Chapter 42 Circulation & Gas Exchange

Functions of the Circulatory System Transport oxygen to cells Transport nutrients from the digestive system to body cells Transport hormones to body cells Transport waste from body cells to excretory organs Distribute body heat

Gastrovascular Cavity of Aurelia

Open Circulatory System

Closed Circulatory System

Atrium Ventricle

Circulatory Systems in Fish, Amphibian, & Mammal Ectotherms Endotherm

P = atrial depolarization ~ 0.1 sec atria contracts QRS = ventricular depolarization  ventricles contract (lub), contraction stimulated by Ca ++ uptake T = ventricular repolarization  ventricles relax (dub) Electrocardiogram (ECG)

Artery Vein Valve Tunica intima Tunica media Tunica externa

Artery vein

Arteries Carry blood away from the heart. Thick-walled to withstand hydrostatic pressure of the blood during ventricular systole. Blood pressure pushes blood through arteries.

Veins Carry blood to the heart. Thinner-walled than arteries. Possess one-way valves that prevent backwards flow of blood. Blood flow due to body movements, not from blood pressure.

One-Way Valves in Veins

Capillaries capillary vessel

venule capillaries arteriole

arteriole venule lymphatic capillaries blood capillaries lymphatic vessel

Lymph Transport lacks pump for circulation relies on activity of skeletal muscles and pulsation of nearby arteries for movement of fluid 3L of lymph enters blood stream every 24 hrs proteins easily enter lymphatic system uptake of large particles such as cell debris, pathogens, and cancer cells lymph nodes where it is cleansed of debris and examined by cells of the immune system (WBC)

Formation of Lymph interstitial fluidblood capillarylymphatic capillarytissue cell

Sphygnomamometer

Measuring Blood Pressure

brachial carotid Superficial Pulse Points- arteries, not veins radial femoral Temporal artery Facial artery Common carotid artery Brachial artery Radial artery Femoral artery Popliteal artery Posterior tibial artery Dorsal pedis artery 60 beats/minute popliteal facial temporal Posterior tibial Dorsal pedis

White blood cells Platelets Red blood cells Artery

Deliver O2 Remove metabolic wastes Maintain temperature, pH, and fluid volume Protection from blood loss- platelets Prevent infection- antibodies and WBC Transport hormones

Plasma- 55% Formed elements- 45% Buffy coat- <1%

90% Water 8% Solutes: Proteins Albumin (60 %) Alpha and Beta Globulins Gamma Globulins fibrinogens Gas Electrolytes

Organic Nutrients Carbohydrates Amino Acids Lipids Vitamins Hormones Metabolic waste CO2 Urea

Leukocytes Platelets

Erythrocytes (red blood cells) Leukocytes (white blood cells) Platelets

Erythrocytes

Erythrocyte  7.5  m in dia  Anucleate- so can't reproduce; however, repro in red bone marrow  Hematopoiesis- production of RBC  Function- transport respiratory gases  Hemoglobin- quaternary structure, 2  chains and 2  chains  Lack mitochondria. Why?  1 RBC contains 250 million hemoglobin molecules  Men- 5 million cells/mm 3  Women- 4.5 million cells/mm 3  Life span days and then destroyed in spleen (RBC graveyard)

Types of Leukocytes Granulocytes Neutrophils % Eosinophils- 1-4% Basophils- <1% Agranulocytes Monocytes- 4-8% Lymphocytes % Never let monkeys eat bananas 4,000-11,000 cells/mm 3

Leukocyte Squeezing Through Capillary Wall Diapodisis

Fig a Parapodium (functions as gill) (a) Marine worm

Fig b Gills (b) Crayfish

Fig c (c) Sea star Tube foot Coelom Gills

Fig Anatomy of gills Gill arch Water flow Operculum Gill arch Gill filament organization Blood vessels Oxygen-poor blood Oxygen-rich blood Fluid flow through gill filament Lamella Blood flow through capillaries in lamella Water flow between lamellae Countercurrent exchange P O 2 (mm Hg) in water P O 2 (mm Hg) in blood Net diffu- sion of O 2 from water to blood Gill filaments

Countercurrent exchange system

Fig Air sacs Tracheae External opening Body cell Air sac Tracheole TracheolesMitochondriaMuscle fiber 2.5 µm Body wall Trachea Air Tracheal Systems

Fig Pharynx Larynx (Esophagus) Trachea Right lung Bronchus Bronchiole Diaphragm Heart SEM Left lung Nasal cavity Terminal bronchiole Branch of pulmonary vein (oxygen-rich blood) Branch of pulmonary artery (oxygen-poor blood) Alveoli Colorized SEM 50 µm

Fig Lung Diaphragm Air inhaled Rib cage expands as rib muscles contract Rib cage gets smaller as rib muscles relax Air exhaled EXHALATION Diaphragm relaxes (moves up) INHALATION Diaphragm contracts (moves down)

Fig Anterior air sacs Posterior air sacs Lungs Air Lungs Air 1 mm Trachea Air tubes (parabronchi) in lung EXHALATION Air sacs empty; lungs fill INHALATION Air sacs fill

Fig Breathing control centers Cerebrospinal fluid Pons Medulla oblongata Carotid arteries Aorta Diaphragm Rib muscles

Uptake of Oxygen by Hemoglobin in the Lungs O2 binds to hemoglobin to form oxyhemoglobin High Concentration of O 2 in Blood Plasma High pH of the Blood Plasma

Unloading of Oxygen from Hemoglobin in the Tissues Low Concentration of O 2 in Blood Plasma Lower pH of the Blood Plasma When O 2 is released  deoxyhemoglobin

Carbon Dioxide Chemistry in the Blood CO 2 + H 2 O  H 2 CO 3  HCO H + carbonicacid bicarbonateion enzyme = carbonic anhydrase

Transport of Carbon Dioxide from the Tissues to the Lungs 60-70% as bicarbonate dissolved in the plasma (slow reaction) 7-10% dissolved in the plasma as CO % bound to hemoglobin as HbCO 2 CO 2 + hemoglobin  HbCO 2

Haldane Effect- the amt of CO 2 transported in the blood is markedly affected by the degree of oxygenation of the blood The lower the P0 2 and hemoglobin saturation w/O 2, the more CO 2 that can be carried by the blood

7. Deep-diving air-breathers stockpile oxygen and deplete it slowly Deep Diving Breath-holding Adaptations to pressure -Collapse of lung cavity (ribs) -Collapse of lungs

7. Deep-diving air-breathers stockpile oxygen and deplete it slowly Adaptations to oxygen conservation Oxygen stores 2-3 x more than humans –Humans: 36% of our total O 2 in lungs and 51% in our blood. –Weddell seal holds 5% of its O 2 in its small lungs and stockpiles 70% in the blood. Skeletal muscles and blood as primary storage site (myoglobin) Weddell seal to store about 25% of its O 2 in muscle, 13% in humans

Deep-diving air-breathers stockpile oxygen and deplete it slowly Adaptations to oxygen conservation Reduce heart rate when diving (120 beats/min to 6 b/min) seals and sea lions store oxygenated blood in their extra-large spleen (which can be 45% of their body weight) Maintain blood flow to brain, heart

Average Dive Times Sperm whale: 90 minutes to 2 hrs Northern elephant seal: 20 to 35 minutes Harbor seal: 3 to 7 minutes Walrus: 10 minutes Bottlenose dolphin: 8 minutes Killer whale: 10 minutes Amazon river dolphin: 2 minutes Loggerhead turtle: 20 minutes