Chapt. Object.

Figures & Tables

Trnspcy. Acetates

Masters

1

I. General Features of Blood Vessel Structure

1. Vessels Branch, but System is Continuous

2. Blood Flows

a. From Heart to Capillaries in Arteries and Arterioles

b. To Heart from Capillaries in Venules and Veins

A. Capillaries

Fig. 21.1, p.642

1. Structure

a. Endothelium

1). Single Sheet of Cells w/ Basement Membrane

2). Scattered Pericapillary Cells Inside of Basement Membrane

b. Adventitia

1). Connective Tissue

2). Outside of Basement Membrane

c. Size 7-9 m m Diameter

2. Types of Capillaries

a. Continuous Capillaries; Most Common Type

b. Fenestrated Capillaries - Glomerular Capillaries in Kidney

c. Sinusoidal Capillaries

1). Sinusoids of Liver and Bone Marrow

2). Venous Sinuses of Spleen

d. Substances are Transported Across Endothelial Cell Membranes

e. Substances Pass Through Fenestrae - 70-100 nm Diameter Holes

f. Between Adjacent Capillary Cells

3. Capillary Network

Fig. 21.2, p.643

TA-260

a. Metarterioles & Thoroughfare Channels

b. Smooth Muscle Cells and Precapillary Sphincters

B. Structure of Arteries and Veins

1. General Features - Layers of the Wall

Fig. 21.3, p. 644

TA-261

a. Tunica Intima

1). Endothelium

2). Lamina Propria

3). Internal Elastic Membrane

b. Tunica Media

1). Smooth Muscle

a). Contraction = Vasoconstriction

b). Relaxation = Vasodilation

2). External Elastic Membrane

c. Tunica Adventitia - Connective Tissue

2. Large Elastic (Conducting) Arteries

Fig. 21.4a, p.645

TA-262

3. Muscular (Distributing) Arteries

Fig. 21.4b, p.645

TA-262

1). Smaller - Diameter 40-300 m m

2). Involved in Vasodilation & Vasoconstriction

4. Arterioles

5. Venules (40-50 m m Diameter) and Small Veins (0.2 ñ 0.3 mm Diameter)

a. Small Veins - 0.2 - 0.3 mm Diameter

6. Medium-Sized and Large Veins

Fig. 21.4c, p.645

TA-262

7. Valves (in Veins of Diameter Greater than 2 mm.)

Fig. 21.4d, p.645; Clinical Note, p.646

TA-262

8. Vasa Vasorum of Tunica Adventitia and Tunica Media

Fig. 21.3, p.644

TA-261

9. Arteriovenous Anastomoses - Allow Direct Arterial to Venous Flow w/out Intervening Capillary

a. Physiological Role in Temperature Regulation

b. Pathological Condition Resulting from Some Tumors or Injuries

C. Nerves

Fig. 21.3, p.644

TA-261

1. Unmyelinated Sympathetic Fibers to Tunica Media of Most

2. A Few Also Receive Parasympathetic Fibers

3. Response to Sympathetic Stimulation is Generally Vasoconstriction

2

D. Aging of the Arteries

1. Arteriosclerosis - Loss of Elasticity

2. Atherosclerosis - Fatty Plaque Build-up

Fig. 21.5, p.647

3

II. Pulmonary Circulation

Fig. 21.6, p.648

TA-263

A. Single Pulmonary Trunk from R. Ventricle

B. Branches into Two Pulmonary Arteries

1. One to Each Lung

2. Carry Deoxygenated Blood to Lungs

C. Alveolar Capillaries = Site of Gas Exchange

D. Collect into Four Pulmonary Veins

1. Two from Each Lung

2. Carry Oxygenated Blood Back to Heart

4

III. Systemic Circulation: Arteries

Fig. 21.6, p.648; Clinical Focus, p.676

TA-263

A. Aorta

Clinical Note, p.647

1. From L. Ventricle

2. Regions

a. Ascending

1). 5 cm Length

2). 2.8 cm Diameter

3). Branches - R. and L. Coronary Arteries

b. Arch

c. Descending

1). Thoracic

2). Abdominal

3). Terminal Branches Give Rise to R. and L. Common Iliac Arteries

B. Coronary Arteries (Described in Chapter 20)

C. Arteries to the Head and Neck

Table 21.1, p.651

1. Branches off the Aortic Arch

Fig. 21.7, p.649

TA-264

a. Brachiocephalic A.

1). R. Common Carotid A.

2). R. Subclavian A.

b. L. Common Carotid A.

c. L. Subclavian A.

2. Blood Supply to the Head

Fig. 21.8, p.649; Predict Quest 1

TA-265

a. L. and R. Vertebral A.'s

b. Basilar A.

c. L. and R., Ant. and Post. Cerebral A.'s

d. Ant. and Post. Communicating A.'s

e. Cerebral Arterial Circle (Circle of Willis)

Fig. 21.8, p.649; Fig. 21.9, p.650

TA-265

TM-70

f. Sup. and Inf. Cerebellar A.'s

Clinical Note, p.651

D. Arteries of the Upper Limb

Table 21.2, p.652

1. Branches of the Subclavian A.

Fig. 21.10, p.652; Fig. 21.11, p.653

TA-266

TM-71

a. Axillary A.

b. Brachial A.

1). Ulnar A. - Medial

2). Radial A. - Lateral

2. Blood Supply to Hand

a. Supf. and Deep Palmar Arches

b. Digital A.

E. Thoracic Aorta and Its Branches

Table 21.3, p.653; Fig. 21.12a, p.654

TA-267

1. Visceral Branches

2. Parietal Branches

a. Intercostal A.'s

b. Sup. Phrenic A.'s

F. Abdominal Aorta and Its Branches

Table 21.3, p.653; Fig. 21.12b, p.654; Fig. 21.13, p.655

TM-72

1. Parietal Branches to Inf. Diaphragm and Abdominal Wall

2. Visceral Branches

a. Unpaired

Fig. 21.12, p.654

1). Celiac Trunk

2). Sup. Mesenteric A.

3). Inf. Mesenteric A.

b. Paired

Fig. 21.13, p.655

TM-72

1). Renal A.'s

2). Adrenal A.'s

3). Gonadal (Ovarian or Testicular) A.'s

G. Arteries of the Pelvis

Table 21.4, p.654;

Fig. 21.13, p.655; Fig. 21.14, p.656

TA-268

1. At Level of Fifth Lumbar Vertebra the Common Iliac A.'s Branch

2. Ext. Iliac A.'s Supply Lower Limbs

3. Int. Iliac A.'s

a. Visceral Branches

b. Parietal Branches

H. Arteries of the Lower Limb

Table 21.5, p.656;

Fig. 21.14, p.656; Fig. 21.15, p.657

TA-268

TM-73

1. Continuation of Ext. Iliac A. = Femoral A.

2. Popliteal A.

a. Ant. Tibial A. (Becomes Dorsalis Pedis in Foot)

b. Post. Tibial A. Becomes Fibular (Peroneal) A.

1). Med. Plantar A. w/ Digital Branches

2). Lat. Plantar A. w/ Digital Branches

5

IV. Systemic Circulation: Veins

Fig. 20.6c, p.608; Fig. 20.7b, p.609

TA-252; TA-253

1. Coronary Sinus from Cardiac Veins of Heart Muscle

2. Superior Vena Cava from Upper Body and Thorax

3. Inferior Vena Cava from Lower Body and Abdomen

Fig. 21.16, p.658

TA-269

A. Veins Draining the Heart (Chapter 20)

B. Veins of the Head and Neck

1. Int. Jugular Veins From Brain and Face

Table 21.6, p.659; Fig. 21.17, p.659; Clinical Note, p.656

TA-270

a. Venous Sinuses of Cranial Vault Formed by Spaces in Dura Mater

b. Combine into Int. Jugular V.

2. Ext. Jugular V.'s From Post. Head

3. Ext. Jugular V.'s Join Subclavian V.'s

4. After Int. Jugular V.'s Join Subclavian V.'s to Form Brachiocephalic Veins

Table 21.7, p.659; Fig. 21.18, & Fig. 21.19, p.660

TA-271

TM-74

C. Veins of the Upper Limb

Table 21.8, p.662; Fig. 21.20 & Fig. 21.21, p.661

TM-75

1. Branches of Axillary Vein

a. Continuous with Subclavian V.

b. After Passes Under Clavicle

2. Superficial Veins

a. Cephalic V.

b. Basilic V.

c. Median Cubital V. and Median Antebrachial V.

3. Deep Veins

a. Brachial V.

b. Branches

c. Radial V. - Lateral

d. Ulnar V. - Medial

D. Veins of the Thorax

Table 21.9, p.662; Fig. 21.22, p.663

1. Three Major Veins Empty into Superior Vena Cava

2. R. and L. Brachiocephalic V.'s

a. Int. Thoracic V.'s

b. Ant. Intercostal V.'s

3. Azygous V.

a. Hemiazygos V.

b. Post. Intercostal V.'s

E. Veins of the Abdomen and Pelvis

Table 21.10, p.663 Fig. 21.23, p. 664; Fig. 21.25, p.666

TM-76

1. Ascending Lumbar V.'s Continuous with Hemiazygos and Azygos V.'s

2. Paired Renal V.'s and Gonadal V.'s Empty Directly into Inferior Vena Cava

3. Common Iliac V.'s

a. Ext. Iliac V.'s from Limbs

b. Int. Iliac V.'s from Pelvis

4. Hepatic Portal System

Table 21.11, p.664 Fig. 21.24, p.665; Fig. 21.25, p.666

TA-272

TM-76

a. Carriers Blood from Capillaries of Most Abdominal Organs to Sinusoids in Liver

b. Hepatic Portal Vein to Liver

1). Sup. Mesenteric V.

2). Splenic V.

3). Inf. Mesenteric V.

4). Pancreatic V.

5). Gastric V.'s

c. Hepatic V.'s to Inferior Vena Cava

1). Central Veins

2). Cystic V.'s

F. Veins of the Lower Limb

Table 21.12, p.668 Fig. 21.26, p.667; Fig. 21.27, p.668

TM-77

1. Deep Veins

a. Ant. Tibial V.

b. Post. Tibial V. Receiving Paired Fibular (Peroneal) V.'s

b. Popliteal V.

c. Femoral V.

d. Ext. Iliac V.

2. Superficial Veins

a. Begin with Dorsal and Plantar Veins of Foot

b. Great Saphenous V. - Medial

c. Small Saphenous V. - Lateral

V. Lymphatic Vessels

Fig. 21.28, p.669

A. Lymph Capillaries

Fig. 21.29, p.670

1. Present in Most Tissues except CNS, Bone Marrow and Avascular Tissues

2. Lack a Basement Membrane

3. More Permeable than Blood Capillaries

6

B. Lymph

Fig. 21.30, p.670

TA-273

7

C. Lymph Vessels Resemble Small Veins

1. One-way Valves

2. Movement of Lymph

a. Skeletal Muscle Contractions - External Pressure

b. Contraction of Smooth Muscle in Vessel Wall

c. Pressure Changes in Thorax During Respiration

D. Lymph Nodes

1. Round, Oval or Bean-shaped Collections of Cells along Lymphatic Vessels

2. Filter the Lymph Before it is Returned to Circulation

7

E. Pattern of Lymphatic Drainage

Fig. 21.31, p.670; Fig. 21.28, p.669; Predict Quest. 2

1. Thoracic Duct

a. Empties into L. Subclavian V.

b. Drains Remaining Lymph Vessels

c. Abdominal Expansion Called the Cisterna Chyli

2. R. Lymphatic Duct

a. Empties into R. Subclavian V.

b. Drains Upper R. Quadrant

8

VI. Physics of Circulation

A. Laminar and Turbulent Flow in Vessels

1. Laminar Flow - Central Layer Moves Most Swiftly

Fig. 21.32a, p.671

2. Turbulent Flow

Fig. 21.32b, p.671

a. Occurs Primarily in Heart - Normal Situation

b. Produces Some Sound

c. Can Indicate Abnormal Constriction in Arteries

d. Increases Probability of Thrombosis Formation in Constricted Vessels

9

B. Blood Pressure

1. Force Exerted by Blood Against Vessel Walls - Measured in mm Hg

2. Direct Measurement by Cannulation

3. Indirect Measurement by Auscultatory Methods - w/in 10% of Accuracy of Direct Methods

a. Sphygmomanometer

Fig. 21.33, p.671

b. Korotkoff Sounds

1). Begin at Systolic Pressure

2). End at Diastolic Pressure

C. Rate of Blood Flow

Predict Quest. 3

1. Volume of Blood Moved per Unit Time

2. Directly Proportional to Pressure Difference

3. Inversely Proportional to Resistance to Flow

D. Poiseuille's Law

1. Flow Decreases when Resistance Increases

2. Vessel Factors Increasing Resistance to Flow

a. Decreased Vessel Diameter

b. Increased Vessel Length

E. Viscosity

Predict Quest. 3

1. Property of Fluid - Fluid's Own Resistance to Flow

2. Blood about 3 Times More Viscous than Distilled Water

3. Blood Viscosity Primarily Influenced by Hematocrit

4. Increased Viscosity of Blood Increases Workload on the Heart

F. Critical Closing Pressure and the Law of LaPlace

Formula, p.668

1. Minimum Blood Pressure to Keep Vessel from Collapsing

2. Law of LaPlace = Force on the Wall is Product of Diameter of a Vessel and the Pressure of the Vessel's Contents

a. Weakness in Vessel Can Lead to Aneurysms

b. Increased Diameter at Enlargement Increases Wall Pressure; Chance of Rupture Increases

G. Vascular Compliance

1. Tendency for Volume to Increase as Pressure Increases

Formula, p.669

2. Venous Compliance is About 24 Times Greater than Arterial Compliance

Table 21.13, p.672

10

VII. Physiology of Systemic Circulation

A. Cross-Sectional Area of Blood Vessels

Fig. 21.34, p.672

TM-78

1. Inverse Relationship Between X-Sectional Area and Velocity of Blood Flow

2. Capillaries Have Greatest Total x-Sectional Area and Therefore Lowest Velocity of Blood Flow

B. Pressure and Resistance

Clinical Focus, p.678

1. Arterial Pressure Varies with Cardiac Cycle

Table 21.14, p. 673

a. Highest Pressure (120 mm Hg) During Ventricular Systole

b. Lowest Pressure (80 mm Hg) During Ventricular Diastole

2. Pressure Falls Along Circulatory System

Fig. 21.35, p.674

TM-79

a. Drop Proportional to Resistance to Flow in the Vessels

b. Near 0 mm Hg in R. Atrium

C. Pulse Pressure

1. Numerical Difference Between Systolic and Diastolic Pressures (120 - 80 = 40 mm Hg)

2. Determined by

a. Stroke Volume (Direct Relation)

b. Vascular Compliance (Inverse Relation)

Predict Quest. 4

3. Pressure Waves in Arterial Tree

Predict Quest. 5

a. Correspond to Each Ventricular Contraction

b. Palpable in Arteries Near Surface such as Radial Pulse in Radial Artery of Wrist

11

D. Capillary Exchange

1. Movement of Nutrients and Wastes Primarily by Diffusion

2. Net Loss of Fluid from Plasma

Fig. 21.36, p. 675

TA-274

a. Blood Pressure Higher than Interstitial Fluid Pressure

1). Promotes Movement of Fluid Out of Plasma

2). Greatest Movement Out at Arteriolar End of Capillary Bed

b. Colloid Osmotic Pressure Higher in Plasma than in Interstitial Fluid

1). Promotes Movement of Fluid Into Plasma

2). Greatest Movement In at Venular End of Capillary Bed

c. Excess Fluid Either

Predict Quest. 6

1). Removed as Lymph

2). Builds up = Edema

12

E. Functional Characteristics of Veins

1. Cardiac Output Depends on Preload from Venous Return (Directly Proportional)

2. Venous Tone

a. Continual Partial Contraction of Smooth Muscle in Walls of Veins

b. Result of Sympathetic Stimulation

F. Blood Pressure and the Effects of Gravity

Predict Quest.7

1. Standing Upright Increases Arterial Blood Pressure in Feet by as Much as 90 mm Hg

2. Major Consequence is Edema

13, 15, 16

VIII. Control of Blood Flow in Tissues

Clinical Focus, p.680

A. Local Control of Blood Flow by Tissues

Table 21.15, p.677; Fig. 21.37, p.679

1. Blood Flow Proportional to Metabolic Needs of the Tissue

2. Functional Characteristics of the Capillary Bed

a. Increased Metabolism Causes

1). Increase in Vasodilator Substances [CO₂ , Lactic Acid, Adenosine, AMP, ADP, EDRF, K⁺, H⁺]

Fig. 21.37a, p.679

2). Decreased O₂ and Other Nutrients

b. Cyclic Relaxation of Metarterioles and Precapillary Sphincters = Vasomotion

Fig. 21.37b, p.679

1). Leads to Increased Blood Flow

2). Replenishes Nutrients and Removes Vasodila-tors

3. Autoregulation of Blood Flow

Predict Quest. 8

a. Maintenance of Constant Blood Flow Through Tissue Despite Changes in Arterial Blood Pressure

b. Same Cellular Mechanisms as for Vasomotion

4. Long-Term Local Blood Flow

Clinical Note, p.678

a. Long-Term Regulation Also Matches Flow to Metabolic Requirements of Tissue

b. Long-Term Increases in Metabolic Activity lead to Increased Diameter and Number of Capillaries in the Tissue

c. Lack of O₂ Leads to Increased Vascularization; High O₂ Leads to Decreased Vascularization

B. Nervous Regulation of Local Circulation

1. Coordinates Rapid Routing of Blood with Changes in Tissue Activity

2. Controlled by Sympathetic Division of ANS

Predict Quest. 9; Fig. 21.38, p.679

TA-275

a. Innervate Most Blood Vessels Except Capillaries, Precapillary Sphincters and Metarterioles

b. Vasomotor Center of Medulla Oblongata Tonically Active

c. Resultant Partial Constriction = Vasomotor Tone

1). Increased Vasomotor Tone = Vasoconstriction (Activation of a -Adrenergic Receptors)

2). Decreased Vasomotor Tone = Vasodilation

d. CNS Influences on Vasomotor Center

14, 15, 16

IX. Regulation of Mean Arterial Blood Pressure

Table 21.14, p.673

A. Mean Arterial Blood Pressure

1. About 100 mm Hg; Slightly Lower than Average of Systolic and Diastolic Pressures

2. MABP = CO x PR; or MABP = HR x SV x PR

B. Short-Term Regulation of Blood Pressure

1. Baroreceptor Reflexes

Fig. 21.39, p.681

TA-276

a. Sensory Receptors in Carotid Sinuses and Aortic Arch

b. Constant Low Level of Activity

1). Increased BP, Increases Baroreceptor Activity

a). Vasomotor Center Inhibited = Vasodilation

b). Cardioregula-tory Center Increases Para-sympathetic Stim. to Heart

2). Decreased BP, Decreases Baroreceptor Activity

a). Vasomotor Center Stimulated = Vasoconstriction

b). Cardioregula-tory Center Increases Sympathetic Stim. to Heart

Predict Quest. 10; Clinical Note, p.682

2. Adrenal Medullary Mechanism

1. Activated by Sympathetic Stimulation of Medulla
2. Medullary Hormones Affect Cardiovascular System

3. Chemoreceptor Reflexes

Fig. 21.40, p.683

Fig. 21.41, p.683

TA-277

TA-278

a. Sensory Receptors in Carotid Bodies and Aortic Bodies

b. Stimulated by Marked Decrease in O₂, Increased CO₂, Increased H⁺

c. Increased Chemoreceptor Activity Leads to Increased Vasomotor Tone

4. Central Nervous System Ischemic Response

Fig. 21.42, p.685; Fig. 21.43, p.686

TM-80

a. Important when Arterial BP Falls Below 50 mm Hg

b. Triggered by High CO₂ and High H⁺

c. Stimulates Vasomotor Center and Vasoconstriction

B. Long-Term Regulation of Blood Pressure

1. Renin-Angiotensin-Aldosterone Mechanism [Increases Blood Volume]

Fig. 21.44, p.687

TA-279

2. Vasopressin Mechanism [Increases Blood Volume and Vasoconstriction]

Fig. 21.45, p.688

TA-280

3. Atrial Natriuretic Mechanism [Decreases Blood Volume and Vasodilation]

Predict Quest. 11

4. Fluid Shift and the Stress-Relaxation Response

a. Both Help Compensate for Changes in BP Occurring Over Many Minutes

b. Fluid Shift Mechanism

1). Compensates for Dehydration Loss of Plasma Volume

2). Variable Movement of Fluid Between Blood Plasma and Interstitial Fluid

c. Stress-Relaxation Response

Fig. 21.46, pp.690-691

TM-81

1). Characteristic of Smooth Muscle Cells

2). Decrease in Stretch/ Tension Produces Increas-ed Contraction for Minutes to an Hour

3). Increase in Stretch/ Tension Produces Decreased Contraction for Minutes to an Hour

Clinical Focus, p.689

Clinical Focus, p.692