Blood Vessels Flashcards by Rebecca Warnecke

The tunica media is a continuation of what layer of the heart?

Myocardium

How well did you know this?

Not at all

Perfectly

The tunica adventitia is a continuation of what layer of the heart?

Epicardium (visceral pericardium)

How well did you know this?

Not at all

Perfectly

What are three categories of arteries?

Elastic, muscular, and arterioles

How well did you know this?

Not at all

Perfectly

What is another name for elastic arteries?

Conducting arteries

How well did you know this?

Not at all

Perfectly

What is the tunica intima structure of elastic arteries?

Attenuated endothelium
Thin/incomplete internal elastic lamina
Thicker connective tissue with elastic fibers, collagen type I, fibroblasts, and smooth muscle

How well did you know this?

Not at all

Perfectly

What is the tunica media structure of elastic arteries?

Fenestrated sheets of elastic fibers with some collagen type I and smooth muscle
Thin external elastic lamina is possible
Outer portion typically contains vasa vasorum

How well did you know this?

Not at all

Perfectly

What is vasa vasorum?

Small blood vessels supplying the large blood vessel

How well did you know this?

Not at all

Perfectly

What is the tunica adventitia structure of elastic arteries?

Loose fibroelastic connective tissue

Numerous vasa vasorum

How well did you know this?

Not at all

Perfectly

What is the thickest/most dominant layer of an elastic artery?

Tunica media

How well did you know this?

Not at all

Perfectly

What is another term for muscular arteries?

Distributing arteries

How well did you know this?

Not at all

Perfectly

What is the tunica intima structure in muscular arteries?

Endothelium
Very thin
Some connective tissue (few smooth muscle cells possible)
Internal elastic lamina

How well did you know this?

Not at all

Perfectly

What type of artery has a uniquely thin tunica intima?

Muscular arteries

How well did you know this?

Not at all

Perfectly

What is the tunica media structure of muscular arteries?

Circular smooth muscle
Gap junctions between smooth muscle cells
Elastic and reticular fibers, chondroitin sulfate
External elastic lamina possible
Richly innervated with sympathetics (strong contraction over a small area)

How well did you know this?

Not at all

Perfectly

What is the thickest and most dominant layer of the muscular artery?

Tunica media

How well did you know this?

Not at all

Perfectly

What is the tunica adventitia structure of muscular arteries?

Fibroelastic connective tissue with sulfated GAGs
Fibroblasts
Vasa vasorum present

How well did you know this?

Not at all

Perfectly

What is the tunica media of muscular arteries primarily made of?

Smooth muscle

How well did you know this?

Not at all

Perfectly

What are the smallest arteries?

Arterioles

How well did you know this?

Not at all

Perfectly

Overall, arterioles are very structurally similar to what kind of artery?

Muscular

How well did you know this?

Not at all

Perfectly

What is the tunica adventitia of arterioles primarily made of?

Connective tissue

How well did you know this?

Not at all

Perfectly

What is the tunica media of arterioles primarily made of?

Smooth muscle

How well did you know this?

Not at all

Perfectly

What is significant about the lumen size of arterioles?

Usually about the same width as the vessel wall

How well did you know this?

Not at all

Perfectly

Is the tunica media the thickest and most dominant layer of all types of arteries?

Yes

How well did you know this?

Not at all

Perfectly

What type of artery has the most developed internal elastic lamina?

Muscular artery

How well did you know this?

Not at all

Perfectly

Which is the thinnest of the major luminal wall layers in arteries?

Tunica intima

How well did you know this?

Not at all

Perfectly

What effect does aging have on elastic arteries?

Width increases into your 20s | Number of elastic laminae increase in the tunica media

What effect does aging have on muscular arteries?

Collagen and proteoglycans increase after middle age so there is a decrease in flexibility

Which specific muscular arteries are largely affected by aging leading to decreased flexibility?

Coronary arteries

What is the artery-based reason for increased systolic blood pressure around the age of 50?

Decreased elastic fibers and increased collagen type I

What arteries are usually affected by arteriosclerosis?

The largest ones

What happens to the tunica intima during arteriosclerosis?

Becomes infiltrated with soft lipid causing lumen diameter to decrease

What happens to the tunica media during arteriosclerosis?

Accumulation of collagen type I and sulfated GAGs

The tunica intima is a continuation of what layer of the heart?

Endocardium

What part of the artery increases in width and results in a decreased lumen size during atherosclerosis?

Tunica intima

What is a short terminal arteriole branch that lacks a true tunica media?

Metarteriole

Metarterioles lead to what other vessels?

Capillaries and a thoroughfare channel that leads to venules

What structures control blood flow into the capillaries?

Pre-capillary sphincters

What is the purpose of pre-capillary sphincters?

Allow blood to pulse through true capillaries

Where are metarterioles found?

In all capillary beds

How are the vessel walls different in the arteriovenous anastomoses?

Thicker tunica media and tunica adventitia

What innervates the AVA?

Many ANS nerves (sympathetic and parasympathetic)

What is the function of the arteriovenous anastomoses?

To control the lumen size and therefore the amount of blood in the capillaries

What are the major locations of AVAs?

Skin and stomach (also erectile tissues)

What is the activity of the AVA when blood flow into the capillary bed is normal?

AVA is "closed"

What is the activity of the AVA when most of the blood bypasses the capillary bed?

AVA is opened

What is the activity of AVAs when less blood is being sent to erectile tissue capillaries?

AVA is "open"

What is the activity of the AVAs when blood is sent into erectile tissue capillaries?

AVAs are closed

What things control/influence blood flow into capillaries?

Metarterioles, AVAs, lumen size of terminal arteriole, pre capillary sphincters

What cells make up the general capillary structure?

Single layer of flattened endothelial cells

What is the function of capillaries?

Movement of large molecules

What is the function of pinocytotic vesicles seen with capillaries?

Form transient channels through cytoplasm to allow transfer of large molecules

What cell junctions are located between the endothelial cells of capillaries?

Fasciae occludens (discontinuous attachment)

What are the functions of the cell junctions of capillaries?

Exchange of macromolecules, allow cell movement

What is the most common capillary type?

Continuous capillaries

Where can continuous capillaries be found?

Muscle, connective tissue, many organs

Pericytes are considered to be what kind of cell?

Residual mesenchyme cells

Pericytes are numerous on what kinds of vessels?

Capillaries and venules

What can pericytes secrete?

Basement membrane and matrix (ECM) components

What cell types can pericytes change into?

Smooth muscle, endothelial cells, and fibroblasts

Do pericytes have the ability to divide?

Yes

What are the two functions of pericytes?

Healing and possibly regulating blood flow too

Where are fenestrated capillaries located?

Pancreas, intestines, endocrine organs, kidneys

What is the structure of fenestrated capillaries?

Pores with thin protein diaphragm containing 8 fibrils

What is the function of fenestrated capillaries?

To allow greater movement of molecules and cells

What are the locations of sinusoidal capillaries?

Bone marrow, liver, spleen, lymphatic organs, and certain endocrine organs

What is the structure of sinusoidal capillaries?

Enlarged diameter, many large fenestrae with no protein diaphragm

Which has no protein diaphragm: fenestrated or sinusoidal capillaries?

Sinusoidal capillaries

Which lacks a true tunica media: metarterioles or AVAs?

Metarterioles

Which has a thicker tunica media and tunica adventitia: metarticles or AVAs?

AVAs

Which cell type, with reparative potential, is found exterior to the capillaries?

Pericytes

How are veins similar to arteries?

Also have three tunics

How are veins different than arteries?

Not as uniform in structure, often larger in diameter, higher number

What is the structure of the valves of veins?

Two flaps of tunica intima and fibroelastic connective tissue

What are the functions of the valves of veins?

Protection by preventing back-flow, works with skeletal muscle to keep blood moving

What type of venules is the smallest and has the thinnest walls?

Postcapillary venules

Which type of venule has the most pericytes?

Postcapillary venules

What is unique about the layers of the postcapillary venules?

No tunica media nor tunica adventitia

What makes up the tunica intima of postcapillary venules?

Endothelium, small amount of connective tissue, numerous pericytes

What makes up the tunica intima of collecting venules?

Endothelium and small amounts of connective tissue

What makes up the tunica adventitia of collecting venules?

Connective tissues, fibroblasts, some pericytes

Is there a tunica media present in collecting venules?

What is unique about the tunica media of muscular venules?

Incomplete smooth muscle layer

What type of venules have the fewest pericytes in their tunica adventitia?

Muscular venules

What is the effect of an incomplete tunica media in muscular venules?

Leaky venules due to inflammatory products leaking through endothelial cell junctions

What is the difference between small veins and venules?

Small veins have a complete tunica media

What is usually the thickest/most dominant layer in a vein?

Tunica adventitia

Vasa vasorum is possible to be seen in what layer of medium veins?

Tunica adventitia

What is different between the tunica intima of veins and muscular arteries?

Veins would not have an internal elastic lamina

What is the structural exception involved with the superficial veins of the legs?

Tunica media is actually well-developed

What are some examples of veins in the legs with well-developed tunica medias?

Great and lesser saphenous veins

What is the structural exception involving pulmonary veins?

Well-developed tunica media, some cardiac muscle seen in the tunica adventitia near the heart

What large and important veins also exhibit structural exceptions by having some cardiac muscle in the tunica adventitia near the heart?

Superior and inferior cavae

What are the causes of varicose veins?

1. Loss of skeletal muscle tone around the veins 2. Degeneration of vessel wall 3. Valve incompetence

What are varicose veins?

Enlarged and winding superficial veins of the legs

What are esophageal varices?

Varicose veins in the lower esophagus

Esophageal varices are commonly seen among what group of people?

Alcoholics

What is the cause of esophageal varices?

Portal hypertension

What are hemorrhoids?

Varicose veins at the end of the anal canal

What are the functions of the lymphatic system?

Drain excess interstitial fluid Transport lymph to lymph nodes Transport lymph to blood stream

What vascular structures do the lymphatic capillaries resemble?

Blood capillaries

Which has no pericytes: blood or lymphatic capillaries?

Lymphatic capillaries

What in the lymphatic capillaries allows for easy movement of materials into and out of the vessels that is different than blood capillaries?

Endothelial cells can overlap but create clefts between cells

What structure is in the lymphatic capillaries that supports endothelial walls so they capillaries stay open?

Lymphatic anchoring filaments

What kind of fibers make up the anchoring filaments of lymphatic capillaries?

Elastic

What vascular structures do small lymphatic vessels resemble?

Venules

The lymphatic ducts empty into the venous system at the junction of which veins?

Right internal jugular and subclavian veins

What specific ducts are included in the lymphatic duct system?

Short right lymphatic duct and the thoracic duct

What is the pattern of the tunica media of the lymphatic ducts?

Regular: made of longitudinal and circular layers of smooth muscle