Circulation and Respiration
Chapter 22
Up in Smoke
• Most new smokers are under age 15
• Smoking damages circulatory and respiratory systems
• Smokers increase risk of respiratory infections, cancers, high blood pressure, stroke, and heart attack
Impacts, Issues Video
Up In SmokeUp In Smoke
The Circulatory System
• Works with other organ systems
• Maintains volume, solute concentration and temperature of interstitial fluid
• Interstitial fluid and blood are body’s internal environment
Blood Circulation
• Blood flows through blood vessels
• Heart generates force to keep blood moving
• Closed system – Blood is confined to vessels and heart
• Open system– Blood mingles with fluid in tissues
Types of circulatory systemsTypes of circulatory systems
Circulatory SystemsCirculatory Systems
Blood Flow and Gas Exchange
• Rate of blood flow varies with diameter of blood vessels
• Slowest flow in smallest vessels, the capillaries
• Gases are exchanged between blood and interstitial fluid across capillary walls
Vertebrate Circulatory Systems
• Fish– Two-chambered heart, one circuit
• Amphibians– Three-chambered heart, two partially
separate circuits
• Birds and mammals– Four-chambered heart, two entirely
separate circuits
Circulatory systemsCirculatory systems
Circulatory SystemsCirculatory Systems
Double Circuits
• In birds and mammals
• Right half of heart– Pulmonary circuit– Heart to lungs and return
• Left half of heart– Systemic circuit– Heart to body tissues and return
Functions of Blood
• Transports oxygen and nutrients to cells
• Carries carbon dioxide and wastes away from cells
• Helps stabilize internal pH
• Carries infection-fighting cells
• Helps equalize temperature
Components of Blood
• Plasma– Water– Proteins– Dissolved materials
• Cells– Red blood cells– White blood cells– Platelets
red blood cell
white blood cell
platelets
Fig. 22-3a, p.363
Erythrocytes (Red Cells)
• Most numerous cells in blood
• Transport oxygen and carbon dioxide
• Colored red by oxygen-binding pigment (hemoglobin)
• Have no nucleus when mature
Leukocytes (White Cells)
• Function in housekeeping and defense
• Cell typesBasophils Dendritic cells
Eosinophils B cells
Neutrophils T cells
Macrophages
Platelets
• Membrane-bound cell fragments
• Derived from megakaryocytes, which arise from stem cells
• Release substances that initiate blood clotting
Human Heart Is a Double Pump
• Partition separates heart into left and right sides
• Each pumps blood through a different circuit
Pulmonary Circuit
Heart to lungs
Oxygenates
blood
right pulmonary artery left pulmonary artery
capillarybed ofrightlung
pulmonarytrunk
capillary bedof left lung
(to systemic circuit)
pulmonary veins
lungs
(fromsystemiccircuit)
heart
Systemic Circuit
Starts at aorta
Carries
oxygenated
blood to body
tissues
capillary beds of headand upper extremities
(to pulmonarycircuit)
aorta
(frompulmonarycircuit)
heart
capillary beds of otherorgans in thoracic cavity
capillary bed of liver
capillary beds of intestines
capillary beds of other abdominalorgans and lower extremities
Human blood circulationHuman blood circulation
Blood CirculationBlood Circulation
Four Chambers
• Each side has two
chambers– Upper atrium – Lower ventricle
• Valves between
atria and ventricles
Heart Anatomysuperior vena cava
right semilunar valve
right pulmonary veins
right atrium
right AV valve
right ventricle
inferior vena cava
septum myocardium heart’s apex
arch of aorta
trunk of pulmonaryarteriesleft semilunar valve
left pulmonaryveinsleft atrium
left AV valve
left ventricle
endothelium and connective tissue
inner layer ofpericardium
Major Vessels
The human heartThe human heart
The Human HeartThe Human Heart
Cardiac Cycle
Diastole(mid to late).Ventricles fill,atria contract.
Diastole(early). Bothchambersrelax.
Ventricularsystole (atria arestill in diastole).Ventricles eject.
Cardiac cycleCardiac cycle
Cardiac CycleCardiac Cycle
Conduction and Contraction
• SA node in right atrium is pacemaker
• Electrical signals cause contraction of atria
• Signal flows to AV node and down septum to ventricles
SA node
Blood Vessels
• Arteries: carry blood away from heart
• Arterioles: diameter is adjusted to regulate blood flow
• Capillaries: diffusion occurs across thin walls
Blood Pressure
• Highest in arteries, lowest in veins
• Usually measured in the brachial artery
• Systolic pressure is peak pressure – Ventricular contraction
• Diastolic pressure is the lowest pressure– Ventricular relaxation
Measuring Blood Pressure
Hypertension
• Blood pressure above 140/90
• Tends to be genetic
• May also be influenced by diet
• Contributes to atherosclerosis
• “Silent killer”, few outward signs
Atherosclerosis
• Arteries thicken, lose elasticity
• Fill up with cholesterol and lipids
• High LDL increases risk
• Atherosclerosis in arteries of heart
• Causes heart attacks
Coronary Artery Disease
Risk Factors
Smoking Genetics
High cholesterol High blood pressure
Obesity Diabetes
Age Gender
Respiratory System
• Works with the circulatory system to deliver oxygen and remove carbon dioxide
• Also helps regulate acid-base balance
Respiration
• Respiration– Physiological process by which oxygen
moves into an animal’s internal environment and carbon dioxide moves out
• Aerobic respiration– Cellular process, produces ATP– Oxygen is used– Carbon dioxide is produced
Factors In Gas Exchange
• Surface-to-volume ratio– Small, flat animals
• Ventilation– Adaptations enhance exchange rate
• Respiratory pigments– Hemoglobin and myoglobin
Surface-to-Volume Ratio
• As animal size increases, surface-to-volume ratio decreases
• Small, flat animals can use the body surface as their respiratory surface
• Larger animals have special structures to increase respiratory surface, such as gills or lungs
Human Respiratory System
pharynx (throat)
larynx (voice box)
trachea (windpipe)pleural membrane
intercostal muscle
diaphragm
epiglottis
Bronchiole
Alveoli
NASAL CAVITY
PHARYNX (THROAT)
EPIGLOTTIS
LARYNX (VOICE BOX)
TRACHEA (WINDPIPE)
LUNG (ONE OF A PAIR)
BRONCHIAL TREE
PLEURAL MEMBRANE
ORAL CAVITY (MOUTH)
INTERCOSTAL MUSCLES
DIAPHRAGM
Fig. 22-21a, p.374
bronchiole
alveolar duct
alveoli
alveolar sac(sectioned)
Fig. 22-21b, p.374
alveolar sac
pulmonarycapillary
Fig. 22-21c, p.374
Human respiratory systemHuman respiratory system
Human Respiratory SystemHuman Respiratory System
Breathing
• Moves air into and out of lungs
• Occurs in a cyclic pattern called the respiratory cycle
• One respiratory cycle consists of inhalation and exhalation
Inhalation
• Diaphragm flattens
• External intercostal muscles contract
• Volume of thoracic cavity increases
• Lungs expand
• Air flows down pressure gradient into lungs
Normal (Passive) Exhalation
• Muscles of inhalation relax
• Thoracic cavity recoils
• Lung volume decreases
• Air flows down pressure gradient and out of lungs
Respiratory CycleRespiratory Cycle
Respiratory cycleRespiratory cycle
red blood cell
air spaceinsidealveolus
pore for airflowbetween alveoli
Cutaway View of Alveolus
(see next slide)
Respiratory Membrane
• Area between an alveolus and a pulmonary capillary
• Oxygen and carbon dioxide diffuse across easily
alveolarepithelium
capillaryendothelium
fusedbasementmembranesof bothepithelialtissues
Oxygen Transport
• Most oxygen is bound to heme groups in hemoglobin in red blood cells
• Hemoglobin has higher affinity for oxygen when it is at high partial pressure (in pulmonary capillaries)
• Lower affinity for oxygen in tissues, where partial pressure is low
Control of Breathing
• Nervous system controls rhythm and magnitude of breathing
• Breathing is adjusted as a result of changes in– Carbon dioxide levels– Oxygen levels– Blood acidity
Bronchitis
• Irritation of the ciliated epithelium that lines bronchiole walls
• Caused by air pollutants, smoking, or allergies
• Excess mucus causes coughing, can harbor bacteria
• Chronic bronchitis scars and constricts airways
Emphysema
• Irreversible breakdown of lung tissue
• Lungs become inelastic
• May be caused by a genetic defect
• Most often caused by smoking
Emphysema
Effects of Smoking
• Shortened life expectancy
• Increased rate of cancers
• Increased rate of heart disease
• Impaired immune function and healing
• Harmful to fetus
Heimlich Maneuver