Ch.21 questions Flashcards
What are the 3 tissue layers that usually make up the wall of blood vessel?
-Tunica internal (innermost, adjacent to lumen)
-Tunica media (middle, smooth muscle, and elastic fibers)
-Tunica external (outermost, adjacent to surrounding tissue)
What is the advantage of such a thin wall in capillaries?
allow oxygen and nutrients to pass from the blood into tissues and allow waste products to pass from tissues into the blood.
Which as the thicker wall?
Tunica media
Which has more elastic tissue?
Tunica media
What does a vein have that an artery does not have?
a valve
What is the advantage of an artery?
Allows them to absorb the pressure created by ventricles of the heart as they pump blood into the arteries, can regulate their diameter
What are the 2 extra layers of elastic tissue found in arteries, but not in veins?
Elastic arteries (conducting arteries) and muscular arteries (disturbing arteries)
Which has a larger diameter?
Elastic arteries
How do they differ in function?
Elastic arteries function as pressure reservoirs. Muscular arteries function to distribute blood to various parts of the body.
What are the two significant structural features that enhance this function?
Thin layers and are smallest in diameter
What are the three types of capillaries?
Continuous capillaries (no holes), fenestrated capillaries (little pores), sinusoid capillaries (big holes, basement membrane is incomplete, many can easily get out, red bone marrow)
What is the difference in structure?
Many of them don’t have any pores or holes, while others have larger holes and an incomplete base membrane
Which type is the most common?
Continuous capillaries
Which type is found in the red bone marrow? What is the advantage of having this type of capillary in red bone marrow?
Sinusoid capillaries, since it has an incomplete basement membrane, and it has bigger holes where substances can move faster
What are some examples of substances that are transported this way?
Lipid soluble, glucose, amino acids, oxygen, and carbon dioxide
What two types of cytosis are involved in transcytosis?
endocytosis and exocytosis
What are some examples of substances that are transported in this way?
lipid insoluble molecules (insulin)
Which two of these pressures is more important?
reabsorption (blood hydrostatic pressure)
What happens to the remainder of the fluid?
it will get absorb by the capillaries of the lymphatic system, which will recirculate again to the blood plasma
What is filtration?
is pressure driven movement of fluid and solutes from blood capillaries into interstitial fluid
What is reabsorption?
is pressure driven movement of fluid and solutes from interstitial fluid into blood capillaries
What are the factors that affect SVR?
Blood viscosity, vessel length, and vessel diameter
What is the typical blood pressure of a healthy resting adult?
120/80
What is the typical mean arterial blood pressure of a healthy resting adult?
60 mm Hg- 100 mm Hg
Does a larger lumen or a smaller lumen provide more resistance?
smaller
Does more viscosity or less provide more resistance?
more
does longer or shorter total blood vessel length provide more resistance?
longer
what are the three factors that assist venous return?
skeletal muscle pump, valves, and respiratory pump
what is the advantage of blood moving more slowly through capillaries?
allows time for exchange of gases and nutrients
Where is the CV center in the brain?
medulla oblongata
what structures provide input to the CV center?
cerebral cortex, limbic system, and hypothalamus
what effectors receive output from the CV center?
Vagus nerves, cardiac accelerator, and vasomotor nerves
how does the sympathetic system affect the heart?
increases rate and contractility
how does the parasympathetic system affect the heart?
decreases heart rate
