1. Blood Vessels

2. Types of Blood Vessels Arteries - ____________________________
Veins - _____________________
_________ - microscopic blood vessels that allow exchanges between blood and tissues

3. Differences between arteries and veins
Compared to veins, arteries
___________________
Have more smooth muscle and elastic fibers
_____________________

4. Vessel Structure - General
11/10/2018
All vessels same basic structure
3 wall layers (or tunics)
_____________(externa) - elastic and laminar fibers
____________
thickest layer
elastic fibers and smooth muscle fibers
__________________
endothelium – non-stick layer
basement membrane
internal elastic lamina
_____________________

5. Blood flow through tissues
From the heart blood flows into
___________
Arteries
Capillaries
Venules
____________
Superior/ Inferior Vena Cava
Back to the heart

6. Vessel Structure - Capillaries
11/10/2018
Allow exchange of nutrients and wastes between blood and tissue
_______________________
Basal lamina - connective tissue
Endothelial cells
Structure/function

7. Mechanisms of Exchange
____________ - major method used to exchange substances such as O2, CO2, glucose, and amino acids
Vesicular transport - endocytosis and exocytosis of lipid-insoluble molecules
Bulk flow - involves filtration and reabsorption

9. Veins _____________________
Have 3 distinct layers; thinner walled than arteries due to thin tunica interna and media
Varicose veins
____________________

10. Help for venous return ___________________ muscles squeeze veins
11/10/2018
Help for venous return
___________________
muscles squeeze veins
force blood back to heart
valves prevent back flow

11. Blood Flow
____________- is the amount of blood flowing through a tissue in a given period of time
Velocity of blood flow is inversely related to the diameter of the blood vessel
Blood flows most slowly in areas of greatest width

12. Blood Pressure
Force that the blood exerts against the walls of a blood vessels
Factors affecting BP include cardiac output, blood volume, viscosity, resistance, and the elasticity of the arteries

13. Peripheral Resistance
_______________________________________________________________________
Resistance affected by blood viscosity, vessel length and vessel radius

14. Sources affecting Resistance
Blood viscosity- how thick or thin the blood is. Measured by hematocrit.
_________________longer the vessel, the greater the resistance, the greater the BP
Vessel radius- _________________________________________________

15. Measuring Blood Pressure
______________________________________________
It is determined by the contractions of the heart
Your pressure varies depending on the condition of your heart and blood vessels
Pressure is measured in millimeters of mercury (mm Hg)

16. What is Blood Pressure
Blood pressure is the force that blood exerts against blood vessel walls.
______________________________________________________
Pressure occurs when the flow is met by resistance from blood vessel walls

17. Hypertension
The major factors which help maintain blood pressure (BP) include the sympathetic nervous system and the kidneys.
Optimal healthy blood pressure is a systolic blood pressure of <120 mmHg and a diastolic blood pressure of <80
________________
In most forms of hypertension, the hypertensive state is maintained by an elevation in blood volume, which in turn increases cardiac output by the Frank-Starling relationship.  Diuretic drugs, which enhance the removal of sodium and water by the kidneys and thereby decrease blood volume, are very effective in the treatment of hypertension. Hypertension is also commonly treated with drugs that decrease cardiac output. These cardioinhibitory drugs either block beta-adrenoceptors on the heart (i.e., beta-blockers) or L-type calcium channels (i.e., calcium-channel blockers), which decreases cardiac output by decreasing heart rate and contractility (inotropy). Vasodilator drugs, which decrease systemic vascular resistance, are also used to treat hypertension. Included in these drugs are alpha-adrenoceptor antagonists (alpha-blockers), direct-acting vasodilators, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. A complete list of drugs used to treat hypertension can be found by clicking here.
Primary hypertension accounts for approximately 90-95% of patients diagnosed with hypertension. Unlike secondary hypertension, there is no known cause of primary hypertension. Despite many years of active research, there is no unifying hypothesis to account for the pathogenesis of primary hypertension. There is a natural progression of this disease that suggests early elevations in blood volume and cardiac output might initiate subsequent changes in the systemic vasculature (increased resistance). This has suggested to some researchers that a basic underlying defect in many hypertensive patients is an inability of the kidneys to adequately handle sodium. Increased sodium retention could then account for the increase in blood volume.  In chronic, long-standing hypertension, blood volume and cardiac output are often normal, therefore the hypertension is sustained by an elevation in systemic vascular resistance rather than by an increase in cardiac output. This increased resistance is caused by a thickening of the walls of resistance vessels and by a reduction in lumen diameters. There is also evidence for increased vascular tone. This could be mediated by enhanced sympathetic activity or by increased circulating levels of angiotensin II. In recent years, considerable evidence has suggested that changes in vascular endothelial function may cause the increase in vascular tone

18. Hypertension Category Systolic Blood Pressure Diastolic Blood Pressure
Normal
__________
Pre-hypertension
80-89
Hypertension – Stage 1
___________
____________
Hypertension – Stage 2
>160
>100

19. Hypertension
Approximately one in four American adults has hypertension.
As many as 2.8 million children also have high blood pressure.
_____________________________________________________________

20. Prevalence of Hypertension by Age
18-29
30-39
40-49
50-59
60-69
70-79
80+
% Hypertensive 4 11 21 44 54 64 65
Can you see that age is a risk factor?

21. Factors Influencing the Development of Hypertension
________________________
Family history of hypertension
African-Americans have a greater prevalence of hypertension (38% men; 39% of women) than non-Hispanic whites (33% of men; 25% women).
The risk of developing elevated BP is 2-6 times higher in overweight than in normal-weight individuals.
Weight management is a treatment for HBP.
Prevalence of of Hispanic population is similar to the non-Hispanic whites.

22. Factors Influencing the Development of Hypertension
________________________________
Certain segments of the population are ‘salt sensitive’ because their blood pressure is affected by salt consumption
Epidemiological studies of populations support the role of salt in the develop of HBP.
Approximately 30-50% of Hypertensive individuals and ~ 25% normotensive individuals are salt sensitive.
Hypertension and stroke is the leading cause of death in countries with very high salt consumption (9-12 g/day).

23. Factors Influencing the Development of Hypertension
_____________
Cholesterol Levels
______________
Smoking
5-7% of the hypertension
in the population is due to alcohol consumption. Three drinks a day is the threshold for raising BP.

24. Factors Influencing the Development of Hypertension
_________________
Less active individuals are 30-50% more likely to develop hypertension.
In the Framingham Study, medium to high levels of activity were protective against developing stroke.

25. Factors Influencing the Development of Hypertension
Other Dietary Factors
Potassium:
Calcium:
Magnesium:
Other Dietary Factors
Potassium:
In population studies, dietary potassium and blood pressure are inversely related. High potassium intakes are associated with lower BP.
Calcium:
In the Nurse’s Health Study, consuming the RDA for calcium resulted in lower risk of developing hypertension than consuming lower levels (400 mg/day).
Magnesium is a potent inhibitor of vascular smooth muscle contraction and may play a role in blood pressure regulation as a vasodilator.

26. Treatment for Hypertension
Maintain a healthy weight, lose weight if overweight.
_____________________
_______________________________________________________________
Reduce the intake of salt and sodium in the diet to approximately 2400 mg/day.
The relationship between obesity and BP appears to be linear and exists throughout the non-obese range. But the strength of the association of obesity with hypertension varies among different racial and ethnic groups. Generally, risk estimates suggest that approximately 75 and 65 percent of the cases of hypertension in men and women, respectively, are directly attributable to an overweight condition and obesity.
Most Americans consume about 4, ,000 mg sodium/day.

27. Systolic Pressure
Systolic pressure is the maximum pressure exerted by the blood against the artery walls.
____________________________________
Normally, it measures 120 mm Hg.
Systolic

28. Diastolic Pressure
_____________________________________________________________________________
It result when the ventricles are relaxed and is usually around 80 mm Hg.
Diastolic