265e Basic Biology of the Cardiovascular System

Question 1

It consist of a monolayer of endothelial cells apposed to a basement membrane, adjacent to occasional smooth-muscle-like cells known as pericytes

Answer 1

Capillaries

Question 2

It typically have a trilaminar structure

Answer 2

Arteries

Question 3

It is the outer layer of an artery which consists of looser extracellular matrix with occasional fibroblasts, mast cells, and nerve terminals.

Answer 3

Adventitia

Question 4

It is the middle layer of an artery which consists of layers of smooth-muscle cells; in veins, it can contain just a few layers of smooth-muscle cells

Answer 4

Tunica media

Question 5

It controls blood pressure and, hence, regional blood flow and the afterload experienced by the left ventricle

Answer 5

Contraction and relaxation of smooth-muscle cells at the level of the muscular arteries

Question 6

It regulates the capacitance of the venous tree and influences the preload experienced by both ven- tricles.

Answer 6

Vasomotor tone of veins

Question 7

It is the vasculature of large arteries which ourishes the outer aspects of the tunica media.

Answer 7

Vasa vasorum

Question 8

Atherosclerosis commonly affects this type of muscular artery.

Answer 8

Medium-size muscular arteries

Question 9

It forms the interface between tissues and the blood compartment.

It must regulate the entry of molecules and cells into tissues in a selective manner.

Answer 9

Endothelium

Question 10

Endogenous substances produced by endothelial cells that provide tonic vasodilatory stimuli under physiologic conditions in vivo

Answer 10

prostacyclin, endothelium-derived hyperpolarizing factor, nitric oxide (NO), and hydrogen peroxide (H2O2)

Question 11

Potent vasoconstrictor substance produced by endothelial cells

Answer 11

endothelin

Question 12

Endothelia functions:

Homeostatic Properties

Answer 12

Optimize balance between vasodilation and vasoconstriction

Antithrombotic, profibrinolytic

Anti-inflammatory

Antiproliferative

Antioxidant

Permselectivity

Question 13

It is the major cell type of the media layer of blood vessels

Answer 13

vascular smooth-muscle cell

Question 14

It activates postjunctional α1 recep- tors in large arteries and α2 receptors in small arteries and arterioles, leading to vasoconstriction.

Answer 14

Norepinephrine

Question 15

It is the structural and functional unit of contraction

It lies between adjacent Z lines, which are dark repeating bands that are apparent on transmission electron microscopy.

Answer 15

Sarcomere

Question 16

It is a large, flexible, myofi- brillar protein that connects myosin to the Z line.

Its stretching contributes to the elasticity of the heart.

Answer 16

Titin

Question 17

It is a principal determinant of the inotropic state of the heart.

Answer 17

Intracytoplasmic Ca2+

Question 18

It states that the tension of the myocardial fiber is the product of the intracavitary ventricular pressure and ventricular radius divided by wall thickness.

Answer 18

Laplace’s Law

Question 19

Determinants of Stroke Volume

Answer 19

Ventricular Preload
Ventricular Afterload
Myocardial Contractility

Question 20

It is influenced by the extent and speed of myocardial relaxation, which in turn depends on the rate of uptake of Ca2+ by the SR

Answer 20

Ventricular filling

Question 21

Endothelial functions

Dysfunctional Properties:

Answer 21

Impaired dilation, vasoconstriction

Prothrombotic, antifibrinolytic

Proinflammatory

Proproliferative

Prooxidant

Impaired barrier function

Question 22

It is the local changes in intracellular calcium concentration that result from the influx of calcium through the voltage-dependent calcium channel and are caused by the coordinated activation of a cluster of ryanodine-sensitive calcium release channels in the sarco- plasmic reticulum

Answer 22

Calcium sparks

Question 23

It is released from parasympathetic neurons binds to muscarinic receptors (of which there are five subtypes, M1–5) on vascular smooth-muscle cells to yield vasorelaxation.

Answer 23

Acetylcholine

Question 24

Growth factors that activate a signaling cascade that stimulates endothelial proliferation and tube formation, defined as angiogenesis.

Answer 24

vascular endothelial growth factor (VEGF)

fibroblast growth factor (FGF)

Question 25

It is a dark bang at the centre of the sarcomere that has a constant length

Answer 25

A band

Question 26

It is a complex, asymmetric fibrous protein with a molecular mass of about 500,000 Da; it has a rodlike portion that is about 150 nm (1500 Å) in length with a globular portion (head) at its end.

Answer 26

Myosin

Question 27

It is a long cytoskeletal protein that has an amino-terminal actin-binding domain and a carboxy-terminal domain that binds to the dystroglycan complex at adherens junctions on the cell membrane, thus tethering the sarcomere to the cell membrane at regions tightly coupled to adjacent contracting myocytes.

Answer 27

Dystrophin

Question 28

It is the repetitive interaction between myosin heads and actin filaments which results in sliding of the actin along the myosin filaments, ultimately causing muscle shortening and/or the development of tension.

Answer 28

cross-bridge cycling,

Question 29

It inhibits ryanodine receptor (RyR2) and thereby the release of Ca2+ from the SR

Answer 29

Calstabin 2

Question 30

It permits activation of the Ca2+ pump, thereby increasing the uptake of Ca2+ by the SR, accelerating the rate of relaxation, and providing larger quantities of Ca2+ in the SR for release by subsequent depolarization, thereby stimulating con- traction.

Answer 30

Phospholamban