Ch_21_Lecture_Objectives

Layers of blood vessel wall

The three layers are tunica intima, tunica media, and tunica externa.

Arteries vs. Veins: Vessel Wall Thickness

Arteries have thicker walls compared to veins.

Arteries vs. Veins: Vessel Lumen

Arteries have a smaller lumen diameter than veins.

Valves in Veins

Valves prevent backflow of blood in veins.

Blood Reservoir

Veins are considered as blood reservoirs.

Types of Arteries

The three main types of arteries are elastic, muscular, and arterioles.

Examples of Elastic Artery

An example of an elastic artery is the aorta.

Examples of Muscular Artery

An example of a muscular artery is the femoral artery.

Types of Capillaries

The three main types of capillaries are continuous, fenestrated, and sinusoidal.

Precapillary Sphincters

Precapillary sphincters regulate blood flow into capillary beds.

Types of Veins

The three main types of veins are superficial, deep, and pulmonary veins.

Example of Large Vein

An example of a large vein is the superior vena cava.

Angiogenesis

Angiogenesis is the formation of new blood vessels, regulated by vascular endothelial growth factor (VEGF).

Vasoconstriction

Vasoconstriction is the narrowing of blood vessels, occurring when oxygen levels are low.

Venoconstriction

Venoconstriction helps increase venous return during exercise or blood loss.

Blood Pressure leaving Heart

Blood pressure coming out of the heart into the aorta is approximately 120 mmHg.

Blood Pressure in Capillaries

Blood pressure entering the arterial end of capillaries is around 35 mmHg.

Blood Pressure leaving Venules

Blood pressure leaving the venule end of capillaries is about 15 mmHg.

Blood Flow and Blood Pressure

Blood flow is directly related to blood pressure and inversely related to peripheral resistance.

Factors affecting Peripheral Resistance

The three factors are vessel length, vessel diameter, and blood viscosity.

Hypertension

Hypertension is dangerous because it can lead to heart damage and vascular complications.

Role of Muscle Compression

Muscle compression aids in venous return by pushing blood through veins.

Filtration vs. Reabsorption

Filtration refers to the movement of fluid out of capillaries, while reabsorption involves fluid moving back into capillaries.

BCOP

Blood colloid osmotic pressure (BCOP) is generated by proteins in the blood that draw water into the capillaries.

CHP Values

CHP is higher at the arterial end (around 35 mmHg) and lower at the venous end (around 15 mmHg).

NFP Formula

Net Filtration Pressure (NFP) = CHP - BCOP.

Positive NFP Value Meaning

A positive NFP indicates filtration predominates.

Negative NFP Value Meaning

A negative NFP indicates reabsorption predominates.

Effects of Hemorrhage on NFP

Hemorrhaging decreases CHP and increases reabsorption.

Baroreceptor Response to High BP

When BP is too high, baroreceptors stimulate the cardioinhibitory center.

Chemoreceptors and Cardiac Response

Chemoreceptors are stimulated under low O2, high CO2, or low pH conditions, increasing heart rate.

Hormonal Response to High BP

When BP is high, hormones such as atrial natriuretic peptide are released to promote vasodilation.

Hormonal Response to Low BP

When BP is low, hormones such as aldosterone and ADH are released, promoting vasoconstriction.

Hepatic Portal Vein Sources

The three veins draining into the hepatic portal vein are the superior mesenteric vein, inferior mesenteric vein, and splenic vein.

Fetal Circulation: Umbilical Arteries

Umbilical arteries carry deoxygenated blood from the fetus to the placenta.

Fetal Circulation: Umbilical Veins

Umbilical veins carry oxygenated blood from the placenta to the fetus.

Diseases of Blood Vessels

Examples include aneurysm, atherosclerosis, varicose veins, and deep vein thrombosis (DVT).

What are the three layers of blood vessel walls?

Tunica intima, tunica media, and tunica externa.

What is the primary role of arteries?

To carry oxygenated blood away from the heart (except for pulmonary arteries).

What unique feature do veins have to prevent backflow?

Valves.

What is the function of precapillary sphincters?

To regulate blood flow into capillary beds.

What pressure is approximately 120 mmHg associated with?

Blood pressure leaving the heart into the aorta.

What is the effect of vasoconstriction on blood vessels?

It narrows blood vessels, increasing blood pressure.

What are the two main functions of the venous system?

Returning deoxygenated blood to the heart and serving as a blood reservoir.

What phenomenon occurs during angiogenesis?

The formation of new blood vessels.

What represents a negative net filtration pressure (NFP)?

It indicates that reabsorption predominates.

Why are capillaries vital for exchange?

They have thin walls that allow for efficient exchange of gases and nutrients.