Circulatory System

Chapter 32

Be able to :

1. Identify Structure & Function of the heart, arteries, veins, & capillaries.

2. Trace the pathway of blood through all 4 chambers of the heart.

3. Trace the pathway of blood through both parts of the circulatory system.

4. Identify relationship of circulatory system to respiratory & digestive system & body cells.

See Figure 32-3, Fig. on pg 655, Fig. 32-7, Fig. 32-8, & Fig. 32-9

---

Circulatory system - Consists of heart, blood, & blood vessels.

Function: To supply oxygen, nutrients, & hormones to all of the body's cells, and to remove waste materials such as CO2.

---

Heart : Muscular pump with 4 chambers, contracting at regular intervals to force blood through the circulatory system.

Left side of heart receives & pumps oxygen rich blood from lungs.

Left Atrium : Receives oxygenated blood from the lungs via the pulmonary vein. Pumps blood to left ventricle.

Left Ventricle : Pumps oxygenated blood into the aorta & hence to all body cells (except lungs).

Septum : Thick wall that separates the left & right chambers of the heart.

Right side of heart receives & pumps oxygen poor blood.

Right Atrium : Receives oxygen poor blood from the body via the upper & lower vena cavas. Sends blood to right ventricle.

Right Ventricle : Pumps oxygen poor blood to the lungs.

Valve : Valves (like trap doors) between the atria and ventricles which allow flow into the ventricles, but no flow backwards to atria.

Pacemaker : (Sinoatrial node) Nerve tissues that receive impulses from brain or spinal column & transfer signal to heart. Controls heart beat. Found atop right atrium.

Vena Cava (superior & inferior): Large veins collecting oxygen poor blood from smaller veins in body. Superior v.c. brings blood from upper body, inferior v.c. brings blood from the lower body.

Aorta : Large, thick muscled artery through which oxygenated blood leaves the heart (from left ventricle) for the body tissues.

Pulmonary Artery : Artery transporting oxygen poor blood from right ventricle to lungs.

Pulmonary Vein : Vein transporting oxygen rich blood from lungs to left atrium.

Artery : Transports blood outward from heart to all body tissues. Must be thick, muscular & elastic to withstand pressure from heartbeat.

Capillary : Thin blood vessels in the tissues (about one red blood cell wide) through which oxygen & nutrients diffuse to the cells, and wastes & CO2 diffuse into the blood. Found between all arteries & veins.

Vein : Blood vessels carrying blood towards the heart from body tissues or organs. Are thin-walled as blood pressure is low.

Pulmonary Circulation : Movement of blood between heart & lungs & back to heart.

Includes right ventricle--->pulmonary artery--->lungs---> pulmonary vein--->left atrium. Involves oxygenation of blood!

Systemic Circulation : Movement of blood from heart to the rest of the body & return to the heart. Includes left ventricle--->aorta--->arteries--->capillaries in the body tissues--->veins--->vena cava--->right atrium.