Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

DDT > Ischaemia > Flashcards

Ischaemia Flashcards

(67 cards)

Start Studying
1
Q

How are glucose and amino acids moved across the blood brain barrier?

A

Carried mediated active transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the circle of willis?

A

Structure in the brain where cerebral arteries meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the purpose of the circle of willis?

A

Collateral circulation - all areas of the brain still perfused if one cerebral artery becomes blocked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which cerebral artery is the most commonly occluded during strokes?

A

Middle cerebral artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens in the hypoxia-inducible factor under normoxic conditions?

A

Cells continually produce HIF-1a and HIF-1b
In normoxic conditions, oxygen sensors detect oxygen
Prolyl Hydroxylase adds a hydroxyl group onto HIF-1a
Ubiquitin ligase adds a ubiquitin tail onto HIG-1a
HIF-1a is degraded by a proteasome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in the hypoxia-inducible factor under hypoxic conditions?

A

HIF-1a forms a complex with HIF-1b called the HIF-1 transcription factor
HIF-1 translocates to the nucleus and transcribes genes for angiogenesis, glycolysis and cell proliferation such as VEGF and EPO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is t-PA and what does it do?

A

Tissue plasminogen activator
Type of serine protease
Converts plasminogen into plasmin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Name two drugs that may be given as treatment to stroke patients

A

Recombinant t-PA

Alteplase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the name of the procedure during which a stent is inserted?

A

Percutaneous coronary intervention

or Coronary angioplasty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What kind of drug might a drug-eluting stent be coated in?

A

An immunosuppressant, that prevents smooth muscle cell proliferation by causing cell cycle arrest in G1/S phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the steps of the extrinsic coagulation cascade?

A

Damaged cells release tissue factor
Trauma activates factor 7 –> 7a
Tissue factor and factor 7a form a complex in the presence of calcium ions and negative phospholipids
The complex activate factor 10 –> 10a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the steps of the intrinsic coagulation cascade?

A 
Blood comes into contact with subendothelial cells
Kallikrein activates factor 12 --> 12a
Factor 12a activates factor 11 --> 11a
Factor 11a activate factor 9 --> 9a
Factor 9a joins with it's cofactor 8a
9a + 8a activates factor 10 --> 10a
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which clotting factor is also known as Hageman factor?

A

Factor 12a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the common pathway of clot formation?

A

Factor 10a joins with it’s cofactor 5a to form the prothrombinase complex
10a + 5a activates prothrombin –> thrombin
Thrombin activates fibrinogen –> fibrin
Fibrin forms a cross-linked mesh
Aggregates with platelets to form a clot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the four steps of atheroma formation?

A

Endothelial Dysfunction
Stable Plaque Formation
T cell activation
Ulceration and thrombus formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain the step of endothelial dysfunction

A

Damage to the endothelium can occur from many causes
Monocytes adhere via VCAM-1 and migrate into tunica intima
Monocytes differentiate into macrophages
Macrophages phagocytose Oxidised or glycated LDL, forming fatty streaks made of foam cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the step of stable plaque formation

A

Smooth muscle cells migrate from the tunica media to tunica intima
They proliferate and act like myofibroblasts to produce collagen, which forms a fibrous cap, which can last many years with no symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain the step of T cell activation

A

T helper cells 1 and 2 become recruited and activated
They release proinflammatory cytokines and cause foam cells to release MMPs
MMPs breakdown the fibrous cap so it becomes unstable…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Explain the step of ulceration and thrombus formation

A

As the MMPs breakdown the collagen, the damaged endothelium exposes/releases tissue factor, initiating the extrinsic coagulation cascade
A blood clot forms, breaks off and travels up to the brain…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What should blood pH be maintained at?

A

7.35-7.45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What 3 methods control blood pH?

A

Breathing rate
Bicarbonate buffer system
Bicarbonate reabsorption in the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Write out the bicarbonate buffer system equation

A

CO2 + H2O –> H2CO3 –> HCO3- + H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

If blood pH becomes too low, will breathing rate increase or decrease?

A

Low pH indicates lots of CO2

Breathing rate will increase to remove the CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If blood pH becomes too low, will there be more bicarbonate reabsorption or less?

A

There will be more bicarbonate ion reabsorption
Bicarbonate ions combine with H+
Shift the equation right
CO2 exhaled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How is bicarbonate reabsorbed in the kidney?
H+/Na+ antiporters pump H+ into the lumen H+ combines with the bicarbonate ions Forms H2O and CO2 CO2 diffuses into cells as it is lipid soluble Reforms bicarbonate in the cell
26
Where is the respiratory centre located?
Medulla oblongata and pons
27
What is the function of the respiratory centre?
Receives signals from central and peripheral chemoreceptors Controls diaphragm and intercostal muscles Increase/decrease breathing rate accordingly
28
Where are central chemoreceptors located and what do they detect?
On the ventral surface of the medulla oblongata | They detect the pH of CSF
29
Where are peripheral chemoreceptors located and what do they detect?
Carotid body and aortic arch | Detect concentrations of CO2 and O2 in the blood
30
How is excitotoxicity initiated?
``` Blood supply to a region of the brain becomes limited Limited supply of oxygen (hypoxia) Switched to anaerobic respiration Less ATP produced No ATP to power Na+/K+ pumps in membrane Neuronal cell depolarises Release of glutamate ```
31
What are the 6 mechanisms by which intracellular calcium concentration increases following glutamate release?
1. Glutamate activates AMPA and NMDA receptors leading to sodium and calcium influx 2. Sodium influx causes NCX sodium-calcium exchanger to reverse direction, starts bringing calcium in 3. Glutamate binds to mGlu group 1 receptors, causing release of Calcium from the ER 4. Calcium binds to RyR receptors, causing calcium induced calcium release 5. No ATP to power SERCA or PMCA 6. Intramitochondrial potential disrupted, releases calcium
32
Which g protein subunit are mGlu group 1 receptors coupled to?
Gq
33
How does calcium cause cell damage?
Calcium activates nNOS and caspases that damage cellular structures and initiates apoptosis Mitochondria produce ROS
34
What is repurfusion injury?
Reintroduction of O2 causes surge in ROS generation Electron transport chain restarts in mitochondria, forming ATP and ROS ROS damage membrane structures, causing secondary wave of calcium influx Proinflammatory cytokines also released
35
What does plasmin do?
Plasmin breaks down fibrinogen, fibrin and clotting factors 2, 5 and 8 into soluble products Helps to breakdown clots
36
What does the PDK-1 gene code for?
Pyruvate dehydrogenase kinase | Inhibits pyruvate dehydrogenase, inhibiting conversion of pyruvate into acetyl coA
37
What is ischaemia?
Loss of blood flow to an organ
38
What are the symptoms of a blood clot located in one of the internal carotid arteries?
Numbness, weakness or paralysis on the opposite side of the body
39
What type of cells detect changes in oxygen concentration?
Glomus cells
40
What is the acid and conjugate base in the blood buffer system?
Acid = carbonic acid, H2CO3 | Conjugate base = bicarbonate ions, HCO3=
41
What is metabolic acidosis/alkalosis?
Change in blood pH that originate from kidney bicarbonate reabsorption. Caused by changes in bicarbonate ions
42
What is respiratory acidosis/alkalosis?
Change in blood pH that are respiratory in origin. Caused by changes in CO2
43
What are the levels of pH, CO2, HCO3-, and H+ ions during metabolic acidosis?
Low pH Low HCO3- Low CO2 High H+
44
Where in the kidney is bicarbonate reabsorbed?
90 % in Proximal convoluted tubule
45
How does reabsorbed bicarbonate enter the capillary?
Na+/HCO3- cotransporter on the basolateral membrane
46
Where is the sample for arterial blood gas analysis usually taken from?
Radial artery
47
What 5 things are measured during arterial blood gas analysis?
``` CO2 O2 pH HCO3 Base excess ```
48
What is base excess?
Excess bicarbonate ions in the blood
49
What is the sensitivity of a test?
Percentage of patients with the disease who will test positive Higher chance of a false positive
50
What is a type 2 error?
Falsely accepting the null hypothesis | Saying there is no disease when there actually is
51
What is a type 1 error?
Falsely rejecting the null hypothesis | Saying there is disease when there is not
52
What is the specificity of a test?
Percentage of patients without the disease who will test negative Higher chance of a false negative
53
Calculation for sensitivity?
True positives (True positives + False negatives)
54
Calculation for specificity?
True negatives (True negatives + False positives)
55
What is PPV and how is it calculated?
Positive predictive value Proportion of positive results that are true positives True positives/ (True positives + false positives)
56
What is NPV and how is it calculated?
Negative predictive value Proportion of negative results that are true negatives True negatives/(True negatives + False negatives)
57
Functions of the cerebellum | Damage results in?
Balance Coordination of muscles Damage causes tremors, inability to coordinate movement, difficulty performing rapidly alternating tasks
58
What is the ischaemic cascade?
``` Ischaemia Hypoxia Lack of ATP No power for Na/K ATPase Resting potential not maintained Cell depolarises Glutamate release High rise in intracellular calcium ```
59
Functions of the brain stem
Midbrain Pons Medulla oblongata - respiratory centre, controls breathing rate to maintain blood pH
60
What is excitotoxicity?
Over-activation of excitatory neurotransmitter receptors (NMDA and AMPA) Leads to huge rise in intracellular calcium concentration Production of ROS Activation of caspases Neuron damage and apoptosis
61
How many oxygen molecules can haemoglobin bind?
4
62
How is affinity of haemoglobin for oxygen affected by pH, and how does this help gas exchange in the lungs?
High pH = Higher affinity Low pH = low affinity Excess protons stabilise low affinity state Also produce 2,3 BPG that stabilise low affinity state At the lungs there is low CO2, so high pH, and higher affinity
63
2 things that affect haemoglobin affinity for oxygen
pH and Positive cooperativity - once one oxygen molecule is bound, others are more likely to
64
What is atherosclerosis?
Thickening and hardening of the arterial wall due to build up of atheromas (plaques) Causes artery to narrow
65
What are MMPs?
Matrix metalloproteinases
66
What is a zymogen?
Enzyme that needs to be broken down by another enzyme (proteolytic activity) to become active Involved in blood clotting, as you don't want blood to clot unless the process is initiated
67
What is stenosis?
Narrowing of the blood vessel

DDT (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions