Download The Circulatory System

The Circulatory System
Melissa Zelaya
Spring 2010
Senior Seminar
The circulatory system
distributes materials such
as oxygen and nutrients
throughout the body.
The Circulatory System


The heart—
heart— muscular
pump
System of vessels
-Arteries
-Veins
-Capillaries
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Open vs. Closed Systems
 Vertebrates—
Vertebrates—closed
circulatory systems
 Some invertebrates—
invertebrates—open systems
-less efficient
-slower circulatory time
The Human Heart

Four-chambered structure
located in the chest
comprised of:
– 2 ventricles
– 2 atria



Sinoatrial node (SA node)
Atrioventricular (AV)
heart valves
-Tricuspid valve
-Bicuspid valve
Semilunar valves
Coronary Arteries




Supply the heart with
blood
Can become clogged
or blocked
Blocked coronary
artery = heart attack
Heart attack is the
common cause of
death in middle-aged
men in the U.S.
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Cardiac Output
 CO=
stroke volume x heart rate
 Under resting conditions average CO is
5 liter per minute
Cardiac Muscle
 The
more its stretched, the greater its
strength of contraction
 Capable of conducting an electrical pulse
 Internal signals arise within the heart and
spread from heart fiber to heart fiber
 Pacemaker = SA node
 Fibrillations cause stroke or heart failure
Heartbeat
 Cardioaccelerator
releases norepinephrine
which speeds up the heart rate
 Vagus nerve releases acetylcholine which
slows down the heart rate
 Strong vagal stimulation
 Hypervagal response
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Arteries




Carry oxygenated
blood
Innermost layer =
tunica intima
Middle layer = tunica
media
Outermost layer =
tunica externa
Veins
 Similar
to arteries
walls
 Lack pumping pressure
 Dilated by blood moving through them
 Thinner
Blood Pressure
 Force
exerted in the blood vessels by the
blood contained within them
 Produced by 2 primary event
 Not uniform
 Normal blood pressure is
120 mm Hg/ 80 mm Hg
 Systolic blood pressure/diastolic blood
pressure
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Pulse is simply alternate
contractions and dilations
during the passage of blood
from the ventricle into the
aorta.
Hypertension
 High
blood pressure
pressure above 150 mmHg
 Diastolic pressure above 95 mmHg
 Norepinephrine and epinphrine naturally
increase blood pressure
 Increase cardiac output, stroke volume,
heart rate
 Treatment= antihypertensive drugs and
diuretics
 Systolic
Atherosclerosis



Hardening or
thickening of the
artery wall
Pulse pressure
High pulse pressure
may be a high-risk
factor for stroke
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Blood


Fluid made up of 55%
liquid plasma
Plasma is made up of
water and 45%
floating cells
- contains dissolved
proteins, lipids, and
carbohydrates
Lymph is similar to
plasma just less
concentrated
 Blood,
lymph, and fluids bathing the
tissues makes up 1/5 of the total body
weight
 Blood alone comprises 1/12 of the body
weight, just under 5 liters in volume
Blood Constituents




Red blood cells
(erythrocytes)
White blood cells
(leukocytes)
Platelets
(thrombocytes)
thrombocytes)
Highly viscous
(resistance to flow)
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Red Blood Cells
 Carry
oxygen
 Relatively small
 When mature they lack a nucleus and
other organelles
 Bulk of the RBC is taken up by the
conjugated protein—
protein—hemoglobin
 Erythropoietin
White Blood Cells


Involved in guarding against invading organisms
Divided into 2 large groups:
-granulocytes
- agranulocytes
Granulocytes
 Neutrophils
 Eosinophils
 Basophils
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Blood pH
 pH
of blood is always maintained within
the range of 7.3 and 7.5
 pH maintained through buffer systems
 Less than 7.3—
7.3—acidosis
 Higher than 7.5—
7.5—alkalosis
 Both severely life threatening
The Immune System
Definitions
 Immunology—
Immunology—refers
to all of the defense
mechanisms that the body can use to fight
the threat of foreign invasions
 Pathogens—
Pathogens—disease-causing organisms
 Natural Flora—
Flora—consisting of indigenous
bacteria that keep each other’
other’s
populations in check (act as barriers)
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Components
Defenses are highly specific in their action
 Skin
 Glands (sweat)
 Mucous membranes
 Secretions
 Lymph vessels and nodes
 WBC’
WBC’s
 Bone marrow
 Thymus
Immune Response
 Mediated
by two types of lymphocytes:
- B lymphocyte
- T lymphocyte
 Both arise from lymphocytic cells in bone
marrow
 Reside in the lymph tissues
B-Lymphocytes


Involved in formation
of antibodies
Humoral response
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T-Lymphocytes


Cell mediated
response
Initiate attack by
various cell types
Antigens
 Invading
entity or organism
contains unique chemical compounds
not found in other entities
 Usually consist of proteins, large
polysaccharides, or large lipoproteins
 Frequently found on surfaces of unicellular
organisms
~A specific antibody exists for every anitgen
 Each
Humoral Response
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Antibodies
 Globular
proteins coded for by specific
genes
 Made up of 4 polypeptide chains:
-2 Heavy chains
-2 Light chains
 Bound by S-S bonds
 Constant region—
region— specific to class
 Variable region—
region—specific to antigen
Mote than 1 million kinds of antigens are
encountered during a person’
person’s lifetime!!
Antibody-Antigen Reaction
 Antibody
has 2 binding sites
has unique conformations for antigen
specificity
 Antigenic determinant (small portion of
antigen) fits into cleft of antibody
 Antibody-antigen reaction initiates
proliferation of lymphocytes
 Also
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Types of Antibodies
5
types
-IgG
-IgG (most common)
-IgM
-IgM (first group found during infection)
-IgA
-IgA (tears, saliva, breast milk)
-IgD
-IgD (function not yet known)
-IgE
-IgE (releases histamine, fights
parasites and allergic reactions)
Antibodies (mini conclusion)
 Primary
weapon of the humoral response
antigen directly or activates
related systems which will attack invader
 Attacks
Mode of Direct Attack
 Agglutination—
Agglutination—involves
clumping of
antigens into an antigen-antibody complex
 Network of interconnected Ab and Ag
 Complexes reduce mobility of Ag
 Makes them susceptible to phagocytosis
-leukocytes engulf and ingest invader
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Other forms of Attack
 Certain
Ab can lyse cells they attack
 Others bind to toxic sites of the Ag and
neutralize them
 Activate the complement system
Complement System
 Activated
enzymes eat into cell membrane
of Ag and eventually causes them to
rupture
 Makes cell surfaces more susceptible to
phagocytosis
 Produces a chemotaxic effect
 Elicits a local inflammatory response
Inflammatory Response
 Nonspecific
 Mediated
response to injury of cells
by release of histamine
 Involves
-Increase in blood flow (vasodilatation)
-Local swelling
-Increase in temp.
-systemic fever-caused by pyrogenes
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Cell Mediated Response
 Sensitized
by T lymphocytes
eukaryotic cells:
-Invader cells
-Host cells different from “self cells”
cells”
-Cells invaded by viruses
-Transplanted organs and tissues
 Attacks
Destruction of Invader
 Specialized
T-cells—
T-cells—cytotoxic T cells
attacks directly
 Like Ab’
Ab’s of the humoral response
 Attacks specific Ag
 Releases cytotoxic and digestive enzymes
 Attracts macrophages
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AIDS
 Disease
caused by the retrovirus HTLV-III
 RNA virus is known as HIV
 Virulence –ability to attack a group of T
lymphocytes
 Destruction of cells causes cancers
opportunistic infections
Blood Types
 Antigen
present on RBC determines blood
type
 2 types of antigens—
antigens—A and B
 Type of Blood:
-Type A
-Type B
-Type AB (universal donor0
-Type O (rare type)
Fried, G., Hademenos,
Hademenos, G. 2009. Schaums
Outlines Biology.
Biology. 3rd Editon
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