Cardiovascular system

Cardiovascular system components

Heart, blood vessels, lymphatic system, and blood

Main function of cardiovascular system

Delivers oxygen/nutrients, removes waste, transports hormones

Pulmonary circulation

Exchanges CO₂ for O₂ in lungs

Systemic circulation

Delivers oxygen/nutrients to body and removes waste

Diastole

Heart chambers relax and fill with bloo

Systole

Heart chambers contract and pump blood

SA node

Primary pacemaker (60–100 bpm)

AV node

Backup pacemaker (40–60 bpm)

Heart Function and conduction

Bundle of His — Conducts impulses to ventricles
Bundle branches — Carry impulses through ventricles
Purkinje fibers — Stimulate ventricular contraction

Chemoreceptors

Detect O₂ ↓, CO₂ ↑, pH changes

Baroreceptors

 Detect blood pressure/stretch

Cardiac output (CO)

Amount of blood pumped per minute

Stroke volume (SV)

Blood pumped per beat

Ejection fraction (EF)

% of blood ejected from left ventricle (normal 50–70%)

Preload

Volume of blood returning to heart

Afterload

Resistance heart must pump against

Peripheral vascular resistance (PVR)

 Resistance to blood flow

ADH

Increases water reabsorption → ↑ blood volume & BP

Aldosterone

Retains sodium → water follows → ↑ BP

Decreased cardiac output

Heart pumps insufficient blood

Symptoms →  Fatigue, oliguria, cyanosis, weak pulses

Ineffective tissue perfusion

 Poor oxygen delivery to tissues
Symptoms → Pain, skin changes, necrosis

Dyslipidemia

Elevated lipids in blood

LDL “Bad” cholesterol (to cells)
HDL — “Good” cholesterol (to liver)

Causes — Diet, lifestyle, genetics
Treatment — Lifestyle changes, statins

Atherosclerosis

Plaque buildup in arteries

• Plaque components — Lipids, calcium, fibrin, waste

Complications — Stroke, CAD, PVD, hypertension

Bruit — Swishing sound from turbulent blood flow
Thrill — Palpable vibration

Peripheral Vascular Disease (PVD)

Narrowed peripheral vessels

Arterial signs — Cool, cyanotic
Venous signs — Warm, red

Intermittent claudication — Pain with activity

Coronary Artery Disease (CAD)

Narrowed coronary arteries due to atherosclerosis

Major risk — Myocardial infarction

Thrombus vs Embolus

Thrombus — Stationary clot attached to vessel
Embolus — Traveling clot

Virchow’s triad — Endothelial injury, stasis, hypercoagulability

DVT signs — Red, warm, swollen calf

 Hypertension

BP ≥130/80 mmHg

Primary HTN — No identifiable cause (gradual)
Secondary HTN — Identifiable cause (sudden)

Risk factors — Obesity, smoking, stress, high sodium

Distributive shock

Vasodilation (septic, anaphylactic, neurogenic)

Cardiogenic shock

Heart pump failure

 Hypovolemic shock

Low blood volume

 Obstructive shock

Blocked blood flow

 Where does gas exchange occur in pulmonary circulation?

In the lungs, where carbon dioxide is exchanged for oxygen through diffusion.

 What does the P wave represent on an ECG?

Atrial depolarization (atrial contraction).

What does the QRS complex represent?

Ventricular depolarization (ventricular contraction).

What does increased afterload do to the heart?

It makes it harder for the left ventricle to eject blood, decreasing stroke volume.

What hormone increases blood volume by promoting water retention in the kidneys?

Antidiuretic hormone (ADH).

What are bruits?

Swishing sounds heard over arteries due to turbulent blood flow from plaque buildup.

What is peripheral vascular disease (PVD)?

Narrowing of peripheral arteries or veins, usually from atherosclerosis.

What is the difference between arterial and venous PVD symptoms

Arterial: cool, pale/blue skin
Venous: warm, red skin

What is Virchow’s triad?

Endothelial injury, blood stasis, and hypercoagulability (risk factors for thrombus formation).

What is the difference between a thrombus and an embolus?

 Thrombus = stationary clot attached to vessel wall
Embolus = clot that breaks off and travels

What is the most common cause of hypertension?

Primary (essential) hypertension with no identifiable cause.

What is secondary hypertension?

High blood pressure caused by an identifiable condition (e.g., kidney disease, sleep apnea)

What is the first-line treatment for dyslipidemia?

 Lifestyle changes (diet, exercise), followed by statins if needed.

What is the function of HDL cholesterol?

Removes cholesterol from cells and transports it back to the liver (“good cholesterol”).