Transport Systems Why are they needed? –To allow cells of organism to obtain oxygen, nutrients and other substances –To allow organism to eliminate wastes

Adaptations for Transport Simple Organisms: –cells are in close contact with outside environment, so transport can simply be across the cell membrane Ex: Diffusion, osmosis, active transport

Protists –Amoeba & Paramecium –Single celled –Cell membrane in direct contact with environment –Transport directly through diffusion and active transport across cell membrane –Cyclosis and cytoplasmic streaming moves materials inside cell

Hydra –Two cell layers both in direct contact with environment Ectoderm & Endoderm –Outer layer (ectoderm) absorbs nutrients from inner layer (endoderm) lining gastro-vascular cavity –Wastes eliminated across cell membrane to outside environment ectoderm endoderm

Adaptations for Transport Larger Organisms: –Not all cells are close to location where nutrients and needed substances (like oxygen) are absorbed –Need circulatory systems to transport materials to and from all parts of the organism –Forms a link between cells and the outside environment

Analogy: People who live in a large city How do they get food? Eliminate wastes?

–Fluid in which materials are transported –Network of tubes or body spaces through which fluid can flow –Means of driving fluid through these spaces (pump) Keys Parts to All Circulatory Systems

Earthworm –Most cells not in direct contact with environment –Closed circulatory system Blood contained in vessels or tubes Has dorsal and ventral blood vessels –Blood is red as it contains hemoglobin to transport oxygen to body tissues

–Five pairs of aortic arches connect blood vessels and pump blood –Tubes branch into smaller vessels and finally microscopic capillaries –Exchange of materials takes place through walls of capillaries There are so many capillaries that every cell in body is near one

Grasshopper –Open circulatory system Blood not always enclosed in vessels Blood flows directly into body spaces and “bathes” tissues

–Along its back it has a tubular heart to pump fluids throughout body cavity Blood enters “heart” through holes in tube called ostia –Colorless blood no hemoglobin doesn’t transport oxygen and carbon dioxide Gases are transported to body tissues through separate tubes

Human Circulatory System Closed Circulatory System (like all vertebrates) Single 4 chambered heart (pump) Network of blood vessels including arteries, veins and capillaries Blood flows through vessels, carrying nutrients, wastes, oxygen etc.

Types of Blood Vessels As blood flows through the circulatory system it moves through three types of blood vessels –Arteries –Veins –Capillaries

Arteries –Carry blood away from the heart to the organs and tissues of the body –Walls are thick & elastic Why? –Blood pumped out of heart is under great pressure so walls have to stretch and give with each pump

–Divides into smaller arterioles and eventually capillaries

They can get clogged!

Veins –Return blood to the heart from the body tissues –Smallest veins are called venules –Walls are thin and only slightly elastic

The Importance of Valves: –Veins have valves that allow blood to flow in one direction back to the heart Why? –Blood returning to heart is not under as much pressure and is sometimes traveling against gravity –Needs a way to prevent backflow

Contraction of skeletal muscles also aid in pushing blood back to heart through veins

Varicose veins: veins becomes stretched and lose elasticity

Capillaries (microscopic) –Connect arterioles and venules in an extensive web –Each cell in the body lies near a capillary

–Capillary walls are a single cell thick Red blood cells pass through capillary in single file Diffusion happens across cell membrane Thin walls allow for exchange of dissolved nutrients, wastes, oxygen and other substances with individual cells

Gas, Nutrient and Waste Exchange Happens at the Capillary

Comparing Blood Vessels

The Heart NF68qhyfcoM&safe=active

Heart –Muscular organ as large as your fist –Acts as a pump –Contractions force blood through vessels –Found slightly to the left of middle of chest cavity –Pericardium: tough membrane that covers and protects the heart

Structure of the Heart 4 chambered double pump Atria: two upper chambers –Pumps blood into lower ventricles –Have thin walls Ventricles: two lower chambers –Pumps blood out to lungs and the rest of body –Have thick walls

–Left ventricle wall is thicker than right because it pumps blood to entire body –Right ventricle only pumps blood to lungs for pulmonary circulation Thicker cardiac muscle Thinner cardiac muscle Blood out to entire body Blood out to lungs

Role of Heart Valves Valves: –Can open and close controlling direction of blood flow in heart Atrioventricular Valves: –allow blood to flow from upper atria to lower ventricles –Called the tricuspid and mitral vallves Semilunar Valves: –allow blood to flow from ventricles into arteries that flow away from heart –Called the pulmonary valve and aortic valve

The Flow of Blood Blood enters the 2 atria and flows into the 2 ventricles when heart muscle relaxes When heart contracts the valves leading from the atria close Blood is pushed from the ventricles to rest of body

Pathway of Blood Flow Right Side of Heart (“Blue Side”) Right Atrium: –Deoxygenated blood from body enters through large vein called the vena cava (inferior and superior) –Contracts and squeezes blood through valve into right ventricle Right Ventricle: –Pumps deoxygenated blood to the lungs through pulmonary arteries –Blood then takes on oxygen and releases carbon dioxide to the lungs Blood goes to lungs

Left Side of Heart (“Red Side”) Left Atrium: –Oxygenated blood enters from the from the lungs through the pulmonary veins –Contracts and squeezes blood through valve into left ventricle Left Ventricle: –Pumps oxygenated blood out to the rest of the body –Blood pumped into the aorta (largest artery in body) Pathway of Blood Flow Blood goes out to body

Summary: Right Side of Heart: –Gets oxygen depleted blood that has been to body tissues –Sends it to the lungs to get oxygen Left Side of Heart: –Gets oxygen rich blood from lungs –Pumps it out to the rest of the body Both sides pump together

Septum: tissue between right and left sides of heart prevents mixing of oxygen rich and poor blood –“Blue Babies”: A fetus has an opening in its septum Body tissues don’t get enough oxygen Baby will often die or be very weak if not repaired

Bill Nye: Circulatory Systems Part 1: The Heart 5do9M&safe=activehttp:// 5do9M&safe=active

Cardiac Muscle: –Fibers form a network and never stop beating –Even when removed from the body the heart will keep beating for awhile if placed in a special solution Heart of an Embryo

Pacemaker: (top of right atria) Regulates pumping of heart muscle Generates an electrical impulse that signals atria to contract and then ventricles The medulla oblongata in brain stem regulates the speed of the pacemaker

Pulmonary Circulation: –From heart to the lungs and back –Adds oxygen to blood –Removes carbon dioxide from blood

–Blood circulates to lung capillaries which surround tiny air sacs called alveoli where gas exchange takes place Blood changes color from blue to red as oxygen bonds to the hemoglobin in red blood cells

Systemic Circulation: –From left side of heart oxygen rich blood is pumped out to aorta and rest of body –Flows through arteries to capillaries where exchange of nutrients and gases happens with cells of body tissues

Coronary Circulation: Supplies blood to heart muscle through coronary blood vessels Branches right off the aorta Heart muscle cells need a constant supply of nutrients and oxygen as they never stop contracting and beating

A blood clot or fat deposit in coronary artery can lead to heart attack Coronary bypass: –uses a vein from leg to create a detour around blocked region Stint: –placed inside artery to keep it open and blood flowing through

Bill Nye: Part 2 7iyp8&safe=activehttp:// 7iyp8&safe=active

The Beating of Your Heart 2 main periods of relaxation and contraction of heart muscle –Diastole: relaxation of heart muscle (pressure drops) “filling” –Systole: contraction of heart muscle (pressure rises) “pumping”

Heart Sounds Heart valves open and close making “lub-dub” sound –Lub = closing AV valves (between atria and ventricles) –Dub = closing semilunar valves ( to aorta & pulmonary arteries) If there is a leak or backflow through valves you get a heart murmur

Pulse: –How many beats per minute –Measured at your artery

Resting Heart Rate At neck or wrist Count how many beats in 30 seconds at rest Double that amount for how many beats per minute

Rate after Exercise At neck or wrist Count how many beats in 30 seconds at rest Double that amount for how many beats per minute Why is there a difference?

Blood Pressure: –force that blood exerts on the walls of your arteries –Measured with a sphygmomanometer –Measures high pressure, low pressure (ex: 120/80)

Where is Blood Pressure Highest?

Cardiovascular Diseases Stroke: –A blood clot in brain prevents flow of blood to brain tissue

Cardiovascular Diseases Heart Attack: –blood supply to heart is cut off –caused by a blood clot or blockage in coronary artery causing coronary thrombosis

Hypertension: –High blood pressure –Often be caused by atherosclerosis or “hardening” of the arteries –Arteries become not as elastic and narrower as cholesterol and other fatty materials collect on the inner walls

Preventing Heart Disease Don’t smoke Get blood pressure checked Don’t eat food high in cholesterol –butter, mayo, fatty meats Cut down on salt Exercise regularly to strengthen your heart and improve circulation Avoid obesity Learn to manage stress and anxiety

Bill Nye: Part 3 CEgcM&safe=activehttp:// CEgcM&safe=active

How does the heart work: JCLCE&safe=activehttp:// JCLCE&safe=active The Circulatory System Summary – ehQ&safe=activehttp:// ehQ&safe=active