Anatomy and Physiology II - Chapter 12: Cardiovascular System

This goes over the Cardiovascular System. The specific course is Anatomy and Physiology II (BIOL-2402)

arteries

carry blood away from the heart

• systemic arteries are red (high O₂)

• pulmonary and umbilical arteries are blue (low O₂)

veins

carry blood to the heart

• systemic veins are blue (low O₂)

• pulmonary and umbilical veins are red (high O₂)

atria

atriums, heart chambers that receive blood

ventricles

heart chambers that pump blood

deoxygenated and oxygenated blood sides of the heart

right = deoxygenated

left = oxygenated

layers of the heart

heart is in pericardial sac

• pericardium

  • parietal pericardium

  • visceral pericardium

• pericardial cavity

• myocardium

• endocardium

endocarditis

inflammation of endocardium, usually on valves

• clotting, can be fatal

chordae tendineae

attached to AV (tricuspid and bicuspid) valves and papillary muscles to prevent collapse

papillary muscles

in ventricles, help ventricles pump blood

mitral valve prolapse

backflow of blood into left atrium

• common on left side due to left ventricle contraction to pump blood to the body → increased pressure

• can create heart murmur (abnormal sound)

sulcus

raised ridge/bump on surface

septum

wall that separates chambers

skeleton of heart

made of fibrous tissue made of tough collagen fibers

• reinforces heart around openings and exit vessels → prevents tearing

• electric insulator between atria and ventricles

cardiac cycle

blood flow through heart in 1 heartbeat, causes blood pressure and volume changes

• atrial systole and diastole → ventricle systole and diastole

systole

contraction of the heart

diastole

relaxation of the heart

heart sounds

• lub + dub: heart valves closing

• pause: relaxation

lub

atrioventricular (tricuspid and bicuspid) valves closing

• start of systole

dub

semilunar (pulmonary and aortic) valves closing

• start of diastole

intercalated discs

junctions between cells that anchor cardiac cells

desmosomes

prevents cells from separating during contraction

gap junctions

allows ions to pass from cell to cell

• electrically couple adjacent cells

• lets the heart be a functional syncytium and behaves as 1 coordinated unit

cardiac muscle differences from skeletal

• 1% have automaticity/auto rhythmicity to depolarize the whole heart w/o nervous system stimulation

• all or nothing contraction of cardiomyocytes

• long absolute refractory period (250 ms) to prevent tetanic contractions

factors that raise heart rate

• SNS stimulation of adrenergic fibers → norepinephrine rises

• increased blood pressure in venae cavae

  • 60% of blood is in the veins at rest

  • usually passive, exercise pushes it back to the heart

• increased temperature from fever or exercise

factors that decrease heart rate

• PSNS stimulation of cholinergic fibers → acetylcholine rises

• increased blood pressure in aorta

• decreased temperature from low activity

hypocalcemia

low blood calcium

depresses heart

hypercalcemia

high blood calcium

heart rate and contractility increases

hypokalemia

low blood potassium

feeble heartbeat, arrhythmia

hyperkalemia

high blood potassium

alters electrical activity → heart blockage and cardiac arrest

electrocardiogram (ECG or EKG)

composite of all action potentials from nodal and contractile cells

• depolarization

• polarization/repolarization

• waves

  • p wave

  • QRS complex

  • t wave

depolarization

excited, muscles contract

polarization/repolarization

resting/relaxed state, muscles relax

p wave

depolarization of SA node → atria

QRS complex

ventricular depolarization and atrial repolarization

• usually ventricular depolarization due to the ventricles being larger

t wave

ventricular repolarization

tachycardia

abnormally fast heart rate (>100 bpm)

• can lead to fibrillation

bradycardia

abnormally slow heart rate (<60 bpm)

• can be good for athletes

• can be bad for non-athletes and cause poor blood circulation

arrhythmia

irregular heart rhythms from uncoordinated AV contracts

• can be due to defects in the intrinsic conductor system

fibrillation

arrhythmia

rapid, irregular contractions useless for pumping blood

atria fibrilliation

arrhythmia

atria races → clotting

• chronic

• can cause stroke

• long-term management

ventricle fibrilliation

arrhythmia

ventricles stop circulating blood → brain death

• sudden

• can cause cardiac arrest

• immediate treatment

normal blood pressure

120/80

cardiac output (CO)

volume of blood pumped by each ventricle in 1 minute, usually about 5 liters per minute

• heart rate x stroke volume

heart rate

heart beats per minute

stroke volume

volume of blood pumped out by 1 ventricle with each beat

cardiac reserve

difference between resting and maximal CO

angina infarction

mild chest pain

• cause: exercise or emotion

• relief: rest, nitrates

• severity: mild

• anxiety: none

• nausea/vomiting: no

• sympathetic activity rises: no

myocardial infarction

severe chest pain

• cause: not obvious

• relief: NOT rest, nitrates

• severity: severe

• anxiety: mild to severe

• nausea/vomiting: yes

• sympathetic activity rises: yes

aneurysm

bulge on artery

• usually cerebral or aorta

hemorrhagic stroke

blood hemorrhages into brain tissue

ischemic stroke

clot stops blood supply to the brain

transient ischemic attack (TIA)

stroke

interruption of blood flow to brain or eye