Internal transport in the Cnidarian Aurelia

Open and Closed Circulatory Systems

The Mammalian Heart: A Closer Look

Generalized Circulatory Schemes of Vertebrates

The Mammalian Cardiovascular System: An Overview

The Heart Cardiac muscle Atria have thin walls Ventricles have thick and powerful walls Systole = ventricular contraction blood is pumped Diastole = ventricular filling

The Cardiac Cycle One complete sequence of pumping and filling

Lub dub = heart sounds opening and closing of the valves –Lub = blood recoiling against the AV valves –Dub = blood recoiling against SL valves Heart murmur = valve defect

The Control of Heart Rhythm

The Structure of Blood Vessels

Blood Pressure The force that blood exerts against vessel walls BP is greater in arteries than veins Pulse is measure of BP Exact BP is measured as systolic/diastolic pressures Constricted blood vessels have higher BP than dilated vessels In veins heart has little effect on BP

Measurement of Blood Pressure

The Interrelationship of Blood Flow Velocity, Cross-Sectional Area of Blood Vessels, and Blood Pressure

Blood Flow in Capillary Beds The thoroughfare channels remain open whether or not the sphincter muscles are contracted or relaxed

The Movement of Fluid Between Capillaries and the Interstitial Fluid fluid moves out of capillary fluid moves into capillary

Lymphatic System Lymphatic system returns lost fluid to circulatory system (about 4L per day or 15% of the fluid) Lymph nodes filter the lymph and help fight infection

Differentiation of Blood Cells 5-6 million/mm3

Atherosclerosis: Normal Artery and Artery With Plaque

A cascade of complex reactions converts prothrombin to thrombin and then fibrinogen to fibrin, forming a clot Platelet plug Collagen fibers Platelet releases chemicals that make nearby platelets sticky Clotting factors from: Platelets Damaged cells Plasma (factors include calcium, vitamin K) Prothrombin Thrombin Fibrinogen Fibrin 5 µm Fibrin clot Red blood cell The clotting process begins when the endothelium of a vessel is damaged, exposing connective tissue in the vessel wall to blood. Platelets adhere to collagen fibers in the connective tissue and release a substance that makes nearby platelets sticky. 1 The platelets form a plug that provides emergency protection against blood loss. 2 This seal is reinforced by a clot of fibrin when vessel damage is severe. Fibrin is formed via a multistep process: Clotting factors released from the clumped platelets or damaged cells mix with clotting factors in the plasma, forming an activation cascade that converts a plasma protein called prothrombin to its active form, thrombin. Thrombin itself is an enzyme that catalyzes the final step of the clotting process, the conversion of fibrinogen to fibrin. The threads of fibrin become interwoven into a patch (see colorized SEM). 3 Figure 42.17

Blood Clot

In which type of blood vessel is the blood pressure the highest? What type of blood vessel provides the heart muscle with oxygen?

Name two factors which are under your control that affect your heart and cardiovascular health. What do you think is an “ideal” blood pressure? When is the blood blue?

After leaving the right ventricle blood flows to.. The heart is enclosed in a protective sac of muscle called the ______________. The “pacemaker” of the heart is....

Of what three substances are the walls of arteries, capillaries, and veins composed?

Oxygen and carbon dioxide are exchanged in the lungs in vessels called _____________. During inhalation air passes from the mouth through the pharynx and into the __________.