MCAT 2 Flashcards
What are the four quantum number!
- Principle number - main energy level (shell) n
- Orbital angular momentum - subshell type s (l=0, p (l=1), d (l=2), f (l=3) corresponding to shape of the orbital occupied by the electrons. (n-1)
- Magnetic quantum number - number of orbitals of given type and their orientation within sub level. Mt (all integers from -l to +l)
- Spin quantum number -angular momentum of an electron, Ms
What is the formula for specific rotation?
[a]= a obs/cxl
C-concentration (g/ml)
L- path length (dm)
Specific rotation must be determined experimentally. Observer rotation is dependent on the sample concentration and sample cell length
What is needed for PCR?
Polymerase chain reaction is a thermal cycling technique used to amplify DNA fragments. It needs:
1. Source DNA template
2. C-G rich primer pairs
3. Thermostable DNA polymerase - to replicate the DNA template using pool of dNTPs.
4. Buffer solution with positively charged ions. It provides optimal environment for DNA polymerase to function. Neutralizing the - charge of DNA.
What is bottle neck effect?
Is the drastic reduction in population size that occurs in response to some sudden and uncontrollable disaster (eg flood, famine, humans induced catastrophe). No genotype or phenotype is protective and members of the population are eliminated randomly. This substantially alters the genetic diversity and allele frequencies of the population in a way that doesn’t necessarily follow the principle of natural selection.
What is variable expressivity and incomplete penetrance?
Penetrance -proportion of individuals with a specific genotype who express the corresponding phenotype.
Variable expressivity - range of phenotype outcomes shown by individuals who carry the same gene type
How mitochondrial genome is passed down to the offspring?
They have their own genome, known as mitochondrial DNA which is generally inherited in a maternal fashion (no paternal contribution). Mitochondria within sperm are not transferred into the ovum during fertilization
Why erythrocytes are different than cells in the body?
They are biconcave, disk shaped cells that mainly contain hemoglobin, the carrier protein that transport oxygen to body tissues. They expell their nucleus and other organelles during synthesis in the bone marrow to maximize the available space for hemoglobin. They don’t consume oxygen they are transporting because they produce energy only via anaerobic glycolysis
What is dissociative disorders?
Characterized by disruption to memory and identity.
1. Dissociative identity disorder - presence of two or more distant personalities, amnesia
2. Dissociative amnesia- inability to recall important autobiographical information (eg personal history, traumatic event)
Most sugars in nature are?
D configuration (R)
What is gene flow?
Is caused by migration of individuals (or their gametes) between populations and can result in allele frequency changes
What is genetic drift?
Is a mechanism of evolution, however unlike natural selection, the variability’s in allele frequencies occur randomly by chance. Because of smaller populations have a smaller gene pool, the random variations due to genetic drift can’t be buffered
What is 5 assumptions involved in hardy weinberg assumptions?
- No new mutations
- No natural selections
- No gene flow in and out
- Random mating
- Large population size
What is adaptive radiation?
Is the process of diversifying characteristics (claw and teeth size) to better fill in ecological niche. It can eventually lead to speciation if the subgroup continues to diverge and loses the ability to interbred with individuals from the original species.
What is speciation?
Is the evolutionary process of forming a new species from a previously existing species. The process occurs over many generations and results in organisms that can’t interbreed with the ancestral species!
How stress effects immune system?
In response to stress, hypothalamus stimulates the pituitary gland to release adrenocorticotropic hormone ACTH. As a result ACTH release; the adrenal cortex secretes glucocorticoid hormones such a cortisol. Cortisol mediate stress responses by increasing blood glucose level and decreasing inflammation and protein synthesis. Chronic exposure to cortisol can negatively impede immunological response, increasing the susceptiblility for diseases and affect reproduction health (fecundity)
Why alpha hydrogens are more acidic?
Protons on alpha carbons are more acidic than other protons bonded to a carbon atom because the carbonyl oxygen is electron withdrawing, resulting in less electron density around the alpha protons. Therefore alpha protons have lower pKa values and can be more easily removed by a base to form an enolate which can be stabilized by charge delocalization.
What is retro aldol reaction
Is the reverse of the aldol condensation. When heated and treated with a aqueous base, the carbon carbon bond between the alpha and beta carbons is broken, forming two ketone, two aldehydes, or one of each, sleeping on the substituents on the carbonyl carbon and the beta carbon. Aldehydes form if the carbonyl and beta carbon had hydrogen substituents whereas ketones form if all substituents are carbon chains
What is continuity equation?
Q1=Q2
Q=Av
A1v1=A2v2
Q- volumetric flow rate
A - cross sectional area
V - fluid velocity
The volumetric flow rate of ideal fluids through interconnected segments of any conduit must be equal at every point along the length of the conducts. Continuity equation can be used to relate volumetric flow rate of one conduit segment to another
What are the enzyme name of citric acid cycle that reduce NAD+ and FAD?
Three NADH, 1FADH2 molecules are produces by redox reactions. Enzymes are dehydrogenases because the transfer of electrons is often accompanied by the the transfer of hydrogen atoms.
1. Isocitrate dehydrogenase
2. Alpha ketoglutarate dehydrogenase
3. Succinate dehydrogenase
4. Malate dehydrogenase
What is sensory adaptation?
Occurs when the neural response to an unchanging stimulus is dampened and the perception of that stimulus either disappears or is diminished. Sensory adaptation can occur with vision, hearing, smell, taste and touch.
What is stereopsis?
Is the perception of depth that arise from the integrated information received from both eyes. Binocular depth cues allow accurate perception of depth through the integration of slightly different information from left and right eyes. Binocular depth cues include:
1. Retinal disparity - distance between eyes results in slightly different images.
2. Convergence - angular positioning of eyes. The brain interprets the angle of convergence as an indication of distance from the observer.
What is accommodation of eyes!
As an object approaches the eye, ciliary muscles alter the shape of the lens. This referred as accommodation and is processed by the brain as a depth perception cue. Accommodation is monocular cue
What is subjective contours in gestalt principles?
Also known as reification or illusory contours, describes how our mind fills in the gap.
What is invariance in gestalt principle?
Objects can be recognized despite alterations in orientation, lighting, scale and slight alterations in the objects component features.
What is difference between kinesthetic sense and vestibular sense?
Kinesthetic
1. Proprioceptors in muscles, joints, tendons, and skin detects movement and position of body/limbs.
2. Kinesthetic input provides awareness of location of parts of the body in space and now they are moving.
Vestibular
1. Maintains balance and orientation, detects gravity/acceleration and head rotation.
2. Motion sickness arises from conflict between vestibular system and visual input
Spatial orientation and balance rely on input from?
- Visual
- Vestibular input - semicircular canals, otolith organs.
- Somatosensory input - proprioception
The oral cavity aids in ingestion of what?
Initial digestion of carbohydrates and triglycerides via salivary amylase and lingual lipase respectively
What is pepsinogen do!
In the stomach, gastric chief release the zymogen (inactive) pepsinogen which is activated to pepsin upon mixing with hydrochloric acid in gastric juices. Pepsin is proteolytic enzyme responsible for the initial digestion of polypeptide into smaller peptides
What are the monocular cues?
Are depth cues that can be perceived using one eye only and often rely on comparisons between objects.
1. Interpositions - overlapping objects create a sense of depth
2. Light and shadow- patterns of lights and shadow create the illusion of 3D object
3. Texture gradient - closer objects to lol have coarser texture/ more detailed
4. Relative size - closer objects appear larger than objects further away
5. Relative height - further objects appear at higher distances within a field
6. Linear perspective- distance between parallel lines appear narrower as they become further away.
How conformity influence individual behavior?
Occurs when an individual’s thoughts or actions align with group norms (thoughts/behaviors of others) due to the implicit influence of others. There is no explicit request or command,yet an individual still goes along with the group. Increased conformity is correlated with individual (eg age, gender), group (eg size, power) and social (eg collectivism) characteristics
What is compliance?
Is a type of conformity whereby an individual publicly goes along with the group but privately maintains his or her own stance. Without information regarding the private stance of the subjects, it is not possible to determine if compliance is occurring
What is regression to the mean?
Refers to the tendency of extreme date points in a distribution to regress toward the mean value of the distribution upon repeated measurement. For example, an athlete who has an outstanding performance in one game is likely to underperform in the next game.
What is social facilitation effect?
Refers to the enhancement of performance when an individual has an audience (eg people tie their shoes faster when being watched) but it predicts that only simple or well learned tasks improve
What is social desirability bias
Describes the tendency of research subjects to respond to experimental questions in away that makes them look better in the eyes of the experimenter such as oversimulating positive behaviors and underestimating negative behaviors
What is normative social influence?
Describes when an individual conforms to fit in or avoid rejection by others. Eg a collage freshman noticed that everyone on campus wears yellow wristband so he wears one to fit it.
What is informational social influence?
Describes when people conform to what others are doing because they don’t know what to do. Eg if several group members have medical expertise regarding cancer, another participant of that group may conform because individual believes the others are experts with the best information about cancer risk
What is reliability in scientific finding?
Refers to the consistency of an experiment or measure. Reliable measures produce similar results every time.
What is validity in scientific finding?
Can be internal or external. Internal validity refers to the extent to which an experiment or measure is accurate (produces true result). Eg a broken scale might consistently show your weight as 10 lbs lighter which would be consistent ( reliable) but not accurate (valid)
External validity: known as generalizability is the extent to which study results can be applied outside the laboratory to real life situations.
What is B cells do in immune system?
Identify foreign pathogens, present antigens and produce antibodies
What is T cells do in immune system?
Mediate number of immune responses, including those against viruses, bacteria and parasites.
What is dendritic cells do in immune system?
Identify foreign pathogens present antigen and activate other immune cells
What is macrophages do in immune system
Degrade pathogens and dead body cells via phagocytosis
What is basophils do in immune system?
Release chemical mediators such as histamine that enhance an immune response
What is mast cells do in immune system?
Release chemical mediators such as histamine that makes modulate allergic reaction
What is neutrophils do in immune system?
Kill and phagocytize bacterial cells
What is eosinophils do in immune system?
Defend against parasitic infections and modulate immune response during
Allergic reactions
What is natural killer cells do in immune system?
Release toxins to destroy virus infected body cells
What is function of lymphatic systems? What are the main organs and tissues?
Is the network of vessels that collect and transport lymph ultimately draining this fluid into the bloodstream. It is important to the immune response and includes following lymphoid tissues and organs:
-Bone marrow
-Thymus
-Lymph nodes -filter lymph, macrophages housed within lymph nodes
-Spleen - blood is filtered. White blood cells remove pathogens and damaged or old red blood cells from the blood.
What is ascribed status?
Is an involuntary social position assigned by society that is typically based on a social construct such as age, gender, or race/ethnicity
What is symbolic interactionism?
Person person to interactions that shape society. Through social interactions people develop subjective meaning for things (people, places, events, behaviors) which are more important than objective facts. what people believe to be true is more important than what is actually true. Subjective meaning differ by context and culture. A fundamental concept in symbolic interactionism is “definition of the situation” - describe how people enter into social situations with clearly defined expectations for their own behaviors and the behavior of others. It allows people to understand the statuses and roles of everyone involved in a situation so each person acts accordingly.
Charles Cooley, looking glass self
What is rational choice/ social exchange theory do?
Individuals behaviors and interactions attempt to maximize personal gain and minimize personal cost
What is cognitive dissonance
Occurs when an individual’s thoughts and actions don’t align or if an individual holds two competing attitudes. Eg if a student wants go to medical school but rarely studies for the mcat and this disparity could cause mental distress or discomfort. Individuals are motivated to reduce this dissonance by aligning their thoughts, attitudes and actions
What are the classifications of ion channels.
- Ligand gated ion channels
- Mechanically gated ion channels- responds to mechanical forces like pressure and tension
- Voltage gated ion channels- responds to changes in the membrane potential that have usually been caused by other channels.
What are the approximate pKa value of ionizable amino acid side chains?
Basic: Arg 12, Lys is 10.5, His 6
Polar ionizable: Tyr 10, Cys 8
Acidic amino acid: Glu 4, Asp 4
What is Henderson hasselbalch equation?
pH=pKa +log [A-]/[HA]
At pH values different from the pKa, the concentration predominant and minor forms can be calculated using this equation
How does mass spectrometry works?
Is a technique that measures molecular weight of a molecule. Molecules in a sample are bombarded with a beam of electrons, producing positively charged ions and fragments of the molecule. The ionized fragments are detected and a mass spectrum is generated with the y axis representing ion abundance and the x axis representing the mass to charge ratio m/z
What is coding and non coding RNA?
Coding: messenger RNA (mRNA) - is translated into protein by ribosomes
Non coding:
1. rRNA- associates with specific proteins to form ribosomes
2. t RNA- pairs mRNA codons with specific amino acids during translation
3. Small nuclear RNA (sn RNA) - associates with specific proteins to from small nuclear ribonucleoproteins, the building block of splicesomes
4. Small interfering RNA (si RNA) - functions in RNA i Terence, binds complementary mRNA and signals for its degradation
5. MicroRNA -mi RNA - functions in RNA interference, binds Target complementary sequence on mRNA molecules to silence gene expressions
What is Doppler effect?
Describes a waveform phenomenon in which the frequency of the waveforms perceived by an observer is greater or less than the real, native frequency of waveform emitted from source.
Fo=v+-vs/wavelength
How osmoregulation works in kidney?
The kidney is a vital organ in homeostasis, regulating water and ion content of blood in the process known as osmoregulation. This is accomplished by balancing the intake of specific molecules with the excretion of specific molecules in urine. Eg when large amounts of water are consumed, the osmolarity of blood decreases. To maintain homeostasis, higher concentrations or solutes (eg Na+) will be reabsorbed while more water will be excreted by the kidneys, producing a larger volume of dilute urine.
Microfilaments are one of the three families of protein fibers. What does it do?
- Microfilament - protein subunit: actin, 7nm, motor protein is myosin
Function: help determine cellular shape, cellular locomotion (crawling like movement), responsible for muscle contractions, involved in cytokinesis.
Intermediate filaments are one of the three families of protein fibers. What does it do?
Protein subunit: keratin, lamins, vimentin, desmin
10nm
Function; help determine cellular shape,
Make up the nuclear lamina,
Anchor organellas to specific cellular compartments.
Microtubules are one of the three families of protein fibers. What does it do?
Protein subunit: tubulin
25nm
Motor proteins; kinesin, dynein
Function; help determine cellular shape. Intracellular transport of vesicles and organelles,
Mitotic chromosome movement,
Cellular locomotion (cilia and flagella)
How mitochondria is unique from other organelles?
Have roles in cellular metabolism and the initiation of apoptosis. They are semiautonomous, possessing their own genes and self replicating via binary fission.
What is the equation for acceleration ?
=v+vo/2
Whist is distance travelled equation when initial velocity is not known?
Delta x=vt +1/2at^2
What is the distance traveled when current velocity is not known?
Delta x=vot+1/2at^2
What is velocity equation when time is not known?
v^2=vo^2 +2a deltaX
What is velocity equation when displacement is not known?
V=vo+at
How to find displacement when graph velocity vs time is given?
Displacement of a moving Kinect over an interval of time can be derived from the graph by calculating the total area under the curve during that interval.
A triangle=1/2baseheight
A rectangle =baseheight
What is difference between availability vs representativeness heuristics?
Availability heuristic- tendency to believe that if something is easily recalled from memory, it must be common or likely. Eg several relatives have been diagnosed with lung cancer; an individual might inaccurately assume that lung is the most common type of cancer
Representativeness heuristic- is tendency to compare things (eg people, events) to mental prototype when making judgments. Eg assuming a women dressed in scrubs is a nurse rather than a surgeon.
What is x and y intercept on lineweaver burk plot represents?
X-intercept: -1/Km
Y-intercept: 1/Vmax
Competitive inhibitors bind reversibly to an enzyme’s active site and block substrate access, causing an increase in Km but no change in Vmax.
Noncompetitive- Vmax decreased, upward shift
Uncompetitive- Vmax decreased, Km decreased.
Upward shift for Vmax
Left shift for -1/Km
What is ubiquitination!
Proteins are tagged for degradation in a process known as ubiquitination, which causes the proteasome to recognize and degrade the marked proteins via proteolysis (peptide bond cleavage). This system is responsible for degrading damaged or unnecessary proteins/enzymes
What is loading controls?
They normalize protein detection and ensure that protein loading is standardized across the gel. Proteins used as loading controls tend to be ubiquitously (expressed in all cell/tissue types) and have consistent concentrations across all cell/tissue types. House keeping genes are most common loading controls. Eg alpha beta tubulin proteins.
Types of inhibition and it’s effects on Vmax and Km.
- Competitive inhibitors- bind to active site and prevent substrate binding.
Km increased
Vmax unchanged - Noncompetitive inhibitors- binds to both the enzyme and enzyme substrate complex ES with equal affinity. It’s slow the reaction rate and decrease Vmax.
Vmax decreased
Km unchanged - Uncompetitive inhibitors- only bind to ES. Decreases both Vmax and km same factor
Difference between transverse and longitudinal waves?
A mechanical wave is motion created by a disturbance in a medium. It can propagate through medium in two different wave forms.
1. Transverse - waves displace the components of the medium perpendicular to the direction of the wave’s propagation.
Eg: a water wave in the ocean, where water rises and falls vertically relative to the ocean surface but wave travels horizontally parallel to the surface.
2. Longitudinal waves displace the medium in a direction parallel to the direction of the wave’s propagation. Eg sounds waves, they create disturbances in the air; causing air molecules to oscillating back and forth parallel to the direction of sound wave travels though the air.
What is diastereomers?
Are stereoisomers that are not mirror images. They contain at least 2 stereocenters in which one or more ( but not all) of the stereocenters on corresponding carbon atoms are in opposite configurations
What is conformational isomers?
Are different forms of same molecule that are generated as atoms rotate about their bonds. Unlike other stereocenters, they can rapidly interconvert by rotation without the need to break any bonds
What is difference between kinase, phosphorylase, phosphatase?
- Kinase - adds phosphate, required ATP.
- Phosphorylase - adds phosphate, no ATP required
- Phosphatase - remove phosphate group and generate ATP
During activation of the sympathetic nervous system blood flow is directed where?
Directed toward brain and skeletal muscles,
What is equation for Henry’s law of solubility?
C=Kh*Pgas
Pgas -partial pressure of gas
Kh- solubility constant specific to gas and solution
C- concentration of gas dissolved
For a floating object, what is the buoyant force and the weight of the object?
For the object floating at the surface, the vertical forces (its buoyancy and weight) cancel each other out and there is no net vertical force or acceleration.
Therefore: Fb=W=mg
What is refraction?
The bending of light; occurs at the boundary between two different mediums with different values of n. If light passes from high to low n, such as water (n=1.3) and air (n=1), light bends away from the normal axis and toward the surface. At a critical angle, light is refracted at 90degree and it parallel to the surface. Above this angle, all of the light will be reflected away from the surface (total internal reflection)
What is diffraction?
Is the bending of light around physical corners or very narrow gaps.
What is dispersion?
Is the spreading of light unit it’s different frequencies (colors) due to differences in the index of refraction for different frequencies of light.
What is alternative splicing?
During transcription, mRNA complementary to a DNA template is synthesized. Subsequently, the mRNA is processed with non coding portions (introns) removed, and coding portions (exons) joined. A process known as alternative splicing generates multiple mRNA transcripts and different proteins can be formed from a single gene.
What is cross sectional studies?
Are observational studies that assess date from large section of the population at a given point and can determine the prevalence of a disease.
What is case studies?
Are observational studies that assess one or more individuals in depth over a certain period.
What is illness experience perspective!
Is a symbolic interactionist perspective that examines how individuals understand and cope with serious or chronic illnesses that impact daily life and self identity. Chronically ill individuals employs strategies that involve illness work (eg taking medicine), everyday work (eg maintaining a household), and biographical work (Ed explaining the illness to others) to cope with and make sense of their illness.
What is sick role theory?
In sociology, sick role theory (Talcott Parsons), conceptualize illness as a socially acceptable form of deviance. A sick person has the right to be excuse from normal responsibilities and to be held blameless for the illness. A sick person has the obligation to attempts to get well a soon as possible and to seek and comply with the advice of medical professionals
What is conformational isomers?
Are structures that have the same connectivity and can be inter converted by the rotation of sigma bonds. Because they are identical expect for the bond rotations they are same compound
What is difference between SDS-PAGE and size exclusion chromatography?
Both techniques separate proteins by size but relationship between size and speed of migration differs.
In SDS page- SDS is an anionic detergent that denatures proteins. Native shape is lost and native charge is hidden. Proteins then separated by size only. SDS coats proteins in negative charges and then strong electromotive force pulls the proteins through gel matrix. Smaller proteins navigate more easily whereas larger proteins are hindered by the gels.
SEC- relies on gentler forces like gravity flow. Which allows molecule to diffuse into and out of the porous chromatography resin. Smaller goes slower and larger proteins excluded faster.
What is the formula for percent yield?
%yield=actual yield/theoretical yield *100%
Assesses the extent to which the starting materials are converted into products during a reaction.
Where theoretical yield is the maximum amount of the product that can from if 100% of the limiting reactant is converted into products.
What is the three layers of skin?
- Epidermis - can be further divided into five additional layers (strata) that contain Merkel cell, langerhans cells, keratinocytes and melanocytes. Deepest layer is basale, consists of single row of stem cells that continually dived to give rise to new stem cells.
- Dermis - contains blood vessels, immune cells, sensory receptors, sweat and oil glands and hair follicle.
- Hypodermis - inner most layer, composed of insulating and shock absorbing adipose tissue
What is stratum basale do in the epidermis?
Consists of single row of stem cell that continually divide to give rise to new stem cell. Of the two daughter cells proxies from each mitotic division in the stratum basale, one cells remains in the basal layer and other one begins differentiating into mature keratinocyte. As constant cell division pushes the keratinocyte outward through the epidermal layers, they will work keratin, flatten and lose their organelles.
What is epidermal langerhans cell do?
Are immune (dendritic) cells that recognize and ingest antigens before migrating to nearby lymph nodes to present those antigens to T cells, activating the adaptive immune response.
What is thermoregulation do when body is above the normal temperature!
- Vasodilation- widening of skin arterioles increase blood flow to skin capillaries and maximize heat loss through the skin. Blood is warmed in the body core, transfers heat to the environment when it passes through skin capillaries. Vasodilation occurs when the smooth muscle surrounding the blood vessels relaxes.
- Sweat - hypotonic solution is secreted onto skin surface by sweat glands. Heat loss and subsequent cooling occurs due to the evaporation of the water in sweat and endothermic process that absorb heat from body.
What is entropy?
Is a measure of the disorder within a system. Increased order means negative entropy change whereas increased disorder means positive entropy change. The water molecules surrounding folded protein have greater entropy than those surrounding unfolded proteins because the hydrophobic molecules on the surface of unfolded proteins force water to form a rigid solver ion layer.
What is protease enzymes do?
Proteins can be degraded by protease enzymes. During peptide hydrolysis, a water molecules is used to cleave the C-N bond in a the amide linkage using an acid H+) or base (OH-). In contrast, the reverse of amide hydrolysis is amide bond condensation; which involves the formation of water molecule from two amino acids to form a larger peptide.
What enzyme can alter and can’t alter?
Enzymes don’t alter free energy change delta G or the equilibrium constant Keq of reaction but by increasing the reaction rate they do decrease the time taken for the reaction to reach equilibrium. Deleterious mutations involving the enzyme’s active site are likely to alter the enzyme’s affinity for its substrate (increase Kd) and interfere with enzymatic function (decrease reaction rate).
What is missense mutation do?
It changes to different amino acid
Formula for electrostatic force on a charge in electric field?
F=qE
What is direction of electric field?
+ away
- into
What are the equation current can be represented?
Current refers to movement of electric charge.
I=Q/t
SI unit: ampere A=Coulomb/second
Ohms law: I=V/R
P=IV (watt) =AV
What is in the cell body of motor neuron?
Contains nucleus, the site where transcription of neuronal nuclear encoded genes.
How to calculate mean, median, mode, range?
- Mean- add all the numbers and divide the total sum by number of values
- Mode - count the frequency of values in the data set and mode is value that occurs the most frequently
- Median- order numbers from lowest to highest value, if it is odd amount of numbers it is the middle number. If it is even amount of numbers, add the middle 2 and divide by 2.
- Range- order numbers lowest to highest value, identify minimum and maximum. Subtract minimum from maximum
What is standard deviation indicates?
Is statistic indicting how far the values are spread around the mean
What is divisions of peripheral nervous system?
Sensory
Motor - 1. Somatic 2. Autonomic nervous system
Autonomic nervous system; a. Sympathetic
b. Parasympathetic
What is efferent pathway of peripheral nervous system?
Ganglion is collection of several nerve cell bodies within the peripheral nervous system and is the site where preganglionic nerves synapse with postgangionic nerves. Parasympathetic pathways typically involve acetylcholine released from both pre and postganglionic neurons. Sympathetic pathways employ also acetylcholine released from preganglionic but typically release norepinephrine from postsynaptic neurons.
What is the role of nodes of Randvier in transmission of neural impulses?
They are small interruptions in the myelin sheath. By exposing a short segment of unmyelinated axon, the nodes of randvier promote entry of extra cellular Na+ into axons while limiting the total number of ion channels that must open, thereby greater increasing the rate at which neural impulses are conduction along myelinated axons.
What is reflex arc?
Reflexes are involuntary responses to stimuli that may or may not require input from brain. A reflex arc is the specific neuronal pathway that facilitates the direct muscular or glandular effect associated with a particular reflex. Reflex arcs begin with stimulation of sensory neuron which leads to an electrical impulse that travels toward the spine or brain along a sensory nerve. Impulse can happen in two days:
Directly to the effector neuron
Or
Indirectly through interneuron that interfaces with the effector neuron
What happens to the body when sympathetic nervous system is activated?
Oxygen delivery to skeletal muscles is maximized ( eg increasing heart rate, dilating airways, constricting blood vessels that supply the visceral organs, glands and skin). Glycogen in the liver is broken down into glucose which is then released into circulation to provide energy for skeletal muscles. The pupils dilate to maximize light intake by the eye, facilitating vision. It inhibits nonessential functions auxin as those related to digestion and reproduction. Relaxes bladder and promotes ejaculation and vaginal contraction
Why action potential can’t occur during repolarization?
Repolarization begins when K+ channels open, causing K ions to rapidly leave the cell. Simultaneously, the inactivation gates of the Na + channels close, preventing the re entry of Na+ ions. The absolute refractory period is the period during which no new APs can be generated regardless of strength of stimulus received. The Na+ channel inactivation gates must open and the Na+ channels must be return to a deactivated (closed) state before the next AP can occur
During hyper polarization new AP can be generated because unactivation gates have been opened but a stronger than normal stimulus is would be needed. This period is called the relative refractory period.
What is changes in number of Na+ ions transported into a myelinated axon during transmission of neural impulse along it’s length?
In myelinated fibers, the voltage gated Na+ ion channels only present at the nodes of Ranvier. As a result, the hunger of Na+ ions transported into a myelinated fiber increases in a stair step pattern with increments of approximately equal size in the number of transported Na+ ions at each node of Ranvier.
Wake is Alzheimer’s disease?
Is a progressive neurodegenerative brain disease characterized by the presence of plaques composed of beta Amyloid proteins and neurofibrillary tangles composed of tau proteins. The presence of these amyloid beta plaques and neurofibrillary tangles are toxic to neurons and lead to cell death.
What is multiple sclerosis?
Is a neurodegenerative disease in which immune cells are unable attach myelin sheath surrounding axons in the central nervous system.
What is Huntington disease?
Is an autosomal dominant genetic neurodegenerative disease in which neuronal loss occurs in extensive regions of the brain including the basal ganglia
What is gray and white matter in central nervous system?
The central nervous system, including brains and spinal cord is composed of white and gray matter. Located in the center of spinal cord, gray meter is composed of unmyelinated neuronal cell bodies and dendrites. In the peripheral of the spinal cord; white matter is compared of myelinated and unmyelinated axon that allow for long distance communication between neurons.
White matter consists of afferent and efferent axons
What is pathway communication between presynaptic and postsynaptic neuron?
Axon ->synapse->dendrite ->soma
Neurons are cells that receive, integrate, and transmit information in the nervous system. Communication between neurons involves an electrochemical process in which electrical signals are converted to chemical signals (and vice versa) as they travel from the presynaptic to postsynaptic neuron.
1. An electric signal in the presynaptic neuron travels down a thin fiber called an AXON that conducts the signal to the axon terminals.
2. From there chemical messengers called neurotransmitters are released into the synaptic cleft (synapse), the region between the axon terminals and the dendrites of the next neuron (postsynaptic neuron).
3. Neurotransmitters bind to receptors on the Dendrites of the postsynaptic neuron, altering the electric potential of the cell.
4. Change in electric potential spreads to the cell body ( soma)
What is components of simple somatic reflex?
Stimulus-> sensor-> input signal ->integrating center -> output signal ->response
Neural reflexes can be either somatic (involving skeletal muscle) or autonomic (involving tissues other than skeletal muscle). Both reflexes include afferent neuron carrying sensory info to CNS and an efferent neuron that activates a response in a target tissue. In some somatic ( and all autonomic) reflexes additional neurons called interneurons
What is the difference between monosynaptic and postsynaptic reflexes?
Monosynaptic - somatic reflexes only require an afferent neuron delivering the sensory info to the spinal cord and an efferent motor neuron activating the muscle response. Eg knee jerk by stimulus
Polysynaptic- reflexes incorporate at least one more neuron in the reflex
What are the different kinds of reflexes?
- Neural - neurons plays part
- Endocrine tissue - adjusts hormone production based on level of another hormone in the blood
- Neuroendocrine reflexes- involve both neurons and endocrine
What are the classifications of innate immune system?
- Physical barriers: skin, mucous membranes, stomach acid.
Prevents foreign pathogens from entering the body - Immune cells: white blood cells (leukocytes)
A. Phagocytic cells eg macrophages, nonspecifically engulf and destroy foreign pathogens
B. Chemical releasing cells eg basophils, natural killer cells - secrete chemicals that enhance the immune response response and promote pathogen destruction
What are the function of neutrophil?
They are part of innate immune system. They for many functions:
1. Destruction of pathogens via phagocytosis
2. Release of granules containing antimicrobial compounds
3. Release of neutrophil extra cellular traps containing DNA
4. Neutrophils release cytokines (chemical signal) that regulate different immune responses
They are the most abundant type of white blood cells and first responder to an infection.
What is lymphocytes?
They are 2nd most common type of white blood cell but not all lymphocytes are part of innate immune system. There are 3 types; B cell, T cell and natural killer cells.
B and T are part of adaptive immune system and natural killer cells are innate immune system.
Natural killer cells - respond to cells infected by viruses and tumors to lull them and prevent the spread of infection.
What is difference between. MHC I and MHC II?
T cells recognize antigens through the help of major histocompatibillty complexes.
MHC I - is a protein expressed on the surfaces of all nucleated cells in the human body. It’s role is to take fragments of proteins within the cell and present them on the surface of the cell. When a cell is healthy, the protein being displayed will also be healthy and thus will elicit no response from the immune system. If infected cells present a viral protein, it will be recognized as an antigen and will elicit an immune response to kill those cells.
MHC II- is found in a smaller range of white blood cells that include macrophages, dendritic cells and B cells: these cells use machinery to destroy foreign objects in the body, displaying pieces of these foreign particles on MHC 2.
MHC I- presents proteins that were internal to the call
MHCII- presents proteins that were external to the cell
What is bone marrow do?
Is soft, spongy tissue that line the inside of bones and give rise to most cells involved in the immune response. Cells originating in the bone marrow begin as multi potential hematopoietic stem cells and can differentiate into lymphoid and myeloid progenitor cells.
Lymphoid progenitor cells- go on to become B, T and natural killer cells
Myeloid progenitor cells - further differentiate into erythrocytes, platelet-producing megakaryocytes, neutrophils, basophils, eosinophils, monocytes and mast cells.
What is box and whisker plot do?
Is used to visually represent the median and distribution of dare into quartile ranges.
Upper quartile
Median
Lower quartile
Maximum and minimum - are the whiskers
Outliers
How autoimmune disorders occur?
Due to the immune system’s failure to identify and destroy immune cells that recognize self antigens. Self reactive B cells and T cells are normally eliminated in the bone marrow and thymus respectively.
What is negative selections?
Elimination of T cells that respond too harshly, sometimes against healthy human cells (the self) thus causing an autoimmune disorder. Is the process by which immature T cells and B cells processing receptors that bind to to self antigens are destroyed or inactivated.
What is positive selection?
Elimination of T cells that don’t appropriately respond to antigens and thus leave the body vulnerable to infection.
What is somatostatin?
Is a hormone that is released by pancreatic delta cells, has a generalized inhibitory effect on functioning of the digestive system. It can also suppress the release of insulin and glucagon from the pancreas.
Release of sweat is partially under control of which hormone?
Epinephrine
What are 5 layers of epidermis?
Most superficial:
1. stratum corneum - is composed of many layers of keratinocytes that have pushed up from the deeper layers and flattened in the process. These ones create barrier to invasion by external pathogens and help prevent water and salt loss through the skin surface
2. Stratum lucidum (only present in thick skin of palms and foot soles)
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basale - consist of single layer of stem cells that divide continually to give rise to new stem cells
What is function of helper T cell and the cells get assisted by helper T cells?
- B lymphocyte - promotes its activation and proliferation. Induces differentiation of B lymphocyte in antibody- secreting plasma cells and memory cells.
- Cytotoxic T cell- promotes its cell activation and proliferation
- Macrophage - enhances activity of macrophage
- Other immune system- attracts other immune cells to site of infection
