Transcript blood - Nutley Schools

Chapter 10
NHS
Anatomy/Physiology
BLOOD
Human Red Blood
Cells, Platelets
and T-lymphocyte
(erythocytes =
red; platelets =
yellow;
T-lymphocyte =
light green) (SEM
x 9,900).
INTRODUCTION - Formed - hemopioesis
Mesodermal origins
Functions - transport, Protection, Regulation,
osmotic pressure
Composition - Plasma + formed element - 5.6 L
Blood Composition
•
1.
2.
3.
4.
Blood Plasma
Definition-blood minus its cells
Composition-water containing many dissolved substances
(for example food, salts and hormones)
Amount of blood-varies with size and sex’ 4 to 6 L about
average’ about 7% to 9% of body weight
Slightly alkaline 7.2 pH
B. Formed elements
1. Kinds
a. RBCs (erythrocytes)
b. WBCs (leukocytes)
(1) Granular leukocytes- neutrophils, eosinophils, and
basophils.
(2) Nongranular leukocytes-lympphocytes and monocytes
c. Platelets or thrombocytes
2. Numbers
a. RBCs-4½ to 5 million per mm3 of blood
b. WBCs-5000 to 10,000 per mm3 of blood
c. Platelets-300,000 per mm3 of blood
3. Formation- red bone marrow (myeloid tissue) - hemoposoieses
forms all blood cells except some lymphocytes and monocytes,
which are formed by lymphatic tissue in the lymph nodes, thymus,
and spleen.
C RBCs
1. Structure-Disk-shape, without nuclei
2. Functions-Transport oxygen and carbon dioxide
3. Anemia-inability of blood to carry adequate oxygen to tissues;
caused, for example, by:
a. Inadequate RBC numbers
b. Deficiency of hemoglobin
c. Pernicious anemia-Deficiency of vitamin B12
4. Hematocrit -Medical test in which a centrifuge is used to separate
whole blood into formed elements and liquid fraction
a. Buffy coat is WBC and platelet fraction
b. Normal RBC level is about 45%
c. Polycythemia-Abnormally high RBC count
WBCs
1. General Function- Defense
2. Neutrophils and monocytes carry out
phagocytosis
3. Lymphocytes produce antibodies (Blymphocytes) or directly attack foreign
cells (T-lymphocytes)
4. Eosinophils protect against irritants
that cause allergies
5. Basophils produce heparin, which
inhibits clotting
6. Clinical conditions related to
blood:
a. Leukopeniaabnormally low WBC count
b. Leukocytosisabnormally high WBC count
c. Leukemia-cancer;
elevated WBC count; cells do not
function properly
Platelets and blood clotting
1. Platelets play an essential role in blood clotting
2. Blot clot formation
a. Clotting factors released at the injury site produce
prothrombin activator
b. Prothrombin activator and calcium convert prothrombin
to thrombin
c. Thrombin triggers formation of fibrin, which traps RBC
to for a clot
A.
ABO system
1. Type A blood-type A antigens in RBCs; anti-B type
antibodies in plasma
2. Type B blood-type B antigens in RBCs; anti-A type
antibodies in plasma
3. Type AB blood- type type A and type B antigens in
RBCs; no anti A or anti B antibodies in plasma
4. Type O blood-no type A or type B antigens in RBCs;
both anti-A and ant-B antibodies in plasma
BLOOD TYPES
RH
FACTOR
1. Rh-positive blood-Rh factor antigen present in RBCs
2. Rh-positive blood- Rh factor antigen present in RBCs; no
anti-Rh antibodies present naturally in plasma; anti-Rh
antibodies, however, appear in the plasma of Rh-negative
persons if Rh-positive RBCs have been introduced into their
bodies
3. Erythroblastosis fetalis-may occur when Rh-negative
mother carries a second Rh-positive fetus; caused by mother’s
Rh antibodies reacting with baby’s Rh-positive cells
Chapter 11
The Circulatory System
Lack
System
Closed
Circulatory
Open
Circulatory
System Sluggish
System
Anterior view showing
major arteries (white) and
veins (black)
1 Internal jugular vein
2 Common carotid artery
3 Subclavian vein and
artery
4 Brachial artery
5 Cephalic vein
6 Basilic vein
7 Inferior vena cava
8 Radial artery
9 Ulnar artery
10 Common iliac artery
and vein
11 Femoral artery
12 Great saphenous vein
13 Heart
14 Aorta
15 Femoral vein
Introduction
• Cardiovascular system- vital for supplying
oxygen and nutrients to tissues and
removing wastes from them.
Structure of the Heart
• Cone-shaped, muscular
pump, found in thoracic
cavity
• Size and Location of the
Heart
– The average adult heart is
14 cm long and 9 cm wide
– The heart lies in the
mediastinum under the
sternum; its apex extends
to the fifth intercostal
space.
C. Coverings of the Heart
• The pericardium encloses the heart.
– Fibrous pericardium surrounds a more delicate
visceral pericardium (epicardium) that
surrounds the heart.
– At the base of the heart, the visceral
pericardium folds back to become the parietal
pericardium that lines the fibrous pericardium.
– Between the parietal and visceral pericardia is
the pericardial cavity filled with serous fluid.
• The outermost layer
the epicardium connective tissue and
epithelium - houses
blood and lymph
capillaries along with
coronary arteries.
• The middle layer myocardium is the
thickest layer of the
heart wall.
• The inner layer endocardium is
smooth connective
tissue and epithelium,
and is continuous
with the endothelium
of major vessels
joining the heart.
D. Wall of the Heart
• The heart has four internal
chambers: two atria on top
and two ventricles below
• Atria receive blood
returning to the heart
• The thick-muscled
ventricles pump blood to the
body.
• The right ventricle - thin
wall - pumps blood to lungs
• aortic + pulmonary valves prevent return to ventricles
• Tricuspid between right
atria and right ventricle
• bicuspid (mitral) between
left atria and left ventricle
Heart Chambers and
Valves
Skeleton of the Heart
• Rings of dense connective tissue lie at the plane in
which the A-V orifices and aortic and pulmonary
valves lie; these rings make up the skeleton of the
heart.
• These tough rings prevent dilating of tissue in this
area.
Path of Blood through the Heart
• Blood low in oxygen returns to the right atrium
• The right atrium contracts, forcing blood into the right ventricle
• The right ventricle contracts forcing blood through the pulmonary
valve into the pulmonary trunk and arteries.
• The pulmonary arteries carry blood to the lungs where it can rid itself
of excess carbon dioxide and pick up a new supply of oxygen.
• Freshly oxygenated blood is returned to the left atrium of the heart
through the pulmonary veins.
• The left atrium contracts, forcing blood into the left ventricle.
• The left ventricle contracts forcing open the aortic valve as blood
enters the aorta for distribution to the body. - SYSTEMATIC
CIRCULATION
Blood Supply to the Heart
• The first branches off of the aorta
carry freshly oxygenated blood
• Branches of the coronary arteries
feed many capillaries of the
myocardium.
• The heart muscle requires a
continuous supply of freshly
oxygenated blood, so smaller
branches of arteries often have
anastomoses as alternate
pathways for blood, should one
pathway become blocked.
• Cardiac veins drain blood
from the heart muscle and
carry it to the coronary sinus,
which empties into the right
atrium.
• The cardiac cycle consists of
the atria beating in unison
followed by the contraction
of both ventricles
• pressure within the heart
chambers rises and falls with
the contraction and relaxation
of atria and ventricles.
• When the atria fill, pressure
in the atria is greater than that
of the ventricles, which
forces the A-V valves open.
• As the ventricles contract,
papillary muscles contract,
pulling on chordae tendinae
and preventing the backflow
of blood through the A-V
valves - Mitral, tricuspid
Heart Actions
Heart Sounds
• Heart sounds are due to vibrations in heart tissues
as blood rapidly changes velocity within the heart.
– Heart sounds can be described as a "lub-dup" sound.
• The first sound (lub) occurs as ventricles contract and A-V
valves are closing.
• The second sound (dup) occurs as ventricles relax and aortic
and pulmonary valves are closing.
Cardiac Conduction System
• Specialized cardiac muscle conducts impulses
throughout the myocardium and comprises the
cardiac conduction system
• Path= S-A Node, AV- Node A-V bundle - Perkinje
fibers
– A self-exciting mass of specialized cardiac muscle
called the sinoatrial node (S-A node or pacemaker),
located on the posterior right atrium, generates the
impulses for the heartbeat.
Electrocardiogram
• An electrocardiogram is a recording of the
electrical changes that occur during a cardiac
cycle.
– The first wave, the P wave, corresponds to the
depolarization of the atria.
– The QRS complex corresponds to the depolarization of
ventricles and hides the repolarization of atria.
– The T waves ends the ECG pattern and corresponds to
ventricular repolarization.
Regulation of the Cardiac Cycle
• The amount of blood pumped at any one time must adjust to
the current needs of the body
• The S-A node is innervated by branches of the sympathetic
and parasympathetic divisions, so the CNS controls heart
rate.
• Sympathetic impulses speed up and parasympathetic
impulses slow down heart rate.
• medulla oblongata maintains a balance between the
sympathetic/parasympathetic
• Impulses from cerebrum or hypothalamus may also
influence heart rate, as do body temperature and the
concentrations of certain ions.
• The blood vessels (arteries,
arterioles, capillaries, venules, and
veins) form a closed tube that
carries blood away from the heart,
to the cells, and back again.
• 3 tunics - intima - media - adventita
• Arteries are strong, elastic vessels
adapted for carrying high-pressure
blood.
• Veins - thin walled, valves, towards
the heart
• Capillaries are the smallest vessels,
consisting only of a layer of
endothelium through which
substances are exchanged
• Capillary permeability varies from
one tissue to the next
Blood Vessels
Capillaries
• Areas with a great deal of metabolic activity (leg
muscles, for example) have higher densities of
capillaries.
– If blood is needed elsewhere in the body, the capillary
beds in less important areas are shut down.
Venules and Veins
• Venules leading from capillaries merge to form
veins that return blood to the heart.
• Veins have the same three layers as arteries have
and have a flap-like valve inside to prevent
backflow of blood.
• Veins are thinner and less muscular than arteries;
they do not carry high-pressure blood.
• Veins also function as blood reservoirs.
Blood Pressure
• Blood pressure is the force of blood against the inner walls of blood
vessels
• Arterial Blood Pressure
• Arterial blood pressure rises and falls following a pattern established
by the cardiac cycle.
• During ventricular contraction, arterial pressure is at its highest (systolic pressure).
120 mm Hg When ventricles are relaxing, arterial pressure is at its lowest (diastolic
pressure). 80 mm Hg - Pulse
Paths of Circulation
• Blood vessels can be divided into a pulmonary
circuit and systematic circuit
• Pulmonary Circuit
– The pulmonary circuit is made up of vessels that
convey blood from the right ventricle to the pulmonary
arteries to the lungs, alveolar capillaries, and pulmonary
veins leading from the lungs to the left atrium.
• Systemic Circuit
– The systemic circuit includes the aorta and its branches
leading to all body tissues as well as the system of veins
returning blood to the right atrium.
Hepatic Circulation
• Hepatic portal circulation -stomach , spleen,
gallbaldder, pancreas - venous return by
way of liver
Fetal Circulation
• Fetal placenta
circulation via 2
umbilical arteries
and 1 umbilical
vein
• ductus venosus liver by pass
• ductus arteriosus lung by pass
• foramen ovale lung by pass
• The aorta is the body's
largest artery.
• Principal Branches of the
Aorta
• The branches of the
ascending aorta are the
right and left coronary
arteries that lead to heart
muscle.
• Principal branches of the
aortic arch include the
brachiocephalic, left
common carotid, and left
subclavian arteries.
• The descending aorta
(thoracic aorta) gives rise
to femoral arteries which
supply lower extremities
Arterial System
• Veins return blood to the
heart after the exchange of
substances has occurred in
the tissues.
• Larger veins parallel the
courses of arteries and are
named accordingly; smaller
veins take irregular pathways
and are unnamed.
• Veins from the head and
upper torso drain into the
superior vena cava.
• Veins from the lower body
drain into the inferior vena
cava.
• The vena cavae merge to join
the right atrium.
Venous System
Clinical
considerations
•
•
•
•
Coronary thrombosis
angina pectoris
pulse
cardiac output - volume
per minute
• stroke volume - amount
of blood pumped per
contraction