BODY SYSTEMS

CARDIOVASCULAR SYSTEM

FUNCTION: Transport, protection, and regulation

ARTERY STRUCTURE

• Structure: Outer layer of collagen and elastic fibers
• Purpose: avoid leaks and bulges.

ARTERY STRUCTURE

• Structure: Layers of circular elastic fibres and muscle fibers
• Purpose: Pump the blood after each heart contraction

ARTERY STRUCTURE

• Structure: Narrow lumen
• Purpose: Maintain blood pressure

CAPILLARY STRUCTURE

• Structure: one cell layer thick
• Purpose: Diffusion distance is small

CAPILLARY STRUCTURE

• Structure: Pores in capillary wall
• Purpose: Phagocytes and plasma can pass thru pores

CAPILLARY STRUCTURE

• Structure: Narrow lumen
• Purpose: Many capillaries can fit in a small space

VEIN STRUCTURE

• Structure: Wide lumen
• Purpose: Slow flowing fluid

VEIN STRUCTURE

• Structure: Thin layer with few muscle fibres and circular elastic fibres
• Purpose: Blood doesn't flow in pulses

VEIN STRUCTURE

• Structure: Thin outer layer of longitudinal collagen and elastic fibres
• Purpose: Pressure is low

VEIN STRUCTURE

• Structure: Thin vein walls
• Purpose: muscles can help push blood toward the heart

THE FLOW OF BLOOD THRU THE HEART

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1. Blood enters the right atrium from the superior and inferior venae cavae, and the coronary sinus.

2. As the atrium contracts, it goes through the tricuspid valve to the right ventricle.

3. The tricuspid valve shuts. From the right ventricle, it goes through the pulmonary semilunar valves to the pulmonary trunk.

4. From the pulmonary trunk it moves into the right and left pulmonary arteries to the lungs.

5. From the lungs, oxygenated blood is returned to the heart through the pulmonary veins.

6. From the pulmonary veins, blood flows into the left atrium.

7. From the left atrium, blood flows through the bicuspid (mitral) valve into the left ventricle.

8. The mitral valve shuts. From the left ventricle, it goes through the aortic semilunar valves into the ascending aorta.

9. Blood is distributed to the rest of the body (systemic circulation) from the aorta.

COMPOSITION OF BLOOD

• Plasma:
• a mixture of proteins, enzymes, nutrients, wastes, hormones and gases.

COMPOSITION OF BLOOD

• Formed elements:
• Erythrocytes (RBC)
• Leukocytes (WBC)
• Platelets

BLOOD CELLS

• Erythrocytes (RBC)
• Leukocytes (WBC):

EYTHROCYTES

• Structure: biconcave
• Function: easy to maneuver through capillaries and hold oxygen

CIRCULATORY SYSTEMS

• Open
• Closed

OPEN

• Sinuses fill with hemolymph
• Simple, tubular heart
• Low fluid pressure
• Ex: invertebrates

CLOSED

• System of vessels
• Blood is always enclosed in a vessel
• More efficient
• Ex: vertebrates

Fish have a single systemic circuit for blood. The heart pumps the blood to the gills to be re-oxygenated (gill circulation), then the blood flows to the rest of the body and back to the heart.

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Amphibians have a three-chambered heart that has two atria and one ventricle. The two atria receive blood from the lungs and the systems. There is some mixing of the blood in the heart's ventricle, which reduces the efficiency of oxygenation.

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REPTILE

• two atria - one receives blood from the body and one receives blood from the lungs
• undivided ventricle
• circulation divides into three channels after the conus arteriosus - pulmonary trunk, right and left systemic trunks

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MAMMALS

• 4 chambers
• No mixing of blood
• Most efficient

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STROKE

• Loss of blood to brain
• Speech difficulty
• Muscle weakness on one side
• Drooping face

PREVALENCE AND TREATMENT

• CV disease causes 41% of US deaths
• Treated with lifestyle changes

ATHEROSCLEROSIS

• Build up of fat along artery walls
• No noticeable symptoms until a serious incident

PREVALENCE AND TREATMENT

• 2 million cases in the US per year
• Lifestyle changes
• Blood thinners
• Therapy

SOURCES

• hes.ucfsd.org/gclaypo/circulatorysys.html
• www.hematology.org/Patients/Basics/
• www.innerbody.com/image/card01.html