CIRCULATORY SYSTEM

Question 1

Define anastomoses.

Answer 1

Anastomoses are alternate pathways for blood to detour around occlusion to get to distal sites.

Question 2

Describe the difference between venous and arterial anastomoses.

Answer 2

Venous anastomoses - include the caval system which drains into vena Cavan and the portal system which drains into the hepatic portal vein
Arterial anastomoses - include actual (viable) and potential (inviable) anastomoses

Question 3

Describe an actual anastomose

Answer 3

Viable, effective passages for oxygenated blood to travel.

For example, some can be found in the Palmar arches of the hand or Circle of Willis.

Question 4

Describe a potential anastomose

Answer 4

Inviable pathways for blood in the event of a sudden trauma

Examples include the coarctation of the aorta in adults and those in the joints + scapular regions.

Question 5

What occurs in the Coarctation of the Aorta?

Answer 5

If the aorta is somewhat occluded in infants, blood passes through the transverse cervical artery (viable only in infants) to get to distal regions.

Question 6

Describe Thermoregulation.

Answer 6

Occurs when blood is shunted from the superficial skin if cold outside to redistribute the warm blood to the visceral. Less heat is lost this way as AV shunts in skin channel blood back to important organs.

Question 7

Compare and contrast arteries, veins and capillaries.

Answer 7

Arteries - Holds 15% of body’s blood, elastic, High smooth muscle
Veins - Holds 60% of blood, Highly distendable, with or w/o valves
Capillaries - 5% of body’s blood in beds throughout the body, composed of endothelial cells.

Question 8

Define Atherosclerosis

Answer 8

A build up of plaque shrinks the diameter of the lumen, increasing the risk of thrombus; damaged endothelium also thickens

Question 9

Define the Musculovenous pump

Answer 9

The contraction of limbs provides a compressive force to move blood against gravity back to the heart; prevents backflow.

Question 10

Describe the regions and collateral arteries of the Axillary Artery

Answer 10

Region 1: located between 1st rib and pec minor
[Superior thoracic artery]
Region 2: [Thoracoacromial artery + Lateral Thoracic artery]
Region 3: [Subscapular artery, Anterior Circumflex Humeral Artery, Posterior Circumflex Humeral Artery]
Mnemonic: “Sixties Teens Love Sex And Pot”

Question 11

Describe the two types of end arteries in an anastomose.

Answer 11

True end artery - no collateral circulation (ex: in eye or rectum)
Functional end artery - ineffectual circulation (ex: heart and brain)

Question 12

Explain the significance of the arteriovenous pump

Answer 12

Thermal countercurrent mechanism warms up accompanying veins near arteries.

Question 13

Describe Raynaud’s Syndrome

Answer 13

Overactive sympathetic nervous system frequently vasoconstricting to shunt blood away from fingers. This can lead to blanching of skin.

Question 14

Describe the functions of the lymphatic system.

Answer 14

Is a one-way vascular system where ECF that leaked out of systemic capillary beds is carried back to the heart by lymph vessels, draining into major veins. They empty into the thoracic duct (most of body) OR the right lymphatic duct (above vena cava)

Question 15

Name two functional anastomoses of the upper limb

Answer 15

1. Scapular anastomose = Dorsal scapular artery, suprascapular artery, Circumflex Scapular artery
2. Humeral anastomose = Posterior Circumflex Humeral and Anterior Circumflex Humeral arteries.

Question 16

Most of the body’s lymph empties into the ______ at the left venous angle OR at the ____________ above the superior vena cava.

Answer 16

Thoracic duct;

Right Lymphatic Duct

Question 17

Describe the features and possible cause of lymphedema.

Answer 17

Pitting edema, where the skin does not bounce back because of excess body fluid, occurs when the lymph is not drained from a region of the body. This is possibly due to an obstruction or congestive heart failure, if venous blood stays in a region for an extended amount of time.