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Flashcards in McAuliffe Deck (43):
1

The three layers of the heart:

  1. epicardium: outer; contains coronary blood vessels.
  2. myocardium: myocytes.
  3. endocardium: endothelium

2

Cardiac myocytes communicate via:

gap/communicating junctions.
 

3

The heart twists when it contracts (wrings itself out) due to:

spiral arrangement of cardiac muscle fibers.

4

Three functions of the cardiac fibrous skeleton:

  1. attachment site for cardiac muscle
  2. reinforces bases of valves
  3. insulates ventricles from electrical activity in atria

5

In response to volume expansion atrial myocytes secrete ____ from granules stored in their cytoplasm. 

atrial natriuretic peptide (ANP)

6

Function of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP):
 

  • Hypotensive hormones released by atrium and ventricles.
    • lower blood volume and BP by promoting the excretion of salt (natriuresis) and water by the kidneys. 

7

Volume expansion and pressure overload cause the ventricles secrete:

  • a precursor to B-type natriuretic peptide, proBNP.
  • cleaved in the blood stream to active BNP.

8

Which hormone secreted by the heart is not stored in granules so its production must be
up-regulated before synthesis and secretion can occur?

  • pro-BNP from ventricles.
  • ANP levels change faster in blood.

9

Blood levels of what hormone can be used as an important diagnostic sign of congestive heart failure? 

BNP

10

Role of C-type natriuretic peptides released from vascular endothelium:

promotes clearance of ANP and BNP

11

Bundles of Purkinje fibers run in _____ to the apex of the ventricles and then fan out into the myocardium. 

subendocardial connective tissue

12

The three layers of arteries:

  1. tunica intima (innermost)
  2. tunica media (smooth muscle layer)
  3. tunica adventitia (outermost)

13

How are the endothelial cells of the tunica intima oriented?

  • with their long axes parallel to direction of blood flow.
  • 2 to 3 times as long as they are wide.

14

Contents of the arterial tunica media:

  1. circularly arranged smooth muscle.
  2. circularly arranged elastic tissue. 
     

15

Contents of the tunica adventitia:

  • connective tissue with:
    • vaso vasorum (vessels of the vessels)
    • nervi vascularis (ANS; innervate smooth muscle)
       

16

The elastic tissue in large elastic arteries are made by:

smooth muscle cells in the tunica media

17

As arteries get smaller they have:

  • more smooth muscle and less elastic tissue in tunica media.

18

What makes up the microcirculation/microvasculature?

Arterioles + capillaries + venules 
 

19

What blood vessels are responsible for the drop in arterial pressure before blood enters the capillary beds?

arterioles
 

20

What connects arterioles to capillaries?

metarterioles
 

21

What controls the entrance to the capillary bed and regulates the amount of blood that enters the capillary bed?

a precapillary sphincter of smooth muscle cells 

22

The three types of capillaries:

  1. continuous
  2. fenestrated
  3. discontinuous (sinusoidal) 

23

What type of capillary is the least permeable?

continuous
 

24

What type of capillary is the most permeable?

discontinuous (sinusoidal) 

25

What type of capillary lines the CNS, forms the blood-brain barrier, and are regulated by astrocytes?

continous

 

26

What forces plasma out of the capillaries and into the interstitial tissues?

hydrostatic pressure

27

What transports larger molecules out of capillaries?

transcytosis via pinocytotic vesicles

28

What pushes venous blood back to the heart?

  • muscular activity in lower limb
  • movement of abdominal and thoracic organs

29

What are the smallest elements of the venous system?

Venules or post capillary venules

30

What in the lymph nodes facilitates the migration of T lymphocytes from the blood stream into lymph nodes?

high endothelial venules

31

Lymphatics are similar to capillaries.

What is different about them that allows large proteins and particulate material to easily enter them?

 

  • basement membrane discontinuous or missing altogether

32

How are blood vessels, particularly arteries, nourished?

  • vaso vasorum: tunica adventitia and outer tunica media.
  • diffusion: inner tunica media and tunica intima.

33

What cells in organs produce nitric oxide to promote vasodilation?

endothelial cells

34

Most endothelial cells contain angiotensin converting enzyme (ACE), which:

converts vasoinactive angiotensin I to angiotensin II

35

What do endothelial cells produce that is needed for platelets to adhere to the subendothelial connective tissue and initiate coagulation?

Factor 7, von Willebrand's Factor

36

Process of angiogenesis:

  1. ↓O2 causes ↑HIF-1 and ↑VEGF, which causes:
  2. Secretion of proteases to dissolve basement membrane.
  3. Capillary migration toward signal.
  4. Proliferation of endothelial cells.
  5. Differentiation into mature endothelial cells. 
  6. As O2↑ HIF will ↓.

37

Current hypothesis for atherosclerosis:

  1. endothelium is damaged by one or more insults (hyperlipidemia, mechanical stress, platelet adhesion, inhaled toxins).
  2. invasion of smooth muscle cells from the tunica media.
  3. Proliferation of smooth muscle cells, which deposit extracellular matrix and form plaque. 

38

ANP and BNP lower blood volume and blood pressure by:

  • promoting the excretion of salt (natriuresis) and water by the kidneys.

39

Alcohol causes:

vasodilation and loss of heat. 

40

What may act as preferential or thoroughfare channels through a vascular bed so that the capillaries are bypassed?

metarterioles

41

Where are pericytes found, and what are they?

  • found lining capillaries
  • stem cells, capable of becoming smooth muscle, adipose, osteogenic or chondrogenic cells. 

42

In the liver, spleen, and bone marrow, discontinuous (sinusoidal) capillaries are partially lined by:

fixed macrophages.
 

43

What does ACE activate and inactivate?

  • activates angiotension II (vasoconstrictor) and inhibits bradykinin (vasodilator).
  • Bradykinin is a vasodilator.