Chapter 20 Blood Vessels Study Guide PDF PDF

Preview

Summary

(Chapter 20) Cardiovascular System: Blood Vessels. Textbook: McKinley, O'Laughin, Bidle. Laboratory manual: Marieb & Smith. Covers both the anatomy and physiology. Lecture, lab, and textbook notes when compiling the summary into a study guide. Study guide includes terms, definitions, examples, and h...

Description

SPRING 2019

ANATOMY & PHYSIOLOGY II CARDIOVASCULAR SYSTEM: BLOOD VESSELS AMY LYNN GAGLIANO) MONROE COMMUNITY COLLEGE Professor Christopher Wendtland

Anatomy & Physiology II—Cardiovascular System: Blood Vessels

Structure and Function of Blood Vessels • • • •

There are three primary types of blood vessels: Arteries that convey blood away from the heart Capillaries that exchange substances between blood and tissues Veins that transport blood to the heart

Vessel walls are composed of layers, called tunics, which surround the lumen (hollow part) • Tunica intima— innermost tunic composed of an endothelium over a thin subendothelial layer made up of areolar connective tissue • Tunica media— middle tunic composed of layers of smooth muscle supported by elastic fibers • Tunica externa— outermost layer composed of areolar connective tissue to give shape with elastic and collagen fibers * Capillaries only contain the tunica intima and do not possess a subendothelial layer

Comparison of Vessels • • • • • •

Arteries have a smaller lumen but large tunica media Veins have a larger lumen, smaller tunica media, and one-way valves Capillaries possess only the tunica intima with no subendothelial layer Veins converge Arteries diverge Veins get bigger as they get closer to the heart

Materials developed by Amy Lynn Gagliano [email protected]

1

Anatomy & Physiology II—Cardiovascular System: Blood Vessels

•

Arteries get smaller as they move away from the heart

Types of Arteries • • •

Elastic Muscular Arteriole

Types of Veins • • •

Large vein Small to medium sized vein Venule o Does not have a valve

Types of Capillaries •

•

•

Continuous—most common; allow for the passage of plasma and most of its contents except for most proteins and some leukocytes Fenestrated—mostly in the kidney; allow for the exchange of large amounts of materials to be filtered, released, or absorbed, including small proteins Sinusoid—mostly in the red bone marrow and liver; allow for the passage of large substances such as formed elements, large plasma proteins, and plasma

Capillary Bed • • • •

Arteriole end Venule end Precapillary sphincters When contracted there is no perfusion

Blood Volume Most blood is held in the veins • Pulmonary circulation (18%) • Heart (12%) • Systemic circulation (70%)

Pathways of Blood Vessels • •

Simple—a capillary bed with an arteriole and venule end Arteriovenous anastomosis (shunt)—bypasses around a capillary bed

Materials developed by Amy Lynn Gagliano [email protected]

2

Anatomy & Physiology II—Cardiovascular System: Blood Vessels

•

Portal system—connection of two capillary beds by a portal vein

Capillary Exchange • • • • •

Filtration happens at the arteriole end Reabsorption happens at the venule end Sum of the outward forces – Sum of the inward forces = Net Filtration Pressure (NFP) If the sum of the outward forces minus the sum of the inward forces is positive, more substance has filtered out If the sum of the outward forces minus the sum of the inward forces is negative, more has reabsorbed in

Blood Pressure, Resistance, and Total Blood Flow • • • • • • • • • •

A pressure gradient drives blood through the vasculature Blood experiences resistances while being transported through blood vessels Blood pressure and resistance determine the total blood flow Pressure = (flow)(resitance) Recall: BP = (CO) (TPR) Recall: C0 = (SV)(HR) TPR can only be changed by changing Blood viscosity Tube length Tube radius * Tube radius is the easiest to change

Blood Pressure ❖ Blood Pressure (BP)—force per unit time that the blood exerts against the wall of a vessel • A BP gradient is the change in BP from one end of a blood vessel to its other end, which propels blood through vessels • Blood flow is pulsing in arteries because of the contraction and relaxation of ventricles • The systolic BP is the highest blood pressure • The diastolic BP is the lowest blood pressure • BP is expressed as a ration with the numerator being the systolic and denominator being the diastolic blood pressure ❖ Pulse pressure—the additional pressure placed on arteries from when the heart is resting to when the heart is contracting PP = Systolic – Diastolic ❖ Mean arterial pressure (MAP)—average measure of the blood pressure forces on the arteries MAP = (Diastolic) + (PP/3)

Resistance ❖ Resistance—the amount of friction the blood experiences as it travels through the blood vessels ❖ Peripheral resistance—resistance of blood in the blood vessels Peripheral resistance is affected by Materials developed by Amy Lynn Gagliano [email protected]

3

Anatomy & Physiology II—Cardiovascular System: Blood Vessels

➢ Blood viscosity ➢ Vessel length ➢ Vessel radius * Vessel radius is the easiest to change •

•

Vasodilation increases the blood vessel radius o Decreased oxygen levels o Decreased nutrient levels o Increased carbon dioxide, H+, K+, or lactose levels o Histamine o Bradykinin o Nitric oxide o Atrial natriuretic peptide (ANP) o Epinephrine Vasoconstriction decreases the blood vessel radius o Increased oxygen levels o Increased nutrient levels o Decreased carbon dioxide, H+, K+, or lactose levels o Endothelins o Prostaglandins o Thromboxanes o Angiotensin II o Aldosterone (ALDO) o Antidiuretic hormone (ADH) o Norepinephrine

Relationship of Blood Flow to Blood Pressure Gradients and Resistance • • • • •

Blood flow is equal to the pressure gradient divided by resistance Blood flow is directly related to the pressure gradient Blood flow is inversely related to resistance BP = (CO)(TPR) Blood volume is proportional to blood pressure

Factors that increase total blood flow ➢ Increased CO ➢ Vasodilation ➢ Reduction in vessel length ➢ Decrease in blood viscosity Factors that decrease total blood flow ➢ Decreased CO ➢ Vasoconstriction ➢ Increase in vessel length ➢ Increase in blood viscosity

Materials developed by Amy Lynn Gagliano [email protected]

4

Anatomy & Physiology II—Cardiovascular System: Blood Vessels

Materials developed by Amy Lynn Gagliano [email protected]

5

Anatomy & Physiology II—Cardiovascular System: Blood Vessels

Materials developed by Amy Lynn Gagliano [email protected]

6...