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DDT > Trigger 2 > Flashcards

Trigger 2 Flashcards

1
Q

What is Ischemia

A

restriction in blood supply

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2
Q

What is an atheroma

A

degeneration of the walls of the arteries caused by accumulated fatty deposits and scar tissue, and leading to restriction of the circulation and a risk of thrombosis.

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3
Q

What are the 4 stages of plaque formation

A

Endotheial Dysfunction
Stable Plaque Formation
T- Cell activation
Plaque repture & blood coagulation

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4
Q

What happens in the endothelial dysfunction stage

A

Risk factors = ROS, hyperglyceamia, hypercholesterolaemia, hypertension
Monocytes adhere to endothelium via VCAM-1 (vascular cell adhesion molecule-1) & infiltrate
Monocytes become macrophages in intima
Macrophages uptake modified (oxidised & glycated) LDL
Macrophages become foam cells
= Fatty Streak

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5
Q

What happens in the Stable Plaque Formation stage

A

Many Foam Cells in intima
Vascular Smooth muscle cells migrate from tunica media, proliferate & act like myofibroblasts to produce collagen
Fibrous cap containing collagen fibres forms

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6
Q

What happens in the T- Cell activation stage

A

Th1 & Th2 recruited & activated
Matrix metalloproteinases (MMPs - produced by foam cells
Proinflammatory cytokines released
MMPs start to break down fibrous cap

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7
Q

What happens in the Plaque repture & blood coagulation stage

A

MMPs & Proinflammatory cytokines break fibrous cap
Tissue factor released from endothelium
Start of Extrinsic Coagulation Cascade
TF Binds to Factor VIIa (serine protease) & activates (coagulation factors are inactive zymogens)
Catalyses conversion of Factor X → Factor Xa
Initiates common pathway of blood clotting Prothrombin→ thrombin & fibrinogen → fibrin
Blood vessel stenosis, occlusion or thrombi released

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8
Q

What is reperfusion?

A

Return of blood supply and oxygen

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9
Q

What is the process of reperfusion

A 
O2 returns --> ATP serca pumps restart 
ROS generated --> damage membranes 
ER breakdown, Ca2+ released 
Ca2+ uptake into the mitochondria 
Mitochondira permability tranistion pores open and Na2+/Ca2+ exchanger reversed --> Ca2+ released
Endothelial dysfunction 
Haemostasis and prothrombosis 
Pro-inflammatory cytokines released
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10
Q

What is an ishemic stroke

A

When an artery to the brain is blocked

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11
Q

What is an thrombotic stroke

A

when a cerebral artery becomes blocked with a clot that formed in the brain blood vessels
responsible for 50% of all strokes

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12
Q

What is an embolic stroke

A

when an artery becomes blocked with a clot that formed somewhere other than the brain

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13
Q

what is the ischemic cascade

A

a series of biomechanical reactions that are iniated in the brain and other aerobic tissues after seconds to minute of ischemia

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14
Q

Stages of Ischemic Cascade

A

decrease in O2 - ATP shortage
anaerobic metabolism –> Lactatic acid production
Na2+ build up in neuron –> water moves in causes cytotoxic odema
Na2+/Ca2+ pumps stop working –> excitotoxicity
Cell membrane broken down by phopholipodase
Mitochondarial breakdown
Casacde dependant cascade –> Apoptosis
Inflammatory response

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15
Q

What are stents used for

A

placed in an artery as part of percutaneous conorary intervention procedure
small mesh tube
supports narrow or weak arteries

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16
Q

What are Cardiac Markers

A

molecules that show up in your blood after you heart has been under servere stress due to low oxygen
used in combination with ECG to diagnose heart attacks

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17
Q

What happens to creatine kinase

A 
normally doubles if  youve had a heart attack 
CK-MB 
expressed by the myocardium 
appears 4-6 hours after 
peaks at 24 hours
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18
Q

What happens to troponin levels

A 
cardiac specific troponin I 
expressed by the myocardium 
increases 3-12 hours 
peak 24-48 hours 
highly sensitive and specific
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19
Q

What does the cerebellum control

A

coordination of movement, planning and execution of movement, maintenance of posture, and coordination of head and eye movements.

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20
Q

What symptoms would show if an indivdual had a stroke in the cerebellum

A

A stroke involving the cerebellum may result in a lack of coordination, clumsiness, shaking, or other muscular difficulties. These are important to diagnose early, since swelling may cause brainstem compression or hydrocephalus.

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21
Q

What does the pons control?

A

participates in balance maintenance of posture and in regulation of breathing. In addition, the pons relays information from the cerebral hemispheres to the cerebellum.

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22
Q

What does the medulla control?

A

It contains autonomic centers that regulate breathing and blood pressure, as well as the centers that coordinate swallowing, coughing, and vomiting reflexes

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23
Q

Role of the frontal lobe

A

planning
personality
intelligenece
Brocas area

24
Q

Role of the parietal lobe

A

interprets language
interprest signals from vision, hearing, motor, sensory and memory
sensory strip - touch and heat

25
Q

Role of the occipital lobe

A

processes and interprets colour, light and movement to vision

26
Q

Role of the temporal lobe

A

memory
hearing
wernicks areas

27
Q

Role of the ryhmicity centre

A

controls the rate of breathing

contains the Dorsal and ventral respiratory group

28
Q

Appneustic area

A

prolongs and slow the rate of breathing
stimulates inspiratory neurons of VRG and DRG
overridden by the pneumotaxic

29
Q

Pneumotaxic area

A

inhibirtory impluse, limits breath duration

speeds up breathing

30
Q

peripheral Chemoreceptors

A 
respond to pH - decrease
fall in O2 below 60mmHg
increase in H+ inside the cell
blocks K+ channels
causes a build up of positive charge
Ca2+ rushes in
causes the release of dopamine vesicles
dopamine binds to nerve cells, signal via the vagus nerve to brain, increase breathing
31
Q

Central chemoreceptors

A

Increase in CO2
H+ can’t pass through the blood brain barrier, CO2 moves into the CSF
Binds with water via carbonic anhandrayse to form carbonic acid
H2CO3 dissociates into HCO3- and H+
Decrease in pH is detected by chemoreceptors

32
Q

What does Arterial Blood Analysis measure

A

The acidity and PO2 and PCO2 in the arteries

how well your lungs are able to move O2 into the blood and remove CO2

33
Q

What are the normal values for AGB

A 
pH 7.34-7.45
pO2 10-14kPa
pCO2 4.5-6 kPa
base excess -2 - 2 mmol/L
HCO3 22-26 mmol/L
34
Q

What is the acid base balance

A

the concentration to hydrogen ions in the body fluids

35
Q

How is the acid base balance achieved

A

utiliastion of buffers in extracellular fluid
respiratory mechainsms
renal mechanisms

36
Q

What is respiratory acidosis

A

Increased pCO2
decresed pH
hypoventilation (abnormally slow)

37
Q

What is respiratoty alkalosis

A

decrease pCO2
increased pH
hyperventilation (fast)

38
Q

Outline Bicarb reabsorption in the kidenys

A

Na+/H+ exchanger in luminal membrane, Na+ in, H+ out
H+ combines with HCO3- to form H2CO3
H2CO3 decomposes into CO2 and H2O, catalysed by brush border carbonic anhydrase
CO2 and H2O enter the cell
reaction reversed, H2CO3 formed
Convereted to H+ and HCO3-
HCO3- transported across basolateral membrane via Na+/HCO3- and Cl-/HCO3- transporters
H+ restarts in the cycle

39
Q

Describe the HIF pathway in Normoxia conditions

A

PHD1,2,3 are oxygen sensors
hydroxlate HIFa
HIFa is ubiquinated
sends it to the proteasome where is it degraded

40
Q

Describe the HIF pathway in hypoxic conditions

A

Low O2, HIFa cant be hydroxlated
HIFa translocates to the nucleus where it combines with HIFb and HRE
Transcribes gene
The genes are involved in - metastasis, cell surival, metabolism, immune response, angiogensis
e.g EPO, VEGF, iNOS

41
Q

What is the circle of willis

A

a circle of communincating arteries made up from the cartoid and vertebrobilsilar arteries

42
Q

Where does the anterior cerebral artery supply and what would be affected in a stroke

A

Supplies the frontal lobe

stroke results in opposite leg weakness
profound mental symptoms

43
Q

Where does the middle cerebral artery supply and what would be affected in a stroke

A

Largest branch on the carotid supplying the frontal, temporal and partieal

most often occluded in stroke
symptoms could be severe, even fatal depending where along the artery it occurs
affects speech, motor and senosry fucntion of the face, hands and arms

44
Q

Where does the posterior cerebral artery supply and what would be affected in a stroke

A

stems from the basilar artery, supplying the temporal and occipital lobes

stroke damage is usually secondray to embolsim from lower segments of vertebral basilar system or heart

45
Q

what are lenticulstriates?

A

small deep penetrating arteries branching from the middle cerebral artery

46
Q

How is the intrinsic coagulation pathway activated?

A

activated when blood comes into contact with sub-endothelial connective tissues or negatively charged surfaces

47
Q

Outline the steps of the intrinsic pathway

A 
Hageman factor --> factor XII, binds to subendothlial surafce 
prekallikrein and HMWk also interact
Factor XII actiavated --> factor XIIa
prekallikrein --> Kallikrein
Factor XIIa and Ca2+ activate Factor XI 
Factor IX activated 
Factor X activated by IXa and VIIIa 
Factor Xa is the first molecule of the common pathway
48
Q

Outline the steps of the extrinsic pathway

A

Tissue Factor activated
Binds to Factor VII
Factor VIIa, TF, Ca2+ and a phosophlipid activate factor X

49
Q

outline the steps of the common pathway

A

Factor Xa combines with Va, Ca2+ and a phospholipid to activate Thrombin from Prothrombin
Fibrogen activated by Thrombin to form Fibrin and XIIIa
Cross linked fibrin clot formed

50
Q

What is Fibrinolysis

A

removal of clot of thrombus

51
Q

outline the steps of fibrinolysis

A

Plasminogen –> Plasmin via plasminogen activators e.g tPa
Plamsin digest fibriogen, fibrin and Factors II, V and VIII
plasmin attacks fibrinin at least 50 different sites, reducing its size so it no longer has Hameostatic activity

52
Q

what is excitotoixcity

A

pathological process by which neurons are damaged and killed by the overactivations of receptors for the excitatory neurotransmitter glutamate

53
Q

why does excitotoixity occur

A

Low O2 –> reduced ATP and H+ gradient not maintained = ROS and Ca2+ generation
High Ca2+ activates nNOS, increased ROS
ROS damage dna and membrane proteins leading to activation of caspases (apoptosis)

54
Q

what happens when Glutamine is present

A

Glu binds to AMPA in pre synaptic membrane
NA2+ floods in
depolarises membrane
NMPA Mg2+ block is relased allowing Ca2+ to flood in.
low O2, so mitochondria relase Ca2+
VOCC L-type channels opwn so Ca2+ increases
no ATP generated so SERCA and PMCA pumps stop
IP3 binds to IP3R so Ca2+ released from Smooth ER

55
Q

where is brocas area located and what does it allow

A

located in the frontal lobe

allows the movements required to speak

56
Q

where is wernicks area located and what does it allow

A

in the pareital and temporal lobe

understanding of written and spoken language

57
Q

Which artery is most frequently occluded in patients with stroke?

A

Middle Cerebral artery

DDT (10 decks)

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