Bio. Ch. 8

List the order blood travels through the vessels. Starting with the vessels that take blood away from the heart. (Include arterioles and venules).

Left side of the heart, arteries, arterioles, capillaries, venules, veins, right side of the heart

Which vessel has the thickest walls? Are they under high or low pressure?

Arteries, carries blood away from the heart, transports blood under high pressure

Which vessel has very large lumens and thin walls? Are they under high or low pressure?

Veins, returns blood to the heart, transports blood under low pressure

Which vessel only has one layer to optimize its ability to allow diffusion to and from the blood?

capillaries

What are the three layers of arteries?

1. Innermost layer: endothelium composed of simple squamous epithelial

2. Middle layer: smooth muscle

3. Outer layer: connective tissue

Which vessel contains precapillary sphincters to regulate blood flow?

arterioles

Vasoconstriction

Contraction of vascular smooth muscle; Decreases blood flow to capillaries

Vasodilation

Relaxation of vascular smooth muscle; Increases blood flow to capillaries

Does Vasoconstriction allow blood flow?

No, it decreases blood flow

Which vessel is porous?

capillaries

Where is interstitial fluid located?

surrounding cells

What are the three functions of lymphatic vessels?

1. Maintains blood volume

2. Returns excess interstitial fluid to circulatory system

3. Also functions in immune defenses

Explain the structure of lymphatic vessels

- Blind-ended capillaries- Lymphatic vessels (similar to venous system)

- Lymph—derived from interstitial fluid

Why are lymphatic vessels like the venous system?

Both have thin walls, rely on valves to prevent backflow of fluid, and function to return fluid from tissues back to the bloodstream; both systems transport fluid in a low-pressure environment

Which cardiovascular system vessel contains valves?

veins

Describe the features of veins.

Three layers, thin-walled; Larger lumen than arteries; High distensibility; Low Pressure

Which vessels act as a blood reservoir?

Veins

The venous system (venules and veins) is a very low-pressure system, how does the body overcome this low pressure and gravity, to return blood back to the heart? (3 mechanisms).

1. Contraction of skeletal muscles

2. One-way valves permit only one-way blood flow

3. Pressure changes associated with breathing push blood toward the heart

What is the pericardium?

fibrous sac surrounding the heart that protects and anchors it

What are the three layers of the heart?

Epicardium, Myocardium, Endocardium

Epicardium

thin layer of epithelial and connective tissue

Myocardium

thick layer of cardiac muscle (electrical signals flow from cell to cell; layer that contracts when the heart beats)

Endocardium

thin layer of endothelial tissue

What are the two lower chambers of the heart?

Ventricles

What are the two upper chambers of the heart?

Atria

Name the structure that divides the two lower chambers of the heart.

Septum: muscular partition separating right and left sides of the heart

Which two valves are between the atria and ventricles?

Atrioventricular (AV) valves

Which valves are between the ventricles and the outside of the heart?

Semilunar valves

What are the other two names for the left atrioventricular valve?

Bicuspid or mitral valve

What is the other name for the right atrioventricular valve?

Tricuspid valve

Can gas exchange happen in the bronchioles?

no

What are the two circuits of the heart?

Pulmonary circuit (lungs) and Systemic circuit (rest of the body)

What side of the heart is the pulmonary circuit? What side of the heart is the systemic circuit?

Pulmonary: right side

Systemic: left side

Where is the heart pumping the blood to in the pulmonary circuit? What will happen to the oxygen and carbon dioxide content in the blood?

the heart pumps blood to the lungs through the pulmonary arteries, where the blood picks up oxygen and releases carbon dioxide, meaning the oxygen content in the blood will increase while the carbon dioxide content decreases

Where is the heart pumping blood to in the systemic circuit? What will happen to the oxygen and carbon dioxide content in the blood?

the heart pumps oxygenated blood from the left ventricle to the rest of the body through the aorta; the oxygen content in the blood decreases while the carbon dioxide content increases as it moves through the systemic circuit

Track the blood in the Pulmonary Circuit. Start with the Vena Cava and end with the Pulmonary Veins. Note the valves the blood passes through in the heart.

(Deoxygenated blood) vena cava -> right atrium-> right AV valve -> right ventricle-> pulmonary semilunar valve -> pulmonary trunk ->pulmonary arteries ->lungs-> (oxygenated blood) pulmonary veins ->left atrium

Track the blood in the Systemic Circuit. Start with the Left Atrium and end with Vena Cava. Note the valves the blood passes through in the heart.

(Oxygenated blood) left atrium-> left AV valve-> left ventricle-> aortic semilunar valve -> aorta-> arteries + arterioles-> tissues-> venules + veins-> vena cava -> right atrium

How many times does blood pass through the heart for every trip around the body?

Blood passes through heart twice for every one trip around the body

What vessels supply the myocardium with nutrient rich blood? What vessels drain deoxygenated blood from the myocardium?

Coronary arteries; coronary veins

Describe Diastole. What valves are open and which are closed?

Both atria and ventricles relax; Semilunar valves close; AV valves open

Describe Atrial Systole. What valves are open and which are closed?

Both atria contract; AV valves open, semilunar valves are closed; Ventricles fill

Describe Ventricular Systole. What valves are open and which are closed?

Both ventricles contract; AV valves close; semilunar valves open

What do the heart sounds represent?

Lub-dub

What does the "Lub" sound represent? Which stage of diastole or systole does this occur?

Closing of both AV valves during ventricular systole

What does the "Dub" sound represent? Which stage of diastole or systole does this occur?

Closing of both semilunar valves during ventricular diastole

What is a heart murmur and what can it be a sign of?

Caused when blood flow is disturbed; May be a sign of a defective valve

Where is the Sinoatrial node (SA node)?

small mass of cardiac cells in upper right atrium

What does the Sinoatrial Node do for the heart? Does it need the nervous system's help? What does the nervous system do?

Cardiac pacemaker; Initiates the heartbeat spontaneously; Nervous system can modify pace

Where does the electrical signal pass to after it has spread through the atria? Where is this structure located and where will it pass the signal to next so the electrical signal can spread through the ventricles?

Atrioventricular (AV) node, Atrioventricular (AV) bundle, and Purkinje fibers; located in septum and ventricles; carry impulse to ventricles

What is the name of the graph that recodes the hearts electrical signals? What pathologies of the heart can it detect?

Electrocardiogram (EKG/ECG); arrhythmias and ventricular fibrillation

What does the P-wave on the graph represent?

Impulse across atria

What does the QRS complex represent?

spread of impulse down septum, around ventricles in Purkinje fibers

What does the T-wave on the graph represent?

end of electrical activity in ventricles

which vessel has a pulse?

arteries

What does Systolic Blood Pressure represent? What is the normal value?

highest pressure, as blood is ejected during ventricular systole; normal= <120mmHg

What is the name of the instrument that can measure blood pressure?

Sphygmomanometer

What does Diastolic Blood Pressure represent? What is the normal value?

lowest pressure (relaxation), as blood returns to the heart during ventricular diastole; normal= <80mmHg

Hypertension

When Blood Pressure Is Too high

What is the blood pressure measurement of systolic and diastolic pressure for an individual with hypertension?

- Systolic pressure ≥ 140 mmHg

- Diastolic pressure ≥ 90 mmHg

Why is hypertension a risk factor for cardiovascular disease? What happens to the vessels and heart?

- Higher blood pressure causes greater strain on cardiovascular system

- Blood vessels react by becoming hardened and scarred

- Strain on heart from having to work harder

Hypotension

When Blood Pressure Is Too Low

What conditions or activities can result in hypotension?

abrupt changes in body position (Standing up suddenly); may result from excessive blood loss or fluid loss from burns

Constant arterial pressure is the goal for blood pressure regulation. What two things are controlled to achieve this?

1. Regulation of cardiac output

2. Regulation of diameter of arterioles

What is the name of the receptor that monitors blood pressure? Where are they located?

Baroreceptors: pressure receptors in aorta and carotid arteries

The homeostatic control of blood pressure is a negative feedback loop, what is the initial stimulus the baroreceptor responds to when blood pressure is too high?

When blood pressure rises; increased stretch of the blood vessel walls in the carotid arteries and aortic arch

The signal passed from the baroreceptors to the cardiovascular center. Where is the cardiovascular center located?

In the brain

The response generated is sent to two locations, the heart and the arterioles. How do the arterioles respond? How does the heart respond?

Arterioles: vasodilate (decreasing vascular resistance), increasing blood flow to tissues

Heart: decreases cardiac output

The response generated by the arterioles and heart will lower blood pressure and turn off the initial stimulus by bringing blood pressure back to normal. What happens if blood pressure was too low to start the regulation cycle?

Mechanism is the opposite if blood pressure is too low

If blood pressure is too low the arterioles __________ to increase resistance to blood traveling through the vessel and help bring blood pressure back to normal.

Vasoconstrict

If blood pressure is too high the heart ____________ cardiac output to help bring blood pressure back to normal.

Vasodilate

What structure is responsible for control of local blood flow?

Precapillary sphincters

When the tissue is very metabolically active, are the precapillary sphincters structures vasodilated or vasoconstricted?

needs more O2, sphincters open, vasodilation increases blood flow

An individual has very low blood pressure in the ER due to heavy blood loss, do you expect the precapillary sphincters to be vasodilated or vasoconstricted leading to organs that are NOT the brain and heart?

vasoconstriction of Precap. sphincters to many organs—shunts blood to brain and heart

Is blood flow and cardiac output increased or decreased during exercise?

Increased

What is the cardiac output of a non-athlete?

up to 20-25 liters/min

What is the cardiac output of an athlete?

Up to 35 liters/min

Cardiovascular disorders are a very large issue in the United States, name some examples.

Hypertension, Aneurisms, Atherosclerosis, Angina, Heart attack, Heart failure, Embolism, and Stroke

Define Angina. What is the cause of angina?

Sensation of pain and tightness in chest; Caused by narrowing of coronary arteriesand diminished blood flow to heart muscle

What is an angiography?

Allows visualization of coronary arteries, enables diagnosis of angina

How can the cause of angina be treated?

Medication, Balloon angioplasty, and Coronary artery bypass graft

What is a myocardial infarction? What does it affect the myocardium of the heart?

Sudden death of an area of myocardium and permanent damage to heart tissue; heart attack

What are some symptoms of a myocardial infarction?

Intense chest pain, tightness or pressure on chest, radiating left arm pain, jaw and back pain, nausea

What are some treatments for a myocardial infarction?

Control of arrhythmias, Clot-dissolving medications, and Coronary artery bypass graft (CABG: vein from leg is grafted in order to bypass obstructed coronary artery)