Cardiovascular System: Heart Overview

Where is the Heart located?

in the Mediastinum

• between the lungs— left of midline

Cardiopulmonary Resuscitation (CPR)

chest compressions → keeps blood flowing even when Heart stops pumping

What is the Pericardium?

thin, fluid-filled + double-walled sac

• surrounds & protects the Heart

• prevents friction from Heartbeats

What are the two divisions of the Pericardium?

1. Fibrous— tough, outer layer (prevents overstretching)

2. Serous— doubled inner layer (Parietal → Visceral)

What are the layers of the Heart Wall?

1. Epicardium (“Visceral”)— outermost layer (directly covers)

2. Myocardium— middle layer w/ thick cardiac m. (helps pumping)

3. Endocardium— innermost layer w/ smooth simple squamous (lines 4 chambers)

Pulmonary Circuit

Deoxygenated blood from RV (Heart) → Pulmonary Artery (= Lungs) collecting O2

Systemic Circuit

Oxygenated blood from LV (Heart) → Aortic Artery (= Tissues) delivers O2/nutrients

Why is Circulation important?

• allows for continuous supply of O2/nutrients

• prevents buildup of waste in body cells

Sulci

grooves on the surface that contains Coronary BV & Fatss

Coronary Sulcus

deep external groove encircling the heart

• marks boundary between the Atria & Ventricles

Interventricular Sulci— Anterior & Posterior

marks boundary between R/L Ventricles

Auricles

Wrinkled, pouch-like muscular extensions on ant. surface of Atriums

• expands = increases blood-holding capacity

Right Atrium

RECIEVES deoxygenated blood via…

1. superior/inferior vena cava

2. coronary sinus

Right Ventricle

PUMPS deoxygenated blood → Pulmonary Circuit to Lungs

Left Atrium

RECIEVES (now) oxygenated blood from Pulmonary Veins (Lungs)

Left Ventricle

PUMPS out oxygenated blood → Systemic Circuit to Body Tissues

Coronary Circulation

network of BV that delivers oxygen-RICH blood to the Heart muscle (+ carries away Wastes)

Structural Characteristics of Cardiac Muscle Tissue

thick, branched cells

• intercalated discs

• desmosomes

• gap junctions

Functional Characteristics of Cardiac Muscle Tissue