Lecture 13

Question 1

What 3 things is the cardiovascular system composed of?

Answer 1

Heart, blood vessels, blood

Question 2

What is the heart?

Answer 2

Muscular pump

Question 3

What are blood vessels?

Answer 3

conduits for blood to flow

Question 4

What is blood?

Answer 4

Fluid that circulates through the body and carries materials between the cells

Question 5

What are affiliated organs/tissues of the cardiovascular system?

Answer 5

• Lymph, cerebrospinal fluid (CSF), extracellular fluid
• Lymph & CSF vessels
• Kidney (erythropoietin, filtering)
• Spleen, thymus, tonsils (reservoirs for blood/immune cells)
• Lungs (O2, CO2 removal)
• Bone marrow (stem cell pool)

Question 6

What does the lymphatic system do?

Answer 6

maintains fluid balance & supports immune
system
* Lymph nodes, lymphatic vessels, spleen, tonsils, & thymus
* Filters harmful substances from lymph & transports white blood
cells
* Lymphatic vessels return excess interstitial fluid & substances to
bloodstream i.e. balance between fluid intake & output

Question 7

what does the cardiovascular system do?

Answer 7

Transports blood

Question 8

What are some examples of cardiovascular disease?

Answer 8

• Coronary artery disease
• Stroke
• Heart attack (myocardial
  infarction)
• Heart failure
• Hypertension
• Diabetes
• Etc.

Question 9

What is the continuous loops of blood flow?

Answer 9

• Deoxygenated blood returns to right side
  of heart (enters right atrium) from venous
  circulation
• Atria receive blood
• Heart contracts, pumps blood to ventricles
• From right ventricle to lungs, then left
  atrium
• Oxygenated blood leaves left ventricle via
  the aorta
• Note the deoxygenated blood in the
  pulmonary artery & the oxygenated blood
  in the pulmonary vein

Question 10

What are arteries characteristics?

Answer 10

Thick, muscular walls (smooth muscle) designed to handle high pressures

Question 11

What are arteriole characteristics?

Answer 11

• A bit less muscle (pressures dropping)
• Lots of innervation to control vessel diameter through smooth muscle contraction (main
  site of BP regulation)

Question 12

What are capillaries characteristics?

Answer 12

• No muscle i.e. no control over diameter
• No connective tissue i.e. no ability to withstand high pressures
• Movement of fluid & solutes maximized
• Nutrients, waste, fluid exchange at local leve

Question 13

What are venules characteristics?

Answer 13

• Main site of lymphocytes (white blood cells) crossing from blood to lymph nodes

Question 14

What are veins characteristics?

Answer 14

• Thin-walled & fairly muscular for easy expansion & recoiling

Question 15

What is cardiac output?

Answer 15

• The amount of blood pumped by the heart per minute
• A product of heart rate x stroke volume

Question 16

What happens in veins?

Answer 16

Blood is moving against gravity, toward the heart by pressure gradient between left & right side of heart

Question 17

What are veins facilitated by?

Answer 17

• Expansion of the thoracic cavity during breathing
• Contracting skeletal muscles
• Valves (prevent blood flowing backwards)

Question 18

What are varicose veins?

Answer 18

• One-way valves malfunction
• Allow backwards flow of blood & pooling
• Generally occurs in superficial veins in thigh & calf (saphenous vein – longest vein in the body)

Question 19

What is the heart made out of?

Answer 19

• Heart is made of cardiac muscle tissue (myocardium)

Question 20

What is the neural input regarding the heart?

Answer 20

Involuntary and autonomic

Question 21

What is the neural conduction regarding the heart?

Answer 21

gap junctions (very fast, contract as a
unit)

Question 22

What is the hearts metabolism like?

Answer 22

Many mitochondria (~35% of volume compared to ~5% in skeletal muscle)
* Fatigue resistant (beats ~3 billion times over a lifetime)

Question 23

How do heart valves control blood flow?

Answer 23

AV valves closing, Semilunar valves closing

Question 24

What happens when AV valves close?

Answer 24

• “LUB” (1st heart sound)
• AV valves located between each atrium &
  ventricle
• Closure of tricuspid valve (right) & mitral
  valve (left)

Question 25

What happens when semilunar valves close?

Answer 25

* “DUB” (2nd heart sound, louder) * Semilunar valves located between each ventricle & its artery * Closure of pulmonary & aortic valves

Question 26

What is an example of a heart valve problem?

Answer 26

Stenosis * Narrowing of a valve * May be congenital, due to calcification, or scarring from rheumatic fever * Seriousness varies * Can cause fatigue & shortness of breath, exercise intolerance, or in more serious cases, heart failure

Question 27

How can problemed heart valves be fixed?

Answer 27

Artificial aortic valve replacements per year

Question 28

How durable are artificial valves?

Answer 28

Durability – in theory, material could last 1000s of years (carbon, titanium

Question 29

What are some issues with artificial valves?

Answer 29

* Clot formation – requires consistent anticoagulant therapy * Can get stuck * Resistance to flow; vulnerability to backflow & regurgitation * Biological valves are an alternative, usually porcine – need immunosuppressive drugs

Question 30

What are factors influencing FRS?

Answer 30

* Age * HDL-c * Total-c * SBP * Smoking status * Diabetes diagnosis Note: at the same FRS, risk in males greater than in females