THE CIRCULATORY SYSTEM

MacKenzie Smart, Leah Harris, Emma Dumford, and Anna Sivey

The Circulatory System The Heart Blood Vessels Blood Pressure Blood Plasma Blood Cells

The Heart <3 composed mostly of muscle hollow organ—size of clenched fist enclosed in a protective sac of tissue called

Pericardium two thin layers of epithelial and connective tissue that

surround a thick layer of muscle called Myocardium contractions of the Myocardium (heartbeat) pump

blood through the circulatory system heart muscle contracts an average of 72 times a

minute—pumps 70 mL of blood the Septum divides the right side of the heart from the

left and prevents Oxygen-poor blood from mixing with Oxygen-rich blood

Heart—valves

four chambers-two upper chambers (left and right atria) and two lower chambers (left and right ventricles)

right atrium has thinner walls and is larger than the left

the left ventricle is the strongest and largest chamber in the heart

Heart—valves four types of valves:

Tricuspid valve- separates the right atrium from the right ventricle and regulates blood flow between them

Pulmonary valve- separates the right ventricle from the left pulmonary artery and controls blood flow from each other

Mitral valve- separates the left ventricle from the left atrium

Aortic valve- separates the left ventricle from the Aorta and controls the blood flow from the ventricle into the rest of the body

Heart—arteries arteries push blood through the blood

vessels when the heart relaxes from its contractions

arteries transport Oxygen-rich blood to the capillaries where exchange of CO2 and Oxygen takes place

Heart—arteries

arteries of the heart:Pulmonary artery- carries deoxygenated blood

from the right side of the heart to the lungs for purification, it also divides into right and left branch

Aorta-main artery of the heart which carries oxygenated blood to the rest of the body; branches off to smaller arteries that supply blood for the body

Coronary arteries- attached to the heart and supply blood to heart muscles

Heart—veins

veins are like arteries but do not transport blood at high pressure

after the exchange of CO2 and O, the blood containing waste products is received by the veins

Pulmonary vein- carries oxygenated blood from the lungs to the left side of the heart

Heart—veins

all four pulmonary veins pour oxygenated blood into the left atrium (two left and two right)Venae Cavae- two large veins carry

deoxygenated blood from the body to the heartSuperior Venae Cavae- brings deoxygenated

blood from parts above heart into the right atrium

Inferior Venae Cavae- brings blood from the parts below the heart to the right atrium

Blood Vessels Three types of blood vessels:

ArteriesCapillariesVein 

Arteries: the largest vessels that carry blood from the heart to the tissues.

Except for the pulmonary and umbilical arteries, all arteries carry oxygen loaded blood.

Arteries have thick walls to withstand the pressure from the heart when it contracts and pushes blood into them.

Blood Vessels

Arteries have three layers….Adventitia: outside layer; elastic to

allow the arteries to expand under pressure.

Media: middle layer; contracts to regulate the diameter

Endothelium: inside layer; smooth lining to allow blood to flow

Blood Vessels Aorta: Largest vessel leaving the left ventricle and leads down to

the rest of the arteries. Arterioles: small vessels that branch off from the arteries and

lead to the capillaries  Capillaries: Smallest, “side-streets”. The walls are only one cell

thick. These are the main vessels that nutrients and oxygen is brought to tissues. 

Veins: After passing through the capillary system, blood returns to the heart for oxygen

Blood flows against gravity through the veins. Large veins, like in the leg, have valves that push the blood

towards the heart. Exercising helps keep the blood from accumulating in one spot,

which produces a blood clot.

Blood Pressure Blood Pressure ~ the force of blood

against the walls of the arteries. Systolic pressure: the pressure as the

heart beats Diastolic pressure: the pressure as the

heart relaxes between beats Equation: systolic/diastolic mmHg

(millimeters of mercury) the normal or “desired” number is 120/80

mmHg

Blood Plasma

Blood Plasma-55% of blood is plasma. Plasma is 90% water and

10% dissolved gasses, salts, nutrients, enzymes, hormones, waste products, and proteins.

Plasma proteins:Albumins- helps regulate osmotic pressure and

blood volume, and transports substancesGlobulins- transports substances, and fights viral

and bacterial infectionsFibrinogen- gives blood the ability to clot

Blood Cells Red Blood Cells

1 milliliter of blood has about 5 million red blood cells

Red blood cells transport oxygenThey get their red color from hemoglobin (iron-

containing protein that binds to oxygen in the lungs and transports it to tissue throughout the body)

They are disk-shaped cells without a nucleus made from cells in red bone marrow

Red blood cells last for about 120 days before they are destroyed in the spleen

Blood Cells White Blood Cells

less common, out numbered almost 1000 to 1guard against infections, fight parasites, attack

bacteriathey can slip out of capillaries and fight

infections throughout the bodythe body can increase the number of white

blood cells when fightinghave nuclei and are made in bone marrowlive for days, months, even years

Blood Cells

Plateletsthere are about 150,000 to 350,000

platelets per micro literblood clotting is made possible by

plasma proteins and plateletsthey aren't actually cells, but cell

fragments produced in bone marrow

Diseases 2 Types

Present at BirthAcquired

Aortic AneurysmBulging in the wall of the aorta (largest artery)Caused by a tear or defect in the aortic wallCan be a complication of other diseases such as high

blood pressure Angina

Pain or discomfort in the chest area caused by leakage in the blood vessels leading to the heart

Pain lasts usually about 10 minutes

Diseases Arrhythmia

Irregularity in the heart rhythm, varies from very slow to very fast

Can occur at any point in life Atherosclerosis

The hardening of the arterial wall because of plaque or artheroma

Plaque is composed of cholesterol, calcium, and fatty deposits

Can slow or stop blood circulationThere is a sharp pain in the affected area

Diseases High Blood Pressure

When the systolic pressure Is over 140 mmHg and disastolic pressure is over 90 mmHg

Caused by heredity or unhealthy lifestyle habits such as heavy drinking and smoking

Peripheral Vascular Diseasea disorder in the blood vesselscaused by fatty acid deposits in the arteries of

the leg portioncan be hereditary or acquired by unhealthy living

Diseases

Ways to Prevent Circulatory Diseases:Do not Smoke or use any other

nicotine sourceExercise consistentlyEat HealthyGet enough sleep each 24-hoursAvoid high amounts of stress

Overview Three Major Parts

The Heart The Blood The Blood Vessels

The Heart removes waste materials and pumps and circulates blood The Blood has the oxygen and nutrients necessary for cell survival The Blood Vessels transport blood to and from the heart The Circulatory System is the main transportation and cooling

system of the body It is basically like the roads in cities used to transports goods and

other important materials. When your heart beats, it forces the oxygen-rich blood through the

circulatory system