Principles - The Circulatory System

Question 1

What are the great vessels?

Answer 1

Those directly connected to the heart chambers

Pulmonary trunk (right ventricle)
SVC and IVC (right atrium)

Pulmonary veins (left atrium)
Aorta (left ventricle)

Question 2

What is bifurcation of an artery?

Answer 2

When an artery terminates by dividing into 2 terminal branches e.g. aorta into left and right common iliac arteries

Question 3

What is trifurcation of an artery?

Answer 3

When an artery terminates by dividing into 3 terminal branches

Question 4

What do the terms ‘trunk’ or ‘common’ indicate?

Answer 4

That the named artery will definitely divide again

Question 5

What kind of blood do arteries carry and at what pressure?

Answer 5

Oxygenated blood at high intraluminal pressures

Question 6

What allows the aorta to maintain blood pressure during diastole?

Answer 6

The elastic recoil of the aorta’s elastic walls

Question 7

What is vasoconstriction?

Answer 7

Contraction of smooth muscle in the walls of arterioles and some arteries - narrow the vessel’s lumen, reducing blood flow to the organ/tissue supplied

Question 8

What is vasodilation?

Answer 8

The opposite of vasoconstriction
Relaxation of the smooth muscle in walls of arterioles, widening the lumen nd increasing blood flow to the organ/tissue supplied

Question 9

What is sympathetic tone of arterioles?

Answer 9

There exists a background, low level of contraction of arteriolar smooth muscle
This is due to tonic conduction of action potential to arterioles by sympathetic nerves

Question 10

What are the 4 parts of the aorta?

Answer 10

1 - the ascending aorta (2 branches, right and left coronary arteries)
2 - the arch of the aorta (3 branches - brachiocephalic trunk, left common carotid artery and left subclavian artery)
3 - the thoracic aorta
4 - the abdominal aorta (3 unpaired midline branches - coeliac trunk, SMA and IMA, 3 paired bilateral branches - suprarenal, renal, gonadal)

Question 11

What does the brachiocephalic trunk divide into?

Answer 11

The right common carotid artery and right subclavian artery

Question 12

What does the right common carotid artery bifurcate into?

Answer 12

The right external carotid artery
The right internal carotid artery

The left common carotid artery bifurcates into the left external and internal carotids

Question 13

Name the branch of the right subclavian artery that passes through the transverse foraminae in cervical vertebrae then through the foramen magnum to enter the cranial cavity?

Answer 13

The right vertebral artery

There is also a left vertebral artery which branches from the left subclavian

Question 14

Where is the circle of Willis? What is it?

Answer 14

On the inferior aspect of the brain
A circular anastomosis that supplies blood to the brain - made of right and left internal carotids and the basilar artery (formed from the left and right vertebral arteries)

Question 15

What is the carotid sinus?

Answer 15

The most proximal, usually dilated part of the internal carotid artery
Located at the level of the superior border of the thyroid cartilage

Question 16

What innervates the carotid sinus?

Answer 16

The glossopharyngeal nerve (CN IX)

Question 17

What does the carotid sinus do?

Answer 17

Monitors the blood supply to the brain by detecting beat to beat changes in arterial blood pressure (stretching in the walls of the carotid sinus)

Question 18

What does the carotid body do?

Answer 18

Also supplied by CN IX

Monitors bloods levels/ pH

Question 19

What does the presence of an anastomoses do?

Answer 19

Provides alternative routes for blood to flow to supply the cells distal to an arterial occlusion

Question 20

What is an alternative route formed by an anastomoses called?

Answer 20

A collateral

Question 21

What does untreated occlusion of an end artery cause?

Answer 21

Infarction of its territory as an end artery is the only arterial blood supply to a given area of the body

Question 22

Describe the changes in name of the subclavian artery (left and right) as it travels distally.

Answer 22

It becomes the left/right axillary artery
Then becomes left/right brachial artery
Then it bifurcates anterior to the elbow joint to become the left/right radial and ulnar arteries

Question 23

What are the branches of the thoracic aorta?

Answer 23

Anterior surface:

• bronchial arteries (lung tissue)
• oesophageal arteries
• mediastinal arteries
• pericardial arteries
• phrenic arteries (diaphragm)

Posterior:
- posterior intercostal arteries (supply chest wall)

Question 24

Where is the aortic hiatus?

Answer 24

An opening of the aorta in the diaphragm

Question 25

What do the right and left common iliac arteries supply?

Answer 25

The pelvis/perineum and the lower limbs

Question 26

What do the left and right common iliac arteries bifurcate into?

Answer 26

Right/Left external iliac artery (lower limbs) | Right/Left internal iliac artery (pelvis/perineum)

Question 27

Where are the peripheral pulses in the neck, upper limb and lower limb?

Answer 27

Neck: carotid - at the bifurcation of the common carotid artery, posterior to and at the level of the thyroid cartilage Upper limb: brachial - anterior to the elbow joint, radial - radial side of the solar aspect of the wrist Lower limb: femoral - continuation of the external iliac artery in the midpoint of the groin, popliteal - posterior to the knee joint, posterior tibial - posterior to the medial malleolus of the tibia, dorsalis pedis - on the dorsum of the foot

Question 28

What kind of blood to veins carry and at what pressure?

Answer 28

Deoxygenated blood in a low pressure system

Question 29

How is venous blood pumped back towards the heart?

Answer 29

- the contraction of skeletal muscles in the lower limb (skeletal muscle pump) - chest cavity pressure changes associated with the movements of breathing

Question 30

What do venous pumps require?

Answer 30

There presence of venous valves in limb veins to ensure unidirectional flow back to the heart against gravity

Question 31

What are the 2 sets of veins in the body?

Answer 31

Superficial veins, smaller and run within the superficial fascia Deep veins, larger and run deep to the deep fascia and in cavities often in NVB

Question 32

What are the bodies 2 main venous systems?

Answer 32

Hepatic portal venous system | Systemic system

Question 33

What do lymphatic capillaries collect?

Answer 33

``` Tissue fluid (fluid that normally leaks out when blood flows through capillary beds) Once in lymphatic capillaries, fluid is called lymph ```

Question 34

What do lymphatics do?

Answer 34

Carry lymph through lymph nodes (contain white blood cells to filter out foreign particles and fight infection/cancer)

Question 35

Where is lymph eventually returned to?

Answer 35

The central veins in the root of the neck

Question 36

Where does the right lymphatic duct drain lymph to?

Answer 36

Into the right venous angle

Question 37

Where does the thoracic duct drain lymph to?

Answer 37

Into the left venous angle

Question 38

Where do superficial lymphatics drain into?

Answer 38

into deep lymphatics

Question 39

Which 2 ducts will all lymph eventually drain into?

Answer 39

Depending on where it originated either into the thoracic duct (lower limbs, abdomen, left chest, left side of face and left upper limb) or the right lymphatic duct (right upper limb, right chest and right side of face)