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