Anatomy Presentation Ho 6(circulation)

Circulatory system  The circulatory system transports fluids throughout the body;  it consists of the cardiovascular and lymphatic systems.  The heart and blood vessels form the blood transportation network, the CVS The function of the circulation  to transport nutrients to the body tissues, 

to transport waste products away,

 to conduct hormones from one part of the body to another Cardiovascular System  is a series of tubes (the blood vessels) filled with fluid (blood) and connected to a pump (the heart).  Refers to the heart and blood vessels

 The heart pumps blood through the body's vast system of vessels.  The blood carries nutrients, oxygen, and waste products to and from cells. 1 1

 Blood flows through a network of blood vessels that extend between

 Those blood vessels can be subdivided into  pulmonary circuit  which carries blood to and from the gas exchange surfaces of the lungs, and  systemic circuit  which transports blood to and from the rest of the body.  Each circuit begins and ends at the heart and blood travels through these circuits in sequence.

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Blood Vessels: The Vascular System • Taking blood to the tissues and back • Arteries • Arterioles • Capillaries • Venules • Veins 4 Slide

The Vascular System

Figure 11.8b

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Blood Vessels: Anatomy • Three layers (tunics) • Tunic intima • Endothelium • Tunic media • Smooth muscle • Controlled by sympathetic nervous system • Tunic externa • Mostly fibrous connective tissue 6 Slide

Differences Between Blood Vessel Types • Walls of arteries are the thickest • Lumens of veins are larger • Skeletal muscle “milks” blood in veins toward the heart • Walls of capillaries are only one cell layer thick to allow for exchanges between blood and tissue 7 Slide

Movement of Blood Through Vessels • Most arterial blood is pumped by the heart • Veins use the milking action of muscles to help move blood

Figure 11.9

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Capillary Beds • Capillary beds consist of two types of vessels • Vascular shunt – directly connects an arteriole to a venule

Figure 11.10

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Capillary Beds • True capillaries – exchange vessels • Oxygen and nutrients cross to cells • Carbon dioxide and metabolic waste products cross into blood Figure 11.10

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Diffusion at Capillary Beds

Figure 11.20

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Vital Signs     

Arterial pulse Blood pressure Repiratory Rate Body Temperature All indicate the efficiency of the system

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Pulse • Pulse – pressure wave of blood • Monitored at “pressure points” where pulse is easily palpated Figure 11.16

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Blood Pressure • Measurements by health professionals are made on the pressure in large arteries • Systolic – pressure at the peak of ventricular contraction • Diastolic – pressure when ventricles relax

• Pressure in blood vessels decreases as the distance away from the heart increases 14 Slide

Measuring Arterial Blood Pressure

Figure 11.18

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Blood Pressure: Effects of Factors • Neural factors • Autonomic nervous system adjustments (sympathetic division)

• Renal factors • Regulation by altering blood volume • Renin – hormonal control

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Blood Pressure: Effects of Factors • Temperature • Heat has a vasodilation effect • Cold has a vasoconstricting effect

• Chemicals • Various substances can cause increases or decreases

• Diet 17 Slide

Variations in Blood Pressure • Human normal range is variable • Normal • 140–110 mm Hg systolic • 80–75 mm Hg diastolic • Hypotension • Low systolic (below 110 mm HG) • Often associated with illness • Hypertension • High systolic (above 140 mm HG) • Can be dangerous if it is chronic 18 Slide

The lymphatic system  Includes: lymph, lymphatic vessels, lymphatic tissue, lymphatic nodules, lymph nodes, tonsils, the spleen, and the thymus.  The major functions of the lymphatic system include  fluid balance,  fat absorption, and  defense.  Recall that as blood flows thru systemic capillaries, a small net amount of fluid is exuded into the interstitial space.  While this fluid loss from the capillaries is necessary to maintain the presence and composition of tissue fluid (and thus intracellular fluid as well), too much fluid loss is not a good thing.  Luckily, we have lymphatic vessels, whose main function is to return this fluid to the vascular system.  Additionally, they play a huge role in detecting pathogens and activating the appropriate immune response.

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 Lymphatic vessels  return approximately 3L of fluid to the vascular system per day.  This ensures that blood volume is sufficient.  They also return any leaked plasma proteins back to the bloodstream. 

Fluid within lymphatic vessels is known as lymph.

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Lymph  is similar to plasma except it contains fewer proteins.  It contains water, nutrients, ions, gases, wastes, and hormones.

 Lymphatic vessels are a 1-way system flowing toward the heart.  There are several types of lymphatic vessels including: lymphatic capillaries, lymphatic collecting vessels, lymphatic trunks, and lymphatic ducts.  Lymphatic capillaries  are blind capillaries found almost everywhere blood capillaries are found, i.e., everywhere tissue fluid is formed.  Areas w/o lymphatic capillaries include bones, teeth, and CNS.  Little ISF is found w/i bones and teeth.  CNS ISF drains into the cerebrospinal fluid. 21 21

 The simple squamous epithelial cells of the capillary wall overlap and are loosely attached to another.  This makes the lymphatic capillaries quite permeable (much more so than blood capillaries) and ensures that fluid is able to enter but not leave.  Fluid enters easily, as do proteins, WBCs, pathogens, and cancer cells.  Specialized lymphatic capillaries, known as lacteals, are present in the intestinal mucosa where they assist in absorption of dietary fat.

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 Lymphatic collecting vessels  receive lymph from lymphatic capillaries.  They’re similar to veins (tunics with similar proportions) but contain more valves.  There exist both superficial and deep lymphatic collecting vessels.  They pass thru lymph nodes, where lymph is monitored and “cleaned” of pathogens and cancer cells.  Lymphatic trunks  The union of the largest lymphatic vessels .  The jugular trunks drain the head and neck;  the subclavian trunks drain the upper limbs, superficial thoracic wall, and mammary glands;  the bronchomediastinal trunks drain thoracic organs and the deep thoracic wall;  the intestinal trunks drain the intestines, stomach, pancreas, spleen, and liver; and the lumbar trunks drain the lower limbs, pelvic and abdominal walls, pelvic organs, gonads, kidneys, and adrenal glands.  Lymphatic duct  The union of lymphatic trunks  There are 2 lymphatic ducts: the right lymphatic duct and the thoracic duct.

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 The right lymphatic duct  drains lymph from the right arm and the right side of the head and thorax. 

It receives lymph from the right jugular, right subclavian, and right bronchomediastinal trunks.

 It then empties into the right internal jugular vein.  The thoracic duct  drains lymph from the rest of the body.  It receives lymph from the left jugular, left subclavian, left bronchomediastinal, intestinal, and lumbar trunks.  It empties into the left internal jugular vein.  Note that there is a large degree of variability in the formation and emptying of the lymphatic ducts.

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Lymph • Materials returned to the blood • Water • Blood cells • Proteins

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Lymph • Harmful materials that enter lymph vessels • Bacteria • Viruses • Cancer cells • Cell debris

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Lymph Nodes • Filter lymph before it is returned to the blood • Defense cells within lymph nodes • Macrophages – engulf and destroy foreign substances • Lymphocytes – provide immune response to antigens Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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Lymph Nodes

Figure 12.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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Lymph Node Structure

Figure 12.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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Other Lymphoid Organs • Several other organs contribute to lymphatic function • Spleen • Thymus • Tonsils • Peyer’s patches Figure 12.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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The Spleen • Located on the left side of the abdomen • Filters blood • Destroys worn out blood cells • Forms blood cells in the fetus • Acts as a blood reservoir

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The Thymus • Located low in the throat, overlying the heart • Functions at peak levels only during childhood • Produces hormones (like thymosin) to program lymphocytes

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Tonsils • Small masses of lymphoid tissue around the pharynx • Trap and remove bacteria and other foreign materials • Tonsillitis is caused by congestion with bacteria

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Peyer’s Patches

• Found in the wall of the small intestine • Resemble tonsils in structure • Capture and destroy bacteria in the intestine

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Mucosa-Associated Lymphatic Tissue (MALT) • Includes: • Peyer’s patches • Tonsils • Other small accumulations of lymphoid tissue

• Acts as a guard to protect respiratory and digestive tracts Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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