian motion)? | Water molecules are constantly moving allowing dye molecules to dissolve. Responsible for simple diffusion. |
| What is Flux? | The amount of material crossing a surface at cm^2/sec |
| What is Diffusion Equilibrium? | Dye molecules collide with each other moving equally around both compartments. |
| What is Net Flux? | The difference between two fluxes. |
| If a system has reached diffusion equilibrium, the net flux is... | Zero. |
| The net flux is always from a region of.... | High concentration to low concentration. |
| Diffusion is driven by... | The concentration gradient. |
| The larger the concentration gradient... | The larger the net flux. |
| What is Net Flux affected by? | -Temperature -Molecular Mass -Surface Area -Viscosity of the Medium |
| What is the thickness of a cell membrane? | Approx. 5nm. |
| What is a typical eukaryotic cell diameter? | Approx. 10-100um. |
| Since the membrane is made of phospholipids, substances that dissolve in lipid... | Dissolve rapidly across the cell membrane. |
| What can cross through a cell? | Nonpolar substances and ions. |
| Examples of Selective Channels? | -Sodium channels -Potassium channels -Calcium channels |
| What is Gating? | The mechanism can modify the conformation of transmembrane proteins to result in opening or closing of a channel. |
| What are the 3 ways ion channels can be gated? | -Ligand-gated channels -Voltage-gated channels -Mechanically-gated channels |
| Since Na+ ions are positive and the inside of the resting cell is negative... | Na+ is attracted to the inside of the cell. |
| Ion movements through membranes is governed by an... | Electrochemical gradient. |
| What is Passive Flux? | Diffusion across membranes, no energy required. |
| Small non-polar molecules can diffuse... | Down their concentration gradient. |
| Small ions can diffuse... | Down their electrochemical gradient. |
| What are the 2 mechanisms used to go against gradient? | -Mediated Transport -Vesicular transport |
| What is a Carrier? | Type of transporter used by both mediated and vesicular transport. |
| All membrane transporters are... | Transmembrane proteins. |
| How do Mediated transporters work? | 1. Expose a binding side to one side of membrane. 2. Then they change shape and release solute on other side of membrane. |
| Transporters follow the rules of protein/ligand binding... | 1. Exhibit specificity 2. Require a conformational change in shape 3. Limited in number on membrane |
| What 3 things can affect mediated transport? | 1. Concentration of ligand 2. Rate of transport (protein kinetics) 3. The # of transporters |
| What is Facilitated Diffusion? | Uses a transport to move a solute, used for large, polar molecules that cannot diffuse on their own. |
| What are the 4 Characteristics of facilitated diffusion? | 1. Doesn't require energy 2. Uses transmembrane protein as a carrier 3. Has chemical specificity. 4. Displays Saturation. |
| What is Active Transport? | Moves substances uphill against their electrochemical gradient. |
| What are the 2 reasons some Na+ channels and Na+ tends to leak into the cell? | 1. Concentration gradient 2. Electrical gradient |
| What is Primary Active Transport? | Energy for transport is provided by the hydrolysis of ATP by the carrier protein. The transporter itself is an ATPase enzyme. |
| What is an example of Primary Active Transport? | Na+/K+ ATPase pump. Na+ needs to be pumped out of the cell all the time. |
| What is Secondary Active Transport? | The hydolysis of ATP by one carrier creates an ion gradient that drives a secondary carrier. Potential energy is stored in the gradient and can be used to drive something else. |
| What is Endocytosis? | The plasma membrane folds into the sell and makes a small pocket that encloses the material and eventually pinches off to form a vesicle. |
| What is Exocytosis? | Vesicles in the cytoplasm fuse with the plasma membrane and release their contents outside the cell. |
| What does a Transduction System do? | Converts a cell signal into a meaningful response. |
| What is Signal Transduction? | -Messenger attaches to the binding site on the receptor -Shape of protein changes (allosteric modulation) -Cellular response is elicited. |
| What is Specificity? | The first messenger binding site has a particular shape into which only certain molecules fit. |
| What is an Agonist? | A chemical messenger that binds to a receptor and triggers the normal response. |
| What is an Antagonist? | A molecule that binds to a receptor, but does not elicit a response. (Blocker) |
| What is Physiological Regulation? | The number of receptors in the cell membrane is not constant and can change in response to a stimulus over time. |
| What is Down-regulation? | When there is a high extracellular concentration of a messenger for some time, the total number of receptors for that messenger will decrease. Result in decreased sensitivity. |
| What is Up-regulation? | When there is a low extracellular concentration of a messenger for some time, the total number of receptors for that messenger will increase. Result in increases sensitivity. |
| What are the 4 main types of signal transduction pathways for plasma membrane receptors? | 1. Ion channels 2. Enzymes 3. Cytoplasmic enzymes 4. G-proteins |
| When an ion channel is opened and ions move out of the cell... | The electrical potential of the membrane will change. |
| When the first messenger binds to the receptor... | The enzyme portion of the protein, inside the cell, is activated. |
| When the first messenger attaches to the receptor, a conformational change in the receptor leads to... | Activation of the cytoplasmic enzyme. |
| What are G-Protein coupled receptors? (Most common) | The receptor is linked through G-proteins to effector proteins such as channels or enzymes. |
| How do G-Protein coupled receptors work? | -First messenger binds to receptor -Elicits conformational change in receptor -Causes part of G-protein to dissociate, diffuse along inner surface of the plasma membrane and bind to an effector protein and it gets activated -Causes response |
| If the effector protein is a channel... | The G-protein may cause that channel to open or close. |
| If the effector protein is an enzyme... | A second messenger is produced in the cell, which serves as a relay from the plasma membrane to the biochemical machinery inside the cell. |
| What is the cyclic AMP second-messenger system? | -Activates G-protein -Gs activates effector protein, adenylate cyclase -Adenylyl cyclase catalyzes ATP to cAMP -cAMP is second messenger, activates a protein kinase |
| What is a Signal Amplification? | The more first messenger attaches to the receptor, the more second messenger will be produced and the stronger the cellular response will be. |
| How can we control or turn off cAMP system? | Reduce cAMP by breaking it down via enzyme phosphodiesterase (PDE). Changes in level of PDE will affect the level of cAMP |
| What is NOT a part of a G-protein coupled signal transduction pathway? | Ion Channel opening in the receptor. |
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saradrake46
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