Cardiovascular System - TEAS prep

blood

• red liquid that circulates in the arteries and veins of humans and other vertebrate animals

transportation

• carries oxygen and CO2 to and from the tissue of the body

characteristics of blood

• they are always red in color

• the brighter the color, the more oxygen

• veins are depicted as blue and red to indicate lower and higher oxygen levels

primary function

• maintain homeostasis of pH, temperature, osmotic pressure

• transports hormones, nutrients, gases

blood composition

• circulatory system focuses on how these circulate through our bodies

  • plasma

  • erythrocytes and cells

  • platelets

plasma

• liquid portion

• lipids, salt, proteins, water

erythrocytes and cells

• hemoglobin

• RBC transports gases

• WBC fights infection

hemoglobin

• iron rich protein in our RBC that makes it red

platelets

• helps with clotting (like when we scrape our knee)

arteries

• carry blood away from the heart

• typically oxygen rich, there are some exceptions though

• different in pulmonary circulation*

veins

• carry blood back to the heart

• typically oxygen poor

• VERB = veins efficiently return blood

• different in pulmonary circulation*

pulmonary circulation

• pulmonary arteries carry oxygen poor blood

• pulmonary veins carry oxygen rich blood

capillaries

• the site of gas exchange for oxygen and CO2

• tiny blood vessels where oxygen is delivered to organs and tissues, while CO2 transports back to the lungs

overview of the heart

• *study the diagram

• right and left sides are flipped

• A = atrium

• V = ventricle

• sometimes due to congenital heart conditions, deoxygenated and oxygenated blood tend to mix together

• 4 chambers

atrium

• have thin walls

ventricle

• have thick walls

“right side” of the heart

• deoxygenated blood side

• where blood gets circulated into the lungs and returns to the left side

“left side” of the heart

• oxygenated blood side

4 chambers of the heart

• A comes before V in the alphabet (A on top of V)

  • right atrium

  • right ventricle

  • left atrium

  • left ventricle

heart valves

• help prevent blood from flowing backward

• like one way doors separate chambers and prevent blood from flowing backwards

blood flow of deoxygenated blood to lungs

• superior vena cava/ inferior vena cava → right atrium → tricuspid valve → right ventricle → pulmonic valve → pulmonary artery → lungs

• ex: the blood in our fingertips is deoxygenated and needs to go all the way back to the heart, through this process, to the lungs

superior vena cava

• collects blood from upper half of body

  • head

  • neck

  • upper limbs

  • upper torso

inferior vena cava

• collects blood from the lower half of the body

  • legs

  • back

  • abdomen

  • pelvis

blood flow of oxygenated blood to tissues

• lungs → pulmonary vein → left atrium → bicuspid/ mitral valve → left ventricle → aortic valve → aorta

aorta

• major artery that carries oxygenated blood to all parts of the body, ensuring all organs have O2 to function

coronary arteries

• check diagram

• originate from the aorta and delivers nutrients and oxygen to the heart

coronary veins

• check diagram

• deoxygenated blood returns to the right atrium from the coronary sinus

septal defects

• various conditions can disrupt the heart’s normal function, like altering the flow of blood within the heart

• blood is going to be mixed between deoxygenated and oxygenated blood

• occurs when the septum have some kind of abnormality

• involves the opening that allows oxygen rich and poor blood to mix depending on the defect size, the mixing can lead to significant issues including abnormal heart rhythms, stroke, and heart failure

• treatment includes medications to help manage the symptoms and surgical interventions

septum

• muscular wall that divides the heart’s left and right sides

• function: separate oxygen rich blood from oxygen poor blood between the chambers

interatrial septum

• thin, muscular structure that consists of two parts: fossa ovalis and the limbus of the fossa ovalis

• separate the right and left atria

• disorder: atrial septal defect (ASD)

atrial septal defect (ASD)

• a congenital heart defect where there is an abnormal opening in the interatrial septum, allowing blood to flow between the two atria

interventricular septum

• thick, muscular wall that consists of two-parts: a membranous and muscular portion

• separate the right and left ventricles

• disorder: ventricular septal defect (VSD)

ventricular septal defect (VSD)

• a congenital defect characterized by one or more holes in the interventricular septum, allowing blood to mix between the ventricles

electrical conduction system of the heart

• study diagram

• sinoatrial node

• bachmann bundle

• internodal pathway

• fibrous tissue

• atrioventricular node

sinoatrial node (SA)

• main pacemaker

• start electrical impulse

• triggers atrial contraction

• 60-100 BPM

bachmann bundle

• transmit high speed signal from SA node → left atrium

internodal pathways

• anterior, middle, posterior

• signal from SA node → AV node

fibrous tissue

• found in septum

• is important because it separates the left and right sides of the heart, including the atria and ventricles and hinders direct electrical signal transmission between these heart sections

atrioventricular node (AV)

• secondary pacemaker

• delay signal from SA node, which is crucial because it provides sufficient time for the atria to thoroughly contract

• allows atria to contract to fill ventricles before ventricles can contract

• 40 to 60 BPM

bundle of his

• only route between atria and ventricles

• group of high speed transmission cells from the AV node, through the right atrium, then into the interventricular septum, where it branches off into the left and right ventricles

• note: in individuals without cardiac abnormalities, these pathways represent the sole communication channel between the atrium and ventricles

right bundle branch

• signal to right ventricle

left bundle branch

• signal to left ventricle

purkinje fibers

• last-ditch pacemaker

• connect with myocytes

• initialize depolarization, triggering a contraction

  • ventricular myocytes receive and further transmit those electrical signas to adjacent cells at a slower pace compared to the rapid transmission observed in the high speed bundle branches

• 20 to 40 BPM

• bundle from both right and left bundle branches

• note: the system has its own inherit pacemaker capability of its various cells, which govern the heart rate

• study table

ECG basics

• isoelectric line (baseline)

• P wave

• QRS complex

• T wave

• look at example

P wave

• atrial depolarization (contraction)

QRS complex

• ventricular depolarization (contraction)

• normal QRS range: 0.06 to 0.12 seconds

• atrial repolarization occurs during this, more important because ventricle contracts more forcefully

• note: QRS complex looks like an inverted V, V stands for ventricles

T wave

• ventricular repolarization (relaxation)

depolarization

• contraction

repolarization

• relaxation

systolic pressure

• contraction of the heart “LUB” sound

• top number on reading peak pressure in arteries

• lower than 120

  • a high number could mean heart is too forceful ex: hypertension

diastolic pressure

• relaxation of the heart “DUB” sound

• bottom number on reading lowest pressure in arteries

• lower than 80

  • high number could mean narrow arteries or too stiff increasing risk for heart disease