Cardiology

Question 1

What are the 2 main components of the circulatory system

Answer 1

1. ) Plasma (55%)

2. ) Cellular components (45%) (WBC + RBC)

Question 2

What is Haematocrit?

Answer 2

% of total blood volume that is erythrocytes

Question 3

What is Plasma?

Answer 3

The fluid component of the blood that contains Proteins such as Albumin, CLOTTING FACTORS such as Fibrinogen, and nutrients

Question 4

What is included in the cellular component of blood?

Answer 4

1. ) Eryhthrocytes
2. ) Platelets
3. ) Leucocytes

Question 5

What are leucocytes?

Answer 5

White Blood Cells

Neutrophils
Eosinophils
Basophils
Monocytes
T+B cells

Question 6

What is Serum?

Answer 6

Plasma with Clotting Factors removed

Question 7

Where do all blood cells descend from?

Answer 7

Multipotent Haematopoietic Stem Cells

Question 8

What is the precursor to Lymphocytes?

Answer 8

Bone Marrow Precursor Lymphocytes

Question 9

What is the precursor cell for every blood cell except lymphocytes

Answer 9

Blast Cells

Question 10

Where are Erythrocytes produced in the Adult?

Answer 10

Bone Marrow in Axial Skeleton

Question 11

Where are Erythrocytes produced in the foetus?

Answer 11

Yolk Sac
Liver
Spleen

Question 12

What is the average lifespan of a RBC and where are they removed?

Answer 12

120 days

The Spleen

Question 13

What do Neutrophils do?

Answer 13

Most Numerous WBC

Phagocytose

Question 14

What do Eosinophils do?

Answer 14

Kill Parasites

Question 15

What do Basophils do?

Answer 15

Involved in Inflammation via the secretion of Histamine

Question 16

What do Monocytes do?

Answer 16

Regulate the Immune Response via secretion of Cytokines

Give way to Macrophages

Question 17

What do Macrophages do?

Answer 17

Engulf and Ingest

Antigen Presentation

Question 18

What do T+B cells do

Answer 18

Specific Immune Response

Antibody Production

Question 19

What are the Granulocytes

Answer 19

Neutrophils
Basophils
Eosinophils

Question 20

What are the Agranulocytes

Answer 20

T+B Lymphocytes

Monocytes

Question 21

What is the main factor that influences blood flow?

Answer 21

Pressure

Question 22

What are the 2 circulations

Answer 22

Pulmonary

Systemic

Question 23

Stages of the Microcirculation

Answer 23

Arteries -> Arterioles -> Capillaries -> Venules -> Veins

Question 24

What is Preload?

Answer 24

End Diastolic Volume

Question 25

What is Afterload?

Answer 25

Pressure in the Aorta that the LV must overcome in order too pump blood around the body

Question 26

Blood flow is from regions of .... to regions of ....

Answer 26

Higher Pressure to Lower Pressure

Question 27

Equation for Force of contraction?

Answer 27

Change in Pressure/ Resistance

Question 28

Forces is Directly Proportional to...

Answer 28

Change in Pressure

Question 29

Force is indirectly proportional to...

Answer 29

Resistance

Question 30

What is the main variable that impacts resistance in blood vessels

Answer 30

Diameter of Blood Vessels

Question 31

What do Gap Junctions do?

Answer 31

Allow action potentials to pass between myocytes

Question 32

What triggers contraction of Cardiac Muscle?

Answer 32

Depolarisation of Myocyte plasma membrane

Question 33

Where does the initial depolarisation in the heart occur?

Answer 33

SA Node

Question 34

Why is the SA node referred to as the 'Pacemaker of the Heart"

Answer 34

Initial depolarisation occurs there

Question 35

Sequences of Cardiac Depolarisation

Answer 35

SA Node -> Atrial Contraction -> Internodal Pathways -> AV node -> Bundle of His -> L/R Bundle Branches -> Purkinje Fibres -> Ventricular Contraction

Question 36

Describe what happens during a Cardiac Myocyte Action Potential?

Answer 36

1. ) Na+ channels open; Na+ moves into the cell causing DEPOLARISATION (causes more Na+ channels to open via + feedback) 2. ) K+ channels open temporarily, causing momentary repolarisation 3. ) Ca++ channels open, balancing out the K+ lost out of the plasma membrane, causing a PLATEAU 4. ) Ca++ channels close, whilst more K+ channels open -> REPOLARISATION

Question 37

Describe the Action Potential in Nodal Cells?

Answer 37

1. ) K+ channels close at a - voltage 2. ) Ca++ and Na+ channels open at - voltage, causing PACEMAKER POTENTIAL - gradual depolarisation 3. ) Once a threshold value has been reached, Ca++ channels open, depolarising the cell and causing an AP 4. ) K+ channels open and Ca++ channels close, leading to the formation of a Pacemaker Potential Again

Question 38

What does the P wave represent?

Answer 38

Atrial Depolarisation

Question 39

What does the QRS complex represent?

Answer 39

Ventricular Depolarisation | Atrial Repolarisation

Question 40

What is the T wave?

Answer 40

Ventricular Repolarisation

Question 41

Describe the Process by which Cardiac Muscle Contracts? (Excitation- Contraction Coupling)

Answer 41

1. ) Na+/K+ pump keeps resting potential 2. ) Na+ channels open, depolarising the cell 3. ) Depolarisation causes Voltage-Gated Ca++ cells to open, causing Ca++ to enter the cell 4. ) Ca++ entry causes Ryanodine Receptors to release more Ca++ into the SR 5. ) Ca++ binds to Troponin, causing a conformational change in the shape of Troponin, which results in the movement of Tropomyosin away from the Actin-Myosin binding sites 6. ) Actin- Myosin cross bridges formed, resulting in muscle contraction 7. ) Ca++ is removed back into Ryanodine Receptors by Ca++/ATPase

Question 42

What are Ryanodine Receptors?

Answer 42

Ca++ gated Ca++ stores found in the SR

Question 43

What removes Ca++ from the SR following muscle contraction

Answer 43

Ca++/ATPase

Question 44

How can the strength of cardiac muscle contraction be increased?

Answer 44

Increased concentration of Ca++ in Cytosol