Transcript File

Chapter 15
The Cardiorespiratory System
 Includes function of the heart, blood vessels,
circulation, and gas exchange, between the blood and
atmosphere.
 Heart pumps blood through the body through pathways
(arteries, veins, and capillaries)
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Blood is enriched with oxygen when it passes through the
lungs
As oxygen enters the bloodstream, carbon dioxide leaves it
(respiration)
The Circulatory System
 Course taken by blood through the arteries, capillaries,
and veins & back to heart
 Uses blood to transport dissolved materials
throughout body
 Oxygen, carbon dioxide, nutrients, waste
 Picks up waste products of cell metabolism & takes to
lungs and kidneys (to be expelled from body)
The Heart
 Two major circulations
 Each has its own pump
 Both pumps are
incorporated into the
heart
 Location
 Middle of chest, behind
sternum, within ribcage
 Pericardial cavity
 Above diaphragm
 Structure
 Primarily a shell with four
chambers inside
Heart Facts
 Adult human heart approx size of closed fist
 About 5 inches long and 3 ½ inches wide
 Weighs just less than 1 pound
 Beats about 100,000 times each day
 Pump about 8,000 gallons of blood through 12,000
miles of vessels each day
 Contracts and relaxes 70-80 bpm
Structure of Heart
 Four cavities
 Atria
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Form curved top of heart
 Ventricles
 Meet at bottom of heart to
form pointed base
 Points toward left side of
chest
Structure of Heart
Left Side
Right Side
 One ventricle
 One ventricle
 One atrium
 One atrium
 Mitral valve—connects left
 Tricuspid valve—connects
atrium to left ventricle
 Wall, septum, separates right
and left sides
right atrium to right ventricle
Structure of Heart
 Aorta
 heart’s main artery
 carries blood away from
heart to body’s cells
 Pulmonary artery
 artery that connects
heart to lungs
 Two largest veins:
 Superior vena cava
 Inferior vena cava
Heart Anatomy
Blood Flow
 Two sides of heart are
anatomically and
functionally separate
pumping units
 Right side pumps
blood through
pulmonary circulation
 Left side pumps blood
through systemic
circulation
Blood Flow
 As heart contracts, it pushes blood though chambers
and into the vessels
 Nerves connected to the heart regulate the speed of
contractions
 Greater the activity, faster the heart will pump; faster
heart pumps, more oxygen and nutrient are carried
throughout body
Flow of Blood through Heart
 Superior/inferior vena cava
 Right atrium
 Tricuspid valve
 Right ventricle
 Semi-lunar valve
 Pulmonary artery
 Lungs
http://www.nhlbi.nih.gov/health/dci/Disease
s/hhw/hhw_pumping.html
Flow of Blood through Heart
 Back to heart via
pulmonary vein
 Left atrium
 Bicuspid valve
 Left ventricle
 Semi-lunar valve
 Aorta
 Organs in the body
Heart’s Conduction System
 Heart’s electrical system
 Consisting of specialized cells within heart muscle that
carry an electrical signal
 Regulates pumping of heart
Heart Muscle
 Pericardium
 Epicardium
 Myocardium
 Endocardium
Blood
 Only tissue that flows throughout body
 Carries oxygen & nutrients to all parts of body and
transports waste products back to lungs, kidneys, and
liver for disposal
 Essential part of immune system
 Crucial for fluid and temperature balance
 Hydraulic fluid for certain functions
 Highway for hormonal messages
 Composed of plasma and billions of cells
Plasma
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The yellowish, liquid part of blood
River in which blood cells travel
Makes up 55% of total volume
Carries blood cells +
 Nutrients (sugars, amino acids, fats, salts, minerals)
 Waste products (CO2, lactic acid, urea)
 Antibodies
 Clotting proteins (called clotting factors)
 Chemical messengers (hormones)
 Proteins that help maintain body’s fluid balance
Blood—RBCs & Hemoglobin
 Red Blood Cells (erythrocytes)
 Highly specialized cells that have been “stripped” of
everything, including nucleus
 Major job: transporting oxygen
 Percentage of RBCs in total blood volume called
hematocrit
 Hemoglobin
 Special red-colored molecule that fills RBCs
 Picks up oxygen in areas where O2 is abundant and
releases O2 in tissues where O2 concentration
lowest
Blood—White Blood Cells
 5 distinct kinds
 Neutrophils, monocytes, lymphocytes, eosinophils, basophils
 Able to change according to need and situation in body
 Can leave blood stream , sliding out through vessel walls &
attacking invaders at site of infections
Blood—Platelets
 Fragments of much larger cell (megakaryocyte) which stays
in bone marrow after it differentiates and matures from
stem cell
 Platelets leave bone marrow & circulate throughout the
body
 When stimulated by substance from
damaged tissue, platelets release
substance to help clot blood
Blood Vessels
 Hollow tubes running throughout the body
 5 types
 Arteries
 Arterioles
 Veins
 Venules
 Capillaries
 Provide 2 measurements:
 Pulse
 Blood pressure
Arteries
 Blood vessels that carry
blood from the heart to
organs & cells
 Muscular walls that allow
them to dilate or constrict
 Arterioles: very small
arteries
 Largest artery=aorta
 Runs from chest into
abdomen
 Receives blood directly
from left ventricle
Veins
 Blood vessels that carry blood
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back to heart
Thinner wall
Contain numerous one-way
valves (keep blood moving
toward heart)
Deep veins in LE surrounded
by large muscle groups;
compress the deep veins
when muscles contract
Contractions in extremities
helps propel blood toward
heart; increase venous return
Veins
 Largest vein=superior &
inferior vena cava
 Bring blood from upper
and lower body into
right atrium
 Venules: smallest veins
Capillaries
 Tiny, microscopic blood
vessels that connect
arteries to veins
 Responsible for
transferring oxygen and
nutrients to cells
 Wall so thin that O2 passes
from arterial blood
through them into cells in
organs/tissues
 Waste products (CO2) pass
into capillaries to be
carried back by veins to
heart/lungs
Coronary Arteries
 The heart’s own system of blood vessels
 Located around heart muscle to provide blood and
oxygen to all parts of heart
 Two primary coronary arteries branch
off into smaller vessels
 Right coronary artery: feeds right atrium &
ventricle and bottom of left ventricle
 Left main coronary artery: supplies blood
to rest of heart
 Left anterior descending
 Circumflex
Blood Pressure
 Heart pumps blood into arteries; surge of blood filling
vessels creates pressure against vessel walls
 Pressure measured by 2 numbers:
 Systolic: highest pressure in heart
 correlates to ventricular contraction
 Average 120 mm/Hg
 Diastolic: lowest pressure in heart
 correlates to ventricular relaxation
 Average 80 mm/Hg
 Pulse pressure: difference between
diastolic and systolic pressures
Pulse
 Rhythmical beating of heart
 Created by alternating expansion and
contraction of artery as blood flows through
 7 areas where pulse can be felt
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Brachial artery
Common carotid artery
Femoral artery
Dorsalis pedis artery
Popliteal artery
Radial artery
Temporal artery
Target Heart Rate
 Percentage of the maximum heart rate that is safe to reach
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during exercise
AHA recommends 50-75% for average healthy person
Calculated 220-age
THR is sliding scale that decreases with age
Tool for measuring cardiovascular exercise
Maintain THR for 15-30 min daily health benefits
Flow of Blood through Heart
Can you label the heart?