FoM_FoNF Flashcards
define aetiology
cause of disease
define pathogenesis
how disease develops
define symptoms
what patients notice and feel
define signs
what the doctors observe
define diagnosis
the identification of the nature of an illness or other problem by the symptoms
define prognosis
the likely course of a medical condition
define natural history
collects health information in order to understand how the medical condition or disease develops and how to treat it
what is pathology
the study of disease
what are the different classifications of disesae
inflammatory disorder of circulation disorder of cell growth degenerative developmental unnatural
what is inflamation
succession of changes occurring in living tissue when it is injured
e.g. meningitis
what is circulatory disturbances
abnormalities of flow, vessel wall, components of the blood
e.g. myocardial infarction
what is disorders of growth
abnormal cell growth: maturation, differentiation, quantity, control
e.g. cervical carcinoma
what id degenerative disorders
heterogeneous group
abnormalities of tissue and organs
e.g. amyloidosis
what is developmental
abnormalities of gametogenesis and embryogenesis
e.g. down syndrom
what can unnatural conditions be
traumatic
iatrogenic
what is traumatic
accidental or deliberate
e.g. fractured bone
what is iatrogenic
treatment related
e.g. immunosuppression in chemotherapy for malignancy
what is general organisation of the body systems
the human body is a complex society of cells, structurally and functionally organised into tissues and organs
the cell is the smallest unit of the body we commonly refer to but it is made up many internal components
these components form machinery that create energy to power the cell and allow it to function
what is the equation of life
nutrients + O2 = energy (ATP) + waste (incl. CO2)
define homeostasis
maintaining an optimum internal environment within the body
how do the major systems maintain health and optimal homeostasis
involves cooperative action of organ systems, coordinated by nervous system and endocrine system (hormones)
why is it important to maintain constancy of the internal environment
in an effort to prevent disturbance and maintain optimum “similar conditions” or, in other words, a relatively constant internal environment in which all processes work optimally
what is negative feedback mechanism
when a condition that is homeostatically regulated is sensed to have shifted from the normal range, a signal is generated that produces a response that corrects the original disturbance
Causes a return to a set point
Negative feedback is the most common type of homeostatic feedback.
It aims to reduce the disturbance of a monitored variable – think about the example of getting dehydrated when working outside on a hot day. The threat to water balance in the body is countered by an increased thirst, driving the individual to seek water
Negative feedback is a key aspect of maintaining homeostasis
cannot prevent the disturbance from happening
what is feed forward systems
more sophisticated than negative
additional receptors permit system to anticipate (predict) change and therefore activate response earlier
the threat to water balance is counteracted by the kidney detecting the increased body fluid concentration and pre-empts a state of dehydration. It responds by producing smaller volumes of urine, and a more concentrated form of urine, thus conserving water
what is positive feedback mechanism
uncommon in homeostasis but does occur and is vitally important when it does
opposite of negative feedback as negative aims to restore disturbed conditions, positive sets off a train of events that lead to an even greater disturbance
amplifies the response
e.g. nerve action potential
what is the daily water balance in man and how does this affect homeostasis
Water makes up 60% body weight so about 42L
Homeostatic maintenance of water is crucial because water affects the concentration of everything else in the body
what are the different body fluid compartments and what is the distribution of water
intracellular fluid and extracellular fluid
intracellular fluid (ICF) is found within the cells
ECF is made up of :
- plasma, the dynamic component of ECF that is contained within blood vessels (it surrounds blood cells)
- interstitial fluid (ISF), the fluid outside blood vessels that surrounds cells other than blood cells.
2/3 of the water is in the intracellular fluid while 1/3 is in the extracellular fluid
intracellular - 28L
interstitial - 11L
plasma - 3L
what is the nature of the barriers which separate the body compartments
the cell membrane separates the ICF and the ECF and has selective permeability
the capillary wall - separates plasma and the ISF and is permeable to everything but plasma protein and blood cells
water has no barriers and moves by osmosis
what is the dilution principle
based on the DILUTION PRINCIPLE, (3 things to remember )
- c = m/v, v = m/c = Dilution Principle
- ONLY plasma can be sampled, only compartments of which plasma is a component can be measured directly (plasma, ECF, TBW).
- The NATURE of BARRIERS which separate compartments is crucial in determining the test substance.
describe the use of the dilution principle in the measurement of body fluid compartments
Compartments that can be measured directly using the Dilution Principle:
- Plasma Volume (PV): Since plasma proteins cannot cross the capillary walls, can use dyes or radioactive labels that attach to plasma proteins, e.g. Evans blue or I125albumin.
- Extracellular Volume (ECF): Need something that freely crosses capillary walls, but cannot cross cell membranes, e.g. inulin, sucrose, mannitol, which are all too large to cross cell membrane or 24Na+ , 36Cl-, which are actively extruded from cells.
- Total Body Water (TBW): There is no barrier to water in the body, so can use a loading dose of heavy water/ deuterated water (D2O).
Other compartments (where plasma is not a component) cannot be directly sampled, calculate volume indirectly;
ISF = ECF-PV, ICF = TBW-ECF
which structures are present in all cell types
plasma membrane cytoplasm cytosol ribosomes nucleus (eukaryote) / nucleoid (prokaryote)
what is the role of the nucleus
Contains DNA, nucleoprotein and some RNA
Nucleoli are sites of ribosomal RNA synthesis and ribosomal assembly
The nucleus is enclosed in the nuclear membrane which, like all biological membranes, is a phospholipid bilayer. It is closely associated with the Rough Endoplasmic Reticulum
what is the role of the endoplasmic reticulum
membrane bound
Endoplasmic reticulum comes in rough (RER) and smooth (SER) varieties
RER has ribosomes attached giving it the “rough” appearance
RER modifies proteins
SER has no ribosomes attached and is mainly associated with lipid and steroid hormone production and metabolism of toxins
what is the role of ribosomes
synthesise proteins
what is the role of the golgi apparatus
packages up protein in preparation for transport out of the cell
what is the role of lysosomes
re membrane bound vesicles containing enzymes – they separate enzymes from the rest of the cell
what is the role of mitochondria
also organelles bound by a phospholipid bilayer
Outer membrane contains pores
Inner membrane has cristae (folds)
Matrix contains most of the enzymes required for metabolising food molecules (e.g. Krebs cycle)
They have their own circular DNA
They have their own ribosomes – similar to bacterial ribosomes
They synthesise most of their own proteins
They can self-replicate
what is the structure and function of the eukaryotic plasma membrane
Comprises a double layer of lipid with attached phosphate groups = phospholipid bilayer
Forms a selective barrier, being choosy about what it allows to cross in or out of the cell
Embedded in the membrane are proteins which act as receptors to detect chemical messengers and signalling molecules in the fluid surrounding cells (extracellular fluid)
what is the role of the cytoskeleton and what classes of protein form the cytoskeleton
only found in eukaryotes and is organised into internal compartments
supports and maintains cell shape
holds organelles in position
helps move organelles around the cell
it is composed of one of three forms of protein:
microfilaments
intermediate filaments
microtubules
what is apoptosis
controlled, programmed cell death
It is a normal process and essential for normal function
Apoptosis and cell proliferation are intimately coupled
Loss of balance between apoptosis and proliferation is associated with some cancers
what is necrosis
untimely death of cells in response to injury or infection. It is not a normal process.
what are stem cells
cells that can differentiate into many (multipotent) or any (pluripotent) cell types of the body
what are cilia and fagela
both are made of microtubules
Cilia—short, usually many present, move with stiff power stroke and flexible recovery stroke
Flagella—longer, usually one or two present, movement is snakelike
what are the major elements used to construct human biomolecules
Hydrogen (H) (1)
Oxygen (O) (2)
Nitrogen (N) (3)
Carbon (C) (4)
these make up more than 99% of the mass of most cells
they are the lightest atoms and are able to make bonds (the numbers in the brackets show hoe many bonds they make)
which of the four atoms (H,O,N,C) is the most versatile
carbon
It can form stable
- Single bonds (with H)
- Single and double bonds (with O and N)
- Single, double and sometimes triple bonds with other C atoms
This variety of bonding capability underlies the evolution of all the different combinations of H, O, N and C into biological molecules
what do biomolecular functionality depend on
the presence of particular functional groups and the way in which these are arranged in space define biomolecular function
which biochemical reactions are the 5 chemical reactions of life
Redox reactions
Making and breaking C-C bonds
Internal rearrangements
Group transfers
Condensation and hydrolysis reactions
give an example of a redox reaction
In many biological redox reactions two e-’s (and two protons) are gained or lost
Often 2 hydrogen atoms (protons) are transferred from one molecule to another in dehydrogenation reactions
e.g.
NAD+ being reduced to NADH (as it gains electrons and thus list its positive charge
NADH is the reducing agent (as It donates electrons to pyruvate causing pyruvate to be reduced to lactate. In doing so NADH loses an electron thus gains +ve charge and becomes oxidised to NAD+. )
NADH a reducing agent (which becomes oxidised itself to NAD+ as it reduces other compounds)
NAD+ is an oxidising agent (which becomes reduced itself as it oxidises other compounds)
give an example of making and breaking C-C bonds
e.g. Cleavage of glucose in the glycolysis pathway
give an example of internal rearrangements
e.g. Also in glycolysis, a rearrangement of the conformation of G6P occurs before the sugar is split
give an example of group transfers
e.g. Also in glycolysis…
In an enzyme catalysed reaction, a phosphoryl group (PO32-) is transferred from ATP to F6P
ATP provides energy for cellular reactions
give an example of condensation and hydrolysis
Condensation reactions occur where two smaller molecules combine to form a larger molecule and in doing so release water (or other small molecules e.g. methanol).
Hydrolysis reactions involve adding water to a molecule, and most commonly simultaneously breaking down a large molecule into smaller units.
The sub-units of proteins, polysaccharides and nucleic acids are all joined by condensation and broken by hydrolysis reactions
what is the general structure of nucleic acids
These form the core structure of DNA and RNA
Put simply, they are polymers of nucleotide monomers linked by 3’,5’-phosphodiester bonds
A nucleotide monomer is formed from a base (see below), a sugar molecule and a phosphate group:
There are 2 kinds of base in nucleic acids
Pyrimidines – cytosine (C), thymine (T) (DNA only) and uracil (U) (RNA only)
Purines – adenine (A) and guanine (G)
RNA is formed from “normal” ribose sugars
DNA is formed from deoxyribose sugars, which lack an oxygen atom
what is the general structure of lipids
A family of molecules made up of fatty acids There are three classes of lipids: Triacylglycerides Phospholipids Sterols
what are triacylglycerides
Also called triglycerides
Storage lipids
Non-polar
3 fatty acid chains linked to glycerol
what are phospholipids
Similar to triacylglycerides,
But they have only two fatty acids chains and a phosphate group attached to the ‘head’ of these chains
This makes them polar
They form biological cell membranes – very important!
what are steroids
Produced in plants, animals and some micro-organisms
Most important one in humans is cholesterol
Another essential component of cell membranes
Precursor to steroid hormones and fat soluble vitamins (A, D, E)
what does hydrophobic mean
water hating
water repelling
lipophilic
what does hydrophilic mean
water loving
water soluble
lipophobic
e.g. sugars, alcohols, aldehydes, ketones, compounds with N-H groups, charged particles such as ions
what does amphipathic mean
have both water loving (hydrophilic) and repelling (hydrophobic) parts
e.g. most proteins, phospholipids
what does polar mean
charge within the molecule is not evenly distributed
e.g. water, the polarity gives rise to hydrogen bonding, such bonding are not unique to water
what are hydrogen bonds
link groups/molecules in precise pattern in space
H bound to N,O,F
molecules containing what tend to be hydrophobic/hydrophilic
molecules which form hydrogen bonds tend to be water-soluble
O2 and CO2 are non-polar and poorly water-soluble
charged molecules tend to be water soluble
how do non-polar (uncharged) molecules arrange themselves
arrange themselves in water so as to minimise disruption of water-water hydrogen bonding
what is pH
a convenient way of expressing [H+] over a wide range of concentrations
Water has a neutral pH because [H+] and [OH-] are equal
Acidic solutions have a greater [H+] and lower [OH-]
Basic (alkaline) solutions have a lower [H+] and higher [OH-]
Note: 1 pH unit represents a ten-fold increase or decrease in [H+]
