• A series of vessels delivers blood from the heart to the capillaries, where exchange of substances takes place, and then another series of vessels delivers blood from the capillaries back to the heart.

1. What types of blood vessels are there?
   Answer
   
   
2. What is the structure and function of these vessels?
   Answer

• Vessels I (25.0K)
• Blood Vessels II (32.0K)
• Anatomy of a Capillary Bed (37.0K)

• The human heart is a double pump; the right side pumps blood to the lungs, and the left side pumps blood to the rest of the body.
  
  
• The heartbeat rate is under intrinsic and extrinsic control.

1. Why is the heart called a double pump?
   Answer
   
   
2. What keeps the heartbeat regular?
   Answer

• Cardiac Cycle Blood Flow-Normal Speed
• Cardiac Cycle Blood Flow-Slow Speed
• Cardiac Cycle-Electrical
• Cardiac Cycle-Muscular

Art Labeling Activity

• External Heart Anatomy I (34.0K)
• External Heart Anatomy II (32.0K)
• External Heart Anatomy III (41.0K)
• Internal View of the Heart I (36.0K)
• Internal View of the Heart II (35.0K)
• Internal View of the Heart III (33.0K)
• Internal View of the Heart IV (32.0K)

Essential Study Partner

• Heart Blood Flow

• The pulse rate of a person indicates the heartbeat rate.
  
  
• Blood pressure accounts for the flow of blood in the arteries. Skeletal muscular contraction, the presence of valves, and breathing movements account for the flow of blood in the veins.

1. How does the pulse rate of a person indicates the heartbeat rate?
   Answer
   
   
2. What accounts for the flow of blood in the arteries?
   Answer
   
   
3. What accounts for the flow of blood in the veins?
   Answer

• Vessels and Pressure

Bioethical Focus

• Health Insurance

• The pulmonary arteries transport O₂-poor blood to the lungs, and the pulmonary veins return O₂-rich blood to the heart.
  
  
• The systemic circuit transports blood from the left ventricle of the heart to the body and then returns it to the right atrium of the heart.

1. What is the relative oxygen content of the blood flowing in the pulmonary artery compared to the pulmonary vein? Explain.
   Answer
   
   
2. What is the pathway of blood in the pulmonary circuit?
   Answer

• Portal System

Art Labeling Activity

• Human Circulatory System I (45.0K)
• Human Circulatory System II (44.0K)

• The lymphatic vessels form a one-way system, which transports lymph from the tissues and fat from the lacteals to certain cardiovascular veins.
  
  
• The lymphoid organs (red bone marrow, spleen, thymus, lymph nodes, and tonsils) play critical roles in defense mechanisms.

1. How does the lymphatic system assist the cardiovascular system?
   Answer
   
   
2. What role do lymphatic organs play in purifying the lymph and blood?
   Answer

• Lymphatic System

Art Labeling Activity

• Lymphatic System (33.0K)
• The Lymphoid Organs (29.0K)
• Thymus Gland (38.0K)
• Lymph Node (39.0K)
• Spleen (37.0K)
• Bone Marrow (37.0K)

Animation Activity

• The Lymph System

• Although the cardiovascular system is very efficient, it is still subject to degenerative disorders.

1. What degenerative circulatory disorders are common in humans?
   Answer

• Myocardial Infarction

Art Labeling Activity

• Plaque (53.0K)

Bioethics Case Study

• Heart Transplant

• The cardiovascular system works with the other systems of the body to maintain homeostasis.

1. How does the cardiovascular system work with other systems of the body to maintain homeostasis?
   Answer

• Systems Scramble
• Systems Review Quiz