Cardiovascular system 1

Question 1

what components make up the cardio vascular system

Answer 1

• Fluid medium
• pump
• system of channels

Question 2

What are the names of the 2 cardiovascular circuits

Answer 2

• systemic

- pulmonary

Question 3

what are the layers of the heart wall starting from the outside

Answer 3

• Pericardium
• Myocardium
• Endocardium

Question 4

describe the pericardium

Answer 4

consists of an outer fibrous layer, then the outer serous layer (parietal layer), then the pericardial fluid and then the inner serous layer (visceral layer/epicardium)

Question 5

describe the myocardium

Answer 5

• this is a thick muscular layer between endocardium and epicardium
• this layer is thicker on the left side
• consists of y shaped myocardial cells connected together with intercalated disks

Question 6

what 2 features make up intercalated disks and describe them

Answer 6

• gap junctions; allow depolarisation to pass between sells to synchronise contraction
• desmosomes; like the glue that binds the myocytes together

Question 7

what is the endocardium?

Answer 7

the inner surface of the heart

Question 8

what is the difference in pressures and shape between the ventricles

Answer 8

• left pressure is 80-100 mmHg, cylindrical shape
• right pressure is <15 mmHg, pouch shape
• both hold same volume of blood

Question 9

what are the 2 types of cardiac muscle cell

Answer 9

• contractile cell

- pacemaker cell

Question 10

What are the jobs of the contractile and pacemaker cells

Answer 10

• contractile; produce the contractions

- pacemaker; within the AVN, SAN and Purkinje fibres, and these cells control contractile cells

Question 11

Describe an ECG graph

Answer 11

• first dome is the P wave
• short flat line
• indent in line which is Q
• huge spike which is R
• small indent is S
• flat line followed by a larger dome the T wave

Question 12

What is occurring during the P wave

Answer 12

• Atrial depolarisation

Question 13

what is occurring during the flat line between the P wave and Q

Answer 13

• the conduction down the bundle of His, causes this 100mS delay

Question 14

what does Q represent on the ECG

Answer 14

start of ventricular depolarisation

Question 15

what does QRS represent on the ECG

Answer 15

complete ventricular depolarisation as the Purkinje fibres contract and hence ventricular systole

Question 16

what does the T wave represent on the ECG

Answer 16

ventricular repolarisation

Question 17

what are catecholamines and how do they affect heart rate

Answer 17

• hormones like adrenalin, released from adrenal medulla
• binds to adrenergic receptors on the heart
• increasing heart rate and contractility

Question 18

what affect does Noradrenaline have on the heart

Answer 18

• initially increases heart rate but with longer exposure reduces it
• released from adrenal medulla but mostly spill over from sympathetic nerves innervating blood vessels
• also binds to adrenergic receptors on the heart

Question 19

where can chemoreceptors be found

Answer 19

• carotid and aortic bodies and Medulla Oblongata

Question 20

where can baroreceptors be found

Answer 20

• in carotid sinus and aortic arch