Valves And Vessels (and thorax radiography)

Question 1

What is the function of valves?

Answer 1

Prevent back flow of blood

Counteract gravity

Question 2

What are valves supported by?

Answer 2

A fibrous skeleton

Question 3

What is isovolumetric relaxation/contraction?

Answer 3

When the ventricles relax/contract but the volume of blood stays the same
No blood moves

Question 4

What is a cusp?

Answer 4

The individual flap of a valve

Question 5

What are valves attached by? What are they attached to?

Answer 5

Tendons (heartstrings)attached to papillary muscles

Question 6

Which valves do not have tendons?

Answer 6

Semilunar valves

Question 7

What causes blood to move?

Answer 7

Force from diastole

Recoil of arteries

Question 8

Which 3 things control blood flow?

Answer 8

Precapillary sphincter zone
Thoroughfare channels
Arteriovenous anastomoses (connections)

Question 9

What type of cells make up the endothelium?

Answer 9

Squamous

One cell thick

Question 10

What do the intercellular clefts in endothelium cells do?

Answer 10

Allow diffusion (gap junctions)

Question 11

How do large molecules move across the endothelial cells?

Answer 11

In vesicles

Question 12

What do tight junctions in the epithelial layer do? Epithelial layers can be fenestrated, what does this mean?

Answer 12

Seal the endothelial layer

Perforated

Question 13

What is a sinusoid?

Answer 13

A type of capillary in organs

Question 14

What does collateral circulation mean?

Answer 14

There is more than one pathway of circulation

Question 15

What are 3 types of arterial communications?

Answer 15

Collateral circulation
End arteries
Interarterial anastomoses

Question 16

Interarterial anastomoses create side routes for circulation. What are interarterial anastomoses?

Answer 16

Vessels which connect one artery to another

Question 17

What two veins make up the venae cavae?

Answer 17

Cranial VC

Caudal VC

Question 18

The cranial vena cava leads to which major veins? (JACS)

Answer 18

Axillary (armpit), internal/external jugular, cephalic(head), subclavian (upper thorax)

Question 19

The caudal vena cava leads to which major veins? (RITH)

Answer 19

Renal (kidney), iliac (pelvis), testicular/ovarian, hepatic (liver)

Question 20

What are the names of the left and right coronary arteries?

Answer 20

L- caudosinistral sinus

R - cranial sinus

Question 21

Why do tumours often spread to the lung?

Answer 21

Blood must pass through all lung capillaries as it cannot to another route
More likely to form tumour

Question 22

When doing an x-ray of the thorax, why do both ventrodorsal and lateral views need to be taken? Why do both lateral views need taking?

Answer 22

2D image of 3D object

Laying on the side causes one lung to deflate- difficult to see

Question 23

What is the cardiac silhouette?

Answer 23

The heart inside the pericardium

Question 24

Why is the outline of the cardiac silhouette never clear? If it is, why is this?

Answer 24

Heart is beating so causing fluid to move in pericardium

Build up of fluid can cushion the beating

Question 25

Why do fluid and tissue look similar on radiographs?

Answer 25

Similar density