Circulation & Circulation & Respiration Respiration

Chapter 42Chapter 42

Circulatory systems

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

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– Hormones– Temperature regulation (Endotherms)

3. Protection– Clotting

• Proteins, platelets

– Immune defense• WBC, AB

Components of the system

Heart Blood vessels Blood

Heart

4 chambered Separates systemic & pulmonary

blood systems Systemic circulation: Blood flow in the body Pulmonary circulation: Blood flow between the heart &

lungs

Circulation

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 & ventricles Tricuspid---right Bicuspid or Mitral---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

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

Heart structure

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

Coronary arteries

Circulation

Path of Blood Flow

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 left ventricle to the body 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

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 Ventricles 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

Structure (except capillaries) Inner layer is endothelium Next is a layer of elastic fibers Smooth muscle layer Connective tissue Capillaries 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

Capillaries

Passage of oxygen & nutrients Into cells or extracellular fluids Passage of carbon dioxide &

wastes From cells to blood

Blood

Blood

Plasma (matrix) yellow Metabolites, wastes, hormones Ions Proteins Albumin (fluids), globulins (antibodies),

fibrinogen (clots) Cells RBC, WBC, platelets

Blood cells

Blood formation

RBC (erythrocyte)

O2 & CO2 transport Hemoglobin (protein) Erythropoietin Hormone (Kidney ) Stimulates RBC production Erythropoiesis 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 & FB Interstitial fluid as well as blood Granulocytes: neutrophils,

eosinophils, basophils Non-granulocytes: lymphocytes,

monocytes

WBC

Platelets

Megakaryocyte (bone marrow) Cell fragments Clotting First to site of injury Fibrin (protein that forms clot)

Platelets

Clotting

Tissue damage Platelets arrive Cascade reactions start Prothrombin changes 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 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

Varicose veins

Too much blood in legs Valves veins do not work

MI

Flutter

Atherosclerosis

Aneurysm

Infarct

Pacemaker

VSD

MVP