Blood Vessels

Interesting Cardiovascular System Fact:

The human body has 60,000 miles of blood vessels – long enough to

go almost 3 times around the Earth!

THE CARDIOVASCULAR SYSTEM (A.K.A. THE CIRCULATORY SYSTEM)

3 main parts:1. Heart

2. Blood Vessels

3. Blood

Blood Vessels

3 types of vessels:1. Veins

2. Arteries

3. Capillaries

Arteries

✘ Take blood away from the heart✗ Exception- the pulmonary artery

✘ Branches off into smaller vessels known as ARTERIOLES

✘ Thick, and muscular walls, elastic in structure✘ Major artery: the Aorta

Other major arteries

Carotid Artery: Delivers blood from the aorta to head and neck

Coronary Arteries: Supply blood to the heart

Capillaries

✘ Once blood vessels become only one cell thick, they become capillaries

✘ This is how every cell in our body gets blood✘ Capillaries are the ONLY site of molecular

exchange (one cell thick)✗ Gas, nutrients, water, nitrogenous, wastes, hormones, etc.

Veins

✘ Carry DEOXYGENATED blood TO the heart✘ Heart valves- prevent back flow✘ Very thin walls✘ Branch off into smaller Venuoles ✘ The biggest vein is the vena cava

Major Veins

Superior Vena Cava✘ Collects deoxygenated blood

from head and neckInferior Vena Cava✘ Collects blood from legs and

lower bodyJugular Vein ✘ Returns blood from the head to

superior vena cava

Which way is the blood flowing?

Veins vs. Arteries

Arteries1. Have a pulse2. Transport blood away from the heart;3. Carry Oxygenated Blood (except the Pulmonary Artery);4. Have relatively narrow lumens (openings)5. Have more muscle / elastic tissue;6. Transports blood under high pressure;7. Do not have valves (except for the semi-lunar valves of the pulmonary artery and the aorta).

Veins1. Do not have a pulse

2. Transport blood towards the heart; 3. Carry De-oxygenated Blood (except the

Pulmonary Vein); 4. Have relatively wide lumens (openings)5. Have less muscle / elastic tissue;6. Transports blood under low pressure; 7. Have valves to prevent blood flowing in

the wrong direction

Varicose Veins and Deep Vein Thrombosis

Varicose Veinshttps://www.youtube.com/watch?v=Ce2TjGY-r1o

Deep Vein Thrombosishttps://www.youtube.com/watch?v=0QEo9QAqA3k

Blood Components

Blood Components

1. Plasma

✘ Clear/straw colored liquid portion of blood ✗ Can look cloudy after a fatty meal

✘ Components of plasma:✗ 90% water, but also dissolved gases, proteins,

hormones, electrolytes, sugar, vitamins, and waste products

✘ 55% of blood volume

1. Plasma

✘ Function is to carry:✗ nutrients to cells (especially glucose

which is needed for respiration)✗ hormones (which are chemicals that

control body processes)✗ waste materials (to bring to the lungs &

kidneys for removal)

2. Red Blood Cells (RBCs)

✘ Aka erythrocytes ✗ (Greek: erythro = red, cyte = mature cell)

✘ 45% of blood volume✘ Primary function: carry oxygen from your lungs to

your body✘ DO NOT have a nucleus✘ Contain iron and hemoglobin - gives it red colour

✗ hemoglobin gives the red blood cells the colour red✘ produced in the bone marrow

2. Red Blood Cells (RBCs)

When red blood cells arrive at the lungs, capillaries run along side small air sacs called alveoli.

The carbon dioxide that is bound to the red blood cell is released and oxygen takes it place. The red blood cell then carries the oxygen to the heart before it is pumped around the body to where it is needed.

2. Red Blood Cells (RBCs) cont’d

✘ 30 trillion RBCs✘ Life span = 120 days✘ About 2 million die & are replaced every second✘ Worn out RBC’s are filtered out by the liver and

spleen

3. White blood cells (WBCs)

✘ Aka leukocytes✗ Greek: leuko = white, cyte = mature cell)

✘ <1% of blood volume ✘ Are a part of the immune system and help our bodies

fight infection✘ HAVE a nucleus✘ Circulate in the blood so that they can be transported

to an area where an infection has developed.✘ More white blood cells usually means there’s an

infection somewhere

Two main types of White Blood Cells

•

•

4. Platelets

✘ Aka thrombocytes✘ <1% of blood volume✘ Platelets are sticky, irregularly-shaped cell

fragments (NOT CELLS)

Blood Clots

● A blood clot is a solid mass that plugs up a break in a blood vessel.

● Blood clots to stop the escape of blood. It’s a protective mechanism!

How a clot is formed

✘ Platelets detect air/injury and become sticky ► also begin to break apart ► these react with stuff in plasma to make thromboplastin ► Thromboplastin + prothrombin (+ Ca+ & Vit K) = Thrombin ► Thrombin + Fibrinogen ► Fibrin (tiny threads) ► fibrin threads form a web-like mesh ► traps the blood cells within it ► This hardens as it dries, forming a clot, or "scab/bruise“

✘ What do you think happens if Calcium and vitamin K are low/missing?

✘ https://www.youtube.com/watch?v=--bZUeb83uU&feature=related

Blood clot process

What is the role of the blood?TO HELP MAINTAIN HOMEOSTASIS by:1.Transport

✘ O2, CO2, food, nitrogenous wastes, hormones, etc

2.Protection – through immune system✘ Guards against microbial invasion (immune system)3.Circulate clotting factors to prevent blood loss in case of injury4.Regulation ✘ controls levels of hormones, enzymes, temperature, pH