Anatomy Unit 3 Cardiovascular System

what are the 3 components of the cardiovascular system?

• blood

• blood vessels

• the heart

what are the 2 circuits of the cardiovascular system? describe their function

• pulmonary circuit: transports blood to and from lungs

• systemic circuit: transports blood to and from the rest of the body

what are the formed elements of blood? what percentage of blood do they make up?

makes up 45% of blood

• erythrocytes (RBC)

• leukocytes (WBC)

• thrombocytes (platelets)

describe the appearance, shape, functions, and life span of red blood cells

• appearance:

  • atypical (no DNA, no nucleus)

  • appears red

• shape: disk-shaped with an indent in the center

  • increases surface area, allowing more O₂ to bind to it

• functions: (carries out tasks using enzymes)

  • facilitates the transport of O₂ and CO₂

  • contains iron and a protein called hemoglobin

• life span: 120 days

describe the function of white blood cells

• defends and protects the body from foreign invaders

• uses blood as a way to move from bone marrow to the rest of the body

• less common than RBC

describe the appearance and function of platelets

• appearance:

  • covered with many proteins to allow materials to stick (sticky)

  • not true cells (cell fragments)

• function:

  • clots to prevent blood loss

what are arteries? describe the location and functions of arteries

muscular blood vessels

• located deep to skin

• functions:

  • carries oxygenated blood from the heart to the body

  • changes diameter as needed

  • has higher pressure (how pulse is taken)

what are arterioles?

small arteries that connect to capillaries

what are veins? describe the location and functions of veins

flexible vessels with thin walls

• located closer to the surface of the skin

• functions:

  • carries deoxygenated blood from the body back to the heart

  • transports CO₂, O₂, and other waste products

  • pumps blood at lower pressure: uses valves to prevent backflow

what are venules?

small veins near capillaries

describe the location, functions, and appearance of capillaries

• located everywhere

• functions:

  • site of exchanges (O₂, nutrients, and waste)

  • connects arteries to veins

• appearance:

  • has a single layer of simple squamous endothelium

  • connected with tissue

what is vasoconstriction? what can it help with?

narrowing or constriction of blood vessels; making the opening smaller

• can help stabilize/raise blood pressure, reduce heat loss, send more O₂ or nutrients to organs, protect the body against blood loss

what is vasodilation? what can it lead to?

opening of blood vessels

• can lead to increased blood flow and decreased blood pressure

what is the heart and what does it do (generally)?

muscular 2-part pump that forces blood throughout the body

what does the left side of the heart do?

sends blood at high pressure to all parts of the body (except lungs)

what does the right side of the heart do?

pumps blood at a lower pressure through the lungs

where is the heart located?

• in the thoracic cavity; between the pleural cavities and in the mediastinum

• surrounded by pericardial sac

what is the base of the heart? where is it located?

• the attached base where the great veins (aorta, vena cava) connect to the superior end of the heart

• located posterior to the sternum

what is the apex of the heart?

inferior pointed tip

what are atria? describe its appearance

superior superficial chambers of the heart

• appearance: when not filled with blood, each atrium deflates and becomes a lumpy, wrinkled flap (called auride)

what are ventricles?

inferior chambers of the heart

what are the 2 types of pericardium?

• visceral pericardium (inner layer)

• parietal pericardium (outer layer)

where is the pericardial cavity located? what does it contain?

• located between parietal and visceral layers of the heart

• contains pericardial fluid

what does the parietal sac do? what is it made of?

• surrounds and stabilizes the heart

• made up of fibrous tissue

what is the pericardium? describe its functions

double lining of the pericardial cavity

• functions:

  • protects the heart and greater vessels

  • releases fluid to lubricate the heart to reduce friction

what are sulci?

deep groves within the heart

what are the 3 layers of the heart? describe them

epicardium (outer layer)

• serous layer

• areolar connective tissue

myocardium (middle layer)

• cardiac muscle tissue

• coordinates and controls heartbeat

endocardium (inner layer)

• simple squamous epithelium

describe the location, appearance, and connections of cardiac muscle tissue

• found in the myocardium

• appearance:

  • single, central nucleus

  • branching interconnections between cells

  • intercalated discs

• desmosomes: allow for strong & connected contractions

• gap junctions: allows ions to pass through (allowing muscle to contract)

what are coronary arteries and veins generally?

the blood vessels of the heart

what are coronary arteries? describe their location and function

• larger vessels located along the surface of the heart and branch off into smaller vessels & capillaries

• function:

  • system of vessels that carry oxygenated blood from the left ventricle to heart muscle tissue (myocardium)

what are coronary veins? describe its function

• function: collects deoxygenated blood from heart muscle tissue (myocardium) and takes it to the right atrium

what does coronary artery/vein blockage lead to?

• cardiac infraction: death of cardiac muscles due to diminished blood flow

• cardiac ischemia: malfunction of muscles due to lack of oxygen (can lead to infraction)

what are the 3 types of heart diseases?

• coronary artery disease (CAD)

• angina pectoris

• myocardial infarction (MI or AMI)

what is coronary artery disease (CAD)?

• when coronary circulation is partially/completely blocked by atherosclerotic plaque (fatty deposit)

  • plaque narrows vessel wall

what is angina pectoris?

• when the workload of the heart increases, causing temporary ischemia

  • painful during exercise; comfortable at rest

what is myocardial infarction (MI or AMI)?

• when cardiac cells die from a lack of oxygen

  • usually diagnosed by EKG and blood studies

  • consequences depend on the site and nature of the circulatory blockage

what are the treatment options of CAD and MI/AMI?

• Risk Factor Modification

  • stop smoking, high blood pressure treatment, lower cholesterol diet, stress reduction, increased exercise

• drug treatment

• surgery

describe the non-invasive/invasive surgical treatments of CAD and MI/AMI

non-invasive

• atherectomy

• angioplasty/stents

invasive

• coronary artery bypass surgery

what are the functions of heart valves?

• facilitates pumping action

• keeps blood flowing in correct direction

what are the 4 heart valves and what do they connect?

• tricuspid valve (AV)

  • connects RA and RV

• pulmonary valve (SL)

  • connects RV and pulmonary artery

• bicuspid/mitral valve (AV)

  • connects LA and LV

• aortic valve (SL)

  • connects LV and aorta

what is the interatrial septum?

• ‘wall’ that separates the atria

what is the interventricular septum?

• ‘wall’ that separates the ventricles

where does the right atrium receive blood from?

• 2 great veins

  • superior vena cava

  • inferior vena cava

where does the superior vena cava receive blood from? where does it transfer blood to?

• receives blood from:

  • head

  • neck

  • upper limbs

  • chest

• transfers blood to the right atrium

where does the inferior vena cava receive blood from? where does it transfer blood to?

• receives blood from:

  • trunk

  • viscera

  • lower limbs

• transfers blood to the right atrium

what is the coronary sinus? where is it located?

• where the coronary veins bring deoxygenated blood from the heart to the right atrium

describe the interatrial septum, posterior & anterior wall of the right atrium

• interatrial septum & posterior wall

  • smooth surface

• anterior wall

  • prominent muscular ridges called pectinate muscles

what is foramen ovale? describe its function and where it is found

• function:

  • oval opening that connects the 2 atria of the fetus, since lungs are still developing

  • closes within 3 months of birth

• found only in the right atrium of newborns (3 months or younger)

  • fossa ovalis (small depression in the heart wall) appears after foramen ovale closes

describe the internal surface of the right ventricle

• has trabeculae carnaea (muscular ridges)

• has papillary muscles

describe the location and function of the tricuspid valve

• found in the right ventricle

  • goes from RA to RV

• function:

  • connects to chordae tendineae

  • opening and closing controlled by papillary muscle

where does the left atrium receive blood from?

• left and right pulmonary veins

what is auscultation?

listening to heart & lung sounds

• heart sounds:

  • “lub” AV valves closing

  • “dub” SL valves closing

  • heart murmur (unusual sound)

• lung sounds:

  • airflow

what is a heartbeat?

• single contraction of the heart in sequence

  • atria contracts first

  • ventricles contract second

    & repeats

what is a cardiac cycle?

• series of pressure changes within the heart due to the movement of blood

what is diastole?

• when the ventricles are relaxed in the cardiac cycle

how long does the average heartrate (bpm) last in a cardiac cycle?

• at 75 bpm, the cardiac cycle lasts about 800 milliseconds

what happens when heartrate increases?

• all phases of cardiac cycle shorten, particularly diastole

what does automaticity mean?

to beat on its own

what are the 2 parts of the conducting system of the heart? briefly describe their function

• conducting system

  • function: controls and coordinates heartbeat

• contractile cells

  • function: produce contractions that expel blood

describe the 3 components of the cardiac conducting system and its functions

• sinoatrial (SA) node

  • natural pacemaker of the heart

  • function: initiates heartbeat and determines heartrate

• atrioventricular (AV) node

  • function: passes signal to AV bundle (bundle of His)

• conducting cells

  • function: interconnect nodes and distribute the contractile stimulus throughout the myocardium

describe the sequence of a heartbeat

1. SA node & pacemaker cells initiate heartbeat

2. the action potential travels from SA node to AV node, while the contractile cells stimulate both atria

3. AV node receives the signal after 100 millisecond delay

4. signal travels to AV bundle (bundle of His)

5. then travels to the interventricular septum

6. then travels to right and left bundle branches

7. signal is conducted to Purkinje fibers

8. then to the moderator band & papillary muscles

9. ventricles begin to contract

what is an arrythmia?

any deviation in the normal heartbeat rhythm

what are the 5 types of arrythmia?

• tachycardia: too fast

• brachycardia: too slow

• premature contraction: too early

• fibrillation: too erratic

• etopic pacemaker: contractile cells start trying to send conduction signals

what are the 3 types of ECG/EKGs?

• 3 lead (portable)

• 5-7 lead (portable)

• 12 lead (standard type in hospitals and ambulances)

what is the resting membrane potential (polarized state)?

when the heart is ready to contract

what is depolarization?

when the heart is contracting

what causes polarization and depolarization?

• sodium-potassium pump

  • allows cells to change from resting potential to excitable, enabling it to contract

what is an electrocardiogram?

a tool to see what the heart is doing

how do you read an ECG/EKG?

• P wave

  • atrial depolarization

• QRS complex

  • ventricle depolarization

• T wave

  • ventricle repolarization

how do you calculate heartrate?

6 second rule

• (#of R waves in a 6 second period) x 10

what portion of the conducting system does the right ventricle contain? describe its functions

moderator band

• functions:

  • coordinates contractions

  • delivers contraction stimulus to papillary muscles

    • so that the chorea tendinea is put under tension before the ventricle contracts

briefly describe the features of the left atrium

• has less prominent pectinate muscles

• contains the bicuspid/mitral valve

  • leads blood from the left atrium to the left ventricle

how does blood move out the left ventricle?

• leaves the left ventricle through the aortic valve into the ascending aorta then out to the rest of the body

describe the physical features of the left ventricle

• has trabeculae carneae (muscular ridges)

• no moderator band

• contains papillary muscles

  • opens and closes the mitral valve

• thick walls for a more powerful contraction

label #1, 9, 10

aortic artery

label #2

superior vena cava

label #3

aortic valve

label #4

pulmonary semilunar (SL) valve

label #5

tricuspid valve

label #6

leaflet

label #7

pectinate muscle

label #8

papillary muscle

label #11

aorta

label #12, 13

pulmonary artery

label #14

mitral/bicuspid valve

label #15

leaflet

label #16

chordae tendineae

label A

right atrium

label B

right ventricle

label C

left atrium

label D

left ventricle

describe the 2 types of sulci

• coronary sulcus: border between atria and ventricles

• anterior & posterior interventricular sulcus: divides the ventricles on the anterior & posterior sides of the heart