Blood Vessels and Lymphatics

Question 1

What is the function of capillary beds?

Answer 1

1- Exchange of tissue fluid, nutrients, oxygen and waste.

2- In inflammatory situations, cells can also be exchanged

Question 2

What are the three layers present in blood vessels?

Answer 2

1- Tunica intima (innermost)
2- Tunica media (middle)
3- Tunica adventita (outermost)

Question 3

Which vessels are mainly elastic?

Answer 3

Large arteries such as the aorta and pulmonary trunk as they are conducting arteries

Question 4

Which vessels are mainly muscular?

Answer 4

Medium arteries such as the femoral, axillary and carotid arteries are muscular to control distribution and flow

Question 5

Which vessels are thin-walled and often with valves?

Answer 5

Veins in order to store and return blood to the heart

Question 6

When do muscular arteries dilate?

Answer 6

When a major artery to an area is occluded, smaller collateral muscular arteries enlarge to carry the needed blood to the ischaemic area

Question 7

What do muscular arteries do when injured?

Answer 7

They contract to prevent haemorrhage

Question 8

Give examples of muscular arteries.

Answer 8

1- Internal and external carotid in the neck
2- Axillary artery in UL
3- Femoral artery in LL

Question 9

What is the difference between arteries proximally and distally?

Answer 9

1- Proximally arteries are elastic or mixed (elastic becoming muscular)
2- Distally arteries are muscular but gradually decrease in thickness and calibre

Question 10

Describe the distribution of the UL arteries.

Answer 10

Subclavian > axillary > brachial > ulnar and radial

Question 11

What is arterial anastomosis?

Answer 11

1- A connection between two arteries resulting in an extensive supply of blood vessels
2- E.g. Superficial and deep palmar arches
3- All joints have anastomoses around them

Question 12

Describe the distribution of LL arteries.

Answer 12

Femoral > popliteal > anterior and posterios tibial > fibular

Question 13

What is the relationship of the femoral artery with its vein and nerve?

Answer 13

The femoral artery lies between its vein and nerve, with the vein being most medial and the nerve most lateral.

Question 14

What are venae comitantes?

Answer 14

1- Large arteries have venae comitantes, which are smaller separate veins which lie close to them
2- Arterial movement or pulsation encourages venous return

Question 15

How are thrombi formed?

Answer 15

In arteries, plagues of atheroma may form leading to a thrombus and vascular occlusion.

Question 16

What is the approximate diameter of arterioles?

Answer 16

~0.5mm

Question 17

What is the approximate diameter of metarterioles?

Answer 17

Same diameter as capillaries (~5-10µm), but with only one layer of smooth muscle cells in their walls

Question 18

What are capillaries?

Answer 18

1- Sites of exchange for CO2, O2, nutrients, hormones and tissue fluid
2- Present in virtually all tissues
3- Capillaries cannot contract as they do not have smooth muscles in their walls. However, the basal lamina splits to enclose pericytes which contract and constrict capillaries

Question 19

What are pericytes?

Answer 19

1- Myoepithelial cells
2- Present in basal lamina of capillaries
3- Contract and constrict capillaries

Question 20

What is the basic structure of capillaries?

Answer 20

1- Smallest vessels
2- Endothelial linings which are only one cell thick
3- Supported on a basal lamina
4- ~8µm in diameter

Question 21

What are postcapillary venules?

Answer 21

1- Located just after capillaries, delivering to venules

2- Smallest venules

Question 22

What are precapillary sphincters?

Answer 22

1- Sphincters which close or limit blood supply to organs and/or conserve oxygen
2- This does not apply to certain organs which must have their blood flow maintained e.g. brain, heart, lungs and kidneys

Question 23

Describe the basic structure of the layers of veins and venules.

Answer 23

1- Tunica media is thin and often incomplete, with only a few smooth muscle fibres
2- As the vessel becomes thicker, the amount of muscle in the media increases and a thick tunica adventita develops
3- Tunica intima has a continuous endothelium with a thin basal lamina

Question 24

What is diapedesis and how does it apply to venules?

Answer 24

1- Passage of leukocytes through walls of venules, which then escape into surrounding connective tissue

Question 25

1- Passage of leukocytes through walls of venules, which then escape into surrounding connective tissue

Answer 25

1- Valve leaflets arise from tunica intima and are covered by endothelium
2- When the blood pressure proximal to the leafelets is greater than distally, the valves close, preventing backflow.

Question 26

Describe the distribution of veins in the LL.

Answer 26

1- LL arteries, which are situated depply within the muscle compartments, are accompanies by venae comitantes
2- These converge to form the popliteal vein
3- Popliteal > femoral > external iliac > common iliac > inferior vena cava
4- Superficial veins: great long saphenous vein medially and small short saphenous vein laterally, both with many tributaries

Question 27

How does venous blood flow in the LL?

Answer 27

1- Superficial to deep
2- Against gravity
3- Via perforators and then muscle pump, arterial pulsation and negative intrathoracic pressure

Question 28

Describe the distribution of veins in the UL.

Answer 28

1- Arranged around arteries
2- Superficial system also present
3- Median cubital vein links cephalic and basilic veins across the front of the elbow joint, site of venipuncture

Question 29

What does the superior vena cava drain?

Answer 29

Drains head, neck and upper limbs into the right atrium.

Question 30

What does the azygos vein drain?

Answer 30

Drains thoracic wall into the superior vena cava.

Question 31

What does the inferior vena cava drain?

Answer 31

Drains lower limbs, pelvic organs, kidneys and abdominal walls into the right atrium.

Question 32

What is the hepatic portal vein?

Answer 32

1- Venous blood from the components of the GI tract and spleen does not return directly to the heart
2- Instead it forms the hepatic portal vein, which takes the venous blood through the liver before draining into the inferior vena cava

Question 33

Give an example of another portal circulation.

Answer 33

1- Pituitary gland

2- Hypophyseal portal system

Question 34

What is the lymphatic system?

Answer 34

1- A network of lymph nodes
2- Mops up interstitial tissue fluid, some of which ends up back in the circulation
3- Lymph capillaries are thin-walled, endothelial tubes
4- Superficial lymphatics are related to veins while deep lymphatics are related to arteries

Question 35

Where are lymph nodes usually clustered?

Answer 35

Iliac and para-aortic lymph nodes

Question 36

What are lymphocytes and where are they made and stored?

Answer 36

1- Protective cells of the body

2- Made and stores in the lymph nodes as well as the tonsils, thymus, spleen and intestinal wall

Question 37

What are the three superficial, palpable lymph node collections?

Answer 37

1- Superficial inguinal and deep inguinal
2- Axillary
3- Superficial and deep cervical

Question 38

Where can the superficial inguinal nodes be palpated?

Answer 38

Inferior to inguinal ligament and alongside the great saphenous vein in the groin

Question 39

Where do the superficial inguinal nodes drain?

Answer 39

Drain into the deep inguinal nodes

Question 40

Where can the deep inguinal nodes be palpated?

Answer 40

Alongside femoral vein

Question 41

Where do the deep inguinal nodes drain?

Answer 41

External iliac lymph nodes

Question 42

Where do inguinal nodes receive afferents/lymph drainage from?

Answer 42

1- LL
2- Buttock
3- External genitalia
4- Lower back 
5- Abdominal wall bellow umbilicus

Question 43

Where can the axillary nodes be palpated?

Answer 43

1- Axillary nodes are groupes in the axilla
2- Related to the axillary vein and artery
3- Lateral, deep to and medial to pectoralis minor (axillary nodes are arranged in many groups)

Question 44

Where do axillary nodes receive afferents/lymph drainage from?

Answer 44

1- UL
2- Anterior and posterior thoracic walls
3- Upper abdominal wall above umbilicus
4- Breast

Question 45

Where can superficial cervical lymph nodes be palpated?

Answer 45

Under the jaw, over parotid, behind ear or on the occipital bone (cervical nodes are arranged in many groups)

Question 46

Where can deep cervical lymph nodes be palpated?

Answer 46

Alongside the internal jugular vein

Question 47

What do the cervical lymph nodes drain?

Answer 47

Head and neck structures

Question 48

What is the largest lymph vessel?

Answer 48

Thoracic duct

Question 49

Where does the thoracic duct enter?

Answer 49

It enters the junction of the left subclavian, internal jugular veins at the level of the brachiocephalic vein