Cardio System Flashcards

0
Q

Weibel-Palade bodies, what is it?

A
  • Contain clotting factor VII aka von Willebrand factor
  • present in heart endothelium, elastic arteries, medium or muscular arteries, small arteries & arterioles but NOT IN CAPILLARIES
  • Absence of W-P bodies can cause cutaneous & mucosal bleeding including menorrhagia
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1
Q

ACE, where is it produced and what’s its fx?

A

Endothelial cells contain ACE, which facilitate conversion of ATI & ATII (especially in lung capillaries) -> vasoconstriction -> increased BP

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2
Q

Elastic or Large Arteries fx?

A
  • Conducting
  • Ex. Aorta & main branches
  • large number of elastic sheets or laminae in tunica media (40-70 laminae, smooth m. cells, type III collagen)
  • Elastic laminae are arranged concentrically with interconnecting elastic fibre networks
  • Structural significance: expansion of vessel wall to accomodate the large volume of blood during systole
  • Elastic recoiling to maintain intravascular pressure
  • Tunica adventitia: Type III & I collagen, elastic fibres, fibroblasts and macrophages
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3
Q

Muscular or medium arteries fx?

A
  • Distributing
  • most abundant in body
  • contain more smooth muscles in tunica media than elastic fibres
  • IEL is strongly characteristic of muscular arteries
  • Significance: serve as a muscular conduit to distribute blood to specific organs and muscles from large, elastic arteries to smaller arteries
  • Tunica media: 8 to 40 layers of smooth muscle cells arranged in circular fashion
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4
Q

Small artery features?

A
  • No vasa vasorum

- T. Media: 3 to 8 layers of smooth muscle cells, arranged in apparent circular fashion

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5
Q

Arterioles features? Very high yield

A
  • Major determinants of BP
  • T. Media: 1 or 2 layers of smooth muscle cells
  • T. Adventitia: ill-defined, it merges with surrounding CT
  • Architecture in parallel; blockage can lead to series architecture
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6
Q

Capillaries features?

A
  • single layer of endothelial cells + basal lamina
  • may be encircled by pericytes (derived from mesenchymal cells; can squeeze capillary) in continuous capillaries
  • 3 types of capillaries:
    1. Continuous (or classic) capillary: complete control over diffusion & transcytotic processes; pinocytotic & exocytotic vesicles, including receptor mediated endocytosis
    2. Fenestrated capillary: with diaphragms or/and circular pores; often found in peptide-secreting endocrine organs and kidney glomerulus, gut capillaries; continuous basal lamina; tight junctions present b/w cells; eye cillary processes, choroid plexus
    3. Discontinuous or Sinusoidal capillary: perforations large and variable; sites liver and some lymphoid organs (bone marrow, spleen, lymph nodes)
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7
Q

High Endothelial Venules (HEV) significance?

A

Homing effect in lymphoid organs like lymph node

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8
Q

Large vein features?

A
  • T. intima: subendothelial layer with few smooth muscles
  • T. media circularly arranged smooth muscles + CT
  • T. Adventitia: Longitudinal smooth muscle bundles; continuous milking of blood towards heart
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9
Q

Atherosclerosis histopathology?

A

Lesions of T. intima called atheroma or fibro fatty plaques that protrude into and obstructs the vascular lumen

  • excessive LDL oxidized by free radicals produced by endothelial cells
  • Smooth muscles become fatty and macrophages engulf oxidized LDL forming foam cells; proliferate and secrete collagen and other ECM which thickens T. intima forming fatty streaks
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10
Q

Continuous capillary location

A

fat, muscle, nervous system

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11
Q

Fenestrated capillary location

A

intestinal villi, endocrine glands, kidney glomeruli

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12
Q

Discontinuous (aka discontinous) capillary location

A

liver, bone marrow. spleen

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