Circulation. Chapter 34. Mader: Biology 8 th Ed.

Transcription

1 Circulation Chapter 34

2 Transport in Invertebrates Invertebrates Without a Circulatory System Each cell can independently exchange gases and rid itself of wastes.

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4 Open or Closed Invertebrate Circulation Two types of circulatory fluids: Blood - contained within blood vessels. Hemolymph - flows into hemocoel. Open Circulatory System Heart pumps hemolymph via vessels into tissue spaces. Closed Circulatory System Blood pumped by the heart into a system of blood vessels.

5 Open Circulatory System

6 Closed Circulatory System

7 Figure 42.2 Open and closed circulatory systems

8 Transport in Vertebrates All vertebrates have a closed, cardiovascular system. Atria receive blood. Ventricles pump blood from the heart. v Arteries - Carry blood away from heart. Ø Arterioles v Capillaries - Exchange materials with tissue fluid. v Veins - Return blood to heart. Ø Venules

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10 Figure 42.8 The structure of blood vessels

11 Comparison of Circulatory Pathways Fish - Blood flows in single loop. Single atrium and single ventricle. Amphibians - Blood flows in double loop. Two atria with single ventricle. Other vertebrates - Blood flows in a double loop. Heart divided by septum into separate sides.

12 Circulatory Circuits

13 Figure 42.0 External gills of a salmon

14 Human Heart Transport in Humans Fist-sized, cone-shaped, muscular organ. v Myocardium composed largely of cardiac tissue. Lies within a sac (pericardium).

15 External Heart Anatomy

16 Transport in Humans Septum separates halves. Four chambers v Two upper, thin atria. v Two lower, thick ventricles. Ø Atrioventricular valves Tricuspid Bicuspid Ø Semilunar valves Pulmonary Aortic

17 Internal Heart Anatomy

18 Figure 42.5 The mammalian heart: a closer look

19 Figure 42.4 The mammalian cardiovascular system: an overview

20 Transport in Humans Blood must go through lungs to pass from the right side to the left side of the heart. Right side of heart pumps blood to the pulmonary circuit. Left side of the heart pumps blood to the systemic circuit. Oxygen-poor blood never mixes with oxygen-rich blood.

21 Heartbeat Systole - Contraction of heart chambers. Diastole - Relaxation of heart chambers. Pulse - Wave effect that passes down the walls of arterial blood vessels when aorta expands and then recoils following ventricular systole.

22 Figure 42.6 The cardiac cycle

23 Heartbeat Rhythmic contraction due to cardiac conduction system. Sinoatrial node (SA) keeps the heartbeat regular. Atrioventricular node (AV) signals ventricles to contract. v Purkinje Fibers

24 Heartbeat Electrocardiogram (ECG) is a recording of the electrical changes that occur in myocardium during a cardiac cycle. When SA node triggers an impulse, the atrial fibers produce an electrical charge (P wave). v P wave indicates atria are about to contract.

25 Figure 42.7 The control of heart rhythm

26 Conduction System of the Heart

27 Vascular Pathways Human cardiovascular system includes two major circular pathways: Pulmonary Circuit v Takes oxygen-poor blood to the lungs and returns oxygen-rich blood to the heart. Systemic Circuit v Takes blood throughout the body from the aorta to the vena cava.

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29 Blood Pressure Systolic Pressure results from blood forced into the arteries during ventricular systole. Diastolic Pressure is the pressure in the arteries during during ventricular diastole. Blood pressure normally measured with a sphygmomanometer on the brachial artery. Systolic/Diastolic

30 Velocity and Blood Pressure

31 Figure The interrelationship of blood flow velocity, cross-sectional area of blood vessels, and blood pressure

32 Blood Pressure The beat of the heart supplies pressure that keeps blood moving in the arteries. Skeletal muscle contraction pushes blood in the veins toward the heart.

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34 Figure Measurement of blood pressure (Layer 1)

35 Figure Measurement of blood pressure (Layer 2)

36 Figure Measurement of blood pressure (Layer 3)

37 Figure Measurement of blood pressure (Layer 4)

38 Cardiovascular Disorders Hypertension - High blood pressure. Atherosclerosis - Accumulation of fatty materials in inner linings of arteries. Stroke - Cranial arteriole bursts or is blocked by an embolus. Heart attack - Myocardial infarction. Coronary artery becomes partially blocked. Angina pectoris - Squeezing sensation.

39 Coronary Arteries and Plaque

40 Figure The composition of mammalian blood

41 Figure 42.14x Blood smear

42 Figure Differentiation of blood cells

43 Blood - A Transport Medium Homeostasis Functions Transports substances to and from capillaries for exchange with tissue fluid. Guards against pathogen invasion. Regulates body temperature Clots preventing blood loss

44 Plasma Plasma contains many types of molecules including nutrients, wastes, salts, and proteins. Buffer blood. Maintain osmotic pressure. Proteins involved in clotting.

45 Red Blood Cells Small, biconcave disks that, at maturity, lack a nucleus and contain hemoglobin. Hemoglobin contains four globin protein chains, each associated with an ironcontaining group. v Manufactured continuously in bone marrow of skull, ribs, vertebrae, and ends of long bones.

46 White Blood Cells Usually larger than red blood cells, contain a nucleus, and lack hemoglobin. Inflammatory Response Neutrophils enter tissue fluid and phagocytize foreign material. Lymphocytes help fight infection. v T Cells attack infected cells. v B Cells produce antibodies. Antigens cause body to produce antibodies.

47 Platelets Platelets result from fragmentation of megakaryocytes. Involved in coagulation. v Blood clot consists of platelets and red blood cells entangled within fibrin threads.

48 Blood Clotting

49 Figure 42.16x Blood clot

50 Capillary Exchange Oxygen and nutrients exit a capillary near the arterial end. Carbon dioxide and waste molecules enter a capillary near the venous end.

51 Capillary Exchange

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