Circulation Circulation

By Nick OnuskaBy Nick Onuska

Evolutionary Development of Evolutionary Development of Circulation Circulation

In unicellular protists, nutrients and In unicellular protists, nutrients and oxygen can be obtained by basic diffusion oxygen can be obtained by basic diffusion in an aquatic environment in an aquatic environment

This is true because of the simple body This is true because of the simple body structure of the animalsstructure of the animals

In larger animals, cells and tissues are In larger animals, cells and tissues are simply too far away from the surface or simply too far away from the surface or digestive cavity to obtain oxygen in this digestive cavity to obtain oxygen in this wayway

Instead, they obtain oxygen through an Instead, they obtain oxygen through an internal fluidinternal fluid– This is the circulatory systemThis is the circulatory system

Evolutionary Development of Evolutionary Development of CirculationCirculation

Two main types of Two main types of circulationcirculation– OpenOpen– ClosedClosed

In an open system there is In an open system there is no distinction between the no distinction between the blood and the extracellular blood and the extracellular fluid fluid – This fluid is known as This fluid is known as

hemolymphhemolymph In a closed system, the In a closed system, the

blood is always enclosed blood is always enclosed with blood vessels that with blood vessels that transport it to a pumping transport it to a pumping system.system.– Ex. HeartEx. Heart

Purpose of Circulatory Purpose of Circulatory SystemSystem

The circulator system serves several The circulator system serves several purposespurposes– TransportationTransportation– RegulationRegulation– ProtectionProtection

TransportationTransportation

Substances needed for cellular Substances needed for cellular metabolism are transported by the metabolism are transported by the circulatory systemcirculatory system– This can be broken down intoThis can be broken down into

Respiratory: Red blood cells carry oxygen Respiratory: Red blood cells carry oxygen and CO2and CO2

Nutritive: Nutrients from broken down foodNutritive: Nutrients from broken down food Excretory: Waste products being transferred Excretory: Waste products being transferred

top kidneystop kidneys

RegulationRegulation

The circulatory system helps to The circulatory system helps to regulate the body by transporting regulate the body by transporting hormones and regulating hormones and regulating temperaturetemperature– Hormone Transport: Carries hormones Hormone Transport: Carries hormones

from endocrine glands from endocrine glands – Temperature Regulation: Maintains Temperature Regulation: Maintains

temperature by using countercurrent temperature by using countercurrent heat exchange heat exchange

ProtectionProtection

The circulatory system protects the The circulatory system protects the body from injury and toxinsbody from injury and toxins– Blood Clotting: Prevents against blood Blood Clotting: Prevents against blood

loss loss – Immune Defense: White blood cells Immune Defense: White blood cells

provide immunity against diseaseprovide immunity against disease

Structure and Function of the Structure and Function of the Circulatory systemCirculatory system

BloodBlood

Blood is made up of Blood is made up of a fluid called plasma a fluid called plasma and several different and several different types of cells that types of cells that exist in this fluidexist in this fluid

Metabolites, wastes, Metabolites, wastes, and hormonesand hormones

IonsIons ProteinsProteins

OMNOMNOMNOMNOMNOMNOMNOMNOMNOMNOM

NOMN

Metabolites, wastes, and Metabolites, wastes, and hormoneshormones

Plasma contains many dissolved Plasma contains many dissolved metabolites that are used by cells metabolites that are used by cells – Ex. Glucose, Amino Acids, and vitaminsEx. Glucose, Amino Acids, and vitamins

Hormones that regulate cell activity Hormones that regulate cell activity are also dissolved in plasmaare also dissolved in plasma

In addition, wastes like CO2 are also In addition, wastes like CO2 are also contained and transported in plasma contained and transported in plasma

IonsIons

Similar to a sea, Similar to a sea, plasma is a salt plasma is a salt solutionsolution

It contains many It contains many different ions different ions – Ex. Na+, Cl+, Ex. Na+, Cl+,

bicarbonate ionsbicarbonate ions However, plasma However, plasma

has a lower ion has a lower ion concentration then concentration then seawaterseawater

ProteinsProteins

Most proteins in plasma are Most proteins in plasma are produced by the liverproduced by the liver– Albumin: Most of the plasma proteinAlbumin: Most of the plasma protein– Alpha and Beta Globulins: Carry lipid Alpha and Beta Globulins: Carry lipid

and steroid hormones and steroid hormones – Fibrinogen: essential for clottingFibrinogen: essential for clotting

Plasma without Fibrinogen is known Plasma without Fibrinogen is known as serumas serum

Types of Blood CellsTypes of Blood Cells

ErythrocytesErythrocytes

LeukocytesLeukocytes

PlateletsPlatelets

ErythrocytesErythrocytes

Erythrocytes are also Erythrocytes are also known as red blood cellsknown as red blood cells

In vertebrates, In vertebrates, Erythrocytes contain Erythrocytes contain hemoglobin, a substance hemoglobin, a substance that transports oxygenthat transports oxygen

Erythrocytes also Erythrocytes also develop from stem cells develop from stem cells and are constantly and are constantly developed in the bone developed in the bone marrow marrow

LeukocytesLeukocytes

Leukocytes are also known as white blood Leukocytes are also known as white blood cells. Their primary job is to defend the cells. Their primary job is to defend the bodybody

There are several kinds of Leukocytes There are several kinds of Leukocytes each with their own specialized functionseach with their own specialized functions

Granular leukocytesGranular leukocytes– NeutrophilsNeutrophils– EosinophilsEosinophils– BasophilsBasophils

Non Granular leukocytes Non Granular leukocytes – MonocytesMonocytes– LymphocytesLymphocytes

PlateletsPlatelets

The primary goal of The primary goal of Platelets is to help Platelets is to help blood to clotblood to clot

They come from They come from Megakaryocytes, Megakaryocytes, large cells in bone large cells in bone marrowmarrow– A piece of the A piece of the

cytoplasm is cytoplasm is pinched off and pinched off and becomes a plateletbecomes a platelet

PlateletsPlatelets When a blood vessel When a blood vessel

breaks, platelets breaks, platelets build up at the site build up at the site and plug it up by and plug it up by sticking to each sticking to each otherother

The protein fibrin The protein fibrin reinforces this plug reinforces this plug

Often red bloods are Often red bloods are caught in this plug caught in this plug and create a blood and create a blood clot clot

Blood VesselsBlood Vessels

Blood exits the heart Blood exits the heart through vessels called through vessels called arteries. arteries. – These eventually These eventually

branch out, reaching branch out, reaching every organ in the bodyevery organ in the body

The smallest vessels The smallest vessels are known as are known as arteriolesarterioles– Blood from these enters Blood from these enters

the capillaries, a large the capillaries, a large quantity of very narrow, quantity of very narrow, thin walled tubes thin walled tubes

Blood VesselsBlood Vessels After leaving the capillaries, blood flows After leaving the capillaries, blood flows

into the vessels which will eventually lead into the vessels which will eventually lead back to vessels called veinsback to vessels called veins– Veins carry blood back to the heartVeins carry blood back to the heart

The walls of capillaries are thin enough The walls of capillaries are thin enough that molecules and ions can diffuse out of that molecules and ions can diffuse out of them, leave by filtration from pores on the them, leave by filtration from pores on the cell, or transport through the endothelial cell, or transport through the endothelial cells.cells.

This means that blood traveling in This means that blood traveling in capillaries exchanges nutrients with fluids capillaries exchanges nutrients with fluids and cells in the bodyand cells in the body

ArteriesArteries

ArteriesArteries

Arteries work by transporting blood Arteries work by transporting blood away from the heartaway from the heart

Arteries often have elastic fibers that Arteries often have elastic fibers that allow them to recoil along with the allow them to recoil along with the beating of the heartbeating of the heart

Having so many arteries often Having so many arteries often presents a risk with frictionpresents a risk with friction– Smaller arteries have the highest Smaller arteries have the highest

resistance resistance

ArteriesArteries

There are several ways Arteries can get There are several ways Arteries can get around this resistancearound this resistance– Vasoconstriction: contracts smooth muscle, Vasoconstriction: contracts smooth muscle,

increase resistance, decreases flowincrease resistance, decreases flow– Vasodilatation: relaxes smooth muscle, Vasodilatation: relaxes smooth muscle,

decreases resistance, increases blood flowdecreases resistance, increases blood flow Some organs regulate blood flow by a ring Some organs regulate blood flow by a ring

of muscle around the arteroids where they of muscle around the arteroids where they empty into capillaries empty into capillaries – Known as precapillary sphincters Known as precapillary sphincters

Exchange in Capillaries Exchange in Capillaries

Exchange in CapillariesExchange in Capillaries

Capillaries are very smallCapillaries are very small– 1mm in long and 8 micrometers in 1mm in long and 8 micrometers in

diameter diameter – However, the is a very large amount of However, the is a very large amount of

Capillaries in the human bodyCapillaries in the human body This allows blood more time to This allows blood more time to

exchange molecules with exchange molecules with extracellular fluidextracellular fluid

Venules and VeinsVenules and Veins

Blood flows back to Blood flows back to the heart in the heart in Venules and VeinsVenules and Veins

The have the same The have the same tissue layers as tissue layers as arteries arteries

However, the However, the pressure in veins is pressure in veins is much less, so less much less, so less smooth muscle is smooth muscle is neededneeded

Venules and VeinsVenules and Veins

Sometimes the Sometimes the pressure in veins is pressure in veins is not enough to not enough to return the blood return the blood back to the heart back to the heart – In that case, In that case,

muscles around the muscles around the vein contract vein contract around it. around it. This is called venous This is called venous

pumppump

Lymphatic SystemLymphatic System

The circulatory system is consider The circulatory system is consider closedclosed– There are no open ended vesselsThere are no open ended vessels

However, water and solutes enter the However, water and solutes enter the walls of capillarieswalls of capillaries– Interstital (tissue) fluid Interstital (tissue) fluid

Lymphatic SystemLymphatic System

This is caused by the pressure of This is caused by the pressure of blood and helps to supply tissues blood and helps to supply tissues with oxygen and other molecules and with oxygen and other molecules and nutrientsnutrients

Fluid return occurs due to osmosis Fluid return occurs due to osmosis If blood pressure is too high, If blood pressure is too high,

interstital fluid would start to build up interstital fluid would start to build up – However, excess fluid drains into the However, excess fluid drains into the

lymph nodelymph node

Lymphatic SystemLymphatic System

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

Interdependence Interdependence

The circulatory and respiratory The circulatory and respiratory systems are very closely related systems are very closely related – The respiratory system draws oxygen The respiratory system draws oxygen

into the lungs into the lungs – The circulatory system exchanges The circulatory system exchanges

carbon dioxide for oxygen. carbon dioxide for oxygen. – The respiratory system expels the waste The respiratory system expels the waste

gas during exhalationgas during exhalation– The circulatory system delivers oxygen The circulatory system delivers oxygen

to cells throughout the bodyto cells throughout the body

REMEMBER!REMEMBER!

Vertebrates have a closed circulatory Vertebrates have a closed circulatory systemssystems

Blood is fluid plasma in which Blood is fluid plasma in which different types of cells are suspended different types of cells are suspended

Blood leaves through arteries and Blood leaves through arteries and travels back though veinstravels back though veins

Diffusion occurs in capillaries Diffusion occurs in capillaries

Diseases and DisordersDiseases and Disorders Anemia: Anemia occurs when there is a Anemia: Anemia occurs when there is a

below normal level of red blood cells. This below normal level of red blood cells. This can be caused by a poor diet or excessive can be caused by a poor diet or excessive bleedingbleeding

Hypertension: Elevated blood pressure Hypertension: Elevated blood pressure caused by a hardening of the arteries over caused by a hardening of the arteries over time. Once the arteries have hardened, time. Once the arteries have hardened, they can no longer regulate pressurethey can no longer regulate pressure

Thrombosis: a clot in vessels that blocks Thrombosis: a clot in vessels that blocks the path to the heart. Often caused by the path to the heart. Often caused by cholesterol deposits and the narrowing of cholesterol deposits and the narrowing of blood vessels disrupts the secretion of blood vessels disrupts the secretion of prostacyclin and causes clots prostacyclin and causes clots