Intro To The Cardiovascular System

Question 1

How do single cell organisms obtain nutrients?

Answer 1

By diffusion/active transport

Question 2

Why do large multicellular organisms need a transport system?

Answer 2

-diffusion is not efficient (only 50%)
-v metabolically active so need to deliver O2, nutrients and remove waste
-platelets and immune cells need to move around body
-chemical messages also need to be transported

Question 3

what does the cardiovascular system consist of?

Answer 3

-blood
-heart
-arteries
-veins
-capillaries
-lymphatic vessels

Question 4

What is the function of the cardiovascular system?

Answer 4

• Transport of nutrients, gases, hormones, water, defense cells and growth factors
• Collection of metabolic and cellular excretions and delivery to
excretory organs (eg kidneys)
• Defense against infections
• Thermo-regulation (heat - peripheral vasodilation; cold - peripheral vasoconstriction)

Question 5

describe pressure of double circulatory system

Answer 5

-low pulmonary pressure in lungs
-high systemic pressure in arteries

Question 6

describe the heart

Answer 6

-muscular pumping organ - v specialised
-4 chambers - 2 atria, 2 ventricles
-2 systems - one carries oxygenated blood, other carries deoxygenated blood
-pacemaker (autorhythmic) cells generate electrical signals

Question 7

what does it mean to say the heart has an intrinsic conduction system?

Answer 7

-heart is wired to transfer signals to certain parts of the heart at certain times
-signals are transferred after short delay to allow filling of heart before it pumps

Question 8

what is diastole?

Answer 8

relaxation of heart as blood fills

Question 9

what is systole?

Answer 9

contraction of heart as blood is pumped

Question 10

what are the valves in the heart?

Answer 10

-tricuspid valve - right atrium to right ventricle
-bicuspid valve - left atrium to left ventricle
-pulmonary valve - right ventricle to pulmonary artery
-aortic valve - left ventricle to aorta

Question 11

describe the pressure in the heart

Answer 11

-left ventricle is largest muscle so massive variation in pressure
-pressure generally gets lower from artery to vein
-measured as systolic pressure over diastolic pressure

Question 12

What are the 2 main components of blood

Answer 12

-Formed elements - blood cells and platelets
-Plasma - clear extracellular fluid

Question 13

What is the function of blood

Answer 13

Transport
Protection
Regulation

Question 14

3 main types of blood vessels

Answer 14

Artery
Vein
Capillary
Different types of vessel differ in:
diameter, wall thickness & constituents

Question 15

what are the three layers of a blood vessel?

Answer 15

-intima - endothelium which provides non-adhesive surface
-media - smooth muscle, elastic tissue
-adventitia - fibrous tissue

Question 16

Blood vessels table

Answer 16

Question 17

describe the arteries

Answer 17

-thick wall and muscular
-large diameter so low resistance
-carries oxygenated blood away from heart

Question 18

describe arterioles

Answer 18

-smaller diameter
-major role in blood pressure regulation by controlling their diameter

Question 19

describe capillaries

Answer 19

-single tube of endothelial cells
-v close to cells so things can easily diffuse in and out
-can be leaky or tight - kidneys have fenestrated capillaries so larger pores

Question 20

describe veins and venules

Answer 20

-low pressure (<15mmHg), large lumen
-some smooth muscle but less than in arteries
-veins are capacitance vessels bc they carry 60% of blood
-have unidirectional valves to prevent backflow
-returns blood to heart

Question 21

describe the lymphatic system

Answer 21

-system of vessels and nodes
-returns interstitial fluid to circulation - into subclavian vein and is moved by muscular contraction
-involved in immunity - contain lymphocytes that are concentrated in lymph nodes

Question 22

Describe the lymphatic system

Answer 22

-system of vessels and nodes
-returns interstitial fluid to circulation - into subclavian vein and is moved by muscular contraction
-involved in immunity - contain lymphocytes that are concentrated in lymph nodes

Question 23

where are baro receptors located and what do they do?

Answer 23

-in carotid sinuses and aortic arch
-sense chemical or pressure changes
-they are stretch receptors so respond to pressure induced stretching of blood vessel

Question 24

what is the control centre for homeostasis of the circulatory system?

Answer 24

medulla oblongata

Question 25

what are the effectors for homeostasis of the circulatory sytstem?

Answer 25

heart rate, stroke volume, vascular tone (dilation/constriction)

Question 26

describe intrinsic control of the heart

Answer 26

-frank-starling response -stroke volume of left ventricle increases as left ventricular volume increases so more forceful contraction occurs

Question 27

describe extrinsic control of the heart

Answer 27

-autonomic nervous system -hormones e.g. adrenaline, thyroxin -ions generate signals e.g. Na+, K+, Ca2+ -age , exercise

Question 28

what happens during vasoconstriction?

Answer 28

-blood vessels contract -lumen decrease in size so bp goes up

Question 29

what happens during vasodilation?

Answer 29

-blood vessels dilate -lumen increases in size so bp decreases

Question 30

how do blood vessels receive signal to dilate/constrict?

Answer 30

via sympathetic nerve fibres which innervate smooth muscle of most blood vessels

Question 31

what impact does decrease of 1/2 in lumen size have?

Answer 31

16 fold impact

Question 32

What is the baroreflex?

Answer 32

an automatic, negative feedback response to changes in blood pressure

Question 33

How do baroreceptors respond to hypotension?

Answer 33

-baroreceptors send signal to brain which sends signal to heart and blood vessels -this increases cardiac output and increases vasoconstriction to increase bp

Question 34

how are the cardiovascular and respiratory systems linked?

Answer 34

-both work to circulate oxygen around body -both are homeostatic systems -when chemoreceptors detect change in pH, pO2 or pCO2, both heart rate and ventilation rate changes

Question 35

Describe cardiovascular diseases

Answer 35

Very common (Leading cause of death worldwide) -Coronary heart disease (angina, heart attack, heart failure) -Cerebrovascular disease (stroke) -Peripheral arterial disease -Aortic disease (aneurysm)

Question 36

what is atherosclerosis?

Answer 36

when plaque build up in arteries cause them to narrow

Question 37

what diseases can be caused by atherosclerosis and blood clots?

Answer 37

-stroke or transient ischaemic attack -coronary heart disease which can cause angina or myocardial infarction -peripheral artery disease -aneurysm

Question 38

what are the effects of hypertension?

Answer 38

-damage to arteries so increased deposition of fat -increased risk of aneurysm -heart has to work harder -increased risk of haemorrhagic stroke

Question 39

what lifestyle choices can contribute to CVD?

Answer 39

-smoking -activity -weight -diet

Question 40

what can cause diabetes?

Answer 40

-hypertension -obesity -decreased activity -poor lipid profile

Question 41

what is the Renin-Angiotensin system?

Answer 41

hormone system that regulates blood pressure and fluid balance

Question 42

what do ACE inhibitors do?

Answer 42

Block conversion of angiotensin I to angiotensin II so blood vessels can widen and bp decreased

Question 43

What do anticoagulants do?

Answer 43

prevent the extension & formation of clots by inhibiting factors in the clotting cascade & decreasing blood coagulability

Question 44

What do beta adrenergic blockers do?

Answer 44

reduce cardiac output by decreasing sympathetic input

Question 45

what do calcium ion channel blockers do?

Answer 45

lowers bp by blocking Ca ions from entering blood vessel bc they cause the vessels to constrict more strongly

Question 46

what do statins do?

Answer 46

reduce cholesterol in blood

Question 47

Medicine for cvd

Answer 47