anatomy of the heart and blood vessels

Question 1

how big is the heart?

Answer 1

fist sized organ 250-350g

Question 2

where does the heart lie?

Answer 2

in the mediastinum which is the area of the thoracic cavity between the lungs

Question 3

what 2 circuits does the heart pump blood too?

Answer 3

systemic circuit- brings oxygenated blood to the body and deoxygenated blood to the heart
pulmonary circuit- brings deoxygenated blood to the lungs and oxygenated blood to the heart

Question 4

what are the coverings of the heart?

Answer 4

1. visceral pericardium “epicardium” inner covering
2. pericardial cavity filled with serous fluid
3. parietal pericardium 2nd outermost layer
4. fibrous pericardium which is dense ct that anchors heart and prevents over filling

Question 5

what are the innermost layer on the heart?

Answer 5

epicardium- (visceral pericardium) = simple squamous +areolar
myocardium- cardiac muscle
endocardium- (membrane lining chambers) =simple squamous - areolar

Question 6

what are the 4 chambers of the heart?

Answer 6

2 atria- right atrium receives blood from the body)
left atrium receives blood from the lungs
2 ventricles- right ventricles receives blood from r atrium
left ventricles receives blood from L atrium

Question 7

what are heart valves?

Answer 7

flaps of endocardium +dense c.t and prevent backflow of blood

Question 8

what is the atrioventricular valve?

Answer 8

between atria and ventricles
prevents back flow of blood into atria from ventricle

Question 9

what are the two valves?

Answer 9

tricupsid valve between RA and RV
bicupsid valve between LA and LV

Question 10

what are the valves valves anchored to?

Answer 10

anchored to papillary muscles by chordae tendenae
these strands of connective tissue prevent collapse of valves when ventricles contract

Question 11

what are the semilunar valves?

Answer 11

between ventricles and large arteries of heart
prevent backflow into ventricles from arteries leaving the heart

Question 12

what are the two valves?

Answer 12

pulmonary semilunar valve between the pulmonary trunk and RV
aortic semilunar valve between aorta and LV

Question 13

what creates the hearts sounds?

Answer 13

blood turbulence associated with valve closure

Question 14

what 2 distinct sounds does the heart make?

Answer 14

lub = s1 AV valve closure following atrial contraction
dub = s2 SL valve closure following ventricular contraction

Question 15

what other sounds may be heard but faint?

Answer 15

s3 as blood flows into the ventricles
s4 as atria contracts

Question 16

what do blood vessels consist of?

Answer 16

arteries + veins + capillaries

Question 17

what are the three tunics of blood vessels?

Answer 17

tunica externa
tunica media
tunica interna

Question 18

what is the tunica externa/adventilia

Answer 18

it is superficial
fibrous c.t (collagen + elastic fibres)

Question 19

what is the tunica media?

Answer 19

the middle
smooth muscle + elastic c.t

Question 20

what is the tunica interna? 3 components?

Answer 20

deep
endothelium- simple squamous and lines vessels)
basement membrane- loose areolar c.t
elastic membrane- elastic c.t abscent in veins

Question 21

what do cappilaries consist of?

Answer 21

only one layer of endothelium with thin basement membrane

Question 22

what are arteries/ functions?

Answer 22

thick tunica media which allows smooth muscle constiction/ dilation
carry blood away from the heart
most carry oxygenated blood

Question 23

what pressure are arteries under?

Answer 23

high pressure elastic membranes faciliatates stretching

Question 24

what are the different type of arteries?

Answer 24

1.elastic arteries- large, thick layer of elastic tissue: stretch and recoil with high pressure ex aorta \
2. muscular arteries- midsized several mm, thick smooth muscle layer
3, arterioles- smallest under 5mm no externa

Question 25

what are veins/ function?

Answer 25

carry blood towards the heart
most carry deoxygenated blood
blood under low pressure
thin tunica media less smooth muscle and very little elastic fiber

Question 26

what do veins contain?

Answer 26

valves which prevent back flow

Question 27

what are venules?

Answer 27

smallest drains blood into veins and have no smooth muscle

Question 28

how does the venous system return blood to heart if pressure is low?

Answer 28

skeletal muscle pump- muscle contraction massages veins and valves prevent back flow
respiratory pump- changes in thoracic and abdominal pressure

Question 29

what are cappilaries/ functions?

Answer 29

smallest blood vessels about 10um and have a diameter of a single RBC
site of exchange between blood and tissues

Question 30

what do cappilaries form?

Answer 30

form capillary beds which is a network of capillaries which has a huge sruface area

Question 31

what does cappillaries consist of?

Answer 31

endothelium only which makes it thin and permeable

Question 32

what is continuous cappilaries?

Answer 32

continuous capillaries- endothelium continous and are moderately permeable
main exchange vessels in tissue (nutrients, wastes, blood gases, hormones)

Question 33

what is fenestrated capillaries?

Answer 33

endothelium has pores/fenestrations which makes it more permeable
for absorption of filltration in kidneys and intestines

Question 34

what is sinusoid capillaries?

Answer 34

endothelium has large gap which makes it most permeable
allows passage of large molecules/cells
in spleen, liver, and bone marrow

Question 35

what are capillary beds?

Answer 35

networks of capillaries connecting arterioles with venules
flow regulated by rings of smooth muscle called precaapillary sphincters