1. Circulatory system

3. Components of a Circulatory System Three fundamental features in all circulatory systems: 1.A fluid that transports materials throughout the body 2. A network of tubes in which the fluid circulates 3.A pump that pushes the fluid through the tubes

4. Functions of a circulatory system delivers oxygen, nutrients, and hormones to cells carries metabolic wastes away from cells to the lungs and kidneys Helps distribute heat to maintain constant body temperature in warm-blooded animals

5. Why the need for circulation? Unicellular organisms (bacteria, sponge, algae) do not have a circulatory system. Use surface for exchange In larger multicellular organisms, body cells cannot move and do not come in contact with the external environment. A circulatory system develops as an evolutionary adaptation

6. Open (circulatory) System e.g. insect, crustaceans  no closed vessels - blood bathes the cells directly  No distinction between blood and interstitial (tissue) fluid  have one blood vessel that has chambers called sinuses  Hemolymph: mixture of blood and tissue fluids

7. e.g. earthworms, frogs, birds, humans  need faster blood flow to get O 2 to all cells  blood contained in a network of true blood vessels that separate blood from tissues and interstitial fluid  blood circulates in only one direction Closed (circulatory) System

8. Blood and its functions carry nutrients, O 2, CO 2 equalize body temperature transport hormones & antibodies helps clotting removes wastes Disturbing?

9. Components of Blood

10. Blood average 4-5L in a human body Blood is a connective tissue When centrifuged, blood separates into two major components: Plasma(55%) Formed elements (45%)

11. Blood’s components 1. Plasma Fluid part of the blood –92% water –1% ions (Ca 2+, Na +, K +, Cl -, etc.) –7 % proteins (albumins, globulins, fibrinogen) Serum = plasma –( fibrinogen +clotting factors) 2. Cellular components: RBC, WBC, and platelets

12. To fill in the info on slide 13-17; use the provided summary table on Cellular component of blood. Your table should look like the page on the right here

13. DescriptionFunction Red Blood Cell (erythrocytes_) 99% of Cellular Components  tiny biconcave disks (135 RBC = 1mm)  Made from stem cells in bone marrow  Lack mitochondria and nuclei  Stored in spleen  Constantly being destroyed and replaced (~120 days)  Carry O 2 & CO 2  Have iron-containing protein called hemoglobin (~ 280 mill/1 RBC) specializing at transporting O 2  1 hemoglobin can bind 4 O 2  Thalassemias and Anemia are conditions of abnormal haemoglobin and haemoglobin shortage, respectively 2. Cellular Components (previously called Formed elements)

14. White Blood Cell (Leucocytes)  Produced in the bone marrow  Do have nuclei  5-9 mill./1cm 3 of blood  Many different types 1. Neutrophils 2. Basophils 3. Eosinophils 4. Lymphocytes 5. Monocytes Defend against diseases and infections Function in allergic reactions Produce antibodies stimulated by binding of foreign particles Phagocytize (i.e. engulf) to destroy invaders Leukemia – cancer of the wbc (wbc can’t stop dividing) 2. Cellular Components of Blood (Cont) Pus

17. 2. Cellular Components of Blood (Cont) Platelets (thrombocytes)  Fragments of cells  1-3um; no nuclei  Break down after 7- 10 days  Responsible for blood clotting  Prevent excessive blood loss  Hemophilia – Sex-linked condition resulting in excessive bleeding How blood clots? https://www.youtube.com/watch?v=--bZUeb83uU Let’s go to the ER: https://www.youtube.com/watch?v=cFmmmj6a2sY

18. The Heart Ventricle: heart chamber that pumps blood to the body Atrium: heart chamber that receives blood from the body Septum (a wall of tissue)

19. Pathway of blood flow through the heart Deoxygenated blood from rest of body to right atrium via superior and inferior vena cava  right atrium  right ventricle  pulmonary artery  lung where blood picks up O 2  left atrium via pulmonary veins  left ventricle  oxygenated blood left heart via aorta to rest of the body Blood from upper body Blood from lower body  https://www.youtube.com/watch?v=KSbbDnbSEyM

20. Cardiac (heart) System Circulates blood through tissues of the heart. Pulmonary (lung) System Circulates blood from heart, to lungs, & back to heart Systemic System Supplies nutrients, O 2 to body cells except for heart and lungs Also picks up CO 2

21. Blood Vessels Red – Arteries (Oxygen rich blood) Blue – Veins (Oxygen poor blood)  The largest blood vessel has a diameter of 3 cm, the smallest between 5-10um Three major types of blood vessels: arteries, veins and capillaries

22.  carry blood away from heart  usually O 2 rich (Except for pulmonary artery)  connective tissue and muscle - walls elastic and thick  Pre-capillary sphincters control blood flow Arteries

23. Arterioles = smaller arteries Vasoconstriction: Decrease arterioles’ diameters restricting blood flow  prevent heat loss to environment Vasodilation: Increase arterioles’ diameters increasing blood flow  facilitates heat loss to cool down (Flushing)

24. Veins  carry blood to the heart  usually O 2 poor (Except for pulmonary vein)  Thinner walls and not elastic as arteries  valves push blood towards heart  smooth surface Varicose vein: Are veins that lose their elasticity as we age Leads to blood pooling in the legs that results in bulging condition When sitting or standing for a long time

25. Blood flow in veins  Less pressure than arteries (A)Small muscles surrounding the veins contract and relax to squeeze blood along the veins. (B)One-way valves inside the veins prevent blood from flowing backward due to the pull of gravity

26. Arteries and Veins

27. Capillaries Found in the muscles and lungs Thin, semi-permeable wall- only a single cell layer thick Very narrow; blood cells move through in single file Cover a large surface area: no body cell is more than 2 cells away from a capillary Movement of blood through capillaries is controlled by pre-capillary sphincters Capillaries in the hand can leak excess fluid accumulates in the tissues due to an allergic reaction

28. Carries blood away from the heart Branch into arterioles Small veins Converge into veins Veins Carries blood towards the heart Small arteries Branch into capillaries Site of gas, nutrient and waste exchange Converge to form venules