The Circulatory System (Unit Test)

The Circulatory System

• Provides the force and channels for the distribution of blood which carries food and oxygen to cells and removes wastes

• Organized into 3 primary cycles:

  • i) Coronary system: within the heart

  • ii) Pulmonary system: lungs

  • iii) Systemic system: body

• The circulatory system transports oxygen and nutrients throughout the body and carries away any waste products.

• It is made up of the blood, the heart and blood vessels.

The Importance of Circulatory System

• Blood flows through the lungs, picks up oxygen and then flows through the body to deliver oxygen to all your cells.

• Blood also carries waste products from the body tissues for disposal.

  • CO2 is brought to the lungs

  • Other waste is brought to the kidneys (excreted via urine)

• The circulatory system also regulates your body temperature and transports your disease fighting white blood cells to where viruses and bacteria may exist in your body!

Circulation - “The Double Pump”

• Blood passes through the heart twice each time it completes a circuit

1. Right side of the heart receives deoxygenated blood from body tissues and pumps it to the lungs

2. Left side of the heart receives oxygenated blood from the lungs and pumps it to all body tissues

Parts of Circulatory System

• The three main parts of the circulatory system are:

  • Blood

  • Heart

  • Blood vessels:

    • Arteries – large blood vessels

    • Capillaries – smallest blood vessels

    • Veins – larger blood vessels that returns blood to the heart.

1. Blood

• Blood is a connective tissue that circulates in your body:

• It is made up of four parts:

  • 1. Red blood cells → most plentiful type of blood cell in the body

  • 2. White blood cells → less than 1% of your blood volume

  • 3. Platelets → less than 1% of your blood volume

  • 4. Plasma → makes up over half your blood volume

• Importance of Blood

  • Transport of gases (oxygen and carbon dioxide)

  • Transport of waste

  • Transport of nutrients

  • Fighting disease and infection

  • Blood clotting

Red Blood Cell (Erythrocytes)

• Makes up most of your blood cells; contains a protein called hemoglobin which transports oxygen (hemoglobin makes your blood red)

• Produced in the bone marrow and has a life span of 120 days

• Body can stimulate growth of red blood cells when there is reduced oxygen in the blood (e.g. high altitudes)

• Lacks a nucleus

• Most numerous of the blood cells

White Blood Cell (Leukocytes)

• Infection-fighting cells.

• They detect invading bacteria and viruses and destroy them!

• They have a nucleus (red blood cells do not)

• Has a life span from a few days to a few weeks

Platelets

• Platelets are very small cells that assist in the formation of blood clots.

• Blood clotting helps prevent excessive bleeding!

Plasma

• A protein rich liquid that carries the blood cells along through the body.

Blood Disorders

• Anemia

  • Insufficient hemoglobin/iron in red blood cells reduces oxygen carrying capacity

  • Results in tiredness and low energy levels

  • Iron supplements often help

• Leukemia

  • Cancer of the blood

  • Characterized by an increased number of white blood cells in circulation

  • White blood cells are immature and incapable of fighting disease

2. The Heart

• The heart is made up of three different types of tissue:

  • Cardiac muscle tissue (found only in the heart)

  • Nerve tissue

  • Connective tissue

• All of the cardiac muscle tissue in each part of the heart contracts at the same time allowing blood to move around the body.

• The muscles and nerves are covered by a smooth layer of epithelial tissue.

  • This reduces friction and protects the heart from damage.

• Composed of cardiac muscle which beats involuntarily

• Beats an average of 72 times/minute

• Two sides of heart beat in unison

• Two sides of the heart separated by a muscular wall called the septum

• Systole:

  • Contraction of the heart muscle

• Diastole:

  • Relaxation of the heart muscle

Chambers of the Heart

• Each pump contains two chambers:

  • an atrium

  • a ventricle

• Heart has four chambers total

• Blood flows from atrium → ventricle

Diseases and Disorders

• Coronary Artery Disease

  • Coronary arteries provide blood to heart muscle tissue

  • Arteries can become partially blocked with plaque

  • Plaque is a build-up of fat, cholesterol, calcium and other substances that are found in blood

  • Symptoms – tired, dizzy, pain or burning sensation in arms or chest

  • Angiogram is used to diagnose this disease

    • Angiogram: fluorescent dye that detects any blood flow abnormalities.

• Cardiovascular Disease

• Heart Attack

  • Arteries can become completely blocked with plaque or with a blood clot

  • Heart muscle cells no longer receive the oxygen and nutrients they need to function

  • Heart stops pumping and heart tissue starts to die

  • Symptoms – chest pain or pressure, shortness of breath, nausea, anxiety, sweating, dizziness

  • Blood test and electrocardiogram (ECG) are used to diagnose a heart attack

  • Heart attacks are very serious and life-threatening