Cardiovascular l Flashcards
Which take blood away from the heart, arteries or veins?
Arteries
Which take blood towards the heart, arteries or veins?
Veins
Name the external layer of the venous circuit (large vein)?
Tunica externa
Name the middle smooth muscle layer of the venous circuit (large vein)?
Tunica media
Name the inner layer of the venous circuit (large vein)? This area has 3 of its own layers (Elastin, endothelium, proteins, etc).
Tunica interna
Why does the venous system contain most of the blood in the body?
Contains most of the blood to function as a reservoir from which more blood can be added to the circulation under appropriate conditions (such as exercise). For example, during exercise, there is an increased metabolic demand, and so blood is moved from the venous to arterial pathways).
In greatest to least order, describe the distribution of blood in the body.
Systemic veins, Lungs/Systemic arteries, Heart, Capillaries
Systemic veins: 60-70%
Systemic arteries: 10-12%
Lungs: 10-12%
Heart: 8-11%
Capillaries: 4-5%
Most of the blood volume is in the ______ system.
Venous
Unlike arteries, which provide _______ to the flow of blood from the heart, veins are able to ________ as they accumulate addition amounts of blood (capacitance vessels).
Resistance, expand
What is the average pressure in veins vs arteries?
Veins : 2 mmHg
Arteries: 100 mmHg
The venous press is too low to return blood to the heart. To help veins of the lower limbs return blood, the veins pass between skeletal muscle groups which provide _______ to help move the blood back. What is this described as?
Contractions. This is known as the “skeletal muscle pump”. As the muscle contracts, blood is massaged up the vein to bring it to the heart. This is a one way valve, blood does not go back down due to gravity.
Describe the mechanism used by the veins to help venous blood from the abdominal and thoracic regions return to the heart.
To help the venous blood from the abdominal to thoracic regions, the act of breathing: contraction of the diaphragm and pressure in the abdomen from breathing squeezes the veins and helps the venous blood return to the heart.
What helps to ensure the one-way flow of blood back to the heart?
Venous valves
Describe the phenomenon of varicose veins.
- Decreased movement in the leg
- Less skeletal movement pump
- Blood stays in the limb
- 1 way valves pull apart not as well working
- Clots develop
- Cannot deliver nutrients as well - dead tissue
In the aorta, the major artery of the heart, and other larger arteries, there are numerous layers of elastin fibres between the smooth muscle cells of the ____________ (middle layer).
Tunica media
The large elastic artieries (found in the aorta and other large arteries) _________ when the pressure of the blood rises as a result of the ventricles’ contraction.
Expand. They expand with increasing levels of blood.
Describe the activity of blood in the arteries when the level of blood increases and decreases.
The large elastic arteries expand when the pressure of blood rises as a result of ventricles’ contraction. The arteries recoil like a stretched rubber band when the blood pressure falls during relaxation of the ventricles.
The elastic recoil of the arteries drives blood during the ______ phase when the heart is resting and not providing pressure.
Diastolic.
There are over _______ capillaries in the body.
40 billion
Capillaries provide a total surface area of ___________ for exchanges between blood and interstitial fluid.
1000 square miles
________ decreases blood flow to the capillary bed, _________ increases it.
Vasoconstriction decreases blood flow to the capillary bed, vasodilatation increases it.
Unlike the arterial and venous tissues, the walls of the capillaries are composed of how many cell layers?
One cell layer
A lack of SM and CT makes it ______ to exchange materials between blood and tissues.
Easier
At the arterial end of capillaries what enter? What exits the venous end of capillaries?
At the arterial end of arteries, oxygen, nutrients, hormone, small molecules, etc enter at approximately 37 mmHg. At the venous end of the capillaries, carbon dioxide and wastes exit the capillary at approximately 17 mmHg.
Describe the difference between net filtration pressure and net oncotic pressure.
Net filtration pressure describes the difference in hydrostatic pressure. Net oncotic pressure describes the difference is osmotic pressure.
At the arterial end of a capillary, blood pressure forces fluid out of the capillary to the fluid _____________. At the venous end, fluid is drawn back into the capillary from neighbouring tissue cells by ________.
Surrounding the tissue cell, by osmotic pressure
Describe the location of blood pressure in decreasing order from highest to least blood pressure in the areas of the heart.
Left ventricle, large arteries, small rates and arterioles, Capillaries, venues, large veins
Blood flow is a representation of driving forces / __________.
Resistance
________________, a 19th century physician helped with the discovery of blood flow.
Jean Leonard Marie Poiseuille
Resistance in blood flow depends on three major factors. List them.
- Tube/blood vessel radius
- Viscosity of the blood
- Tube/blood vessel length
Describe the trend associated with blood flow and vessel radius.
Lower radius = higher resistance = less blood flow
Increased radius = less resistance = more blood flow
How is vessel radius regulated in the heart?
By smooth muscle contraction. Smooth muscle contraction lowers the radius of the blood vessel and lowers blood flow
Describe the trend associated with blood flow and blood viscosity.
Higher viscosity = higher friction = higher resistance = decreased blood flow
Lower viscosity = less friction = less resistance = increased blood flow
Increased hematocrit (%of volume plasma in red blood cells) = higher interaction between RBCs = higher clots = higher blood clots = decreased vessel radius = decreased blood flow
Describe the trend associated with blood flow and vessel length.
Increased length = increased friction = increased resistance = decreased blood flow
Decreased length = decreased friction = decreased resistance = increased blood flow
Describe the distribution of blood within the circulatory system at rest.
Review slide 28.
Where does gas exchange occur?
Capillary beds of the lungs and all body tissues.
The ______ carries de-oxygenated blood to the hearts right atrium.
Vena cava
Which vein carries highly oxygenated blood to the heart?
Pulmonary veins
Describe the uniqueness to do with the pulmonary artery and pulmonary vein.
The pulmonary artery is an artery with low O2 but is still considered an artery because it is travelling AWAY from the heart. The pulmonary vein is a vein that carries oxygenated blood to the blood, but it still considered a vein because it carries blood TO the heart.
Put these terms in order according to air passageways.
Bronchus
Oral cavity
Pharynx
Larynx
Nasal cavity
Trachea
Lung
- Nasal cavity
- Oral cavity
- Pharynx
- Larynx
- Trachea
- Bronchus
- Lung
Review slide 30
The nasal cavity leads to the _____ (throat), a nasal passage connecting the nasal cavity with the larynx.
Pharynx
The larynx is where air is diverted towards the _______ and food is diverted to the esophagus to the _______.
Lungs, stomach
Where are the vocal cords located?
The larynx. These are folds in the lining tissue of the larynx.
What are the two main functional zones of the respiratory system?
The conducting zone and the respiratory zone.
List some functions of the conducting zone of the respiratory system.
- No gas/air exchange
- Humidifies, warms , and transports air to the lungs and then out