CV 2 Flashcards
Describe the general anatomy of the vascular system to the general anatomy of the vessels.
Arteries- transport blood under high pressure
Arterioles- regulating conduits
Capillaries-Nutrient exchange
Venules-Collect blood from capillaries
Veins- Conduits for blood back to the heart
How does this anatomy (arteries and veins) vary across different types of blood vessels? tunica intera squamous epithelium tunica media tunica externa
Tunic interna- inner layer, composed of simple squamous epithelium, plus a basement membrane
Tunic media- middle layer; composed largely of smooth muscle tissue, site of inflammatory injury leading to plaque
Tunica externa- outer layer; composed of connective tissue
How are these anatomic differences related to the function of the vessel? arteries arterioles capillaries venules veins
Arteries- have all three layers
Arterioles- smooth muscle, epithelial layer
Capillaries- only epithelial layer
Venules- epithelial and fibrous tissue
Veins- epilital,elastic tissue, Smoother muscle, and fibrous tissue, larger crossetional area than arteries
How does velocity and pressure change as blood goes from the left ventricle to the right atria?
The velocity and pressure is high when pumping through the heart due to the force generated by LV systole, but as blood moves through the capillary beds, the velocity and pressure diminishes.
What is the major function of elastic arteries? Explain the phrase “pressure reservoir”
Allow stretch as blood is pumped into them and recoil when ventricles relax, maintains blood flow during diastole. Pressure reservoirs maintain blood flow through the tissues during ventricular diastole.
What type of vessel offers the greatest resistance to blood flow? Can this resistance be altered?
Arterioles have the greatest resistance to blood flow. Resistance can be altered by vasoconstriction and vasodilation by the band of smooth muscle in walls of arterioles.
The venous side of circulation is a low pressure side of circulation. What does this mean in terms of blood flow? Explain venous return.
A. Skeletal muscle pump- muscles surrounding the veins help pump blood.
B. Venous valves- ensure one-directional flow of blood.
C. Breathing- inhalation increases abdominal cavity pressure in relation to thoracic pressure creates a pressure gradient which moves blood toward heart.
D. Contracting atria- pulls blood into atria
Explain the different anatomical types of capillaries and link their anatomy to their function.
Continuous capillaries
Fenestrated capillaries
Discontinuous capillaries
a. Continuous capillaries- adjacent cells are close together; found in capillaries in muscles, adipose tissue, and CNS (Forces control mechanisms to move materials into or out of the capillaries. Add to blood-brain barrier)
b. Fenestrated capillaries- have pores in vessel walls and small gaps between cells; found in kidneys, intestines, and endocrine glands (openings periodically along the wall to allow materials to move out of the capillaries to the interstitial fluids and back)
c. Discontinuous- have huge gaps between cells; found in bone marrow, liver, and spleen; (allow passage of proteins)
How does the anatomy of the veins allow the venous system to function as a reservoir for blood. Is blood stored in the venous side of circulation?
Thinner walls than arteries, larger lumen = low pressure. Yes, blood is stored in the venous side of circulation. At rest, 60% of blood in the body is in the veins.
Why is the venous side of circulation a low pressure system?
Low pressure due to their structure (thin, less muscular walls) and the movement of blood against the force of gravity
How is cardiac output redirected in order to meet changing tissue O2 needs?What mechanisms control these changes?
Inc HR, Inc SV, ∆P, Inc venous return, sympathetic input, and increased blood volume will increase blood flow
Explain the phrase “The distribution of CO is often predicated on tissue/O2 need”. Which organs are not following this rule?
Blood flow to heart and muscle is dependent on immediate need. Except to the brain, kidney, and liver.
Explain the relationship between radius of the arterioles and redistribution of cardiac output.
Vasoconstriction of arterioles reduces blood flow. Vasodilation of arterioles increases blood flow.
Define ischemia
Ischemia is when the function of blood flow becomes compromised and causes a restriction in blood flow that will result in an oxygen shortage.
In order to maintain the same blood flow in vessels that has narrowed (↓ r), what characteristic of blood flow has to be changed?
Changes in blood pressure is needed to maintain flow in the face of decreased radius.
↓in r = ↑ in BP
What is blood vessel compliance?
The ability of any compartment to expand to accommodate increase content
What mechanism compensates for a reduction in vascular compliance?
–Reduced compliance increases resistance to blood flow and, if not compensated, reduced blood flow.
-Blood pressure increases as compliance decreases
Provide a definition of blood pressure
-The force of your blood pushing against the walls of your arteries
How does vasoconstriction and vasodilation affect blood pressure?
Vasoconstriction causes Blood Pressure to INCREASE
Vasodilation causes Blood Pressure to DECREASE
How would the radial pulse feel to you in an individual who has a blood pressure of 120/60 mmHg versus that of a person who has a blood pressure of 100/70 mmHg?
-The pulse would feel stronger and quicker
Describe mechanisms of extrinsic regulation of blood flow.
Arterioles innervated by sympathetic fiber. These fibers release mainly Norepinephrine at the terminal synapse which bind to alpha-adrenergic receptors. Which causes smooth muscle to vasoconstriction.
Explain mechanisms of local regulation of blood flow.
Metabolic factors??
-Extrinsic: Arterioles innervated by sympathetic fibers. Causing smooth muscle contraction
-Intrinsic: Autoregulation or localized regulation of arteriolar smooth muscle
> Myogenic control mechanism: vascular smooth muscle directly responds to changes in arterial BP (decrease in BP to the brain→ vessel dilation and inc BF) (increase in BP to the brain→ vessel constriction and dec BF)
Metabolic Factors: Lactic Acid Decreased PO2 ADP CA2+ NO
What is edema and what are possible causes of it?
Excessive accumulation of interstitial fluids. Caused by high blood pressure, venous obstruction, leakage of plasma proteins into interstitial space
Provide a brief description of the anatomy of the lymphatic system.
Lymphatic vessels found throughout the body. The spleen, thymus, and tonsils are organs associated with the lymphatic system.
What is the function of the lymphatic system?
Transport excess interstitial fluid from issues to the veins thus returning this fluid to the circulation. Transports proteins from the interstitial fluid. 2/3ds of the lymph comes from the liver and intestine.
Obstruction of lymphatic vessels can result in what?
Lymphedema: swelling due to the blockage of lymphatic vessels
