By Derek, Eric, and Zack

Evolution of the Circulatory System and gas exchange: early organismsNo circulatory systemGas exchange through direct diffusion of gases

with the environmentGastro Vascular Cavity

increase surface areaPhylum:ProtistsPoriferaCnidariansCtenophoresPlatyhelminthes

Open circulatory systemPhylum:ArthropodsMollusks (except Cephalopods)

Organs bathed in intercellular fluid rather than surrounded by vessels.

Heart used to create a currentGas exchange through gills or air sacs

EchinodermsSpecialized circulatory systemWater vascular system (opened or closed)

Aids in the transport of food, gases, and wastePapulli : gills aiding in gas exchange

Closed circulatory SystemBlood inside vesselsA chambered heart pumps blood throughout

the bodyUsually well developed organs for circulation

and gas exchange

Phylum:AnnelidsMollusks (Cephalopods)Chordates

Fish (2 chambered)Reptiles(3 chambered)Mammals and birds(4 chambers)

Humans Circulatory system and gas Exchange Overview

Four chambered heartDouble circulationBlood vesselsBlood pressureBloodLymphatic systemLungs (alveoli, diaphragm, trachea)Interdependence of circulatory system and

gas exchangeHomeostasis Diseases

Human Heart4 chambers (2 atria and 2 ventricles)Cardiac muscle tissueFunction:

To pump blood around the body in vessels

Important parts:Sinoatrial node (pacemaker)Atrioventricular node Atruim (blood entering)Ventricle (blood exiting)ApexSeptum

Double CirculationDefinition:Blood passes through the

heart twice before completing a cycle around the body

Advantages:Maintain velocity of bloodIncreased blood pressure

to organsOne heart makes

coordination easy

Blood vesselsTransport blood around the body and contain it in

a permeable wall (endothelium)Types:VeinsArteriesCapillaries

Veins and arteries also havesmooth muscles and connectivetissues surrounding the vessel(main purpose is to maintainblood pressure)

Blood PressureFluids flow from high to low pressures and by

contracting, the heart becomes the high forcing the blood away from the heart

Aids in the support of the human bodyAids in the delivery and return of blood back

to the heartBlood pressure also caused by

the contraction of smoothmuscles and other nearby muscles

BloodPlasma (55%): water mixed with ions, proteins,

hormones, waste products, and cellsCell types (45%):Erythrocytes (RBC)Leukocyte (WBC)Platelets

Hemoglobin bind O2 and transports it to cells. Italso transfers CO2

Lymphatic systemDue to high pressures in the vessels, blood

leaks constantly from capillaries. Most of the blood is reabsorbed through osmotic pressure. The rest is collected by the lymphatic system

The lymphatic system then directs the absorbed fluid, now lymph, to the heart where it reenters the circulatory system

Lungs and the respiratory systemFunction: bring gas from the outside and aid in the

exchange of gases from the environment with the ones produced by the body

Parts: Alveoli – increases surface area for gas exchangeDiaphragm – muscle used for pulling in airTrachea – tube that leads air to and from the lungs

Other functions:Alter pH of blood through altering levels of CO2 in

bloodFilter out small clots and air bubbles in blood

vessels

Interdependence of circulatory system and respiratory systemWith out the circulation system, none of the

cells inside the organism will get any oxygen and will die. By supplying them with and taking away gases, other cells can go about their functions that will overall help the body, either it be muscle cells for capturing and eating food, neurons used in thinking about science, or any of the other many tissue types in the human body, each with a specialized task.

HomeostasisThe main purpose of the circulatory and

respiratory system in to bring high levels of oxygen and other nutrients to cells that can not get it on their own while taking away waste products and gases that would be harmful if the concentrations increased

By constantly moving blood through the body, cells can live happily and specialized with their needs being met and their garbage taken away.

Analogy: the circulatory system is like servants who bring food and take away the leftovers for their lazy overlords

DiseasesRheumatic Fever

Caused by a fever, a damaged heart valve at birth can become damaged further

Heart attack/Stroke the blockage of a vein or artery from

something, usually plaque or platelets, in the heart or the brain respectively

AnemiaDeficiency of hemoglobin in Red Blood Cells

(RBC) or the deficiency of RBCTuberculosis

Infection of Mycobacterium tuberculosis that leads to increase mucus creation in trachea