Cardiovascular

Question 1

What are the functions of the cv system

Answer 1

Transport

Maintenance - regulation, homeostasis, thermoregulation, ph,

Protection - white blood cells, clotting

Question 2

What are the components

Answer 2

Blood
Vessels
Heart

Question 3

What are the 2 divisions

Answer 3

Pulmonary circuit
Blood to and from lungs

Systemic
Blood to and from rest of the body

Question 4

What kind of tissue is blood

Answer 4

Connective

Question 5

What does blood carry

Answer 5

Dissolved gases
Nutrients
Hormones
Metabolic wastes

Question 6

What does the right atria do

Answer 6

Receives blood from systemic circuit and passes it to right ventricle

Question 7

What does the right ventricle do

Answer 7

Received blood from right atrium and pumps it into pulmonary circuit

Question 8

What does the left atrium do

Answer 8

Receives blood from pulmonary circuit and passes to left ventricle

Question 9

What does the left ventricle do

Answer 9

Receive blood from left atrium and pumps to systemic circuit

Question 10

How much blood does the heart pump per minute

Answer 10

5L/min at rest

15-20 during exercise

= 8000L per day

Question 11

What is the Q equation

Answer 11

Hr x sv

Question 12

Why is the left side of the heart bigger

Answer 12

Left ventricle has to pump to whole body, rather than lungs

Question 13

What are the layers of the heart wall

Answer 13

Myocardium

Epicardium

Pericardial fluid/space

Pericardium (outer)

Question 14

What is the pericardium

Answer 14

Made up of fibrous connective tissue, limits expansion

Stabilises the heart

Contains pericardial fluid in pericardial cavity which lubricates

Parietal pericardium = outer serous membrane

Visceral = inner serous membrane- epicardium

Question 15

What does the pericardial fluid do

Answer 15

Reduce friction during contraction

Question 16

What is the myocardium

Answer 16

• a thick muscular layer between epicardium and endocardium
• forms both atria and ventricles
• contains cardiac muscle tissue, blood vessels and nerves
• interconnects with other muscle cells via intercalated disks
• large central nucleus and lots of mitochondria

Question 17

What is the endocardium

Answer 17

Covers all inner surfaces of the heart
- internal chambers
- heart valves

Consists of epithelial tissue and is continuous with epithelium if the great vessels

Question 18

What are intercalated disks

Answer 18

The junction between cardiac cells

Gap junctions- allowing depolarisation to pass between cells, synchronising muscle contraction

Desmosomes: bind adjacent myocytes together

Question 19

Explain the ventricular differences

Answer 19

• both hold same amount of blood
• LV thicker muscle
• LV cylindrical
  -RV thinner wall
• RV pouch like shape around left ventricle

As right only delivers to lungs, mean pressure much lower

Question 20

What are the cordae tendineae and papillary muscles

Answer 20

CT - right ventricle
PM - left ventricle

Tether valves to ventricular walls to keep them shut during systole

Question 21

What are the two types of cardiac muscle cells

Answer 21

Contractile - produce contractions

Pacemaker - nodal/conducting, sino atrial node, atro ventricular node, purkinjie fibres (control contractile cells)

Question 22

Explain the electrical system of the heart

Answer 22

1. SA node, account for resting hr, depolarise to stimulate depolarisation (autorythmicity)
2. AV node, depolarises more slowly than SA, some auto, delays so blood can finish emptying from atria
3. Travels through Septum
4. Bundle of his
5. Purkinjie - autorythmicity, very slow

Question 23

What is the fist step of the cardiac cycle and how does it relate to ECG

Answer 23

SA node depolarisation on its own, SA node and atrial activation begin

60-100 action potentials per min at rest

(Main pacemaker)

ECG: flat start line

Question 24

What is the second step of the cardiac cycle and how does it relate to ECG

Answer 24

Stimulus (depolarisation) spreads atrial surfaces and reaches av node

50 msec

ECG: P wave

Question 25

What is the third step of the cardiac cycle and how does it relate to ECG

Answer 25

100msec delay at av node, atrial contraction begins

ECG flat again P-R interval

Question 26

What is the fourth step of the cardiac cycle and how does it relate to ECG

Answer 26

Impulse travels down septum to bundle of his branches to purkinjie fibres and by the moderator band to the papillary muscles of the right ventricle

ECG : Q wave, downwards, beginning of ventricular depolarisation

Question 27

What is the fifth step of the cardiac cycle and how does it relate to ECG

Answer 27

Impulse distribution by purkinjie fibres and relayed trough ventricular myocardium. Atrial contractions is completed and ventricular contraction begins

ECG: QRS complex,

Big spike R, back down S

Completion of ventricular depolarisation

Question 28

What happens after the fifth step

Answer 28

Flattening line then t wave, ventricles repolarise

Question 29

What are epinephrine

Answer 29

A catecholamine

Epinephrine- adrenaline

Reased by adrenal medulla, upon activation of sympathetic nervous system

Question 30

What is norepinephrine

Answer 30

A catecholamine

Initial increases in heart rate and contractility but with longer expose decreases these things

Binds to receptors in heart

Released by adrenal medulla and sypatgetic nerves interacting blood vessels

Question 31

What else controls hr

Answer 31

Chemoreceptors

Baroreceptors - carotid sinus senses changes, aortic arch senses increases only

Low bp - low stretch of vessel, less stretch of reception, decreases afferent firing, increased syp and decreased para