PM1A DEFINITIONS Flashcards
Immune system
includes all cells, tissues, molecules and barriers that mediate resistance to infections.
Immunity
The body’s ability to fight off harmful microorganisms (pathogens) that invade it.
e.g. bacteria, fungi and viruses.
Immune response
Is the collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules of the immune system.
Phagocytosis
ingestion and digestion of pathogens
antigen
Is a foreign substance/toxin that stimulates an immune response leading to production of antibodies.
Give a definition of a skeletal motor unit at the NMJ
A motor unit is defined as a single motor neuron and all the muscle fibers that it activates.
Gene therapy
technique for correcting defective genes that are responsible for disease development.
A carrier molecule called a vector must be used to deliver the therapeutic gene to the patient’s target cells (for in vivo therapy).
The most common vector is a virus that has been genetically altered to carry normal human DNA.
Genetics
the study of heredity and the variation of inherited characteristics/ the genetic properties of features of an organism, characteristics etc
Vaccination
the process of induction of immunity to a pathogen by injecting a weakened, modified or related form of a pathogen which is inactivated.
cytokines in immune system
Are regulatory proteins secreted by WBC’s (macrophages and dendritic cells) bind bind to receptors on target cells and trigger signal transduction pathways and alter gene expression patterns, can be pro or anti inflammatory.
Pro- stimulate the immune system
Anti- suppress the immune system
TNF-alpha is the most important mediator of inflammation.
Proprioception
and describe the 2 way process
is defined as ‘the perception of self’, where your body is in relation to the surroundings.
2 way process where
1. proprioceptors signal to the spinal cord (affarent)
2. motor neurons signal to skeletal muscle (efferent)
surfactant
respiratory system topic
is a mixture of amphipatic complex, phospholipids, proteins and neutral lipid produced by type II pneumocytes
Cardiac output and give equation
Volume of blood pumped out of one ventricle in one minute
Cardiac output = heart rate x stroke volume
Define perfusion pressure and vascular resistance. For EACH, describe what happens to blood flow when they are increased
Perfusion pressure is the difference in pressure between arteries and veins
Increase perfusion pressure – blood flow increases
The blood vessels themselves offer resistance to flow this is the vascular resistance
Increase vascular resistance blood flow decreases
negative feedback and example
effector system opposes the initiating stimuli
e.g. increase in BP causes a compensatory decrease in BP
positive feedback and example
effector system amplifies or reinforces the initiating stimuli
e.g. formation of a blood clot leads to further blood clotting.
codon
Anticodon
Codon- found in mRNA, is a sequence of 3 nucleotides in a DNA/RNA molecule used to code for amino acids.
Anticodon- found in tRNA, also a sequence of 3 nucleotides that binds to corresponding mRNA sequence.
Genetic code
is the nucleotide base sequence on DNA and subsequently on mRNA by transcription which will be translated into a sequence of amino acids of the protein to be synthesis
3 features of genetic code
universal- the same code is used in all living organisms, prokaryotes and eukaryotes
specific- a SPECIFIC codon ALWAYS codes for the same amino acid.
Degenerate- more than codon can code for the same amino acid.
telomeres
protective caps at the end of linear chromosomes, they contain a unique repetitive sequence called telomere tandem repeats.
homologous chromosomes
A pair of chromosomes that are the same size, shape and carry the same genes, one is inherited from each parent.
They are numbered according to size.
replication origins
are nucleotide sequences where replication starts
TATA box
DNA sequence that indicates where a genetic sequence can be decoded. is an example of a promoter.
Transcription factors
def of general TF’s
the largest TF?
are proteins that regulate the transcription of genes.
They bind to regulatory DNA sequences are they recognise target sequences in DNA.
Two types are general and promoter:
general TF’s are active in most cell types and ALWAYS affect gene transcription positively.
General TF’s are the most basic proteins needed to activate gene expression.
TNF II D is the largest TF
gene regulation topic
gene regulation at chromatin level:
define chromatin remodelling
sliding the nucleosomes along the DNA to expose the promoter region, chromatin must be open for gene expression to take place.
promoter
region of DNA where RNA polymerase ( and transcription factors) binds to initiate transcription.
Defines the direction of transcription as well as which DNA strand will be transcribed.
mutation
permanent change in the genetic material of an organism, mutations can be neutral
( neither positive or negative consequences).
neither beneficial nor detrimental to the ability of the organism to survive and reproduce.
mutation
permanent change in
mutation
Permanent change in the genetic material of an organism
mutations can be neutral (neither positive or negative consequences)
neither beneficial nor detrimental to the ability of the organism to survive and reproduce.
Nervous system
All or nothing or principle
If threshold is exceeded, action potentials have a similar magnitude and duration
Nervous system
Absolute refractory period ( ARP)
In the period that Na+ channels are open or inactivated, an action potential cannot be generated, neurones CANNOT fire
respiratory system:
compliance and elastance
compliance- the measure of the distensibility of a system, specifies the ease at which matter can be stretched or distorted.
elastance- measure of ability of system to oppose stretch or distortion and to return to the original form (recoiling)
lung compliance
lung elastance
lung compliance- the volume change that could be achieved in the lungs per unit pressure change .
Describes the ability of the lungs to expand under pressure.
lung elastance- the pressure change required to elicit a unit volume change.
Is a measure of the resistance of a system to expand.
respiratory system:
loading and unloading
loading- binding of O2 to Hb, takes place in the lungs where high partial pressure of O2, Hb has a high affinity for O2, therefore loads oxygen. =Positive cooperativity.
unloading-Hb unbinds from O2, takes place in tissues, where low PO2, Hb has a low affinity for oxygen therefore O2 is unlaoded.
Bohr effect
how is it advantageous?
Increase in Co2 conc, causes the o2-Hb dissociation curve to shift to the right, as affinity decreases, leading to dissociation of O2.
When RO respiration high, high conc of co2 is released which lowers the blood pH as carbonic acid and lactic is produced.
Advantageous: as it provides more o2 for tissues for aerobic respiration, increasing metabolic activity in cells when exercising.
humoral response
removes extracellular microbes and their toxins, mediated by antibodies
cellular response
removes intracellular microbes that survive within phagocytes or other infected cells, involves T cells.
Nervous system:
Relative refractory period
In the period that K+ channel are open (activated), membrane is hyperpolarised and makes therefore makes it more difficult to fire action potential = a stronger stimuli is required to generate an AP.
