Circulation & Respiration Chapter 42

Circulatory systems 2 types Open circulatory system Mollusks & arthropods No distinction between blood & lymph Flow through a network of vessels Hemolymph Circulating fluid

Circulatory systems Closed circulatory system Vertebrates Blood Enclosed in blood vessels & heart Lymph Lymph system Interstitial fluid

CLOSED CIRCULATORY SYSTEM OPEN CIRCULATORY SYSTEM

Functions 1. Transportation Substances needed for cellular respiration A. Respiratory CO2 and O2 B. Nutritive glucose C. Excretory Metabolic wastes, ions, water

Functions 2. Regulation 3. Protection Hormones Temperature regulation (Endotherms) Vessels constrict cold Vessels dilate hot 3. Protection Clotting Proteins, platelets Immune defense WBC, AB

Components of the system Heart Blood vessels Blood

Heart Fish 2 chambered Amphibians/some reptiles 3 chambered Cutaneous circulation: Oxygen diffuses in from environment Birds/mammals 4 chambered Separation of systemic & pulmonary blood systems

Circulation

Heart Systemic circulation: Blood flow in the body Pulmonary circulation: Blood flow between the heart & lungs

Circulation

Heart structure Atrium Small chambers Receive blood Ventricles Larger chambers Pump blood from heart Septum Separates chambers

Septum

Heart structure Valves Atrioventricular valves (AV) Between the atrium and ventricles Tricuspid is on the right Bicuspid or Mitral is on the left Semilumar valves Exits from the ventricles Aortic valve (L ventricle) Pulmonary valve (R ventricle)

Valves

Heart structure Heart sounds “lub-dub” -valves closing “lub” closing of the AV valves “dub” closing of the semilunar valves Murmur: Abnormal heart sound Harsh sound of blood flowing over valve

Heart structure Superior & inferior vena cava Brings blood to heart from body Pulmonary arteries Blood from right side of heart to lungs Pulmonary veins Returns blood from lungs to heart Aorta Blood goes from the heart to body

Circulation

Blood flow E:\Chapter_42\A_PowerPoint_Lectures\42_Lecture_Presentation\42_06PathOfBloodFlow_A.html

Blood flow Vena cava Right atrium Tricuspid valve (AV) Right ventricle Pulmonary valve (semilunar) Pulmonary artery Lungs

Blood flow Pulmonary veins Left atrium Mitral valve (AV) Left ventricle Aortic valve (semilunar) Aorta

Blood flow

Blood flow Cardiac cycle: One cycle of heart filling & emptying Diastole Heart resting Heart filling with blood AV valves open Semilunar valves closed

Diastole

Blood flow Systole Ventricles contracting Pumping blood out of the heart AV valves closed Semilunar valves open

Systole

Blood pressure Measurement of pressure of blood in the arteries Systolic measures ventricular contraction Diastolic measures ventricular resting Sphygmomanometer or BP cuff Brachial artery 120/80 normal

Blood pressure

Cardiac output Volume of blood pumped by the left ventricle into systemic circuit per minute 5 liters per minute Depends on heart rate Stroke volume Amount of pumped out per contraction (70 ml)

Cardiac output Increases with exercise Increased HR Better stroke volume

Blood pressure Cardiac output Flow resistance in the arteries Affect BP More constriction higher BP More dilation lower BP Baroreceptors Aorta & carotids Medulla oblongata

Blood pressure Depends on blood volume Decreased volume Decreased cardiac output Decreased BP

Heart structure Coronary arteries First branches off the aorta Supply blood to the heart

Coronary arteries

Conduction Depolarization of heart muscle stimulates contraction Heart contains autogenic cells Self stimulate SA node (sinoatrial) Pacemaker of the heart Located in R atrium wall Near the superior vena cava

Conduction SA node Causes atrium to contract Sends signal to the AV node AV (atrioventricular) node Located in wall between R atrium & ventricle Sends signal to the bundle of His

Contraction Bundle of His Sends signal to the Purkinje fibers Cause the ventricle to contract SA⇨AV⇨Bundle of His⇨Purkinje fibers

Conduction

Conduction

EKG Electrocardiogram Records electrical impulses of the heart P-wave First wave-atrium contraction QRS-wave Ventricles contracting T-wave Heart re-polarization

EKG or ECG

Vessels Arteries, arterioles Veins, venules Capillaries arteries⇨arterioles⇨capillaries⇨venules⇨veins

Capillaries

Blood vessels

Vessels Basic structure (except capillaries) Inner layer is endothelium Next is a layer of elastic fibers Smooth muscle layer Connective tissue Capillaries are single cell layer thick Endothelium only

Arteries Carry oxygen rich blood away from heart Arterioles: Smaller arteries Larger the artery More elastic & recoil as blood is pumped

Arteries Vasoconstriction: Contraction of smooth muscle in arterioles Decrease blood flow Vasodilation: Relaxation of smooth muscle Increase blood flow Precapillary sphincters: Regulate blood flow

Veins Carry oxygen poor blood to heart Venules Smaller veins Less smooth muscle Skeletal muscles constrict Help flow of blood to heart Venous valves: Help blood flow to heart prevent backflow

Varicose veins Too much blood in legs Valves veins do not work

Capillaries Passage of oxygen & nutrients Into cells or extracellular fluids Passage of carbon dioxide & wastes From cells to blood

Blood

Blood Plasma (matrix) yellow Fluid part of the blood Metabolites, wastes, hormones Ions (sodium, chlorine, bicarbonate) Proteins Albumin (fluids), globulins (antibodies), fibrinogen (clots) Cells RBC, WBC, platelets

Blood cells

Blood formation

RBC Erythrocyte O2 & CO2 transport Hemoglobin (protein) Erythropoietin Hormone secreted by kidney that stimulates RBC production Erythropoiesis Process of RBC production from stem cells Spleen, bone marrow & liver remove RBC

Heme

Hemoglobin

RBC

WBC Leukocyte Larger than RBC Contain a nucleus Fights against infection and FB Interstitial fluid as well as blood 5 types of WBC split into 2 groups Granulocytes: neutrophils, eosinophils, basophils Non-granulocytes: lymphocytes, monocytes

WBC

Platelets Cell fragments Megakaryocyte Large cell in bone marrow that forms platelets Clotting First to site of injury Fibrin (protein that forms clot)

Platelets

Clotting Tissue damage Platelets arrive Cascade reactions are started Prothrombin is changed to Thrombin (enzyme) Changes fibrinogen to fibrin Forms clot

Fibrin

Blood More RBC than WBC Hematocrit Measurement of RBC’s in the blood RBC last about 120 days

Lymph system Interstitial fluid Fluid from the blood plasma that leaves the capillaries Surrounds the tissues Lymph: Returns to circulation via lymph system Lymph nodes, lymph vessels & organs (spleen & thymus)

Edema Swelling of tissues Usually ankles or feet Interstitial fluid cannot be returned Low protein (albumin) Liver disease Heart disease Pregnancy

MI

Flutter

Atherosclerosis

Aneurysm

Infarct

Pacemaker

VSD

MVP