Circulation By Nick Onuska

Evolutionary Development of Circulation In unicellular protists, nutrients and oxygen can be obtained by basic diffusion in an aquatic environment In unicellular protists, nutrients and oxygen can be obtained by basic diffusion in an aquatic environment This is true because of the simple body structure of the animals This is true because of the simple body structure of the animals In larger animals, cells and tissues are simply too far away from the surface or digestive cavity to obtain oxygen in this way In larger animals, cells and tissues are simply too far away from the surface or digestive cavity to obtain oxygen in this way Instead, they obtain oxygen through an internal fluid Instead, they obtain oxygen through an internal fluid –This is the circulatory system

Evolutionary Development of Circulation Two main types of circulation Two main types of circulation –Open –Closed In an open system there is no distinction between the blood and the extracellular fluid In an open system there is no distinction between the blood and the extracellular fluid –This fluid is known as hemolymph In a closed system, the blood is always enclosed with blood vessels that transport it to a pumping system. In a closed system, the blood is always enclosed with blood vessels that transport it to a pumping system. –Ex. Heart

Purpose of Circulatory System The circulator system serves several purposes The circulator system serves several purposes –Transportation –Regulation –Protection

Transportation Substances needed for cellular metabolism are transported by the circulatory system Substances needed for cellular metabolism are transported by the circulatory system –This can be broken down into  Respiratory: Red blood cells carry oxygen and CO2  Nutritive: Nutrients from broken down food  Excretory: Waste products being transferred top kidneys

Regulation The circulatory system helps to regulate the body by transporting hormones and regulating temperature The circulatory system helps to regulate the body by transporting hormones and regulating temperature –Hormone Transport: Carries hormones from endocrine glands –Temperature Regulation: Maintains temperature by using countercurrent heat exchange

Protection The circulatory system protects the body from injury and toxins The circulatory system protects the body from injury and toxins –Blood Clotting: Prevents against blood loss –Immune Defense: White blood cells provide immunity against disease

Structure and Function of the Circulatory system

Blood Blood is made up of a fluid called plasma and several different types of cells that exist in this fluid Blood is made up of a fluid called plasma and several different types of cells that exist in this fluid Metabolites, wastes, and hormones Metabolites, wastes, and hormones Ions Ions Proteins Proteins OMNOMNOMN OMNOMNOMN

Metabolites, wastes, and hormones Plasma contains many dissolved metabolites that are used by cells Plasma contains many dissolved metabolites that are used by cells –Ex. Glucose, Amino Acids, and vitamins Hormones that regulate cell activity are also dissolved in plasma Hormones that regulate cell activity are also dissolved in plasma In addition, wastes like CO2 are also contained and transported in plasma In addition, wastes like CO2 are also contained and transported in plasma

Ions Similar to a sea, plasma is a salt solution Similar to a sea, plasma is a salt solution It contains many different ions It contains many different ions –Ex. Na+, Cl+, bicarbonate ions However, plasma has a lower ion concentration then seawater However, plasma has a lower ion concentration then seawater

Proteins Most proteins in plasma are produced by the liver Most proteins in plasma are produced by the liver –Albumin: Most of the plasma protein –Alpha and Beta Globulins: Carry lipid and steroid hormones –Fibrinogen: essential for clotting Plasma without Fibrinogen is known as serum Plasma without Fibrinogen is known as serum

Types of Blood Cells Erythrocytes Erythrocytes Leukocytes Leukocytes Platelets Platelets

Erythrocytes Erythrocytes are also known as red blood cells Erythrocytes are also known as red blood cells In vertebrates, Erythrocytes contain hemoglobin, a substance that transports oxygen In vertebrates, Erythrocytes contain hemoglobin, a substance that transports oxygen Erythrocytes also develop from stem cells and are constantly developed in the bone marrow Erythrocytes also develop from stem cells and are constantly developed in the bone marrow

Leukocytes Leukocytes are also known as white blood cells. Their primary job is to defend the body Leukocytes are also known as white blood cells. Their primary job is to defend the body There are several kinds of Leukocytes each with their own specialized functions There are several kinds of Leukocytes each with their own specialized functions Granular leukocytes Granular leukocytes –Neutrophils –Eosinophils –Basophils Non Granular leukocytes Non Granular leukocytes –Monocytes –Lymphocytes

Platelets The primary goal of Platelets is to help blood to clot The primary goal of Platelets is to help blood to clot They come from Megakaryocytes, large cells in bone marrow They come from Megakaryocytes, large cells in bone marrow –A piece of the cytoplasm is pinched off and becomes a platelet

Platelets When a blood vessel breaks, platelets build up at the site and plug it up by sticking to each other When a blood vessel breaks, platelets build up at the site and plug it up by sticking to each other The protein fibrin reinforces this plug The protein fibrin reinforces this plug Often red bloods are caught in this plug and create a blood clot Often red bloods are caught in this plug and create a blood clot

Blood Vessels Blood exits the heart through vessels called arteries. Blood exits the heart through vessels called arteries. –These eventually branch out, reaching every organ in the body The smallest vessels are known as arterioles The smallest vessels are known as arterioles –Blood from these enters the capillaries, a large quantity of very narrow, thin walled tubes

Blood Vessels After leaving the capillaries, blood flows into the vessels which will eventually lead back to vessels called veins After leaving the capillaries, blood flows into the vessels which will eventually lead back to vessels called veins –Veins carry blood back to the heart The walls of capillaries are thin enough that molecules and ions can diffuse out of them, leave by filtration from pores on the cell, or transport through the endothelial cells. The walls of capillaries are thin enough that molecules and ions can diffuse out of them, leave by filtration from pores on the cell, or transport through the endothelial cells. This means that blood traveling in capillaries exchanges nutrients with fluids and cells in the body This means that blood traveling in capillaries exchanges nutrients with fluids and cells in the body

Arteries

Arteries Arteries work by transporting blood away from the heart Arteries work by transporting blood away from the heart Arteries often have elastic fibers that allow them to recoil along with the beating of the heart Arteries often have elastic fibers that allow them to recoil along with the beating of the heart Having so many arteries often presents a risk with friction Having so many arteries often presents a risk with friction –Smaller arteries have the highest resistance

Arteries There are several ways Arteries can get around this resistance There are several ways Arteries can get around this resistance –Vasoconstriction: contracts smooth muscle, increase resistance, decreases flow –Vasodilatation: relaxes smooth muscle, decreases resistance, increases blood flow Some organs regulate blood flow by a ring of muscle around the arteroids where they empty into capillaries Some organs regulate blood flow by a ring of muscle around the arteroids where they empty into capillaries –Known as precapillary sphincters

Exchange in Capillaries

Capillaries are very small Capillaries are very small –1mm in long and 8 micrometers in diameter –However, the is a very large amount of Capillaries in the human body This allows blood more time to exchange molecules with extracellular fluid This allows blood more time to exchange molecules with extracellular fluid

Venules and Veins Blood flows back to the heart in Venules and Veins Blood flows back to the heart in Venules and Veins The have the same tissue layers as arteries The have the same tissue layers as arteries However, the pressure in veins is much less, so less smooth muscle is needed However, the pressure in veins is much less, so less smooth muscle is needed

Venules and Veins Sometimes the pressure in veins is not enough to return the blood back to the heart Sometimes the pressure in veins is not enough to return the blood back to the heart –In that case, muscles around the vein contract around it.  This is called venous pump

Lymphatic System The circulatory system is consider closed The circulatory system is consider closed –There are no open ended vessels However, water and solutes enter the walls of capillaries However, water and solutes enter the walls of capillaries –Interstital (tissue) fluid

Lymphatic System This is caused by the pressure of blood and helps to supply tissues with oxygen and other molecules and nutrients This is caused by the pressure of blood and helps to supply tissues with oxygen and other molecules and nutrients Fluid return occurs due to osmosis Fluid return occurs due to osmosis If blood pressure is too high, interstital fluid would start to build up If blood pressure is too high, interstital fluid would start to build up –However, excess fluid drains into the lymph node

Lymphatic System This fluid, now known as lymph, travels though vein like structures and eventually dumps into veins on the side of the neck. This fluid, now known as lymph, travels though vein like structures and eventually dumps into veins on the side of the neck.

Interdependence The circulatory and respiratory systems are very closely related The circulatory and respiratory systems are very closely related –The respiratory system draws oxygen into the lungs –The circulatory system exchanges carbon dioxide for oxygen. –The respiratory system expels the waste gas during exhalation –The circulatory system delivers oxygen to cells throughout the body

REMEMBER! Vertebrates have a closed circulatory systems Vertebrates have a closed circulatory systems Blood is fluid plasma in which different types of cells are suspended Blood is fluid plasma in which different types of cells are suspended Blood leaves through arteries and travels back though veins Blood leaves through arteries and travels back though veins Diffusion occurs in capillaries Diffusion occurs in capillaries

Diseases and Disorders Anemia: Anemia occurs when there is a below normal level of red blood cells. This can be caused by a poor diet or excessive bleeding Anemia: Anemia occurs when there is a below normal level of red blood cells. This can be caused by a poor diet or excessive bleeding Hypertension: Elevated blood pressure caused by a hardening of the arteries over time. Once the arteries have hardened, they can no longer regulate pressure Hypertension: Elevated blood pressure caused by a hardening of the arteries over time. Once the arteries have hardened, they can no longer regulate pressure Thrombosis: a clot in vessels that blocks the path to the heart. Often caused by cholesterol deposits and the narrowing of blood vessels disrupts the secretion of prostacyclin and causes clots Thrombosis: a clot in vessels that blocks the path to the heart. Often caused by cholesterol deposits and the narrowing of blood vessels disrupts the secretion of prostacyclin and causes clots