Circulatory System

Question 1

The three parts of the circulatory system:

Answer 1

1. Non-vascular circulation
2. Cardiovascular system
3. Lymph vascular system

Question 2

Non-vascular circulation:

Answer 2

• Fluid leaves vascular system, passes through extravascular space, re-enters vascular system.
  
  • e.g. CSF, synovial fluid

Question 3

Cardiovascular system:

Answer 3

• Two-way system: from heart to tissues, from tissues to heart.
• Heart serves as pump.

Question 4

Lymph vascular system:

Answer 4

• One-way system: from tissues to heart
• No intrinsic pump.

Question 5

The only direction of flow in the lymph vascular system is:

Answer 5

toward the heart

Question 6

The only structure in which exchange between blood and tissue occurs is:

Answer 6

capillaries

Question 7

Movement of fluid in the low pressure veins of the cardiovascular system is aided by:

Answer 7

• externally generated pressure.
  
  • e.g. compression from nearby contracting skeletal muscles.
• valves allow flow in only one direction.

Question 8

What veins of the cardiovascular system do not have valves?

Answer 8

• veins of the portal system.
• veins communicating between the veins of the face and scalp and dural venous sinuses within the skull.

Question 9

Pathway of cardiovascular system:

Answer 9

1. Right atrium
2. Right ventricle
3. Pulmonary arteries
4. Lungs
5. Pulmonary veins
6. Left atrium
7. Left ventricle
8. Systemic arteries [gut - portal vein - liver - hepatic vein]
9. Body tissues
10. Systemic veins
11. Right atrium

Question 10

What vein is in between the gut and the liver?

Answer 10

• portal vein
• connects capillaries to capillaries

Question 11

What vein is in between the liver and the systemic veins?

Answer 11

• hepatic vein

Question 12

Why do the portal and hepatic veins exist?

Answer 12

• Nutrients absorbed by blood passing through the gut needs to be detoxified.
• Portal vein brings blood from the gut to the liver.
• Liver detoxifies blood.
• Purified blood re-enters circulation via the hepatic vein.

Question 13

Steps in the detoxification of nutrients absorbed in the gut:

Answer 13

1. Nutrients absorbed by blood passing through the gut.
2. Portal vein brings blood from the gut to the liver.
3. Liver detoxifies blood.
4. Purified blood re-enters circulation via the hepatic vein.

Question 14

What is the only vein that connects to capillaries?

Answer 14

• portal vein
• all of veins connect capillaries to the heart

Question 15

Pathway of the lymph vascular system:

Answer 15

1. extracellular space
2. lymph capillaries
3. lymphatic vessels
4. lymph nodes
5. lymphatic vessels
6. systemic veins
7. heart

Question 16

The lymph from the left side of the head, neck, and thorax, the left upper limb and everything below the diaphragm drains into the:

Answer 16

• thoracic duct
  
  • drains into junction of left subclavian vein and left internal jugular vein.

Question 17

The lymph from the right side of the head, neck and thorax and right upper limb drains into the:

Answer 17

• right lymphatic duct
  
  • drains into junction of right subclavian vein and right internal jugular vein.

Question 18

What drains into the thoracic duct?

Answer 18

• lymph from:
  
  • left head, neck, thorax, upper limb
  • everything below the diaphragm

WHITE

Question 19

What drains into the right lymphatic duct?

Answer 19

• lymph from:
  
  • right head, neck, thorax upper limb

GRAY

Question 20

Lymph from thoracic duct drains into:

Answer 20

• junction of left subclavian vein and left internal jugular vein.

Question 21

Lymph from right lymphatic duct drains into:

Answer 21

• junction of right subclavian vein and right internal jugular vein.

Question 22

Role of lymph nodes:

Answer 22

• filter lymph:
  
  • trap diseased cells, abnormal cells, and foreign cells
  • contain lymphocytes and other cells of the immune system which attack these trapped cells.

Question 23

The two vessels surrounding lymph nodes:

Answer 23

1. afferent lymphatic vessels
   
   • bring lymph into node
2. efferent lymphatic vessels
   
   • carry lymph away from node

Question 24

The three functions of the cardiovascular system:

Answer 24

1. transportation (oxygen, nutrients, etc.)
2. communication (hormones)
3. thermoregulation (AV shunt, countercurrent)

Question 25

An anatomical end artery is:

Answer 25

* an artery that has full responsibility for providing blood to an organ or part of an organ. * occlusion = cell death.

Question 26

A functional end artery is:

Answer 26

* an artery that "shares" responsibility for blood supply to a region. * **"sharing" is inadequate.** * occlusion = cell death.

Question 27

Anastomosis:

Answer 27

* Collateral artery connects one artery to another. * Occlusion of one pathway results in shunting of blood to a collateral pathway. * Bypasses occlusion; no cell death.

Question 28

What determines the direction of flow through collateral arteries (anastomosis)?

Answer 28

* pressure gradient. * flows from high to low pressure. * absence of valves in arteries allows this.

Question 29

Intercostal arteries connect:

Answer 29

* aorta to the internal thoracic arteries

Question 30

Costal notching occurs when:

Answer 30

* intercostal arteries used as collateral pathways in coarctation (narrowing) of the aorta, increase in diameter, and cause bone resorption with the margin of rib they come in contact with due to expansion.

Question 31

Costal notching is due to:

Answer 31

* intercostal artery expansion in the setting of aorta coarctation (narrowing).

Question 32

What two parts of the body have relatively high amounts of collateral pathway?

Answer 32

* brain * limbs ## Footnote **COLLATERAL PATHWAYS ARE ESSENTIALLY A SURVIVAL TACTIC.**

Question 33

Cutaneous AV shunts control:

Answer 33

* how much warm blood reaches cutaneous capillary beds to lose heat to the environment.

Question 34

Mechanism of AV shunts:

Answer 34

* **_Shunt open:_** blood shunted from artery to vein and bypasses a cutaneous capillary bed. Less blood reaches cutaneous capillaries and less heat lost. * **_Shunt closed:_** blood flows to cutaneous capillary bed. More blood reaches the cutaneous capillaries and more heat lost.

Question 35

What can result from AV shunting?

Answer 35

* tissue ischemia. * when blood is shunted away from cutaneous capillaries, the cutaneous tissue supplied by these capillaries receives less oxygen and nutrition. ## Footnote **FROSTBITE**

Question 36

When do AV shunts open?

Answer 36

* in very cold weather when heat is trying to be retained.

Question 37

Venae comitantes are:

Answer 37

* paired veins that run along a single artery. * allow for heat transfer to venous blood without compromising arterial blood flow to the skin. * conduction of heat.

Question 38

Venae comitantes are found primarily in:

Answer 38

* cutaneous regions with a large surface area that lose a lot of heat. ## Footnote **LIMBS AND BODY WALL**

Question 39

What mechanism allows for a reduction in heat loss without a reduction in blood flow to the skin?

Answer 39

* venae comitantes * thermal countercurrent mechanism

Question 40

Mechanism of thermal countercurrent:

Answer 40

* two veins surrounding a single artery (venae commitante). * heat transferred from arterial blood to venous blood. * arterial blood is cooler once it reaches cutaneous surface. * venous blood returning to the heart is warmer.