circulatory system - index 12 & 13

Explain Atherosclerosis

• generic term - systematic disease (can happen all over the body)

• Is a buildup of fat droplets (also known as plaque) in the arteries, causing blockage and not letting blood to pass through

• It narrows the diameter of the artery which increases blood pressure

• Fat buildup (plaque) is made up of calcium and other minerals (like cholesterol)

Explain Carotid artery disease

• type of atherosclerosis : plaque buildup in the carotid artery

• Carotid artery’s are the arteries in the neck that supply the brain with oxygenated blood, therefore when clogged (with plaque), it can cause a stroke (due to a reduced amount of blood going into your brain).

• Causes: poor diet, lack of exercise, drinking/smoking, genetics

What are the 3 treatments for carotid artery disease

1. Angioplasty :

• an incision made in the femoral/common iliac, a catheter w/ a camera & deflated balloon

• Is inserted from the femoral/common iliac to the carotid artery

• They press a button to inflate the balloon to reopen the artery

• Then deflates it

2. Stenting :

• similar to angioplasty, but it more efficient

• Exact same processes, however the deflated balloon in covered with a mesh (stent - hence the name “stenting”)

• When he balloon deflates after reopening the artery, the stent is left inside, leaving the walls permenently open

3. Endarterectomy :

• the physical removal of the plaque - rare procedure

• blood is rerouted to the brain

• Clamp on the top & bottom of artery

• make an incision and remove the plaque

Explain abdominal aortic aneurysm

• an abdominal bulge or ballooning in in the wall of an artery

• Caused by a weakness in the arteries - when a thin layer breaks down overtime (could also be genetic)

• can cause internal bleeding if bursts

• If in brain: can cause stroke or death

More common in women cause they contain estrogen which breaks down the walls faster

How can abdominal aortic aneurysm be treated

The process is called abdominal aortic aneurysm repair:

• similar to endarterectomy

• Blood is rerouted, clamped above and below, make an incision, inserts an artificial tube that mimics and artificial blood vessel

• symptoms include:

  • severe abdominal pain

  • severe abdominal pulsation

Explain raynaud syndrome

• only for arterioles

• Brief episode of vasoconstriction of the smooth muscles around the arterioles

• Caused by decreased blood flow to fingers, toes, nose (rarely), ears and lips

• Encouraged by:

  • extreme stress & extreme temperature changes

  • Genetics

Explain arterioles (including vasoconstriction & vasodilation)

• smaller vessels branched off of the arteries

• Covered w/ layers of smooth muscles that can constrict and relax

  • Which increases and decreases the diameter

Vasoconstriction (squeezing):

• when the nervous system innervates (sends nerves) the arterioles, it causes them to contract

• decreases the diameter of the arterioles

Vasodilation (relaxing):

• When he nervous systems allowed the arterioles to relax, it increases the diameter

• Increasing blood flow to the tissues

Explain capillaires

• smallest blood vessel

• Towards and away from the heart (site for gas exchange)

  • Allow exchange of oxygen and nutrients thought the tissues and cell

  • Every cell has a capillary

• Blood moves from arterioles to capillaries

• Very thin (has a diameter that allowed RBC to go through it

  • Thin walls called endothelium, regulate movement of fluid and other materials in and out often the blood stream

Explain the 3 parts of the artery

1. Connective tissue - outermost layer

2. Smooth muscles (w/ circular bands of elastic fibers) - middle layer, thickest

3. Endothelium - innermost layer, only 1 cell thick, reduces friction as blood flows through

Why do arteries have strong walls?

• to withstand great pressure

• When your heart contracts, blood surges from your heart and enters your arteries, making them stretch

• When your heart relaxes, your arteries recoil (causing a pulse)

  • Pulse: is the change in the diameter of the arteries after the heart contracts and blood surges through them

Explain veins

• Capillaries merge and become larger vessels called venues

  • And venues merge to become veins (which have an even greater diameter)

• Brings blood back into the heart

• The preasure is very low, there for they have valves in them which push and give speed to the blood, directing it back into the blood

Describe skeletal muscle contraction

• They surround the veins

• when the skeletal muscles contract, it causes the diameter of the veins to decrease, increasing the pressure inside

• This causes the increase of pressure to push the valves open, opening the veins

Describe varicose veins

• when veins are, distorted, extended, or twisted

• Usually visible as a blush-green color

Veins have THINNER walls than arteries, so the pressure increases the diameter of the veins

• more common in females bc of estrogen (causes the walls to thin faster)

Describe pericardium

• a thin transparent membrane surrounding the heart, contains liquids that reduce friction as the heart beats

What are the 2 circuits of the circulatory system

1. Pulmonary circuit

• to oxygenate blood

• Made of vessels (arteries and veins) that carry blood to and from the lungs

  • Pulmonary arteries carry oxygen poor blood to the lungs

  • Pulmonary veins carry oxygen rich blood to the heart

2. Systematic circuit

• to supply the body with oxygenated blood

• Make up of vessels (arteries and veins) that carry blood to and from the body tissues

  • Carries oxygenated blood to the tissues

  • Carries deoxygenated blood back to the heart

How does oxygen poor blood come back in the heart from (explain)

Superior and inferior vena cava:

• Brings oxygen poor blood from the upper and lower parts of the body to the heart: through the superior (up) and inferior (down) vena cava

Explain aorta + the pathway

• the largest artery in the body

• Transports oxygen rich blood from the heart to the rest of the body

1. Ascending aorta

2. Aortic arch

3. Thoracic aorta

4. Abdominal aorta

5. Descending aorta (thoracic + abdominal)

Describe the different valves

1. Atricoventricular valve (AV valve)

• separates atria from ventricle (prevents from flowing back to the atria

• 2 types:

  • Tricuspid (right AV valve, 3 cusps)

  • Bicuspid valve (left AV valve, 2 cusps)

2. Semilunar valves

• separates ventricles from arteries that leave the ventricles

  • Prevents blood from reentering the ventricles from the arteries (after leaving)

  • Does NOT contain chordae tendineae

• 2 types:

  • Pulmonary semilunar valve

  • Aortic semilunar valve

Explain chordae tendneae

• thin string like fibres that anchor valves

• One side is attached to the backside of the cusp, other is attached to the ventricular wall, which prevents them from flipping inwards

Explain the route of blood through the heart

superior vena cava → inferior vena cava → right atrium → Tricuspid valve → right ventricle → pulmonary semilunar valve →pulmonary trunk → left and right Pulmonary arteries (branches into the left and right lungs) → lungs → Pulmonary veins → Left atrium → Bicuspid valve → Left ventricle → aortic semilunar valve → Aorta → Body

Describe coronary arteries

• Supplies oxygenated blood to the heart, branches off the base of the aorta and goes towards the apex of the heart

Describe cardiac veins

The deoxygenated blood from the heart is carried into the right atrium (but first goes thought the superior and inferior vena cava to get to the right atrium)

Explain coronary artery disease

• Type of atherosclerosis

  • Causes by the blockage of the coronary Artie’s due to fat buildup

  • Results in not enough O2 being delivered to the heart muscles

    • Chest pain occurs due to the lack of blood and oxygen : this is called angina

• If this worsens, the oxygen starved cardiac muscle cells die

  • This is called myocardial infraction (heart attack)

Explain the 3 ways coronary artery disease can be treated

1. Coronary angioplasty

• same as normal angioplasty, but performed through the femoral artery

1. Stenting

• same as normal stenting

1. Coronary artery bypass surgery

• when multiple arteries are blocked

• A blood vessel from another part of the body is removed (great saphenous vein)

  • Bypasses the blocked artery, creating a new route

  • Runs from the aorta to the distal (which is the unclogged) part of the artery