THE CIRCULATORY

SYSTEMChapter 15

The Circulatory System◦Course taken by blood through the arteries, capillaries, and veins & back to heart

◦Uses blood to transport dissolved materials throughout body◦Oxygen, carbon dioxide, nutrients, waste

◦Picks up waste products of cell metabolism & takes to lungs and kidneys (to be expelled from body)

Circulatory System Rap

http://www.youtube.com/watch?v=LqhvmUEdOYY

The Heart◦Two major circulations

◦Each has its own pump◦Both pumps are incorporated into the heart

◦Location◦Middle of chest, behind sternum, within ribcage

◦Pericardial cavity◦Above diaphragm

◦Structure ◦Primarily a shell with four chambers inside

Blood Flow◦Two sides of heart are anatomically and functionally separate pumping units◦Right side pumps blood through pulmonary circulation

◦Left side pumps blood through systemic circulation

Heart Facts

◦Adult human heart approx. size of closed fist

◦About 5 inches long and 3 ½ inches wide◦Weighs just less than 1 pound◦Beats about 100,000 times each day◦Pump about 8,000 gallons of blood through 12,000 miles of vessels each day

◦Contracts and relaxes 70-80 bpm

Heart Muscle◦Pericardium◦Sac around the heart

◦Epicardium◦Outer Surface

◦Myocardium◦Heart Muscle

◦Endocardium◦Inner Lining

Structure of Heart◦Four cavities

◦Atria◦Form curved top of heart

◦Ventricles ◦Meet at bottom of heart to form pointed base

◦Points toward left side of chest

Structure of Heart◦Left Side

◦One ventricle◦One atrium◦Mitral valve—connects left atrium to left ventricle

◦Right Side◦One ventricle◦One atrium◦Tricuspid valve—connects right atrium to right ventricle

◦Wall, septum, separates right and left sides

◦Aorta◦heart’s main artery◦ carries blood away from heart to body’s cells

◦Pulmonary artery◦artery that connects heart to lungs

◦Pulmonary Vein◦Vein that connects lungs to heart

◦Two largest veins:◦Superior vena cava◦Inferior vena cava

◦As heart contracts, it pushes blood though chambers and into the vessels

◦Nerves connected to the heart regulate the speed of contractions

◦Greater the activity, faster the heart will pump; faster heart pumps, more oxygen and nutrient are carried throughout body

Blood Functions◦Transportation

◦Transports nutrients, waste products, gases, and hormones

◦Regulation◦Regulates fluid-electrolyte balance, acid-base balance, and body temperature

◦Protection◦WBC protect us against pathogens◦Blood clotting mechanism prevents excessive loss of blood

Blood Characteristics◦Each person has 4 to 6 liters of blood depending on person’s size

◦Blood is 3 to 5 times thicker than water

◦Viscosity is increased by presence of blood cells and plasma proteins

◦Thickness contributes to normal blood pressure

Blood◦Only tissue that flows throughout body

◦Carries oxygen & nutrients to all parts of body and transports waste products back to lungs, kidneys, and liver for disposal

◦Essential part of immune system

◦Crucial for fluid and temperature balance

◦Hydraulic fluid for certain functions

◦Highway for hormonal messages

◦Composed of plasma and billions of cells

Plasma◦The yellowish, liquid part of blood◦River in which blood cells travel◦Makes up 55% of total volume◦Carries blood cells +

◦Nutrients (sugars, amino acids, fats, salts, minerals)

◦Waste products (CO2, lactic acid, urea)◦Antibodies◦Clotting proteins (called clotting factors)◦Chemical messengers (hormones)◦Proteins that help maintain body’s fluid balance

Blood—RBCs & Hemoglobin◦Red Blood Cells (erythrocytes)

◦Highly specialized cells that have been “stripped” of everything, including nucleus

◦Most numerous type of blood cell◦Typically last for 120 days◦Major job: transporting oxygen◦Percentage of RBCs in total blood volume called hematocrit

Hemoglobin◦RBC contain a protein called hemoglobin

◦Hemoglobin gives the RBC the ability to carry oxygen

◦Each RBC contains approximately 300 million hemoglobin molecules◦Each bonds to 4 oxygen molecules

◦Hemoglobin picks up oxygen where it is abundant creating an oxyhemoglobin

◦In systemic capillaries oxyhemoglobin gives up as much of its oxygen and is reduced to a hemoglobin

◦Iron is what bonds to the oxygen and makes the RBCs red

Blood—White Blood Cells◦5 distinct kinds

◦Neutrophils, monocytes, lymphocytes, eosinophils, basophils

◦Able to change according to need and situation in body

◦Can leave blood stream , sliding out through vessel walls & attacking invaders at site of infections

Blood—Platelets ◦Fragments of a very large cell found in the bone marrow

◦Platelets leave bone marrow & circulate throughout the body

◦When stimulated by substance from damaged tissue, platelets release substance to help clot blood

◦Have the ability to stick together and function in the first states of blood clotting

◦Can last 5 to 9 days◦Normal platelet count is 150,000 to 300,000 microliters

Blood Vessels◦Hollow tubes running throughout the body

◦5 types◦Arteries◦Arterioles◦Veins◦Venules◦Capillaries

◦Provide 2 measurements:◦Pulse◦Blood pressure

Arteries◦Blood vessels that carry blood from the heart to organs & cells

◦Muscular walls that allow them to dilate or constrict

◦Arterioles: very small arteries◦Largest artery=aorta

◦Runs from chest into abdomen ◦Receives blood directly from left ventricle

Veins◦Blood vessels that carry blood back to heart

◦Thinner wall◦Contain numerous one-way valves (keep blood moving toward heart)

◦Deep veins in LE surrounded by large muscle groups; compress the deep veins when muscles contract

◦Contractions in extremities helps propel blood toward heart; increase venous return

Veins ◦Largest vein=superior & inferior vena cava◦Bring blood from upper and lower body into right atrium

◦Venules: smallest veins

Capillaries◦Tiny, microscopic blood vessels that connect arteries to veins

◦Responsible for transferring oxygen and nutrients to cells

◦Wall so thin that O2 passes from arterial blood through them into cells in organs/tissues

◦Waste products (CO2) pass into capillaries to be carried back by veins to heart/lungs

Coronary Arteries and Veins◦Heart has its own system of blood vessels due to its demand of oxygen rich blood

◦Located around the heart to provide blood and oxygen to all the different parts and remove wastes

Heart’s Conduction System◦Heart’s electrical system◦Consisting of specialized cells within heart muscle that carry an electrical signal

◦Regulates pumping of heart

CARDIORESPIRATORY SYSTEM

AND BLEEDING

Cardiorespiratory System◦Includes the functions of:

◦Heart◦Blood vessels◦Circulation◦Gas exchange between blood and the atmosphere

◦Within in the lungs, blood is enriched with oxygen and carbon dioxide is released ◦Respiration

◦Each side of the heart has its own type of circulation

Pulmonary circulation◦Right side pumps blood to lungs and back to heart’s left side

◦Oxygen poor blood enters the Right Atrium through the Superior Vena Cava and the Inferior Vena Cava

◦Blood then flows through the Tricuspid Valve and enters the Right Ventricle

◦Blood leaves the Right Ventricle through the Pulmonary Artery after going through the Pulmonary Semilunar valve and goes to the lungs

◦Blood returns to the heart through the Pulmonary Vein after being oxygenated

Systemic circulation◦Left side pumps blood to rest of the body and back to heart’s right side

◦Oxygen rich blood enters the Left Atrium through the Pulmonary Veins

◦Blood enters the Left Ventricle through the Mitral Valve◦Blood travels through the Aortic Semilunar Valve and enters the Aorta

◦After traveling through the Aorta the blood is dispersed through the various arteries to the rest of the body

◦Deoxygenated blood then returns to the heart through the Superior Vena Cava and the Inferior Vena Cava

Types of Bleeding◦All need prompt attention to prevent shock, infection, and possible loss of life

◦Arterial◦Severe bleeding◦Bright red blood that spurts or pulses◦Corresponds to the heart beat◦Can lose a large amount in a short period of time

◦Most serious type and can be fatal ◦Apply pressure and activate EMS immediately

◦ Venous◦ Steady blood flow◦ Blood will appear bluish-

red due to lower oxygen levels

◦ Veins are closer to surface to easier to control

◦ Direct pressure and compression best way to control bleeding

◦ Capillary ◦ Slow and oozes◦ Blood clotting occurs

rapidly◦ Slow bleeding carries a

risk of infection◦ Bandage with sterile

dressing

Flow of Blood through Heart◦ Superior/inferior vena cava◦ Right atrium◦ Tricuspid valve◦ Right ventricle◦ Semi-lunar valve◦ Pulmonary artery ◦ Lungs

http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html

Flow of Blood through Heart◦ Back to heart via

pulmonary vein◦ Left atrium◦ Bicuspid valve◦ Left ventricle◦ Semi-lunar valve◦ Aorta◦ Organs in the body

Flow of Blood through Heart

Heart Anatomy

Can you label the heart?