Vessels and Capillary Exchange Slideshow Flashcards
Carry blood away from ventricles of heart
Arteries
Receive blood from arteries
Carry blood to capillaries
Arterioles
Sites of exchange of substances between blood and body cells
Capillaries
Receive blood from capillaries
Venules
Carry blood toward ventricle of heart
Veins
Thick strong wall
Endothelial lining
Middle layer of smooth muscle and elastic tissue
Outer layer of connective tissue
Carries blood under relatively high pressure
Artery
Thinner wall than artery
Endothelial lining
Some smooth muscle tissue
Small amount of connective tissue
Helps control blood flow into a capillary
Arterioles
Smallest diameter blood vessels
Extensions of inner lining on arterioles
Walls are endothelium only
Semipermeable
capillaries
Uninterrupted layer around capillary
Muscle and nervous tissue
Continuous
Endothelial cells is pierced with a pore
Intestines and kidney
Fenestrated
Wider with opening that allow transport of larger material such as proteins
Bone marrow, liver, spleen
Sinusoids
Sites where two or more arteries (or veins) merge to supply the same body region.
Provide alternative blood supply routes to body tissues or organs.
More vein anastomosis than arteries.
anastomosis
are capable of vasodilation and vasoconstriction, and regulate the flow of blood to capillaries through the precapillary sphincter.
arterioles
Thinner wall than arteriole
Less smooth muscle and elastic tissue than arteriole
Venule
Thinner wall than artery
Three layers to wall but middle layer is poorly developed
Some have flaplike valves
Carries blood under relatively low pressure
Serves as blood reservoir
vein
blood volume systemic veins
60-70%
blood volume lungs
10-12%
blood volume heart
8-11%
blood volume systemic arteries
10-12%
blood volume capillaries
4-5%
Blood supply to the heart:
Right coronary artery
Posterior interventricular artery
Ventricular walls
Cardiac veins
Coronary sinus
Right atrium
aorta
Blood supply to the heart:
Walls of right atrium and right ventricle
Cardiac veins
Coronary sinus
Right atrium
Marginal artery
Blood supply to the heart:
Circumflex artery
Walls of left atrium and left ventricle
Cardiac veins
Coronary sinus
Right atrium
Left coronary artery
Blood supply to the heart:
Ventricular walls
Cardiac veins
Coronary sinus
Right atrium
Anterior interventricular artery
Factors influencing BP: Peripheral Resistance
Blood viscosity
RBC count, albumin
Vessel Length
Vessel Radius
Autonomic effects
Viscera vs. skeletal/cardiac
Controlling cardiac output and peripheral resistance regulates blood pressure
control of low BP
If blood pressure rises, baroreceptors initiate the cardioinhibitory reflex, which lowers the blood pressure
control of high BP
Movement of substances between blood and interstitial fluid
3 basic methods:
1. Diffusion
2. Transcytosis
3. Bulk Flow
capillary exchange
Most important method
Substances move down their concentration gradient
O2 and nutrients from blood to interstitial fluid to body cells
CO2 and wastes move from body cells to interstitial fluid to blood
Can cross capillary wall through intercellular clefts (fenestrations) or through endothelial cells
Large proteins cannot cross
capillary exchange diffusion
Small quantity of material
Substances in blood plasma become enclosed within pinocytotic vesicles that enter endothelial cells by endocytosis and leave by exocytosis
Important mainly for large, lipid-insoluble molecules that cannot cross capillary walls any other way
capillary exchange transcytosis
Passive process in which large numbers of ions, molecules, or particles in a fluid move together in the same direction
Based on pressure gradient
Diffusion is more important for solute exchange
Bulk flow more important for regulation of relative volumes of blood and interstitial fluid
Filtratuon - from capillaries into interstitial fluid
Reabsorption - from interstitial fluid into capillaries
capillary exchange bulk flow
Arterial end net filtration pressure = + 10 mm Hg
Fluid exits capillary since capillary hydrostatic pressure (35 mm Hg) is greater than blood colloidal osmotic pressure (25 mm Hg)
filtration
Mid capillary net filtration pressure = 0 mm Hg
No net movement of fluid since capillary hydrostatic pressure (25 mm Hg) = blood colloidal osmotic pressure (25 mm Hg)
No net movement
Venous end net filtration pressure = - 7 mm Hg
Fluid re-enters capillary since capillary hydrostatic pressure (18 mm Hg) is less than blood colloidal osmotic pressure (25 mm Hg)
reabsorption
Sedentary life + vigorous exercise =
death
Increased myocardial mass
Increased stroke volume
Decreased heart rate
Thick ventricles
No extra risk when exercising
Effects of being fit (regular exercise)
what is regular exercise?
Heart rate elevated to 70-85% of maximum for 30 minutes, 3 times a week
Maximum equals 220 minus age
