Pulmonary and Systemic Circulation in Blood Vessels

What is the major role of conducting arteries?

Carry blood to smaller arteries

What are the major components of elastic arteries' media?

Elastic lamellae and smooth muscle fibers

How many elastic lamellae does the adult aorta typically have?

About 50

What is the function of carotid sinuses in the arterial system?

Act as important baroreceptors monitoring arterial blood pressure Signup and view all the answers

Which cranial nerve provides sensory nerve endings to the adventitia of carotid sinuses?

Cranial nerve IX (glossopharyngeal nerve) Signup and view all the answers

What is the role of baroreceptors in the aortic arch?

Adjust vasoconstriction to maintain normal blood pressure Signup and view all the answers

What are the two major divisions that make up the circulatory system?

Pulmonary circulation and Systemic circulation Signup and view all the answers

What are the three main components found in the walls of all blood vessels?

Smooth muscle, Connective tissue, Epithelium (endothelium) Signup and view all the answers

What is the endothelium, and what is its function?

The endothelium is a specialized epithelium that acts as a semipermeable barrier between blood plasma and interstitial tissue fluid. It mediates the bidirectional exchange of molecules through various mechanisms. Signup and view all the answers

How are vascular endothelial cells shaped?

Vascular endothelial cells are squamous, polygonal, and elongated with their long axis in the direction of blood flow. Signup and view all the answers

What are some functions of the endothelium related to clot formation?

The endothelium presents a nonthrombogenic surface, actively secretes anti-clotting agents such as heparin, tissue plasminogen activator, and von Willebrand factor, and controls local clot formation. Signup and view all the answers

How are the amount and arrangement of tissues in blood vessels influenced?

The amount and arrangement of tissues in blood vessels are influenced by mechanical factors, primarily blood pressure, and metabolic factors reflecting the local needs of tissues. Signup and view all the answers

What are the main components of the chemoreceptors in the carotid and aortic bodies?

Glomus (type I) cells and satellite (type II) cells Signup and view all the answers

What stimuli do the ion channels in the glomus cell membranes respond to?

Hypoxia, hypercapnia, or acidosis Signup and view all the answers

Which nerve forms synapses with the glomus cells in the carotid and aortic bodies?

Glossopharyngeal nerve Signup and view all the answers

What neurotransmitters are contained in the dense-core vesicles of the glomus cells?

Dopamine, acetylcholine, and other neurotransmitters Signup and view all the answers

What is the main function of the muscular arteries in the body?

They distribute blood to the organs and help regulate blood pressure Signup and view all the answers

What is the role of the internal elastic lamina in muscular arteries?

It is prominent and helps maintain the structure of the artery Signup and view all the answers

What is the last component of the media in larger muscular arteries?

External elastic lamina Signup and view all the answers

What do arterioles indicate the beginning of in an organ's microvasculature?

Exchanges between blood and tissue fluid Signup and view all the answers

What is absent in arterioles, unlike in larger arteries?

Elastic laminae Signup and view all the answers

What type of muscle cells make up the media in arterioles?

Smooth muscle cells Signup and view all the answers

What surrounds the parenchymal cells of an organ?

Capillaries Signup and view all the answers

What structures are found in the adventitia of arteries?

Lymphatic capillaries, vasa vasorum, and nerves Signup and view all the answers

What is the function of smooth muscle fibers in arterioles?

Act as sphincters closing arterioles and producing periodic blood flow into capillaries. Signup and view all the answers

What specialized function do arterioles serve in thermoregulation by the skin?

Arterioles can bypass capillary networks and connect directly to venules. Signup and view all the answers

How are arteriovenous shunts different from regular arterioles?

Arteriovenous shunts are thicker in media and adventitia and richly innervated by autonomic nerve fibers. Signup and view all the answers

What is the role of autonomic fibers at arteriovenous shunts?

Control the degree of vasoconstriction, regulating blood flow through capillary beds. Signup and view all the answers

What is the benefit of high capillary blood flow in the skin?

Allows more heat dispersion from the body during hot environmental temperatures. Signup and view all the answers

Describe the venous portal system and its purpose.

Blood flows through two successive capillary beds separated by a portal vein, allowing efficient delivery of hormones or nutrients to cells. Signup and view all the answers