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

1
Q

ARTERIAL AND VENOUS CIRCULATION

OBJECTIVES OF THIS LECTURE ARE:

A
  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
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2
Q

ARTERIAL AND VENOUS CIRCULATION

•Physical characteristics (2 circulations)

A

–Systemic circulation

–Pulmonary circulation

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3
Q

ARTERIAL AND VENOUS CIRCULATION

Systemic circulation

A

Supplies all tissue except lungs

AKA greater circulation or peripheral circulation

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4
Q

ARTERIAL AND VENOUS CIRCULATION

Pulmonary circulation

A

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5
Q

ARTERIAL AND VENOUS CIRCULATION

Functional parts of circulation:

A

Arteries

Arterioles

Capillaries

Venules

Veins

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6
Q

ARTERIES AND ARTERIOLES

Arteries

A

Transports blood under high pressure to the tissues

This is why arteries Have strong vascular walls

Blood flows at high velocity

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7
Q

ARTERIES AND ARTERIOLES

Arterioles

A

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

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8
Q

ARTERIES AND ARTERIOLES

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

A

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

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9
Q

CAPILLARIES, VENULES & VEINS

Capillaries

A

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

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10
Q

CAPILLARIES, VENULES & VEINS

Venules

A

Collect blood from the capillaries and gradually grow larger into veins

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11
Q

CAPILLARIES, VENULES & VEINS

Veins

A

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)

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12
Q

CAPILLARIES, VENULES & VEINS

Which characteristics of veins make them reservoir of extra blood?

A

Thinner walls than arteries

Much more distensible than arteries

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13
Q

ARTERIAL AND VENOUS CIRCULATION

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

A

Systemic circulation: 84%

(64% of which is in the veins)

Heart and pulmonary circulation: 16%

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14
Q

WALLS OF ARTERIES AND VEINS

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

A

Lumens

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15
Q

WALLS OF ARTERIES AND VEINS

Btw arteries and veins which has smaller lumen?

A

Arteries

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

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16
Q

WALLS OF ARTERIES AND VEINS

There three layers to each vessel knowns respectively as:

A

Tunica externa/adventitia

Tunica media

Tunica intima

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17
Q

WALLS OF ARTERIES AND VEINS

Tunica externa/adventitia

A

Outermost layer of a blood vessel

(reponsible for maitaining protection and prevents collapse)

Strengthens/Anchors to surrounding tissue

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18
Q

WALLS OF ARTERIES AND VEINS

Tunica media

A

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

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19
Q

WALLS OF ARTERIES AND VEINS

Tunica intima

A

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)

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20
Q

WALLS OF ARTERIES AND VEINS

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

A

Damage to the endothelium is the reason for clot formation

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21
Q

WALLS OF ARTERIES AND VEINS

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

A

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

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22
Q

DIFFERENCE BETWEEN ARTERIES AND VEINS - Arteries

Direction of flow - Pressure - Walls - Lumen - Valves

A

Direction of flow: Blood away from Heart

Pressure: Higher

Walls: Thicker: Tunica media thicker than tunica externa

Lumen: Smaller

Valves: None

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23
Q

DIFFERENCE BETWEEN ARTERIES AND VEINS - Veins

Direction of flow - Pressure - Walls - Lumen - Valves

A

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

24
Q

DIFFERENCE BETWEEN ARTERIES AND VEINS

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

A

Veins have valves b/c they are low pressure vessels

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

25
Q

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

A

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

26
Q

AORTIC SEGMENTS

The thoracic aorta is divided into three sections:

A

Ascending aorta

(Portion that leaves the LV)

Transverse aorta

(aka aortic arch)

Descending aorta

(Portion that descends into the thorax)

27
Q

AORTIC SEGMENTS

When does the Descending aorta becomes the Abdominal aorta?

A

after in penetrates the diaphragm

This occurs around level T12

28
Q

ANATOMY OF THE CEREBRAL CIRCULATION

Ascending aorta ascends from the

A

aortic valve

29
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Brachiocephalic artery

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

Left subclavian artery

30
Q

ANATOMY OF THE CEREBRAL CIRCULATION

What the other name for the Brachiocephalic artery?

A

Innominate artery

31
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Right subclavian artery

Right common carotid artery

Right common carotid artery bifurcates with right subclavian

Left common carotid arises from aortic arch

32
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

External Carotid Artery

(Will not be discussed for this lecture)

33
Q

ANATOMY OF THE CEREBRAL CIRCULATION

Internal Carotid Artery divides into which arteries?

A

Middle cerebral artery

Anterior cerebral artery

34
Q

ANATOMY OF THE CEREBRAL CIRCULATION

Which artery provides Arterial blood supply to the brain?

A

Internal carotid artery

Provides 80% of cerebral blood flow

35
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Middle cerebral artery

36
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Anterior cerebral artery

37
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Vertebral arteries (2)

Arise from subclavian arteries to form basilar artery

Then give rise to the Posterior cerebral artery

38
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Circle of Willis

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

39
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Anterior cerebral arteries

Middle cerebral arteries

Posterior cerebral arteries

40
Q

ANATOMY OF THE CEREBRAL CIRCULATION

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

A

Anterior and posterior communicating arteries,

AKA Willsians channels

41
Q

CIRCLE OF WILLIS

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

A

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

42
Q

THORACIC AORTA

The Thoracic aorta is also known as:

A

Descending aorta

43
Q

THORACIC AORTA

What’s the thoracic aorta span?

A

Begins at T4 and extends to T12

44
Q

THORACIC AORTA

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

A

begins left of the vertebral column

but approaches midline as it descends into the chest

45
Q

THORACIC AORTA

Arterial Branches of the thoracic aorta include:

A

Bronchial arteries

Mediastinal arteries

Oesophageal arteries

Pericardial arteries

Superior phrenic arteries

Intercostal and subcostal arteries

46
Q

ABDOMINAL AORTA

Thoracic aorta becomes abdominal aorta once it passes through

A

Diaphragm

Ends above pelvis, dividing into iliac arteries

47
Q

ABDOMINAL AORTA

Major branches of abdominal aorta include:

A

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

48
Q

ABDOMINAL AORTA

Where does the abdominal aorta terminates?

A

Common illiac arteries (L4)

Which branches into internal and external iliacs

Internal iliacs => pelvic structures

External iliacs => legs

49
Q

BLOOD SUPPLY TO SPINAL CORD

How does the Spinal cord receives its blood supply?

A

about 25% from two posterior arteries and

about 75% from one anterior spinal artery

50
Q

BLOOD SUPPLY TO SPINAL CORD

Thoracic portion of anterior spinal artery supplied by

A

2-3 anterior radicular arteries

The larger radicular artery is the Artery of Adamkiewicz

Artery of Adamkiewicz, also known as the Great Radicular Artery

51
Q

BLOOD SUPPLY TO SPINAL CORD

Artery of Adamkiewicz rpovides blood supply to:

A

Major blood supply to lower 2/3 of spinal cord

Provides major blood supply to lumbar and sacral cord

52
Q

BLOOD SUPPLY TO SPINAL CORD

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

A

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)

53
Q

LOWER EXTREMITY ARTERIAL CIRCULATION

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

A

L4

54
Q

LOWER EXTREMITY ARTERIAL CIRCULATION

Internal iliac artery provides blood supply to:

A

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

55
Q

LOWER EXTREMITY ARTERIAL CIRCULATION

External iliac artery provides blood supply to:

A

Lower extremities

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