MCS Flashcards
(479 cards)
1
Q
What is conformation?
A
Unique 3D shape of a protein
- Conformation depends on amino acid sequence
2
Q
FUNCTIONS: (7)
A
1) Enzymatic catalyst
2) Systematic movement ( muscles)
3) Transport and storage of small molecules and ions.
4) Mechanical System ( skin and bones)
5) Immune system ( Anti bodies)
6) Communication:
- Hormones: Some hormones are proteins
-cellular receptors and neurotransmitters are proteins
7) Growth and Differentiation( Controlling gene expression):
- Repressor proteins supress DNA sequences
- Transcription and Translation.
3
Q
All amino acids are optically active, except which one?
A
Glycine
4
Q
What is an Imino acid?
A
An amino acid with a secondary amino group..
5
Q
What is an example of an imino acid?
A
Proline.
6
Q
What configuration is required for amino acids to be optically active?
A
L configuration.
7
Q
What is D- configuration?
A
Bacteria and Invertebrates.
8
Q
What does amphoeteric mean?
A
BOTH acidic and basic properties.
- amphoteric properties, depend on how easily side chains dissociate.
9
Q
What is a “left handed isomer” classified as?
A
L isomer
10
Q
What is a “right handed isomer” classified as?
A
D isomer.
11
Q
isoelectric point:
A
Point at which overall charge of protein is ZERO
12
Q
Are proteins branched or unbranched
A
Proteins are unbranched polymers.
13
Q
What is a “residue” ?
A
Amino acid in a poly peptide chain.
14
Q
Poly peptides are formed by what type of reaction?
A
Condensation.
15
Q
When is an amino acid protanated/deprotanated?
A
If ph is higher than pka, then it is deprotonated.
If ph is lower than pka, then it is protonated.
16
Q
Globular:
A
tight folding poly peptide chains.
SOLUBLE
17
Q
Fibrous:
A
Straight poly peptide chains forming fibres or sheets
INSOLUBLE.
18
Q
STRUCTURE? Covalent, back bone
and amino acid sequence:
A
Primary Structure
19
Q
STRUCTURE? Bonds between other neighbouring residues
A
Secondary strucure
20
Q
Bonds involved in the Secondary structure
A
Hydrogen bonding
Ultimately, forming alpha helix or beta pleated sheets
21
Q
Hydrogen bonding (HELICAL):
A
If the h-bonds form between peptide bonds in the SAME CHAIN.
22
Q
Hydrogen bonding( EXTENDED structures):
A
If h-bonds form between peptide bonds in different chains.
23
Q
Alpha helix brief description:
A
Rod like structures with peptide bonds coiled tightly inside.
- side chains face outwards
- coils turn in a clockwise direction.
- There are 3.6 residues, per turn of helix.
24
Q
Beta- pleated sheets
A
c-c bonds are tetrahedral
chains lay side by side
- chains may run in the “same directions” ( Parallel beta sheets)
25
What does "pleated" mean?
C-C bonds are tetrahedral, and can't be in straight lines.
26
What's the anti-parallel Beta strucutre:
E.g. when chains run in opposite directions to each other.
For example, in a globular protein.
27
How would an anti parallel beta structure be likely to form?
When an EXTENDED structure folds back on itself.
28
STRUCTURE? Spatial arrangement of residues:
Tertiary Strucuture.
29
Hydrophillic chains are
OUTSIDE
30
Hydrophobic chains are
INSIDE
31
What is the electrical state of a monoamino?
Electrically neutral
32
what does folding indicate?
State of greatest stability.
33
Conformation: At points of instability:
At points of instability, FLEXIBILTY in the chain allows water to gain maximum energy.
- Which helps form the strucuture.
34
STRUCTURE? Arrangement of polypeptide chains in a multi-chain protein:
Quaternary strucutre.
35
What is Denaturation?
Disruption of weak types of interactions:
such as:
- h-bonds
-vdw
-ionic links
- Hydrophobic/hydrophilic interactions
36
Advantage of "disruption" :
Helps to maintain the 3D shape of a protein
37
Disadvantage of Disruption
Causes a decrease in biological activity.
38
What does "LABILE" mean?
Means a protein is EASILY DISRUPTED
39
What external factors could cause disruption?
- extreme temperature/ pH
- High salt concentrations
- Organic solvents.
40
Where is collagen found in the body?
Skin, cartilage, tendons, blood vessels, bones and teeth
41
How many strands in collagen and how long is each strand roughly?
Fibrous protein
3 strands
each strand is roughly 1000 residues long.
42
Repeating motif of collagen?
GLY-PRO-PRO
I
OH
43
What is2 things are special about collagen?
1) LOCKING EFFECT
2) SUPER HELIX FORMATION
44
Locking effect:
- Due to stability of PRO-PRO
I
OH
- And due to H-bonding between residues.
45
Super helix formation:
Due to amino acid occupying every 3rd residue.
46
Is a globular soluble/insoluble
SOLUBLE
47
Is a fibrous protein soluble/insoluble
INSOLUBLE
48
Protein folding disease:
Ultiamately causes anemia.
A single mutation changes a glutamic acid in B-globulin chain, into a valine.
- Causing protein to change conformation
- which causes hydrophobic part to become EXPOSED
which causes polymerisation
Which causes genetic mutation in homozygous individuals.
49
What does GENETIC MUTATION from protein folding disease cause?
Reduces ELASTICITY in red blood cells
Causing Sickle cell anemia.
50
5 ways to treat sickle cell anaemia?
1) Sickle cell pain: Hydroxycarbamide
2) Sickle cell crisis: paracetamol/ibuprofen
- A warm towel on affected body part
3) Prevent infections: Daily dose of antibiotics. (e.g. penicillin)
4)If SEVERE: blood transfusions, folic acid, hydroxycarbamide
5) Sickle cell care: Stem cell/bone marrow transplant
51
Advantage of Hydroxycarbamide as a treatment?
Increases levels of haemoglobin.
52
Disadvantage of hydroxycarbamide as a treatment of sickle cell anaemia?
Could decrease levels of white blood cells and platelets
53
What is a disadvantage of stem cell/ bone marrow transplant as a treatment:
Transplanted cells could attack host cells.
54
Strongest to weakest bonds:
From strongest->weakest
Covalent
Ionic
Hydrophobic/hydrophilic interactions
H-bonds
Van der Waals.
55
Calculating buffer range of an amino acid:
Calculating buffering range of an amino acid:
pH= pka +- 1
56
pH calculations
pH = pka + log (HCO3-)/ (H2CO3)
Ka= (H+)(A-)/(HA)
Pka= -log ka
Ka= 10^-pka
57
Pneumonic to remember amino acids:
Phenyloanine - aromatic non-polar
R
Valine
Trytophan - aromatic non polar
Isoleucine
Methionine
Thernonine- aliphatic hydroxyl
Histidine- polar
Arginine- polar
Leucine- polar
Lysine- polar
58
What is an enzyme?
proteins that act as biological catalysts
59
What is a cofactor
organic molecules.
60
Where are enzymes found?
mitochondria
lysosome
Endoplasmic reticulum
61
What are coenzymes?
Small cofactors
62
prosthtic group is a .....
Tightly bound coenzyme
63
Cosubstrate is a...
loosely bound coenzyme.
64
What is glycolysis
Pyruvate -> glucose
65
What is gluconeogenesis
Opposite of glycolysis
Glucose -> pyruvate
66
What enzyme breaks down long fatty acid into "acetate" ?
Beta-ox
whereas acetate-> long fatty acid chain
is catalysed by the enzyme "FAS"
67
4 ways how enzymes catalyse reactions:
1) provide reactive surfaces and a suitable environment
2) Brings reactions together and allows transition state to be reached.
3) Weakening bonds in reactants
4) Reduces energy required to reach "transition state"
68
What is transition state?
State where the substrate is no longer a substrate, but not a product either.
69
Enzymes vs Inorganic catalysts: (4)
1) Enzymes are chemically similar, whereas inorganic catalysts are chemically diverse
2) Enzymes are LABILE, whereas I.O are stable to heat
3) Enzymes are specific whereas I.O are non-specific
4) Enzymes are inhibited in a specific way, whereas I.O tends to not be inhibited.
70
Things in common between Enzymes and Inorganic catalysts:
BOTH unchanged at the end of a reaction
BOTH don't affect final equilibrium.
( But allow equilibrium to be reached faster)
71
Enzyme specificity (In DECREASING order);
1) ABSOLUTE
2) STEREOCHEMICAL: PREFERS "D" OVER "L"
3) Group/function
4) LOW: gluthathione- s transferse: can catalyse a large number of substrates.
72
Denaturation of an enzyme=
Loss of biological activity
73
DEFINTION
What is a "unit of enzyme activity" ?
The amount of enzyme causing transformation of 1 micro mol of substrate per minute at 25 degrees celcius.
74
DEFINITION
What is "specific activity" ?
Number of units of enzyme activity per mg of enzyme protein.
75
DEFINITION
What is KATAL (KAT)
Amount of enzyme activity that transforms one mol of substate per second.
76
For "reaction velocity" , [ S] graphs:
Increasing [E] will increase reaction velocity, as long as there is enough substrate molecules to bind to it.
77
For reaction velocity, [E] graphs:
Increasing substrate concentration will increase rate at which products formed up to a max value (Vmax).
78
Vmax graph:
At Vmax active sites are full, so graph plateaus.
79
Turnover number of an enzyme equation:
Vmax = K2 [ E ] T
80
What is "Kcat"
Kinetic constant
81
DEFINITION
Turnover number of enzyme
Number of substrate molecules converted to products, when enzyme's active site is occupied with substrate.
82
Catalytic efficiency equation:
See notes
83
When [ S ] is less than Km: (4)
1) [E] is roughly same as [ET]
- [ET] is just the total enzyme concentration
2) Velocity of catalysis depends on Kcat/Km, [S] and [ET] values.
3) Kcat/Km is rate constant for S and E and can be used as a measure of catalytic efficiency.
4) You can use Kcat/Km values to determine an enzymes preference for different substrates.
84
What does it mean if a reaction is at Vmax?
Enzymes cant work any faster
Active sites are full
Units: Conc/time
85
DEFINITION
Km:
[S] at which reaction velocity is at half maximal.
units: Molar (M)
86
Siginificance of Km
Using mathematical proof
We find that Km = [S]
87
How can Km be applied to "affinity" ?
Km is a measure of affinity of an enzyme for its substrate.
88
What does a lower km mean for "affinity" ?
Lower km means
GREATER AFFINITY
89
What does inverting michaelis-Menten equation do graphically?
Turns hyperbolic curve into a straight line equation.
- kinetic parameters can be accurately estimated.
90
What type of graph is lineweaver bunk plot?
Straight line graph
91
What are the 2 types of enzyme inhibition:
Competitive and non-competitive inhibition
92
Competitive inhibition:
- Bind to the active site through intermolecular bonds
- Reversible reactions
- Increase in substrate concentration lowers the chance of competitive inhibitor binding.
- DON'T alter Vmax.
93
Non competitive inhibitor:
- Bind to allosteric site: can inhibit reaction without affecting strength of substrate bonding.
- Km unchanged
- Non competitive inhibitors decrease Vmax.
-Reversible/irreversible
- Non competitive inhibition disrupts active sites.
94
Allosteric enzymes:
Modulation
I
Inhibition
I
Activation
I
Co-operating
95
DEFINITION:
Homotropic Allostery:
Binding of identical molecules in a co-operative manner.
96
DEFINTION:
Heterotrophic Allostery:
Co-operative binding of some other substances as well as the substrate.
97
What does Allosteric activator do?
Increases activity
98
What does Allosteric inhibitor do?
Decreases activity.
99
What is Kcat and K2.
They are the same thing.
The kinetic constant K2 is Kcat
100
What are the rate laws for competitive and non competitive inhibitors?
Look at rate laws on notes.
- competitive inhibitor only binds to E
- non competitive inhibitor only binds to ES
101
What is Ki?
How potent an inhibitor is.
- concentration required to produce half maximum inhibition
102
Catabolism:
Breaking down of large complex molecules, into smaller simpler ones.
103
tricarboxylic acid pathway=
Kreb cycle.
104
cori cycle:
Cycle involving glucose lactate and alanine.
105
What is the normal level of plasma NH3
0.5mg/L
106
Urea cycle:
- only in the liver
- MAIN PURPOSE: DETOXIFICATION
Irreversible
- maintain ratio of urea: ammonia ( 500:1)
107
What does fumarate break down into:
Fumarate
malate
oxaloacetate ( NH2 transferred to oxaloacetate makes Asparate)
Asparate (Asparate combines with Acetyl CoA to create citrate)
Citrate
Pyruvate -> glucose
108
What are the basic metabolites?
1)Acetate
2) Acetone
3) urea
4) pyruvate
109
Glycolysis process:
glucose
fructose1,6-bisphosphate
2x3 carbon compounds ( oxidised to pyruvate) and ATP is produced
pyruvate
110
Enzymes involved in Glycolysis: (the 3 kinases)
1) Hexokinase - catalyses the phosphorylation of glucose
2) Phosphofructokinase- catalysed fructose 6 phosphate to fructose 1,6 bisphosphate using ATP
3) Pyruvate kinase
111
What is the function of hexokinase:
- Catalyses transfer of phosphate from ADP to Oh group on the 6th carbon to form glucose 6 phosphate.
112
What is the function of phophofructokinase?
Catalyses phosphorylation of fructose 6 phosphate to produce fructose 1,6 phosphate.
113
What is the function Pyruvate Kinase?
Catalyses transfer of phosphate group from phosphoenolpyruvate (PEP) to ADP to produce pyruvate.
114
Regulation of glycolysis pathway:
1) Hexokinase inhibited by glucose 6-phophate.
2) Phosphofructokinase: Inhibited by ATP, lowers affinity for fructose 6 phosphate
3) Pyruvate kinase: L- type found in the liver
M- type found in the muscle and brain
115
What does fructose 1,6 bisphosphate do?
Activates both pyruvate kinase isozymes (L and M type)
116
What does ATP do (regarding pyruvate kinase)?
Inhibiting both forms (L- type and M type)
- to slow down glycolysis
117
How is alanine involved with pyruvate kinase?
Alanine allosterically inhibits it.
118
What is Beriberi?
A neurologic and cardiovascular caused by deficiency of thiamine.
119
Beriberi:
prosthetic group: Thiamine pyrophosphate
for the enzyme pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase
- transketolase.
120
What does low transketolase activity indicate:
Beriberi of red blood cells.
121
What are the end products of KREBS:
CO2 and NADH
High energy electrons from NADH passed onto ETC.
122
KREBS carbon input and output:
2 carbons IN from acetyl CoA
2 carbons OUT as they leave as CO2
123
Regulation of Krebs cycle
Main regulators are Allosteric enzymes.
124
What are the allosteric enzymes that regulate the krebs cycle?
1) Isocitrate dehydrogenase
2) alpha- ketoglutarate dehydrogenasee
125
Isocitrate dehydrogenase (krebs)
Simulated by ADP, enhances the enzymes affinity for substrates
126
What inhibits isocitrate dehydrogenase?
1) NADH, by displacing NAD+
2) ATP
127
Alpha-ketoglutarate dehydrogenase
What is it inhibited by?
Succinyl Co A ( it's catalytic products)
NADH ( it's catalytic products)
ATP
128
What are the different proton pumps in ETC (3)
1) NADH-Q
2) Q-cytochrome C oxidase
3) Cytochrome C oxidase
Q:ubiquinone
129
Pump 1:
Reduced form "Q"
carries electrons from pump 1 to pump 2.
130
Pump 2:
Ubiquinone carries electrons from FADH2 to pump 2
131
What does succinate Q reductase do?
transfers electrons from FADH2 to ubiquinone.
132
Pump 3:
Cytochrome C allows electrons to pump 2 to pump 3.
133
What does pump 3 do?
Catalyses reduction of oxygen.
134
Proton Pumping: ETC
1) As electrons pass through the ETC, they fall into lower energy states
2) Energy is used to protons from matrix to the intermembrane space
3) A gradient of H+ ions is generated.
ADP + Pi -> ATP
135
What is the electron acceptor?
Oxygen.
136
ATP synthase consists of...
2 sub units (f0 and f1)
137
f0:
forms a channel which protons can cross the lipid bilayer
138
f1:
Gathers free energy derived from proton movement down chemical gradient.
139
How is ETC regulated?
Regulated by ADP levels
- unless ADP- > ATP, electrons don't usually flow through the ETC
140
Way of remembering afferent and efferent.
Afferent
Efferent
Arrives
Exits
141
Afferent neurones:
Signal travels from peripheral tissue to CNS
142
Efferent neurones:
Signal travels from CNS to peripheral tissue
143
what does "amitotic" mean
Not able to divide
144
What is the input region of the neurone?
Dendrites
145
What is the conducting component of the neurone?
Soma
146
What is the output region of the neurone?
Axon.
147
What is the cell body and what is special about it?
The cell body is the biosynthetic CENTRE OF THE NEURONE
- cell body does not contain centrioles.
148
What's a good attribute of dendrites?
They provide a large surface area.
149
DENDRITES:
- receive the signal inputs which gets converted into "charge of membrane voltage" (Vm).
150
CELL BODY:
The cell body= Large nucleus with a nucleolus.
- surrounded by granular cytoplasm
- mitochondria throughout
- microtubules throughout
which are important for intracellular transport and maintaining cell shape.
151
Function of the cell body:
Producing proteins and neurotransmitters.
- And transfers "changes in Vm" to axon hillock.
152
AXON HILLOCK:
First part of the OUTPUT pathway
- generates action potential if enough stimulation is received from the cell body.
- Expresses the ion channels that are needed for action potential.
153
AXON:
Each neurone has 1 axon arriving from the axon hillock.
- Different axons vary in diameter
^ which affects conduction
- Axons allow "axoplasmic transport" to nerve terminals.
154
What are axon branches known as?
Axon collaterals.
155
What is the charge of a membrane at rest on the OUTSIDE and INSIDE?
OUTSIDE= positive charge
INSIDE= Negative charge
156
Depolarisation:
When positive and negative swap themselves, after an action potential has flown down an axon.
157
Repolarisation:
After a nerve has carried out is action, it can be recharged.
- Nerve can carry out its function again.
158
What does "amphipathic" mean?
Readily forms bilayers.
- hydrophillic substnaces cant readily diffuse in/out.
159
What does "amphipathic" mean?
Readily forms bilayers.
- hydrophilic substances cant readily diffuse in/out.
160
What is the Membrane Potential for MOST cell types?
-50mV
161
What is the Membrane Potential for "resting skeletal muscles" ?
-90mV
162
What is the membrane potential for neurones?
(-65 to -70 mV)
163
What is the Na+/K+ ATPase pump?
For active transport powered by ATP
164
Do most animal cells have higher intracellular concentration of "K+ or Na+ ions "
K+
- higher concentration of K+, causes an ionic gradient to be generated.
165
What fraction of a resting cell's ATP is used to power the Na+/K= ATPase pump?
1/3
166
What are the 3 functions of the pump?
1) Control cell volume
2) Allows nerves and muscle cells to get electrically excitable.
3) Drives the active transport of sugars and amino acids.
- BONUS: helps to polarise membranes
167
For NA+/K+ ATPase pump, INSIDE is the cell losing +ve charge or gaining +ve charge?
LOSING +VE CHARGE.
this is because 3Na+ ions are outputted, and 2 K+ ions are inputted.
168
For NA+/K+ ATPase pump, OUTSIDE is the cell losing +ve charge or gaining +ve charge?
OUTSIDE OF THE CELL, GAINS +VE CHARGE
169
What is an ion channel?
Proteins that span across membrane and form selective pores.
- This increases the PERMEABILITY, allowing transfer of ions down their electrochemical gradient.
170
What are the 2 ways ion channels can be operated?
1) Ligand operated (ionotropic)
2) Voltage operated
171
Sodium ion channel:
- Has 4 repeating units
"+" helix contains many lysine and arginine residues.
- membrane depolarisation shifts the position of the helices, OPENING THE CHANNEL.
172
How is the sodium channel caused to be open?
Depolarisation causes positions of helix to shift
opening the channel.
173
What are the general steps of the normal nerve function? ( different types of polarisation etc)
1) Na+ channels open, depolarising the membrane, allowing an action potential to be fired
2) K+ channels open repolarising the membrane
- Na+/K+ ATPase pumps ensure ions are in the right place.
174
What do "volatage operated sodium channels" do?
They control nerve conduction.
175
What are "anaesthetics" and how do they work?
They interfere with the inhibition of nerve conduction,
by diffusing into axons and stopping Na+ channels.
176
What can A LOT of anesthetics cause?
Nerve blockage
as an action potential can not be fired.
177
Types of drugs that block channels:
- Anaesthetics
-Antiepileptics (phenytoin)
- Antidysrhythmic (disopyramide)
- Tetrodotoxin
- Saxitoxin
- Conotoxins
178
Types of drugs that block inactivation:
- Batrachotoxin
- Scorpion toxins
- DDT
- Pyrethroids
179
Where does an action potential start?
At the axon hillock
- Action potentials tend to flow in ONE DIRECTION ( down the axon).
180
If prior to depolarisation the Vm was -65mV, what would it be after depolarisation.
+60mV
181
Action potential propagation:
Small diameter axons and Large diameter axons
182
Small diameter axon=
High resistance
and slow conduction speeds
183
Large diameter axons=
Low resistance
and faster conduction speeds.
184
What is myelin sheath made up of
And what is the function
- Made up of Schwann cells
- Rapid fire of action potentials
185
How does a few ion channels affect myelin sheath?
Ensures that myelin is a good electrical insulator.
186
Oligodendrocytes:
Myelinating cells of CNS
- They insulate multiple axons
187
Are dendrites myelinated or unmyelinated?
Dendrites will always be UNmyelinated.
188
What is saltatory conduction, and what is the benefit of it?
Salatatory conduction is when action potentials JUMP FROM NODE TO NODE (nodes of ranvier)
189
What is saltatory conduction, and what is the benefit of it?
Saltatory conduction is when action potentials JUMP FROM NODE TO NODE (nodes of ranvier)
190
Axon Classification:
A= myelinated axon
alpha, beta, mew, delta = Diameter of axon
C= UNmyelinated neurone
191
What are synapses and what do they do?
Synapses are gaps between neurones.
Synapses are involved in cell signalling and communication.
192
where do the signals jump from?
Signal jumps from synaptic cleft
to
receptors on new cell.
193
What are unipolar neurones:
Sensory neurones
194
Neuromuscular junction:
Somatic neurones release the neurotransmitters ACh which bind to nicotinic receptors.
195
if THRESHOLD is reached (neuromuscular junction)
Then EXCITATION OCCURS, and skeletal muscle fibres contract.
196
What receptors are stimulated via the release of ACh by parasympathetic postganglionic fibres?
muscarinic receptors.
197
What do most sympathetic postganglionic fibres release?
Noradrenaline,
which binds to adrenergic receptors.
- sympathetic postganglionic fibres innervate(give nervous system) sweat glands.
198
Difference between ligand receptors and metabotropic receptors?
Ligand receptors are fast acting, but last for short periods of time,
Metabotropic receptors are slower acting
199
What can G protein's response affect?
May affect secondary activation.
- products formed from these responses are called secondary messengers.
200
At REST what do G protein's alpha sub units bind to?
GDP ( Guanine di phosphate)
201
When STIMULATED what do G protein's alpha sub units bind to?
GTP
202
AXOPLASMIC TRANSPORT:
Transport of vesicles around the axon.
203
What does Na+ ion cause?
DEPOLARISATION
(EPSP) excitatory postsynaptic potential. (more POSITIVE than -65mV)
204
What does K+ ion cause?
HYPERPOLARISATION
(IPSP) Inhibitory postsynaptic potential. (More NEGATIVE than -65mV)
205
What happens when a neurotransmitter is removed from synaptic cleft
( by break down or reuptake)?
Synapses are switched OFF.
206
What predicts the direction of ion movement?
Electrochemical potential. (µ)
207
Nernst Equation:
E = RT / zF ln( [ion]o / [ion]i)
"E" is equilibrium potential of an ion.
( Vm at which the ion will not flow)
208
What is the Goldman equation for?
- Allows us to calculate Vm
- Allows us to calculate Vr (resting potential)
-Allows us to work out relative permeabilities of different ions.
209
Donnan's law (membrane charge distribution):
Describes how charged particles near a membrane fail to distribute evenly between the 2 sides.
210
What are the 3 things that depend on whether or not an action potential is FIRED?
1) Voltage dependent NA+ channels
2) Voltage dependent K+ channels
3) Depolarisation threshold for Na+ channels
211
What is the refractory period of a neurone?
Recovery time, during which a neurone will not respond to a stimulus.
212
What are the 2 types of refractory periods?
1) Absolute refractory period
2) Relative refractory period
213
Absolute refractory period:
When a neurone can't carry another action potential. ion channels close.
214
Relative refractory period:
Occurs during a period where a 2nd action potential can be generated.
- "Initiation step" requires a stronger stimulus though.
215
What does the strength of a stimulus depend on?
Depends on the number of action potentials being carried.
216
What is the Cardiovascular system composed of?
Composed of:
The Heart, 2 networks of blood vessels
( systemic and pulmonary circulation)
217
Multicellualr advantages
1) Efficiency
2) Specialisation of cellular roles increase ability to survive and reproduce
218
Multicellular disadvantages:
1) Dependent on the function of other cells
2) Size of an organism
3) Delivery of nutrients
4) Removal of wastes
5) Communication co-ordination of function.
219
What does a circulatory system mean for large multicellular:
- Transport of nutrients
- Transport of O2
- Transport of CO2
- Transport of other waste products
220
what percentage of our body weight is blood?
Around 8%
221
What is plasma:
Straw coloured fluid containing proteins and dissolved salts.
222
What does plasma consist of:
water (90%)
proteins (8%)
non protein (urea etc)
nutrients ( carbohydrates, amino acids etc)
electrolytes (Na+, K+, Ca2+, Mg2=, Cl-, SO4 2-, HCO3-).
223
What helps to maintain oncotic pressure in the plasma?
Albumin ( protein)
Electrolytes
-Also help to maintain normal blood pH.
224
What are Leukocytes and what is their function?
they can leave the circulation and enter into tissues to kill/get rid of bacteria, viruses, toxins etc.
225
What are the different types of Leukocytes:
1) Granulocytes: granules in the cytoplasm can be easily stained.
- Neutrophils
- Eosinophils
-Basophils
^ all these are types of granulocyte.
226
Neutrophils:
Contain granules of hydrolytic enzymes( lysosomes) and "defensins" (poke holes in the opps membrane)
- Attracted to sits of inflammation, they can engulf invading cells.
227
Eosinophils:
- Don't contain enzymes that specifically target bacteria
- They are focused on attacking parasitic worms (eg. tapeworm).
228
Basophils:
- Contain large amounts of histamine,
which dilates the arterioles when release,, increases postcapillary venule permeability and attracts other leukocytes to the area
229
What is a Agranulocyte?
Include lymphocytes and monocytes
230
What is the difference between granulocyte and agranulocyttes?
One has granuls in cytoplasm , one doesn't.
231
What is the difference between granulocyte and agranulocytes?
One has granules in cytoplasm , one doesn't.
232
Lymphocytes:
Exist in large numbers
- most are found in lymph nodes.
233
What do T lymphocytes and B lymphocytes combat?
- T lymphocytes attack virus infected cells and some tumours.
- B lymphocytes form plasma cells to produce antibodies.
234
Monocytes:
Attack viruses and bacteria
- they leave the blood and enter into tissues to form macrophages.
235
platelets:
Help to reduce or stop blood loss
they are tiny
and have no nucleus
made of fragments called megakaryocytes
platelets can release molecules that activate other platelets
236
What are platelets made up of ?
5-HT ( causes vasoconstriction to reduce blood flow to damaged area)
ADP
platelet-derived growth factor
ca 2+ ions
enzymes
237
What does 5-HT help do in platelets
5-HT
causes vasoconstriction, reducing blood flow to the damaged area.
238
how do platelets help join damaged blood vessels together
Platelets contain smooth muscle, which contract and bring the edges of the damaged vessels together.
239
Erythrocytes:
biconcave in shape (large SA:V ratio, increases rate of gas exchange).
no nucleus
contain Hb
Hb readily binds with O2
240
Gas exchange ( erythrocytes) :
The dark red deoxygenated erythrocytes pick up oxygen from the alveoli.
The oxygen then binds to Hb, causing the enthrocytes to turn bright red (oxyhaemoglobin).
However, for tissues oxygen leaves the blood at tissues and diffuses through extracellular fluid and then into cells.
241
wall structure of a blood vessel: outer layer
3 layers all together
Tunica adventitia ( externa):
Outer layer
strong connective tissue
resits pressure
242
Wall structure of a blood vessel: middle layer
Tunica media:
middle layer
smooth muscle
middle layer allows vasoconstriction and vasodilation to happen.
243
Wall structure of a blood vessel: Inner layer
Tunica interna:
Inner layer
endothelial cells
allows blood to flow smoothly.
244
Why is the pulmonary artery different to other arteries?
Most arteries carry oxygenated blood away from the heart
Whereas, the pulmonary artery carries deoxygenated blood from the heart to the lungs ( still "away" ) .
245
What does the Poiseuille-Hagen formula show?
Shows that small changes to the radius of a vessels, could affect how blood flows.
246
What are the 2 main types of artery:
Muscular artery
Elastic artery
247
Muscular artery:
These type of arteries are normally between the elastic arteries and the capillaries
smooth muscle to contract or relax
which helps to adjust diameter of the lumen
blood flow is controlled through a capillary bed.
248
Elastic artery:
Largest diameter
These type of arteries are NEAREST to the heart.
Thick elastic layer allows flexibility to accommodate blood being pumped from the heart at high pressures.
249
Arterioles:
Arterioles are very small arteries.
arterioles can withstand blood pressure
- they contain smooth muscle.
250
What nervous system ( P or S) regulates the contraction and relaxation of arterioles?
Sympathetic nervous system.
251
capillaries:
very thin walled vessels.
One cell thick
- made of endothelial cells and basement membrane.
- have a very narrow lumen.
- capillaries are responsible for exchange between blood cells and tissues.
252
What type of vessles to cappillarries branch out into:
Venules
venules are tiny vessels
253
What are "postcapillary venules"
These form when capillaries join together.
walls of postcapillary venules are made up of endothelial cells with a few fibroblasts.
Fluids and leukocytes can pass through their walls.
254
What is formed when many venules join together?
A vein.
255
Veins:
Carry deoxygenated blood at low pressure to the heart.
Large lumen
thin walls.
256
Where and what type of blood does the pulmonary vein carry:
The pulmonary vein carries oxygenated blood from the lungs to the heart.
257
What is the vein made up of:
Thin tunica adventitia
Thin tunica media
smooth muscle
258
What is Venoconstriction:
contraction of smooth muscle in the vein.
259
What does venoconstriction help with
Helps with venous return.
( Rate at which blood flows back to the heart).
260
what layer of veins contain semi lunar valves:
The tunica interna.
semi lunar valves open and shut to prevent blood from flowing backwards.
261
What 2 factors positively affect "venous return"
1) Respiratory pump:
2) Muscle pumping: skeletal muscles contract around a vein,, which presses on a vessel wall
allowing blood to flow to the heart.
262
1) Respiratory pump (Venous return) :
thoriac veins expand, causing blood to be delivered to the right atrium faster.
Inhalation also increases abdominal pressure, causing blood to flow to the heart.
263
2) Muscle pumping:
skeletal muscles contract around a vein, which presses on a vessel wall
allowing blood to flow to the heart.
264
Systemic circulation:
Supplies blood to the entire body
(except lungs)
265
Pulmonary circulation:
supplies blood to the lungs.
266
What are the 2 parts of the lymphatic system?
1) Lymphatic vessels
2) Lymphoid tissue (plays a role in defence responses).
267
what does hydrostatic and osmotic pressure do ( lymphatic system) ?
Forces the fluid a out of capillaries ( at the arteriole end) and most of the fluid is reabsorbed ( at the venous end).
268
What do Lymphatic vessels do?
They collect excess fluid and return this fluid back to the blood.
269
What is it called once the fluid is inside the lymphatic vessel ?
the thing inside is then known as "lymph" .
270
Lymph capillaries:
Porous
found in most tissues
271
What is the lymphatic system thoo ?
Basically, its just a one way drainage system.
Where lymph flows back to the heart
via lymphatic vessels.
272
what do a group of lymphatic capillaries form ?
They unite to form "collecting vessels",
These vessels then unite to form "trunks",
these trunks unite to finally form "ducts".
273
Difference between veins and collecting vessels ( Lymphatic system) ?
Collecting vessels have thinner walls than veins.
274
Difference between veins and lymphatic vessels ( Lymphatic system) ?
Lymphatic vessels have more valves than veins do.
275
what are the 2 lymphatic ducts ?
Right lymphatic duct
And the,
Left lymphatic duct.
Right drains the right side of the:
head
neck
arm
and right side of thorax.
Left drains: the rest of the body.
left duct BIGGER than right.
Lymph is then returned to the venous circulation at the junction of the internal jugular vein and subclavian vein on the left and right sides.
276
What is blood pressure:
Drives blood flow around the cardiovascular system.
Blood will flow from an area of high pressure to an area of low pressure.
277
When referring to the term " blood pressure" what are we referring to ?
Systemic arterial blood pressure.
which is expressed as 2 numbers.
278
What are the meaning of the two numbers ( blood pressure)
E.g. 120/80 mmHg
First number is "systolic pressure"
Second number is "diastolic pressure".
279
What is "blood flow" ?
The volume of blood flowing through a certain region.
280
What is peripheral resistance (also known as vascular resistance)
Resistance to blood flow.
281
3 factors that contribute to peripheral resistance:
1) Blood vessel length: longer length= increased resistance.
2) Blood viscosity: thicker blood: more resistance.
3) Blood vessel diameter ( difference in resistance between vasoconstricted and vasodilated vessels).
282
Which is more resistant to blood flow,
vasoconstricted or vasodilated vessels ?
vasoconstricted MORE resistance
vasodilated LESS resistance.
283
Cardiac output (CO) equation:
CO = HR x SV
CO = cardiac output (L/min)
HR = Heart rate (BPM)
SV = Stroke volume
DURING excercise, if HR or SV increase, then CO increases.
284
Cardiac output (CO) equation:
CO = HR x SV
CO = cardiac output (L/min)
HR = Heart rate (BPM)
SV = Stroke volume
DURING exercise, if HR or SV increase, then CO increases.
285
what 2 components form the cardiovascular centres ?
1) cardiac centre
2) vasomotor centre.
286
What's the role of the vasomotor centre ?
The vasomotor centre receives inputs from baroreceptors,
To adjust the diameter of blood vessels.
287
Where is the vasomotor centre located ?
in the medulla oblongata
288
What are Baroreceptors and what do they do ?
Baroreceptors are sensory nerves
that monitor changes in BP.
They do this by sending signals to the medulla oblangata.
289
Where are baroreceptors found?
Found in the carotid sinuses
and
aortic arch.
290
How does an increase in BP affect vasoconstriction and HR ?
increase in BP causes a reduce in vasoconstriction and HR .
291
What types of baroreceptros increase HR ?
THe ones positioned above the heart
292
What type of baroreceptors decrease HR ?
The ones in level with or below the heart.
293
what molecule mediator is released if BP is too high ?
Atrial natriuretic peptide
causes atria to stretch
which causes kidneys to reabsorb less sodium and water.
vasodilation also occurs.
BP reduces.
294
What molecule mediator is released when BP is dangerously low ?
Antidiuretic hormone (ADH)
causes the kidneys to absorb more water.
Vasoconstriction occurs too.
BP increases.
295
What can inhibit the release of ADH ?
Ingestion of alcohol.
296
How can exercise affect BP ?
exercising changes levels of o2 and co2, which regulates BP via chemoreceptors.
297
What are the 3 different types of muscle tissue ?
1) Skeletal (striated).
2) cardiac muscle.
3) Smooth muscle (non-striated).
298
Skeletal muscle (voluntary or involuntary)
VOLUNTARY control.
299
Cardiac muscle
INVOLUNTARY control.
fibres are attached at their ends with intercalatediscs.
these intercalated discs contain gap junctions for quick conduction of action potentials.
300
Cardiac muscle
INVOLUNTARY control.
fibres are attached at their ends with intercalated discs.
these intercalated discs contain gap junctions for quick conduction of action potentials.
301
Smooth muscle
Non striated
thickest fibres
INVOLUNTARY control.
302
Diastole: is heart contract or relax.
relax
- blood is pumped into atria and ventricles.
systemic and pulmonary pressure respectively: 80 and 20 mmHg
303
Systole: is the heart contract or relax ?
contract.
-atria pumps blood into ventricles.
systemic and pulmonary pressure respectively: 120 and 40 mHg.
304
Electrical conductivity of the heart:
SAN is made up of "self-excitatory cells" that depolarise.
This depolarisation spreads around atrial tissue and to the AVN (atrioventricular node).
Action potential then travels down the bundle of his and purkyne tissue, causing the ventricles to contract.
305
Where is the SAN located ?
SAN ( sinoatrial node) is located in the right atrium
306
what is the boiling point of oxygen
-183 degrees celcius
MINUS 183 degrees celcius.
307
how many oxygen atoms in ozone ?
3
o3
308
what do the "conducting zones" do ?
They conduct air to sites of gas exchange.
309
What is the respiratory zone ?
This is where gas exchange occurs.
310
what does "olfactory mucosa" mean ?
It means sense of smell
311
Where does cillia in the nostrils move the mucus to ?
to the pharynx where it is swallowed.
pharynx also acts as the "resonance chamber" for our voice.
312
What nerves trigger sneezing to occur to expel irritants ?
Sensory nerves
313
why does a nose run in the winter ?
In cold environments cilia move a lot slower
which means more mucus remains in the nasal cavity.
314
What do "paranasal sinuses" do ?
help warm and moisten the air we inhale.
315
what is sinusitis ?
Inflammation of sinuses.
This could result in a sinus headache
316
What does the Larnyx do ?
Houses the vocal chords and keeps our airways open.
Diverts air and food down the tracheae and oesophagus.
317
What is the specific mechanism of the larynx that helps to prevent food from going down the tracheae ?
When swallowing a reflex occurs
causing the larynx to pull up
and the epiglottis to cover up the laryngeal inlet.
318
Why is smoking bad for the respiratory system ?
Destroys cilia.
319
which of the two bronchi is wider and shorter ?
The right bronchi.
320
in the lungs what do primary bronchi divide into ?
Secondary bronchi,
which then divide into tertiary bronchi.
then these tertiary bronchi keep dividing to form smaller and smaller bronchi.
321
what 2 mechanism alter airway resistance ?
Bronchoconstrictions and bronchodilations.
322
what 2 mechanism alter airway resistance ?
Bronchoconstriction and bronchodilation.
323
what types of capillaries are alveoli covered by ?
covered by pulmonary capillaries
the basal lamina of these capillaries and the alveoli are fused together.
(basal lamina provides support to epithelial cells)
324
what does the fluid that the type II cells in the alveoli wall secrete do ?
The fluid contains a surfactant,
which helps to reduce surface tension of the alveolar fluid
and prevents "alveolar collapse" .
325
what is the pleura ?
Thin double layered membrane that forms a closed sac.
326
What does pleural fluid released do ?
Acts as a lubricant allowing the lungs to easily move during breathing.
327
What 2 parts is the pleura split up into ?
1) parietal pleura
2) Visceral pleura
328
What are the four different types of inspiration and expiration ?
1) quiet inspiration
2) forced inspiration
3) quiet expiration
4) forced expiration
329
Quiet inspiration:
diaphragm relaxes
external intercostal muscles contract
lifting the ribs and moving the sternum forward.
increasing the volume of the thoracic cavity, lowering pressure
air is drawn into the lungs
330
Forced inspiration:
scalene and sternomastoid muscles
and the pectoralis muscles contract
this raises the ribs upwards even more
Also, the back extends to straighten the thoracic curvature (erector spinae muscles).
331
Quiet expiration:
Passive process
inspiratory muscles relax
volume of thoracic cavity decreases
forcing air out the lungs
332
Forced expiration;
wall of the abdomen contracts
increasing the intra-abdominal pressure
rib cage moves down and inwards
internal intercoastal muscles contract ( cause rib cage to move downwards).
333
how many "respiratory groups are there" ?
2
334
What are the 2 types of respiratory groups ?
Dorsal (DRG)
ventral (VRG)
335
Where are the DRG and VRG located ?
In the medulla
336
What happens to DRG in overdose of alcohol or opioids
DRG will stop
Respiration will stop
could go into coma
and could even be fatal
337
which respiratory group involves "forced breathing"
VRG
338
what do chemoreceptors monitor ?
co2 o2 pH
339
What is the partial pressure of Co2 in the arterial blood ?
40 +- 3mmHg
340
How can respiratory centres and ventrilation be stimulated ( via chemoreceptors) ?
Co2 from the blood diffuses into the cerebrosal spinal fluid and combines with water H2o to form carbonic acid ( HCo3)
this dissociates to form H + ions.
which lowers the pH
Low pH excites chemoreceptors to stimulate respiratory centres, increase in ventilation.
341
what is the normal range for partial pressure of oxygen ?
75 to 100 mmHg
If it goes below 60mmHg then there will be an increase in ventilation.
342
What is acidosis ?
Drop in pH
343
What is alkalosis ?
Increase in pH
344
What is microbiology ?
Study of the biology of microscopic organisms
345
Acellular def
Not containing cells
346
What are 3 differences between prokaryotes and eukaryotes ?
1) E has a nucleus but P does not
2) Undergo cell division in different ways
3) E has cytoskeleton but P does not
347
What type of cell division do prokaryotes undergo ?
Binary Fission
348
What type of cell division do eukaryotes undergo ?
Mitosis and Meiosis
349
When talking about gram positive and gram negative, what are we referring to ?
Bacterial cell walls
350
Difference between gram positive and gram negative ?
Gram positive is thicker than gram negative.
351
What is "capsid" ?
A protective protein coat during transmission
and may be involved in immune response.
352
Are "envelopes" present in all types of viruses ?
Nah
353
What do viruses need to replicate
They need a host cell
354
Do antibiotics affect viruses ?
Viruses are not affected by antibiotics
355
4 stages of "bacterial growth" ?
1) lag
2) log
3) stationary
4) Death
356
lag phase:
increased metabolic activity of cells due to the synthesis of enzymes.
357
log phase:
Exponential phase
Cell POPULATION
DOUBLES at regular intervals.
358
Stationary phase:
No increase or decrease in cell population
359
Death phase:
Decrease in the number of cells.
360
What is Binary fission ?
A type of asexual reproduction
(only one parent cell)
doesn't involve gametes
361
3 Advantages of binary fission ?
Only need one parent cell
Rapid division
Daughter cells are clones of parent cells.
362
Disadvantage of binary fission ?
No genetic variation- change in environment could cause species to become extinct.
363
similarity between eukaryotes and prokaryotes ?
They both under go " semi-conservative replication"
364
What is a "replisome" ?
A Large protein complex that carries out DNA replication.
365
State the 4 techniques used to introduce a foreign gene into host cells ?
1) Transformation
2) Transduction
3) Transferation
4) Conjugation
366
Transfection:
Introducing nucleic acids into cells via non-viral methods
367
Transduction:
where foreign DNA is introduced to the cell via a viral factor.
368
Conjugation:
When bacteria cells transfer their genetic material through direct contact.
369
Transformation:
Process of DNA uptake by bacteria from the surrounding environment.
370
What does transgenic mean ?
Organism whose genome has been altered by foreign genetic material from another species.
371
What type of decomposers are bacteria ?
primary decomposers
They recycle nutrients.
372
What are "probiotics" ?
Good bacteria that keep you healthy and prevents pathogens from gaining access to the body.
373
Bioremediation:
Decontamination hazardous wastes.
where microbes clean up the environment.
374
What is dissemination ?
Exit from host
375
What are the 3 types of transmission routes (contact) ?
1) Direct
2) indirect
3) airborne
376
The 3 main routes of disease transmission ( Human to human) :
1) Respiratory route
2) The faecal route
3) The venereal route
377
What is the definition of "infectious dose" ?
Number of infectious organisms required for 50% of the population to show signs of infection.
378
What can viruses be classed as ?
Obligate parasites ( they need a host to survive to make more viruses) .
379
2 ways that the disease can interact with an organism :
1) Direct; producing microbial toxins that kill immune system cells.
2) Indirect: interactions with the host immune response. (inflammation. puss formation etc).
380
What are the 2 types of microbial toxins:
Endotoxins and exotoxins.
381
Properties of Endotoxins:
1) Heat stable
2) Lipopolysaccharide ( LPS) - Lipid A 0 gram positive
3) May stimulate immune reaction
4) can cause chills, fever, muscle weakness and aches and pains.
382
Properties of Exotoxins:
1) Soluble
2) prone to heat
3) exotoxins have systemic effects
4) can be carried in plasmids
5) can act as targets for vaccine design. ( toxoids)
383
What are "toxoids" ?
Things that can act as targets in the process of designing a vaccine.
384
what is tetanus
A disease that causes " systemic intoxication"
385
What is tetanus caused by ?
CAused by clostridium tetanus
386
What does clostridium tetanus actually do ?
Contaminates deep wounds where oxygen concentration is low.
387
What does tetanospasmin do ?
Blocks nerves
and blocks release of the neurotransmitter GLYCINE
causing muscle spasms
and reduces contraction of muscles.
388
Cholera:
Water disease, found in contaminated water.
389
Is cholera gram negative or positive ?
Gram negative
390
What does the cholera toxin actually do to cells ?
1) toxin is secreted and enters cells
2) This affects c-AMP
3) Decreases the amount of fluid and electrolytes in the body
4) Leading to fatal dehydration
391
What is epidemiology ?
Study of people and disease throughout time.
392
What is a sporadic disease ?
A disease that occurs at irregular intervals
393
What is an endemic ?
A disease that maintains a regular low level in a population.
394
What are the 5 methods of sterilisation ?
1) Filtration (removal) - 2 types ( Dry and wet)
2) Heat (Destruction)
3) Gaseous sterilisation (Destruction)
4) irradiation (Destruction)
5) Chemical (Destruction)
395
What is D value ?
TIME TAKEN at a specific temperature, to achieve a 90% reduction in the number of cells.
396
What is Z value:
INCREASE IN TEMPERATURE needed to reduce the D value by 90%
397
Antibiotic definition ?
A substance produced by a microorganism or by chemical synthesis, which at low concentrations can kill or inhibit the growth of other microorganim.
398
What is " selective toxicity" ?
When only the microbe is affected
399
What does bactericidal do (C) ?
Kills or breaks down bacteria.
400
What does bacteriostatic do (S):
INHIBITS GROWTH of bacteria (reversible effect).
401
Types of metabolic reactions antibiotics are involved in ?
1) Folate metabolism
2) DNA synthesis
3) RNA synthesis
4) Protein synthesis
402
What do " Beta- lactams" do ?
Strengthen the stability of the membrane.
403
Where do beta lactams come from ?
Antibiotics can make them
404
What are the 3 different types of antibiotic RESISTANCE mechanisms :
1) Altering Targets
2) Destroying antibiotics
3) modifying antibiotics
405
3 ways antibiotic resistance can occur :
1) Over prescribing
2) Non-complinat
3) Not using the antibioitc for its intended purpose
406
3 ways to overcome antibiotic resistance:
1) Identification of the pathogen
2) Selection of the antimicrobial agent appropriate for the pathogen
3) Drug combinations may help overcome the antibiotic resistance.
407
What is non specific immunity ?
First line of defence after the host is first exposed to the pathogen.
408
What are the 2 different types of immune systems ?
1) The innate immune system
2) The adaptive immune system
409
What are the 4 defensive barriers of the innate immune system ?
1) Anatomic
2) Physiologic
3) inflammatory
4) Phagocytic
410
What are 3 examples of anatomic barreirs ?
Skin and sebaceous glands and mucous membranes.
411
Skin as an anatomic barrier:
Rarely penetrated by bacteria
"flora" of the skin metabolises substances which are secreted onto the skin,
and produces fatty acids.
412
Sebaceous glands as an anatomic barrier:
They produce sebum.
413
What does "sebum" do ?
Consists of lactic and fatty acids
which help maintain a pH of 3-5.
This pH inhibits the growth of most organism.
414
Where are mucous membranes found ?
Respiratory tracts.
415
what type of cells secrete mucus ?
Epithelial cells
416
What are the 3 main factors of physiologic barriers:
1) temp
2) pH
3) Solubility
417
Example of an innate physiologic barrier:
Gastric acidity
418
How gastric acidity acts as a defence mechanism ?
Very low ph in the stomach = organisms cant survive.
419
One reason new borns might be more susceptible to disease than adults ?
This is because new-borns stomach pH are not as low as adults yet.
420
What are lysosomes ?
Hydrolytic enzymes
421
Where are lysosomes found ?
In mucus secretions and tears.
422
What some examples of phagocytic barriers ?
Monocytes, neutrophils, eosinophils, macrophages can digest microorganism in the "phagolysosome" .
423
How might inflammation occur ?
A microbe may trigger an inflammatory response via ana interaction with cell surface receptors
424
What 2 things is inflmmation related to :
Cell regeneration and scarring
425
What are the 2 types of inflammation ?
Acute inflammation and chronic inflammation.
426
Acute inflammation:
can last anywhere from a few minutes to a few days
characterized by fluid and proteins.
427
Chronic inflammation:
Can last anywhere from weeks to years
characterized by lymphocytes and and macrophages.
428
What are the key features of inflammation:
Vasodilation
Endothelial permeability
Extravasation ( Leakage)
429
What are the 5 signs of inflammation ?
1) heat = caused by vasodilation
2) redness = caused by vasodilation
3) swelling = caused by vascular permeability
4) Pain = caused by mediator release
5) loss of function = caused by mediator release
430
What is "margination" in regards to blood vessels ?
Means "close to wall of blood vessel"
431
How is thee fluid like substance "pus" formed ?
Formed by an accumulation of dead cells and digested material and fluid.
432
What are the 2 types of inflammatory mediators:
1) cell derived mediators
2) plasma derived factors
433
3 examples of cell derived mediators:
1) Arachidonic acid derivatives
2) Cytokines
3) Vasoactive amines
434
What do arachidonic acid derivatives do ?
Cause increased capillary permeability, vasodilation and smooth muscle constriction.
435
What can cytokines do in the inflammatory response ?
Attract inflammatory cells such as neutrophils
436
What does histamine do in the inflammatory response ?
A chemical that is released in response to tissue injury,
that binds to receptors causing vasodilation and increasing permeability of capillaries and vessels.
437
What are the 4 different types of plasma derived factors:
1) Acute phase proteins
2) Kinin system
3) Clotting
4) Complement
438
What is an example of an acute phase protein ?
CRP
its produced by the liver
useful inflammatory marker
439
What are kinins:
Small peptides involved with inflammatory response.
440
Where are "kinins" present ?
In the blood plasma when its in its "inactive form".
441
What do "kinins" do ?
Activate in response to tissue injury permeability of capillaries
causes vasodilation and increased
442
What type of kinin stimulates pain receptors ?
Bradykinin
443
What do enzymes in the "blood-clotting" system do ?
Activate an enzyme cascade that results in deposition of insoluble strands of fibrin.
444
What do fibrin strands do in the "blood clotting" system ?
Wall off injured area and prevent spread of infection.
445
What happens after inflammation has occurred ?
once the inflammation has stopped and debris has been cleared
tissue repair begins
capillaries grow into the fibrin of a blood clot
Fibroblasts ( connective tissue cells) replace the fibrin as the clot dissolves.
as fibroblasts and capillaries accumulate scar tissue forms,
446
How is scar tissue formed ?
Accumulation of fibroblasts and capillaries.
447
What is "abscess" with regards to inflammation ?
A walled off collection of pus
448
What are vaccines ?
Dead or genetically engineered antigens that defend against harmful microorganisms.
449
How do vaccines actually benefit as a defence against harmful microorganisms ?
They promote the development of antibodies, preventing the development of disease.
450
What are the 4 main types of vaccines ?
Whole organism vaccine ( Attenuated vaccine)
INactivated vaccine
Recombinant antigen vaccines
Recombinant vector vaccine
451
What is pathogenicity ?
The ability of a pathogen to cause disease
452
Disadvantage of attenuated vaccine ?
Less pathogenicity
But vaccine can grow within the host
453
Why may there usually be no need for boosters ?
Due to increased immunogenicity
And increased memory cell production
454
What’s safer inactive or active vaccine ?
Inactive
455
How are pathogens that are used in inactive vaccines actually “inactivated” ?
By heat or chemicals.
456
What some examples of purified macromolecules ?
Polysaccharide vaccines
457
What is special about polysaccharide vaccines ?
They only activate B cells.
458
What do polysaccharide vaccines produce ?
IgM with little or no memory cells.
(Immunoglobulin G)
459
What is one advantage of a polysaccharide vaccine ?
They can be conjugated into a protein carrier ( E.g. transport proteins)
460
What does “recombinant antigen vaccines” involve ?
Involves DNA coding for the relevant antigen to be expressed as a suitable vector.
461
An example of a recombinant antigen vaccine ?
Hepatitis B vaccine, where the gene for the major antigen is CLONED in yeast cells.
Antigen vaccine helps the release of antibodies.
462
Recombinant vector vaccines
Genes coded for antigen are inserted into the genome of the attenuated pathogen.
463
With regards to ‘recombinant vector vaccines”, if the gene is coding for envelop protein what happens?
If a gene is coding for envelope protein a cell mediated and antibody response can be generated.
464
What are the 2 different types of immunisation ?
Active and passive immunisation
465
What is passive immunity ?
Transfer of antibodies and immune cells to the patient.
466
What is a key feature of "passive immunity"
immune response is no produced
memory cells is not produced
467
What is an example of natural passive immunity ?
placental transfer of maternal antibodies
468
What is an example of artificial passive immunity ?
antibodies directly into the body.
469
One draw back of passive immunity ?
BOOSTERS required
due to the persistence of "maternal antibodies" ,
which can block epitotes.
470
One draw back of passive immunity ?
BOOSTERS required
due to the persistence of "maternal antibodies" ,
which can block epitopes.
471
What is active immunisation ?
stimulating a primary immune response
which involves T and B cells
Leading to production of memory cells,
which can cause a faster secondary immune response upon exposure to a pathogen.
472
What is an example of natural active immunisation ?
CHICKENPOX
( Generation of memory cells following a childhood infection)
473
What is active artificial immunity ?
Vaccines.
474
What is the primary aim of vaccine design ?
To induce a memory response
475
During vaccine design, what do you have to do to make sure " t helper cells " get involved with the situation ?
Antigens should be processed by APC's
in order for "T h cells to activate "
476
What are the 2 main functions of the kidneys ?
1) to reabsorb water
2) To remove waste products from the blood
477
What does helicase do ?
Catalyses unwinding of DNA
478
What does Topoisomerase do ?
Introduces negative coils into the DNA,
which helps compensate the torsional strain caused by the unwinding of the DNA double helix during DNA replication.
479
What is the order of heart elictrac conduction activity ?
1) SAN
2) Atrial myocardium
3) AVN
4) Bundle of His
5) purkyne fibres
6) Ventricular myocardium
