Lecture 15/16: Cardiovascular System (Part 1)

Question 1

What organs/tissues are affiliated with the cardiovascular system

Answer 1

• extracellular fluid lymphatics (like circulatory system but for extracellular fluid)
• Kidney and spleen
• liver
• lungs
• bone marrow

Question 2

The right side of the cardiovascular system___

Answer 2

returns deoxygenated blood to heart

Question 3

The left side of the cardiovascular system___

Answer 3

carries oxygenated blood away from heart

Question 4

Arteries bring blood ____ the heart

Answer 4

bring blood away from heart

Question 5

Veins bring blood ____ the heart

Answer 5

bring blood to the heart

Question 6

What is unique about the pulmonary circuit

Answer 6

• veins bring oxygenated blood to heart and arteries bring deoxygenated blood away

Question 7

Where is most blood held in the body

Answer 7

• on route to heart in systemic veins and venules

Question 8

Characteristics of arteries

Answer 8

-thick muscular walls, handle high pressures in arterial blood

Question 9

Characteristics of Arteriolds

Answer 9

• smaller diameter to regulate blood flow
• less muscle but lots of innervation to control smooth muscle contraction
• main site of blood pressure regulation ***

Question 10

What are characteristics of capillaries

Answer 10

• no muscle
• does not regulate its dismeter or withstand high pressures
• involved in movement of fluid and solutes (maximize the movement)
• nutrient, waste, fluid exchange at local level

Question 11

What are characteristics of veins

Answer 11

• thin walled, muscular for easy expansion and recoiling

Question 12

How does velocity an area influence blood vessels

Answer 12

• high velocity and small surface area = direct, rapid conductance of blood
• low velocity and large surface area= optimal exchange

Question 13

How do veins move blood against gravity towards heart

Answer 13

pressure gradient between left and right side of heart by:

• expansion of the thoracic cavity during breathing
• contracting skeletal muscles
• valves (preventing blood flowing backwards)

Question 14

What are Vericose veins

Answer 14

• one way valves malfunction
• allow backwards flow of blood and pooling
• generally in superficial veins in thigh and calf
• generally does not effect overall blood flow to heart

Question 15

What type of tissue is the heart made out of?

Answer 15

myocardium

Question 16

How does cardiac muscle differ from skeletal muscle?

Answer 16

Nerval input: involuntary, autonomic
Neural conduction: gap junctions, very fast and contract like unit (skeletal muscle has fibre recruitment)
Metabolism: Very high oxidative capacity
- lots of mitochondria, about 35% of volume
- fatigue resistant

Question 17

How is blood flow controlled in the heart

Answer 17

• valves
• atria always contract together
• lub sound = AV valves closing
• ventricles contract together
• dub sound = semilunar valves contracting

Question 18

What is stenosis?

Answer 18

Narrowing of valve, vary in terms of seriousness but can cause fatigue, shortness of breath, exercise intolerance and in more serious cases heart failure

Question 19

What are some issues with artificial valves

Answer 19

• clot formation, requires consistent anticoagulant therapy
• get stuck
• resistance to flow, vulnerability to back flow/regurgitation

Note: almost 300,000 replacemnts per year and mad eof very durable material

Question 20

What is systole

Answer 20

• contraction, highest BP usually 120/80

Question 21

What is diastole

Answer 21

• relaxation, lowest BP, usually 120/80, 80 is the pressure next pump must overcome

Question 22

What is a very basic overview of cardiac cycle

Answer 22

• contraction of atria
• contraction of ventricles
• rest when neither is contracting

Question 23

What are electrical signals in heart propagated by?

Answer 23

• nodes (SA and AV)
• nerves (bundle of His, bundle branches, purkinge fibres)
• intercalated disks

Question 24

What is tachycardia?

Answer 24

• abnormal SA node firing (too fast)

Question 25

What is bradycardia?

Answer 25

• abnormal SA node firing (too slow)

Question 26

How do blocks at the AV node impact conduction through the heart

Answer 26

• can slow down or prevent propagation from atria to venticles
• ventricles can contract independently with bundle of HIS
• but then different chambers contracting at different rates

Question 27

What is the more serious fibrillation?

Answer 27

when cells depolarize independently

Question 28

How are the Heart’s contractions controlled?

Answer 28

• Sympathetic innervation: inc HR (norepinephrine)
• Parasympathetic innervation: dec HR (Acetyl choline)
• Epinephrine: inc strength of contraction
• note diff between norep and ep

Question 29

How does the heart adapt to hypertrophy?

Answer 29

• heart being over worked
• endurance athletes: inc in LC chamber (to inc cardiac output)
• weightlifters: inc in LV wall and septum thickness
• cons: high BP, narrowing of aortic valve, heart has to work harder to overcome

Question 30

What is atherosclerosis?

Answer 30

• narrowing of arteries due to calcified fatty deposits (plaque) and thickening of tall
• triggered by gamage to arterial wall
• can lead to heart attack/stroke
• also called coronary heart disease if in arteries of heart muscle

factors: elevated blood lipids, hypertension, inflammatory mediators, diet, smoking, obesity, age, genetics
- can be treated by putting in a stent to clear