Transcript Circulatory systems

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 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
Circulatory Systems
Types of circulatory 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 Systems
Circulatory 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
white blood cell
red 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 types
Basophils
Eosinophils
Neutrophils
Macrophages
Dendritic cells
B cells
T cells
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
right pulmonary artery
Heart to lungs
Oxygenates
blood
capillary
bed of
right
lung
left pulmonary artery
capillary bed
of left lung
pulmonary
trunk
(to systemic circuit)
(from
systemic
circuit)
pulmonary
veins
heart
lungs
Systemic
Circuit
capillary beds of head
and upper extremities
(to pulmonary
circuit)
aorta
(from
pulmonary
circuit)
Starts at aorta
Carries
oxygenated
blood to body
tissues
heart
capillary beds of other
organs in thoracic cavity
capillary bed of liver
capillary beds of intestines
capillary beds of other abdominal
organs and lower extremities
Blood Circulation
Human blood circulation
Four Chambers
• Each side has two
chambers
– Upper atrium
– Lower ventricle
• Valves between
atria and ventricles
Major Vessels
arch of aorta
superior vena cava
Heart Anatomy
right semilunar valve
trunk of
pulmonary
arteries
left semilunar
valve
left pulmonary
veins
left atrium
right pulmonary veins
right atrium
left AV valve
right AV valve
right ventricle
left ventricle
endothelium and
connective tissue
inferior vena cava
inner layer of
pericardium
septum
myocardium
heart’s apex
The Human Heart
The human heart
Cardiac Cycle
Diastole
(mid to late).
Ventricles fill,
atria contract.
Diastole
(early). Both
chambers
relax.
Ventricular
systole (atria are
still in diastole).
Ventricles eject.
Cardiac Cycle
Cardiac 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
Coronary Artery Disease
• Atherosclerosis in arteries of heart
• Causes heart attacks
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-tovolume 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)
epiglottis
larynx (voice box)
trachea (windpipe)
pleural membrane
Bronchiole
Alveoli
intercostal muscle
diaphragm
NASAL CAVITY
ORAL CAVITY
(MOUTH)
PHARYNX (THROAT)
EPIGLOTTIS
LARYNX (VOICE BOX)
PLEURAL
MEMBRANE
INTERCOSTAL MUSCLES
TRACHEA (WINDPIPE)
LUNG (ONE OF A PAIR)
BRONCHIAL TREE
DIAPHRAGM
Fig. 22-21a, p.374
bronchiole
alveolar sac
(sectioned)
alveolar duct
alveoli
Fig. 22-21b, p.374
alveolar sac
pulmonary
capillary
Fig. 22-21c, p.374
Human Respiratory System
Human 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 Cycle
Respiratory cycle
Cutaway View of Alveolus
red blood cell
air space
inside
alveolus
(see next slide)
pore for airflow
between alveoli
Respiratory Membrane
• Area between an
alveolus and a
pulmonary capillary
• Oxygen and
carbon dioxide
diffuse across
easily
alveolar
epithelium
capillary
endothelium
fused
basement
membranes
of both
epithelial
tissues
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