Blood Vessels and Lymphatics

Question 1

What are the features of tunica interna/intima

Answer 1

Its lines by simple sqaumous epithelium known as the endothelium.
The endothelium releases the hormone endothelins which can cause constriction of smooth muscle, increasing blood pressure.
Beneath endothelium is a basement membrane/basal lamina that binds the endothelium to connective tissue.
In arteries - layer of elastic fibers called internal elastic membrane (allows streching whilst keeping structure)

Question 2

Describe the features of tunica media

Answer 2

Composed of concentric circles of smooth muscle cells, elastic fibres that support muscle cells. Contraction of the muscles causes vasoconstriction (increases peripheral resistance and increases blood pressure) Relaxation of the muscles causes vasodilation

Question 3

Features of tunica externa/adventitia

Answer 3

A layer of connective tissue made of collagen fibers. Thickest tunica in veins and can be thicker than the tunica media in some larger arteries.

Question 4

Describe the functions of muscular arteries

Answer 4

They have a thick tunica media layer meaning they can control the distribution of blood flow to regions and organs (constricting or relaxing as needed to regulate flow if needed)
They can contract to prevent haemorrhages or accomodate an increase in diameter

Question 5

The subclavian artery changes name as it moves down the upper limb, name these

Answer 5

Becomes the axillary then brachial and then will branch into ulnar and radial (all artery)

Question 6

Name the arterial anastomosis in the hands and what they allow for?

Answer 6

There is the deep palmar arch and the superficial arch both of which are derived from the radial and ulnar arteries. Arterial anastomosis ensures blood flow to the hand even if an artery becomes cut off my movement. Every joint have anastomoses around them.

Question 7

Name the large arteries in the abdomen

Answer 7

Descending thoracic aorta, abdominal aorta and the common iliac artery

Question 8

Describe the position of the femoral artery, vein and nerve.

Answer 8

The femoral artery lies with its vein medially and nerve laterally (importance of locations for when inserting cannulas)

Question 9

Name the major arteries in the thigh

Answer 9

The common iliac, external iliac, internal iliac common femoral, profunda femoris, superficial femoral and popliteal

Question 10

Name the major arteries of the leg and the main artery of the foot

Answer 10

Anterior tibial, tibio-peroneal/fibular trunk, peroneal and posterior tibial. Foot - Dorsalis pedis

Question 11

What are arterioles, metarterioles and capillaries

Answer 11

Arterioles- arteries less than 0.5mm in diameter
Metarterioles - same diameter as capillaries but with one layer of smooth muscles
Capillaries - tubes of endothelium, no smooth muscle

Question 12

Describe the features of capillaries

Answer 12

Endothelium cells supported on a basal lamina (basement membrane)
Form networks called capillary beds
Allow exchange of oxygen and CO2, nutrients and hormones.
VERY small diameter (7 or 9 micrometers), Unable to contract because of the lack of muscle
The basal lamina splits to enclose pericytes (myoepithelial cells) these look after endothelium.

Question 13

What regulates blood flow through a capillary bed?

Answer 13

Pre-capillary sphincter

Question 14

Name the two main capillaries

Answer 14

1 - continuous capillary (most common)
2- Fenestrated capillary, contains fenestrae/pores that permit the exchange of larger molecules so they are found in the intestine, choroid plexus (cells that produce cerebrospinal fluid), endocrine glands and kidneys

Question 15

What prevents the back flow of blood through through a vein

Answer 15

Valve leaflets, they close when the blood pressure proximal is greater than distal to them thus preventing back flow.

Question 16

What are venae comitantes

Answer 16

The veins that accompany smaller arteries. They are all wrapped in a vascular sheath, the pulsing of the artery aids venous returns to the heart.

Question 17

Name the two superficial veins in the lower limb

Answer 17

The great saphenous vein (long) and the small saphenous vein (short.)

Question 18

Deep and superficial veins connected by?

Answer 18

Perforating veins.

Question 19

What is venous flow?

Answer 19

The flow between superficial and deep veins, is due to valves in perforating veins, incompetency of these veins can lead to varicose veins which is where there is too much blood in the superficial veins.

Question 20

How is blood pumped up to the heart?

Answer 20

Muscle contraction, arterial pulsation and negative intrathoracic pressure

Question 21

Upper limb superficial veins used for phlebotomy

Answer 21

Cephalic, Basilic and median cubital veins.

Must avoid the brachial artery and median nerve posteriorly

Question 22

Name some large veins

Answer 22

Inferior vena cave, Superior vena cava, Azygous vein (which drains into the SVC) and the hepatic portal vein which drains all the blood from the GI tract and spleen and joins the ICV

Question 23

What do vaso vasorum do?

Answer 23

Supply larger veins with a blood supply

Question 24

Describe the basics of the lymphatic system

Answer 24

It is part of the immune system formed by the tonsils, spleen, lymph nodes, thymus and intestinal wall.
It helps veins remove interstitial fluid, otherwise the body would become very swollen with the volume of interstitial fluid.

Question 25

Lymphatic capillaries do what?

Answer 25

Absorb interstitial fluid and drain it into lymph nodes (contains a lot of immune cells so when there is an infection, the lymph nodes swell. Therefore you can detect where an infection is coming from due which lymph nodes are inflamed)

Question 26

Superficial/deep lymph nodes relate to what?

Answer 26

veins and arteries respectably.

Question 27

What is metastasis

Answer 27

Where malignant cells detach from a primary tumour and travel along the lymphatic system and until they reach a lymph node where they can give rise to a secondary tumour.

Question 28

Name the three superficial lymph node collections

Answer 28

1) Superficial inguinal (alongside the great saphenous vein and inferior to the inguinal ligament, drain to the deep inguinal nodes)
2) Deep inguinal (below the femoral vein)
3) Axillary (lateral/deep/medial to the pectoralis minor)
4) Superficial cervical (under jaw, over parotid, behind ear; occuipital)
5) Deep cervical (along side the jugular vein) Can communicate with axillary and thoracic nodes.

Question 29

How does lymph enter the bloodstream?

Answer 29

Enters at the subclavian vein via the thoracic duct

Question 30

What is lymph?

Answer 30

Interstitial fluid in lymph vessels