Blood Vessels and Circulation

These flashcards cover essential terms and concepts related to blood vessels and circulation, aiding in exam preparation.

What are the principal veins in the circulatory system?

Internal Jugular Vein, Subclavian Vein, Superior Vena Cava, Inferior Vena Cava, etc.

What is the function of arteries?

Arteries carry blood away from the heart.

What are the smallest branches of arteries called?

Arterioles.

What are the smallest blood vessels where exchange occurs?

Capillaries.

What do veins do?

Return blood to the heart.

What layer of blood vessel walls is the tunica intima?

The innermost layer exposed to blood.

What is the tunica media composed of?

Smooth muscle, collagen, and elastic tissue.

What is the primary role of the tunica externa?

Anchors the vessel to adjacent tissues.

What type of capillaries have a continuous lining of endothelial cells?

Continuous capillaries.

Where are fenestrated capillaries commonly found?

In areas where high fluid transport occurs, such as the intestines and kidneys.

What are sinusoids also known as?

Discontinuous capillaries.

What is the term for the main blood pathway supplying an organ?

Simple pathway.

In a portal system, how does blood flow?

Artery -> capillary bed -> portal vein -> capillary bed -> vein.

What device prevents blood from flowing backward in veins?

Venous valves.

What increases blood pressure during blood loss?

Venoconstriction caused by sympathetic stimulation.

What does viscosity refer to in blood?

The resistance to flow due to the presence of particles in the liquid.

What is diffusion in the context of capillary exchange?

Movement of molecules from an area of high concentration to low concentration.

What process forces water and small solutes through the capillary wall?

Filtration.

What is required to prevent osmosis in blood?

Blood colloid osmotic pressure.

What happens to arterial walls during systole?

They stretch to accommodate blood volume.

What do baroreceptor reflexes monitor?

Blood pressure changes in the body.

What neurotransmitter stimulates smooth muscle contraction in arteries?

Norepinephrine (NE).

What hormone is released in response to low blood pressure or high plasma osmotic concentration?

Antidiuretic Hormone (ADH).

What is the main effect of atrial natriuretic peptide (ANP)?

To lower blood volume and blood pressure.

What is arterial anastomosis?

A convergence of two or more arteries to supply the same region.

What is the function of vasa vasorum?

Supply blood to the cells of the tunica media and tunica externa.

What is vasomotion?

Changes in the diameter of blood vessels due to smooth muscle contraction.

What type of artery is the aorta classified as?

An elastic artery.

What type of capillary has large openings for protein transport?

Sinusoid capillaries.

Where does the exchange of materials between blood and interstitial fluid occur?

In capillaries.

What is the role of the cardiovascular centers in the Medulla Oblongata?

To regulate heart rate and blood vessel diameter.

How does the body respond to elevated CO2 levels?

Increased heart rate and blood flow to the brain.

What happens when blood pressure decreases?

Cardiac output is increased to raise blood pressure.

What are companion vessels?

Veins and arteries that serve the same body region.

What best describes large veins in terms of vessel wall structure?

Thick tunica externa and thin tunica media.

What do peripheral chemoreceptors monitor?

Changes in blood pH, O2, and CO2 concentrations.

What is the effect of angiotensin II in the body?

To stimulate vasoconstriction and increase blood pressure.

How do capillaries generally differ from arteries?

They have thinner walls and a smaller diameter.

Where are baroreceptors located and what is their primary function regulating blood pressure?

Baroreceptors are specialized neural mechanoreceptors located in the aortic arch and carotid sinuses. They monitor stretch in the arterial walls, indicating changes in blood pressure.

Which nervous system activates baroreceptor reflexes and what is their impact?

Baroreceptor reflexes are activated by the Autonomic Nervous System. They send neural signals to the cardiovascular centers in the medulla oblongata, impacting heart rate, contractility, and blood vessel diameter to quickly adjust blood pressure (e.g., inhibition of sympathetic stimulation to cause vasodilation).

What is the location and function of peripheral chemoreceptors, and are they humoral or neural?

Peripheral chemoreceptors are neural receptors located in the carotid bodies and aortic bodies. They monitor changes in blood $pH$, $O<em>2$, and $CO</em>2$ concentrations.

What is the role of central chemoreceptors and how do they impact the body's response to blood gas levels?

Central chemoreceptors are neural receptors located in the medulla oblongata. They primarily monitor $pH$ and $CO_2$ levels in the cerebrospinal fluid. Their activation leads to neural signals that adjust heart rate, blood vessel diameter, and breathing rate to regulate blood gas levels.

Where are the vasomotor centers located, what is their primary role, and are they humoral or neural?

The vasomotor centers are neural control centers located in the medulla oblongata. Their primary role is to regulate the diameter of blood vessels, mainly through controlling vasoconstriction and vasodilation.

Which division of the nervous system largely controls the vasomotor centers, and what is their impact on the circulatory system?

The vasomotor centers are primarily controlled by the sympathetic nervous system through efferent neural pathways. They exert neural control over vascular smooth muscle, influencing total peripheral resistance and thereby systemic blood pressure and blood flow distribution.