The Transport System Core 6 2 Circulatory System

The Transport System Core 6. 2

Circulatory System n Most animals have a circulatory system including a pumping device – heart – Open Circulatory System: § System may have § Organs are bathed in blood § § Ex. – Closed Circulatory System § Blood stays § Ex.

6. 2. 5 Explain the relationship between the structure and function of arteries, capillaries and veins. n Circulation in Vertebrates involves a closed system that consists of: 1. Arteries § Function: - branch into smaller vessels called § Structure: – Have a – Very – Inner diameter is small

6. 2. 5 Explain the relationship between the structure and function of arteries, capillaries and veins. 2. Capillaries: § Function: § Structure: – Walls are – in diameter – RBC’s pass through single file – to increase total crosssectional area – Results in low pressure and slower flow ( – penetration into all tissues for exchange and )

6. 2. 5 Explain the relationship between the structure and function of arteries, capillaries and veins. § Mechanisms for Exchange between Blood and Tissue: – – Materials are in cell membrane of capillary endothelial cell (endocytosis) travel across cell and – Water and dissolved molecules (not proteins) filter through clefts between adjacent endothelial cells

6. 2. 5 Explain the relationship between the structure and function of arteries, capillaries and veins. 3. Veins § Function: ; small veins called lead away from capillaries and branch into the larger veins § Structure: – ; – Smooth muscle layer is inner diameter is and

6. 2. 5 Explain the relationship between the structure and function of arteries, capillaries and veins. – Veins have to assist in moving blood up to the heart (against gravity) and also depend on squeezing from muscles

http: //www. pbs. org/wnet/redgol d/innovators/bio _harvey. html n William Harvey (1628) – English physician that was the first to accurately describe how blood is pumped by heart – published work marked the (understanding bodily processes in terms of chemistry and physics)

6. 2. 1 Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of blood through the heart.

6. 2. 2 State that the coronary arteries supply heart muscle with oxygen and nutrients. 6. 2. 3 Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves. n Circulation Pathway in Humans Valves – 4 chambered heart – 2 separate pumps separated by the – One-way valves separate chambers and – Muscles squeeze the chamber in a powerful Septum

1. & 1 b. Deoxygenated blood returns to heart through 2. through 3. through to to 4. 5. To the – gas exchange takes place and blood is oxygenated 6. 9. 7. Through to 8. through to – very large artery carries oxygenated blood to the body

1 b

n Circulation outside of the heart is divided into: – Pulmonary circulation: Circulation = movement of blood

– Systemic circulation: § The heart itself is supplied with oxygen and nutrients by the.

Pulmonary circulation Right Systemic circulation Left

n Circulation in other vertebrates – are characteristic of birds and mammals § no mixing of oxygenated and deoxygenated blood

– Fish have a § Systemic circulation under very low pressure, blood moves sluggishly

– Amphibians and reptiles have – 2 atria and 1 ventricle § Oxygenated and deoxygenated blood § show beginning of development of septum (reduces mixing)

6. 2. 4 Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline). n Contraction of the heart – Cardiac cells tend to § Contraction of one heart cell stimulates – Contraction of atria is initiated by wave of contraction passes through atria to impulse transmitted to and wave continues

6. 2. 4 Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline). § When the network in the atria contracts, blood in the atria flows into the ventricles. § When the ventricles contract, blood flows out of the heart.

– Heartbeat is initiated by the § Pacemaker is located in the § The impulse spreads from the pacemaker to a network of fibers in the atria. Sinoatrial (SA) node

– The impulse is picked up by a bundle of fibers called the and carried to the network of fibers in the ventricles. § AV node is located on septum between atria § – fibers that extend from AV node into walls of ventricles § further branch into all parts of ventricular muscle Bundle of His Atrioventricular (AV) node Purkinje fibers

n Cardiac muscle cells are electrically coupled by – Intercalated disks consist of desmosomes and gap junctions – Desmosomes are made of intercellular cement and protein – Gap junctions allow ions to pass through to stimulate the neighboring cell

n How is the pacemaker regulated? – Nervous control of heart is a – Heart receives impulses from a control center in the , via 2 nerves § One nerve , the other (antagonistic – opposite)

– (Adrenaline), which is produced by the adrenal glands, travels through the bloodstream and Which response is caused by the release of epinephrine? Why would the heart rate need to increase?

n Cardiac Cycle – Heart chambers alternate between – Contraction phase is called , and relaxation phase is called – Heart sounds heard with a stethoscope are caused by – Sound pattern is “lub-dup, lub-dup” – First heart sound (“lub”) is created by closing of AV valves – Second sound (“dup”) created by closing of semilunar valves

– Heart murmers – occur when – Electrocardiograms –

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n Blood Pressure and Rate of Flow – During systole, heart – During diastole, heart

– is measured to record the regular cycle of pressure in the arteries as the heart contracts § Usually measured in with a § Average pressure for young adult male is

– Blood pressure varies by location in body and § Resulting gradient of pressure causes fluids move from regions of – § Differences in systolic and diastolic pressures diminish with § By the time blood reaches capillaries the flow is (rather than surging as in the arteries)

§ Pressure continually drops through arterioles and capillaries and is the lowest in the veins closest to the heart § Rate of flow – Highest in – Lowest in in – Increases again in Why does rate of flow in the capillaries need to be low?

6. 2. 6 State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets. 6. 2. 7 State that the following are transported by blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat. n Composition of blood 1. Plasma : § liquid matrix constituting § Plasma is with a variety of dissolved substances:

– organic anions (Cl-, HCO 3 -) (Na+, Ca+2, K+, Mg+2) and – (fibrinogen, albumins, and globulins – important for osmotic pressure in plasma, help to transport substances, blood clotting) – (glucose, fats, phospholipids, amino acids, lactic acid, cholesterol) – – urea, ammonia and uric acid – – regulatory chemicals – 3 gases found in small amounts – – – distribution to all tissues

2. White Blood Cells § Five major types: § Fight infections

§ Monocytes and neutrophils are § Eosinophils § Basophils release – causes (increased blood flow to injured site) – part of inflammatory response

§ Lymphocytes – – part of specific immune response resulting from exposure to an (foreign substance in body) – (globulin proteins) to destroy antigen – specifically fight antigen that stimulates production

3. Red Blood Cells – § § Approximately § Live approximately destroyed by liver and spleen § Formed in bones, skull, ribs, and pelvis) § Filled with gives red color) *Some animals (mollusks and arthropods) have – contains Cu instead of Fe – dissolved in plasma not in cells – (in long (carries oxygen,

4. Platelets – play a part in the

n Whole blood – n Blood plasma – n Blood serum –

n Blood – clotting converts to comes out of solution and (forms a hard lump or clot)