Histology Of The Cardiovascular System (Exam II) Flashcards Preview

RUSVM Microanatomy Orange 2016 > Histology Of The Cardiovascular System (Exam II) > Flashcards

Flashcards in Histology Of The Cardiovascular System (Exam II) Deck (32)
Loading flashcards...
1
Q

List the functions of the Cardiovascular System

A

Maintenance of adequate blood flow.
Delivery of O2, nutrients, hormones ,electrolytes and water to peripheral tissues.
Removal of CO2 and other metabolic waste products
Maintenance of normal thermoregulation and glomerular filtration rate

2
Q

Describe the flow of blood through vessels.

A

Artery–> Arteriole –> Metarteriole –> Capillaries –> Venule –> Vein

3
Q

Where are Purkinje Fibers located

A

Subendocardium - thin layer of CT

4
Q

What is the epicardium made of? What do these cells do?

A

Epicardium is formed by a single layer of flattened epithelial cells, the mesothelium - supported by CT including fat.
Mesothelial cells secrete small amount of serous fluid that lubricates the movement of the epicardium on opposite parietal pericardium.

5
Q

What else does the epicardium represent in regards to the pericardium?

A

It represents the visceral layer of the pericardial sac.

6
Q

Describe the 2 regions of intercalated discs.

A

Transverse Regions - Desmosomes - hold cell tightly together

Longitudinal Regions - Gap Junctions - electrical synapses

7
Q

Describe the Myocardium

A
Cross striated
Single, central nucleus
Intercalated discs
Lipofuscin
Sarcoplasmic reticulum
Many mitochondria - requires a lot of O2
8
Q

Describe the epicardium

A

The outer surface of heart (visceral pericardium)
Surface covered by mesothelium (simple squamous epithelium), a thin layer of dense CT and potentially a layer of adipose tissue with blood vessels
Is contiguous with the endocardium at the level of endocardial cushion.

9
Q

What is the cardiac skeleton?

A

Consist of 4 dense bonds of fibrous CT that encircles the base of the pulmonary trunk, aorta and the AV valves - provides structural support to the heart.

10
Q

What is the fibrous trigon?

A

Triangular mass of CT the connects the aortic arterial ring and the left and right atrioventricular ring.

11
Q

What happen in the fibrous trigon as animals age?

A

Can undergo osseous differentiation and forms the “Os Cardis” - primarily in cattle - will see bone in the heart of these older cattle

12
Q

Describe the main differences between arteries and veins.

A

Vein - larger lumen, valves, thickest wall is tunica externa

Artery - smaller lumen, no valves, thickest wall is tunica media

13
Q

Describe a capillary’s structure.

A

Thin wall of endothelium.

14
Q

What are the 3 tunics of vessels and what are they composed of?

A

Tunica Intima - endothelium, internal elastic membrane, subendothelial CT
Tunica Media - smooth muscle, elastic lamellae/fibers
Tunica Adventitia/Externa - CT, principally collagen, may contain blood vessels, nerves, capillaries

15
Q

What are the roles of the vascular endothelium? BE SPECIFIC.

A

Role in Hemostasis: anti-thrombotic and pro-fibrinolytic in normal state; pro-thrombotic and anti-fibrinolytic during injury
Modulates Perfusion: Nitrous Oxide - vasodilation; Endothelin - vasoconstriction
Role in Inflammation: regulates traffic of inflammatory cells, produces pro-inflammatory cytokines, control angiogenesis and tissue repair

16
Q

What is hemostasis? How does endothelium accomplish this??

A

Arrest bleeding by physiological properties of vasoconstriction and coagulation or by surgical mean.

Endothelium has pro-thrombotic and anti-fibrinolytic during injury and anti-thrombotic and pro-fibrinolytic in normal state.

17
Q

What is the vaso vasorum and what is its purpose?

A

Vaso Vasorum - present in the tunica adventitia/externa to supply nutrients to larger vessels.

18
Q

The valves of veins are made of what?

A

They are invaginations of the tunica intima. They are covered by endothelial cells and have a core of elastic fibers.

19
Q

Give an example of an elastic artery. How are the tunics of this artery different?

A

Aorta.
Tunica Media consists largely of repeating elastic lamellae and elastic fibers.
Has all 3 tunics.

20
Q

Give an example of a muscular artery. How are the tunics of this artery different?

A

Femoral Artery.
Tunica media is primarily smooth muscle.
These arteries are generally round in cross-section. Prominent internal elastic membrane.

21
Q

What is the purpose of vascular smooth muscle?

A

Regulates diameter and tone of vessels (vasoconstriction, vasodilation).
Smooth muscle cells are arranged circumferentially within tunica media.

22
Q

Describe the structure of arterioles.

A
1-3 layers of smooth muscle. 
Has greatest effect on BP.
Nuclei bulge into lumen ***
Round appearance of vessel
No internal elastic membrane in smallest arterioles with 1 smooth muscle layer.
23
Q

What are metarterioles?

A

Terminal vessel.

Has precapillary sphincter that can regulate flow into capillary bed.

24
Q

What are pericytes?

A

Mesenchymal like contractile cells (contain actin, myosin, tropomyosin) that wrap around capillaries and ventless and “Communicate” with endothelial cells by physical contact and paracrine signaling.
Have own basal lamina.

25
Q

What is the purpose of pericytes? Where are they often found?

A

Pericytes proliferate after injury. May be replacement stem cell source. Important in angiogenesis - new vessel formation.
Pericytes are often in close proximity with capillary - have tight junctions with capillary endothelial cells.

26
Q

What are capillaries?

A

Thin walled tubules of mesenchymal origin. Only one endothelial cell rolled into a tube.
Represent the site of exchange between blood and surrounding tissue.

27
Q

What are continuous capillaries? Where are they found?

A

Most common.
Found in muscle, brain, bone
No holes in wall.

28
Q

What are fenestrated capillaries?

A

Have gaps 10-100nm in size (tiny little holes).
Found in tissues with substantial fluid exchange.
Intestinal villi, choroid plexus, ciliary process, glomerular capillary.

29
Q

What are discontinuous (sinusoidal) capillaries?

A

Large molecules can exit (RBC, etc.)
Hepatic and Splenic Sinusoids.
Lumen enlarged and irregular.
Basal lamina may be absent.

30
Q

What is the renal corpuscle (glomerulus)?

A

Tightly coiled network of fenestrated capillaries. Responsible for the filtration of plasma.

31
Q

What are venules?

A

Post capillary venules.
Very “leaky” vessels.
No smooth muscle.
Leukocyte diapedesis is possible here.

32
Q

What are lymphatic vessels?

A

Very thin wall, very low pressure, may contain valves.
No RBC in lymph - appear clear on slide.

Lymphatic capillary has similar morphology to a capillary.