Basic Vascular System

Question 1

Are mesodermally derived structures vascularised?

Answer 1

Yes - except for articular cartilage

Question 2

From which germ layer are vascularised structures derived?

Answer 2

Mesoderm

Except for articular cartilage

Question 3

What is an embolus?

Answer 3

A moving thrombus

Question 4

What is an end organ?

Answer 4

An organ supplied by an end artery

Question 5

What are perforating veins?

Answer 5

Superficial veins penetrating deep fascia to deep veins

Question 6

What are the three layers of an artery?

Answer 6

Intima
Media
Adventitia

Question 7

What is the makeup of the intima?

Answer 7

Connective tissue lined with epithelium

Question 8

What is the makeup of the media?

Answer 8

Concentrically-arranged smooth muscle fibers, elastic fibers

Sympathetic innervation

Question 9

What is the makeup of the adventitia?

Answer 9

Mostly collagen fibers

Vasomotor nerves, which convey neurons to the media

Question 10

Two classes of arteries

Answer 10

Elastic

Muscular

Question 11

Factor determining whether an artery is elastic or muscular

Answer 11

Composition of media

Question 12

Role of elastic arteries

Answer 12

Prevent blood pressure drop during diastole

Question 13

Location of elastic arteries

Answer 13

Closest to heart

EG: aorta

Question 14

Composition of elastic artery media

Answer 14

Mostly elastin fibers

Gives a yellow colour

Question 15

Another name for elastic arteries

Answer 15

Conducting vessels

Question 16

Composition of muscular artery media

Answer 16

Mostly smooth muscle

Question 17

Role of muscular arteries

Answer 17

Distribute blood according to demand by contracting or dilating

Question 18

Another name for muscular arteries

Answer 18

Distribution vessels

Question 19

Layout of muscular arteries

Answer 19

Branch extensively, gradually reducing calibre

Question 20

Another name for arterioles

Answer 20

Resistance vessels

Question 21

Which type of vessel has the greatest wall thickness:lumen calibre ratio?

Answer 21

Arterioles

Question 22

Role of arterioles

Answer 22

Contract, dilate to redistribute blood to different capillary beds

Question 23

Arterial branches in the trunk

Answer 23

Parietal

Visceral

Question 24

What can the arterial branches be?
1)
2)
3)
4)
5)
6)

Answer 24

1) Blood vessels
2) Articular
3) Muscular
4) Cutaneous
5) Arteriae nervorum
6) Nutrient (to long bone)

BAMCAN

Question 25

What is an anastomosis?

Answer 25

A linking of tubular structures | The fusion of two arteries without an intervening capillary bed

Question 26

Common locations of arterial anastomoses

Answer 26

Where blood supply could be cut off, EG in a joint articulation (elbow) Common in very vascularised structures (lips, hips)

Question 27

Can functional end arteries anastomose?

Answer 27

Yes, at the arteriolar level

Question 28

Examples of anatomical end arteries

Answer 28

Retina (central retinal artery) Fingertips, toetips Penis

Question 29

Structure of veins

Answer 29

Intima Media Adventita

Question 30

``` Differences between veins and arteries 1) 2) 3) 4) ```

Answer 30

1) Veins have less thick walls, greater luminal calibre 2) Less smooth muscle in venous media 3) Higher blood volume, lower pressure in veins 4) Veins have valves

Question 31

How much blood volume is in the venous system at any one time?

Answer 31

~70%

Question 32

What are venous valves?

Answer 32

One-way | Bicuspid endothelial folds

Question 33

Where are venous valves mostly located?

Answer 33

Deep limb veins, superficial veins

Question 34

Where are there no venous valves?

Answer 34

Deep trunk veins

Question 35

Where are valves often located in a vein?

Answer 35

At the beginning, end of a vein | Distal to the entry of a major tributary

Question 36

Where are veins normally located?

Answer 36

Often follow the path of arteries | In places where venous return can be maximised

Question 37

How is venous blood returned to the heart?

Answer 37

Muscle pump Thoracic pump Venae comitantes

Question 38

Muscular pump

Answer 38

Muscle contraction compresses veins, pumps blood | Main source of blood flow from limbs

Question 39

Thoracic pump

Answer 39

``` 1) Inspiration - Diaphragm lowers SVC lengthens, fills with blood IVC shortens, pumps blood into heart Negative intrathoracic pressure (by ~1mmHg) ``` ``` 2) Expiration Diaphragm rises SVC shortens, pumps blood into heart IVC lengthens, fills with blood Positive intrathoracic pressure ```

Question 40

Venae comitantes/vascular pump

Answer 40

Pair of intercommunicating veins wraps around an artery | Arterial pump compresses veins during systole, pumps blood

Question 41

Venous valve incompetence

Answer 41

Cusps of valves fail to close properly | Often damage to bicuspid valves

Question 42

Effect of venous valve incompetence in lower limbs

Answer 42

Blood in deep veins (of calf) squeezed into superficial veins, instead of towards heart Ulceration of skin

Question 43

Varicose veins

Answer 43

Abnormal vein dilation | Can be a cause and effect of venous valve incompetence

Question 44

Do lymph vessels have valves?

Answer 44

Yes

Question 45

Direction of lymph flow

Answer 45

Superficial to deep Ultimately draining to subclavian area Drained into venous system

Question 46

Which structures drain lymph back into the venous system?

Answer 46

Lymphatic trunk Thoracic duct Right lumphatic duct

Question 47

Major lymph nodes

Answer 47

Cervical Axillary Inguinal

Question 48

``` Other areas of lymphatic tissue 1) 2) 3) 4) ```

Answer 48

1) Thymus 2) Spleen 3) Peyers patches 4) Tonsils