In the large arteries, what is the function of the tunica media?
Large elastic muscular fibers. High pressure pipes with elastic recoil.
What is the function of the arterioles?
Very small muscular arteries that regulate the blood flow to various organs.
What is the function of the capillaries?
Very thin walled vessels that allow for the exchange of nutrients and wastes.
Name and describe the 3 types of capillaries
-Continuous: most common, least permeable
-Fenestrated: highly permeable, rapid filtration and absorption. (Kidneys, sm. Intestine)
-Sinusoidal: Biggest spaces, most so big that proteins can move through. (Liver, spleen, red bone marrow)
Compare veins with arteries
Layers: Same 3 layers as arteries
Walls: Thin and lumen is large
Valves: Paired (shirt pocket valves), to prevent back flow.
Numbers: Many more than arteries
Location: Both deep and superficial
Blood volume: 65% total blood volume is in the veins
Vascular compliance: High compliance, ability to stretch keeps pressure low.
What percentages are the distribution of blood?
Arteries and Arterioles: 15%
Veins and Venules: 65%
Heart and Lungs: 15%
As blood flows into a larger area, the rate of flow ___________.
Slows through capillaries.
The type of vessel with the largest cross-sectional area and therefore the slowest blood flow is the _____________.
In which vessel is the slowest pressure found?
Define peripheral resistance.
The opposition to blood flow.
Define Cardiac output.
The flow out of a ventricle of the heart per minute.
CO= SV x HR
Write an equation to describe the relationship between cardiac output, stroke volume, and heart rate.
CO= SV x HR
The major force that pushes ISF from the capillaries is _________.
The major force allowing ISF to be reabsorbed is __________.
The remaining ISF within the tissues after osmosis enter the _________________.
List 2 basic causes of Edema.
Capillary blood pressure too high.
Blood colloid osmotic pressure (BCOP) too low.
Describe how a decrease of plasma proteins may cause edema.
Because there is less fluid being returned to the capillary.
Decrease in BCOP = Increased edema
If venous return decreases, then cardiac output _______.
Venous pressure stays the same throughout the day.
Blood flow is proportional to need in most tissues.
The regulation of blood flow without the nerves or hormones.
Explain the role of the precapillary sphincter.
Smooth muscle band that contracts when there is an ample supply of oxygen to the capillaries.
Oxygen increase in the tissue will cause the precapillary sphincter to close, thereby increasing the blood flow to the tissues.
Define vasomotor tone.
The partial contraction of the arterioles and veins.
Where are vasoconstrictor fibers found?
All vessels, but most important in the nonvital organs.
What neurotransmitter is associated with the vasoconstrictor fibers?
The effect of widespread vasoconstriction on nonvital organs causes a ___________ in the blood flow to these organs.
When there is an increase in vasoconstriction, one would expect an ____________ in peripheral resistance and a ____________ in blood pressure.
If cardiac output decreases, mean arterial pressure will____________.
If vessel diameter decreases, peripheral resistence will ____________.
Increased viscosity of the blood will ___________ peripheral resistance.
The baroreceptor reflex controls BP by monitoring receptors found in the _____________. A decrease in parasympathetic stimulation of the heart causes an _____________ in peripheral resistance and therefore an _________ in BP.
Neck and aorta, Increase, Increase
List 2 adrenal medullary hormones and their effect on BP.
Norepinephrine and Epinephrine.
Increase BP (sympathetic stimulation)
Explain the chemoreceptor reflex.
Decreased O2 and Increased CO2 cause a decrease in pH, the central chemoreceptors react by increasing SV, HR, and vasoconstriction= Increase in BP. Chemoreceptors monitor O2 and CO2.
List 2 hormones that increase BP.
Aldosterone and ADH
Name a hormone that decreases BP.
Explain the fluid shift mechanism of BP regulation.
An increase in BP= an increase in ISF----> Decrease BV, Decrease BP
Describe Artherosclerosis and it's effect on BP.
Calcium and cholesterol deposits in Tunica media, which increase the PR=increase in BP=increase the workload on the heart and decrease the blood flow to the tissues.
List possible causes of circulatory shock.
Circulatory shock is inadequate CO. Cause could be hemmorhage or massive allergic reaction.
Source: Adrenal cortex
Stimulus: Decrease in NA+ or a decrease on BV.
Effect: Cause kidneys to retain salt and water--> decrease the production of urine--> Increase in BV, Increase in VR, Increase CO, Increase BP.
Source: Posterior pituitary
Effects: Cause the kidneys to retain water--> Increase BV, Increase BP, and also casue vasoconstriction which increase BP.
Atrial Natriuretic Hormone (ANH)
Source: Atria of the heart
Stimulus: Increase VR.
Effect: Causes kidneys to excrete salt and water--> Decrease BV, decrease VR, decrease CO, decrease BP.
List the 6 major classes of Nutrients
What are the functions of carbohydrates?
They are an energy source. There are 3 classes of Carbohydrates.
Monosaccharides: Glucose, Fructose, Galactose
Disaccharides: Double sugars
Polysaccharides: Complex carbohydrates
List the functions of triglycerides
They are an important source of ATP. Components are 3 fatty acids and a glycerol.
Functions are cell membrane fluidity, energy storage, and insulation.
List the functions of cholesterol.
Are used to synthesize the sex hormones and Aldosterone (control BP).
List the functions of phospholipids
They are 2 fatty acids bound with phosphorous.
Functions are to form the phospholipid bilayer of the cell membrane.
List the functions of the essential fatty acids.
Linoleic acid (omega 6)
Linolenic acid (omega 3)
Functions are cell membrane fluidity and synthesize prostoglandins for blood clotting.
What does essential refer to? Nonessential?
Essential means that it must be obtained in the diet. Nonessential means that the body can syntesize it.
Define complete protein. List examples.
Milk, meat, eggs, grains and bean. Foods which contain all essential amino acids.
Large complex organic molecules needed by body cells but not synthesized by cells, obtainable only by other living things.