Mod X - Vacular & EKG - M&M22pg476-486 - Miller 69 & 17 - A&P Cerebral Circulation: ARTERIAL AND VENOUS CIRCULATION

Question 1

_{ARTERIAL AND VENOUS CIRCULATION}

OBJECTIVES OF THIS LECTURE ARE:

Answer 1

1. Identify the functional components of the circulatory system and their roles
2. Identify the branches of the ascending aorta, aortic arch, descending aorta, and abdominal aorta
3. Identify blood supply to the head, neck, thorax, upper extremities, and lower extremities
4. Explain the importance of the Artery of Adamkiewicz
5. Outline the main vessels of cerebral circulation
6. Describe the Circle of Willis

Question 2

_{ARTERIAL AND VENOUS CIRCULATION}

•Physical characteristics (2 circulations)

Answer 2

–Systemic circulation

–Pulmonary circulation

Question 3

_{ARTERIAL AND VENOUS CIRCULATION}

Systemic circulation

Answer 3

Supplies all tissue except lungs

AKA greater circulation or peripheral circulation

Question 4

_{ARTERIAL AND VENOUS CIRCULATION}

Pulmonary circulation

Answer 4

…

Question 5

_{ARTERIAL AND VENOUS CIRCULATION}

Functional parts of circulation:

Answer 5

Arteries

Arterioles

Capillaries

Venules

Veins

Question 6

_{ARTERIES AND ARTERIOLES}

Arteries

Answer 6

Transports blood under high pressure to the tissues

This is why arteries Have strong vascular walls

Blood flows at high velocity

Question 7

_{ARTERIES AND ARTERIOLES}

Arterioles

Answer 7

Last small branch of arterial system

Act as a control conduit through which blood is released into the capillaries

Strong muscular walls

Can vasoconstrict or vasodilate depending on blood flow requirements of each tissue

Question 8

_{ARTERIES AND ARTERIOLES}

What’s a benefit of Arterioles having Strong muscular walls?

Answer 8

Can vasoconstrict or vasodilate depending on blood flow requirements of each tissue

Question 9

_{CAPILLARIES, VENULES & VEINS}

Capillaries

Answer 9

Have the most important function of the circulatory system

Which is diffusion of substances back and fort between blood and tissues

Exchanges fluid, nutrients, electrolytes, hormones, etc

Question 10

_{CAPILLARIES, VENULES & VEINS}

Venules

Answer 10

Collect blood from the capillaries and gradually grow larger into veins

Question 11

_{CAPILLARIES, VENULES & VEINS}

Veins

Answer 11

Conduits for transport of blood from venules back to heart

Veins are the reservoir of extra blood

(small or large amount based on the needs of the circulation)

Question 12

_{CAPILLARIES, VENULES & VEINS}

Which characteristics of veins make them reservoir of extra blood?

Answer 12

Thinner walls than arteries

Much more distensible than arteries

Question 13

_{ARTERIAL AND VENOUS CIRCULATION}

Graphical representation of distribution of blood volume amoung the various component of circulation

Answer 13

Systemic circulation: 84%

(64% of which is in the veins)

Heart and pulmonary circulation: 16%

Question 14

_{WALLS OF ARTERIES AND VEINS}

Passageway by which blood flows and is present in both arteries and veins is known as

Answer 14

Lumens

Question 15

_{WALLS OF ARTERIES AND VEINS}

Btw arteries and veins which has smaller lumen?

Answer 15

Arteries

Smaller lumens help arteries maintain higher pressures as blood moves throughout the system

Question 16

_{WALLS OF ARTERIES AND VEINS}

There three layers to each vessel knowns respectively as:

Answer 16

Tunica externa/adventitia

Tunica media

Tunica intima

Question 17

_{WALLS OF ARTERIES AND VEINS}

Tunica externa/adventitia

Answer 17

Outermost layer of a blood vessel

(reponsible for maitaining protection and prevents collapse)

Strengthens/Anchors to surrounding tissue

Question 18

_{WALLS OF ARTERIES AND VEINS}

Tunica media

Answer 18

Middle layer of blood vessel

Responsible for contraction and relaxation or Vasoconstriction and vasodilation

This is normally the thickest layer in arteries

Much ticker in arteries than in veins

Question 19

_{WALLS OF ARTERIES AND VEINS}

Tunica intima

Answer 19

Thinnest layer

Boundary between blood in the lumen and the wall of vessel

Inner layer of blood vessel

Has innermost lining made up of Endothelial cells (Endothelium)

Question 20

_{WALLS OF ARTERIES AND VEINS}

Damage to which part of the tunica intima is the reason for clot formation?

Answer 20

Damage to the endothelium is the reason for clot formation

Question 21

_{WALLS OF ARTERIES AND VEINS}

Why are the lumen of the arteries more rounded that the lumen of the veins?

Answer 21

This is b/c of the thicker walls and smaller diameters in arteries

The thicker walls in arteries are d/t to their close proximity to the heart, and their higher pressure in relation to veins

Question 22

_{DIFFERENCE BETWEEN ARTERIES AND VEINS - Arteries}

Direction of flow - Pressure - Walls - Lumen - Valves

Answer 22

Direction of flow: Blood away from Heart

Pressure: Higher

Walls: Thicker: Tunica media thicker than tunica externa

Lumen: Smaller

Valves: None

Question 23

_{DIFFERENCE BETWEEN ARTERIES AND VEINS - Veins}

Direction of flow - Pressure - Walls - Lumen - Valves

Answer 23

Direction of flow: Blood toward heart

Pressure: Lower

Walls: Thinner: tunica externa thicker than tunica media

Lumen: Larger

Valves: Present most commonly in limbs and in veins that are inferior to heart

Question 24

_{DIFFERENCE BETWEEN ARTERIES AND VEINS}

Btw arteries and veins, which has valves? Why? What the function of these valves?

Answer 24

Veins have valves b/c they are low pressure vessels

Valves ensure unidirectional flow toward the heart and prevent backward flow toward the capillaries

Question 25

_{DIFFERENCE BETWEEN ARTERIES AND VEINS}

Swollen, twisted veins that you can see just under the skin. They usually occur in the legs, but also can form in other parts of the body

Answer 25

Varicose veins

In pts w/ Varicose veins, blood pools to the lower extremities d/t the pool of gravity. and the increased blood increases the pressure w/in the vein, and promotes the blood accumulation in the vein and ultimately distension, twisting and visibility to the surface of the skin

Question 26

_{AORTIC SEGMENTS}

The thoracic aorta is divided into three sections:

Answer 26

Ascending aorta

^{(Portion that leaves the LV)}

Transverse aorta

^{(aka aortic arch)}

Descending aorta

^{(Portion that descends into the thorax)}

Question 27

_{AORTIC SEGMENTS}

When does the Descending aorta becomes the Abdominal aorta?

Answer 27

after in penetrates the diaphragm

This occurs around level T12

Question 28

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Ascending aorta ascends from the

Answer 28

aortic valve

Question 29

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Ascending aorta ascends from the aortic valve and banches off into:

Answer 29

Brachiocephalic artery

Left common carotid artery (LCA) branches off directly off the ascending aorta

Left subclavian artery

Question 30

_{ANATOMY OF THE CEREBRAL CIRCULATION}

What the other name for the Brachiocephalic artery?

Answer 30

Innominate artery

Question 31

_{ANATOMY OF THE CEREBRAL CIRCULATION}

What does the Brachiocephalic artery (Innominate) branches off into?

Answer 31

Right subclavian artery

Right common carotid artery

Right common carotid artery bifurcates with right subclavian

Left common carotid arises from aortic arch

Question 32

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Which carotid Artery provides Blood supply to neck, face, and base of skull?

Answer 32

External Carotid Artery

_{(Will not be discussed for this lecture)}

Question 33

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Internal Carotid Artery divides into which arteries?

Answer 33

Middle cerebral artery

Anterior cerebral artery

Question 34

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Which artery provides Arterial blood supply to the brain?

Answer 34

Internal carotid artery

Provides 80% of cerebral blood flow

Question 35

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Which artery provides Arterial blood supply to the lateral aspect of cerebrum?

Answer 35

Middle cerebral artery

Question 36

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Which artery provides Arterial blood supply to the Frontal lobe and medial aspect of cerebral hemispheres?

Answer 36

Anterior cerebral artery

Question 37

_{ANATOMY OF THE CEREBRAL CIRCULATION}

The Internal Carotid Arteries provides 80% of CBF. Where does the remaining 20% comes from?

Answer 37

Vertebral arteries (2)

Arise from subclavian arteries to form basilar artery

Then give rise to the Posterior cerebral artery

Question 38

_{ANATOMY OF THE CEREBRAL CIRCULATION}

Which vascular structure is considered Cornerstone of inflow of blood to brain

Answer 38

Circle of Willis

Hexagonal ring shaped that lies in the subarachnoid space and circles the pituitary gland

Question 39

_{ANATOMY OF THE CEREBRAL CIRCULATION}

The Three paired arteries originate from the circle of Willis to perfuse brain are:

Answer 39

Anterior cerebral arteries

Middle cerebral arteries

Posterior cerebral arteries

Question 40

_{ANATOMY OF THE CEREBRAL CIRCULATION}

communicating arteries that complete the circle of Willis are known as:

Answer 40

Anterior and posterior communicating arteries,

AKA Willsians channels

Question 41

_{CIRCLE OF WILLIS}

In what % of the population is the Circle of Willis Abnormal or incomplete

Answer 41

in majority of patients

(50-80%)

W/ complete occlusion of a major vessel, infarction can occur if collateral flow is not adequate

_{CIRCLE OF WILLIS}

_{Under normal circumstances when there is no occlusion, blood flow btw the} anterior-posterior or side-to-side or left-to-right circulations does not mix

In the event of an occlusion, the Circle of Willis can act as a shunt btw either anterior-posterior, or Willisian channels, increase collateral flow in an effort to maintain pressure

Collateral flow can also occur through the extrenal carotid arteries

The Willisian channels become important during periods of vessel occlusion of one of the carotid arteries

Collateral circulation from the Willisian channels allows cross filling of the cerebral vessels to maintain blood flow

Question 42

_{THORACIC AORTA}

The Thoracic aorta is also known as:

Answer 42

Descending aorta

Question 43

_{THORACIC AORTA}

What’s the thoracic aorta span?

Answer 43

Begins at T4 and extends to T12

Question 44

_{THORACIC AORTA}

Where does the thoracic aorta begins in reference the the vertebral column?

Answer 44

begins left of the vertebral column

but approaches midline as it descends into the chest

Question 45

_{THORACIC AORTA}

Arterial Branches of the thoracic aorta include:

Answer 45

Bronchial arteries

Mediastinal arteries

Oesophageal arteries

Pericardial arteries

Superior phrenic arteries

Intercostal and subcostal arteries

Question 46

_{ABDOMINAL AORTA}

Thoracic aorta becomes abdominal aorta once it passes through

Answer 46

Diaphragm

Ends above pelvis, dividing into iliac arteries

Question 47

_{ABDOMINAL AORTA}

Major branches of abdominal aorta include:

Answer 47

Inferior phrenic (T12) => inferior aspect of the diaphragm

Celiac trunk (T12) => organs of upper abdomen

Superior mesenteric artery (L1) =>Jejunum, ileum and transverse colon

Inferior mesenteric artery (L3) => transverse, descending, sigmoid colon and rectum

Renal arteries (L1-2) => kidneys

Question 48

_{ABDOMINAL AORTA}

Where does the abdominal aorta terminates?

Answer 48

Common illiac arteries (L4)

Which branches into internal and external iliacs

Internal iliacs => pelvic structures

External iliacs => legs

Question 49

_{BLOOD SUPPLY TO SPINAL CORD}

How does the Spinal cord receives its blood supply?

Answer 49

about 25% from two posterior arteries and

about 75% from one anterior spinal artery

Question 50

_{BLOOD SUPPLY TO SPINAL CORD}

Thoracic portion of anterior spinal artery supplied by

Answer 50

2-3 anterior radicular arteries

The larger radicular artery is the Artery of Adamkiewicz

Artery of Adamkiewicz, also known as the Great Radicular Artery

Question 51

_{BLOOD SUPPLY TO SPINAL CORD}

Artery of Adamkiewicz rpovides blood supply to:

Answer 51

Major blood supply to lower 2/3 of spinal cord

Provides major blood supply to lumbar and sacral cord

Question 52

_{BLOOD SUPPLY TO SPINAL CORD}

Variations on the origin of the Artery of Adamkiewicz. Where does is originate in most people?

Answer 52

In 75% of people, originates on the left side of the aorta between T9 and T12 vertebral segments

Segmental supplier of Adamkiewicz varies, (T5-L5)

Question 53

_{LOWER EXTREMITY ARTERIAL CIRCULATION}

At what vertebral level does the common iliac artery divides to become the internal and external iliacs?

Answer 53

L4

Question 54

_{LOWER EXTREMITY ARTERIAL CIRCULATION}

Internal iliac artery provides blood supply to:

Answer 54

Pelvic structures

Internal iliac artery => anterior and posterior trunks

Anterior trunk => obturator artery, vesical artery (men) and vaginal artery (females)

Posterior trunk => posterior pelvic wall, gluteal region

Question 55

_{LOWER EXTREMITY ARTERIAL CIRCULATION}

External iliac artery provides blood supply to:

Answer 55

Lower extremities

External iliac artery => femoral and deep femoral artery => popliteal artery –> dorsal artery