Bio 209 Ch 21

An interior opening which blood flows through

Tunica Interna (internal)

Tunica Media (middle)

Tunica Externa (external)

Contraction of the BV, causing a decrease in BV diameter

Widening of BV, causing increase of BV diameter

Conduct blood from heart to muscle arteries

Allows stretching and recoiling during during ventricular systole and ventricular diastole

Distribute blood throughout the body

Controls flow of blood by vasoconstriction and vasodilation

Deliver blood to capillaries

Regulate blood flow by changing resistance and controlling amount of blood entering capillaries

Regulate BP by vasoconstriction and vasodilation

Aorta

Pulmonary Trunk

Brachial Artery

Femoral Artery

Union of arterial branches that supply the same body region

Opposition of blood flow due to friction between blood and BV wall

Resistance increases & Blood flow decreases to capillaries

Resistance decreases and Blood flow increases to the capillaries

Precapillary sphincters into capillaries

Smooth muscle cell at the junction of a metarteriole and capillary

Contraction and relaxation of the smooth muscles either decreases blood flow or increases blood flow

Smallest blood vessels consisting of tunica interna with endothelial cells supported by a basement membrane

Exchange substances between blood and interstitial fluid

Body tissues that have higher metabolic rate (brain & kidneys) have more capillary networks

Flow of blood from a metarteriole through capillaries to postcapillary venules

Alternation contraction and relaxation of smooth muscles in metarterioles and precapillary spincters

Capillaries usually found in brain, muscles, connective tissues and lungs that diffuse substances through intracellular clefts

Capillaries usually found in kidneys, small intestines, choroid plexus of the brain and endocrine glands in which substances diffuse through intracellular clefts and fenestrations (small pores in capillaries)

Capillaries usually found in spleen, liver and pituitary that have large fenestration and intracellular clefts that allow proteins and sometimes blood cells to pass through

Pathway of blood is usually Hearth, Arteries, Arterioles, Metarteriole, Capillaries, Venules, Veins, Heart (HAAMCVVH)

Blood passes from one capillary bed to another by a portal vein

Because when atria relaxes, the pressure decrease causing blood to move from an area of higher concentration to lower concentration

Muscles help blood move through veins and venous valves prevent backflow of blood

Veins and Venules are examples of Blood Reservoirs

60% of blood (at rest) is found in Systemic Veins and Venules

• Diffusion: movement of substances from an area of high concentration to low concentration
• Transcytosis: movement of larger substances by endocytosis and exocytosis
• Bulk Flow: movement of large amounts of ions, molecules or particles in a fluid move together in the same direction from an area of high pressure to low pressure

• Blood Hydrostatic Pressure (BHP): pressure that blood exerts against the capillary walls
• Interstitial Fluid Osmotic Pressure (IFOP): force caused by proteins in interstitial fluid that are too large to pass through intracellular clefts or fenestrations (pulls fluids out of capillaries)

• Blood Colloid Osmotic Pressure (BCOP): force caused by proteins in plasma that are too large to pass through intercellular clefts or fenestrations (causes fluid to move into capillaries from tissues)
• Interstitial Fluid Hydrostatic Pressure (IFHP): pressure of water in interstitial fluid

• 85% is reabsorbed
• Remaining fluid enters lymph

• Excess filtration (due to high BP or increased permeability of capillaries)
• Inadequate reabsorption (due to decreased concentration of plasma proteins related to liver disease, malnutrition, burns, kidney disease)

Volume of blood that flows through any tissue per minute

Blood Pressure is the hydrostatic pressure of blood exerted on blood vessel walls

Contraction of ventricles

Highest BP in the arteries attained during ventricle systole

Lowest BP attained during ventricular diastole

Average BP in the arteries

• BP depends on the total volume of blood volume of the body
• - Decreasing BV causes a decrease in BP

Refers to all the vascular resistance of systemic BV

• - Diameter of BV
• - Blood viscosity
• - Total BV length

Volume of blood flowing from systemic venous vessels to heart

• - Veins have low resistance
• - Skeletal muscle pumps contract and move blood in veins toward heart (milking)
• - Respiratory pump contracts diaphragm

Blood flow is slowest where cross-sectional area is greatest - slowest in capillaries and gives time for substances to diffuse across capillaries

The time required for a drop of blood to flow through the pulmonary and systemic circulations

• - Receives input from higher brain and receptors
• - Integrates input and initiates output to effectors (heart & BV)

• In the case of High BP:
• - Frequency of impulses increases and sent to Medulla
• - Decreases HR and force of contraction, causing vasodilation
• - Decreased CO & SVR causes BP to decrease and returns to normal

• In the case of Low BP:
• - Frequency of impulses decreases and sent to Medulla
• - Increased HR and force of contraction, causing vasoconstriction
• - Increased CO & SVR causes BP to increase and returns to normal

A decrease in BP and blood flow to head caused by going from a prone to erect position

Renin produces Angiotensin II

Angiotensin II increases BP by vasoconstriction (increased SVR) and increases secretion of Aldosterone (increases BV by reabsorption of water and Na)

Increases HR and force of contractgion (increases CO) and causes vasoconstricion and vasodilation of arterioles of skin/abdominal organs and arterioles in skeletal muscles/heart

Increases BP by reduction of urine and causing vasoconstriction (increased SVR)

Reduces blood pressure by causing vasodilation (decreased SVR) and increases loss of water and salt in uring

Regulation of vasomotion to meet the metabolic demands of tissues

• Physical Changes:
• - Warming causes vasodilation
• - Cooling causes vasoconstriction
• - Myogenic response: stretching of BV walls causing forceful contractions

Vasodilating & Vasoconstricting chemicals released by tissue cells

State in which tissues don't receive enough O and nutrients to meet metabolic needs, caused by inadequate blood flow to tissues

Hypovolemic: caused by low BV (hemorrhage, diarrhea, vomitting)

Cardiogenic: caused by poor heart function (insufficient blood flow to tissues)

Vascular: caused by massive vasodilation

Obstructive: caused by obstruction of blood flow (blood clot)

Traveling pressure wave caused by the expansion and recoil of elastic arteries after ventricular systole

Device used to measure BP

Sounds heard when measuring BP with sphygmomanometer

Difference between systolic and diastolic pressure