Cardiovascular System
Chapters 11, 12
Oxygen enters the cardiovascular system by diffusing from
alveoli into blood cells in the capillaries, then binding to
hemoglobin in red blood cells.
Blood
• Hematology- the study of blood,
blood forming tissues, and the
disorders associated with them.
• Blood consists of 2
components.
– Plasma (55%)
• Water (92%).
• Proteins (8%).
– Formed Elements (45%)
• Erythrocytes (99%)- red blood cells.
• Leukocytes (<1%)- white blood cells.
• Platelets (<1%)- a fragment of
cytoplasm enclosed in a cell
membrane.
Characteristics of Blood
•
•
•
•
•
•
1 Drop of blood contains 250 million blood cells.
Blood is denser than water.
Blood temperature is about 100.4 °F.
pH= 7.35-7.45.
Blood is about 8% of total body weight.
Blood volume in
– Men is 5-6 liters (1.5 gallons).
– Women is 4-5 liters (1.2 gallons).
Hemoglobin
• 280 million molecules of hemoglobin per red blood cell.
• Hemoglobin- oxygen binding protein/pigment.
– Globin protein that consists of 4 polypeptide chains.
– Heme molecules are attached to each polypeptide chain.
• Each heme contains an iron ion (Fe+2) that binds to oxygen.
• Transports oxygen from the lungs to tissue cells and
transports part of the carbon dioxide to the lungs.
Hematocrit and Blood Disease
• Hematocrit- percentage
of blood occupied by
cells.
– Female normal range
• 38-46% (aver.- 42%)
– Male normal range
• 40-54% (aver.- 46%)
• Anemia- reduced RBCs
or not enough
hemoglobin.
• Hemoglobinopathyblood disease.
The Heart
• Anatomy
– Cone-shaped, the size of a closed fist (5 inches in
length, 3.5 inches in width, 2.5 inches thick).
– The heart has:
• 2 atria (upper chambers).
• 2 ventricles (lower chambers).
• 4 valves.
– The heart consists mostly of myocardium (cardiac
muscle tissue).
• Function
– Pump blood.
• About 3,600 gallons pumped per day.
• Beats about 72 times per minute, over 100,000 times per day.
The Heart- external
The Heart- internal
The Cardiac Cycle
Atrial Systole
Diastole
Ventricular Systole
Measuring Blood Pressure
• Sphygmomanometer
• Blood Pressure- a
measure of arterial
pressure in the
brachial artery.
– Systolic pressure=
pressure during
contraction (120 mm
Hg).
– Diastolic pressure=
pressure during
relaxation (80 mm Hg).
The valves prevent backflow of blood
Pulmonary valve
Aortic valve
Tricuspid
valve
Bicuspid (mitral valve)
Normal Heart vs. Mitral Valve Prolapse
Internal Conduction System
• Sinoatrial node
(SA, pacemaker).
• Atrioventricular
node (AV).
• Atrioventricular
bundle.
• Purkinje Fibers.
•HeartArteriesArteriolesCapillaries
VenulesVeinsHeart
Heart
Heart
Vein
Artery
Venule
Capillary
Arteriole
Arteries vs. Veins
• Each have the 3 layers.
• The middle layer of an
artery shows more
smooth muscle.
• The lumen is smaller in
arteries.
• Veins often contain
valves.
• Veins are blood
reservoirs, and hold 65%
of blood.
Valve
Smooth
Muscle
Artery
Vein
Capillaries are sites of exchange
• Capillaries are
microscopic, narrow
vessels.
– Substances are exchanged
through the plasma
membrane of the capillary.
• Arterial end of capillary
– Blood pressure forces fluid
out of the capillary.
• Venous end of capillary
– Fluid is drawn back into the
capillary by osmotic
pressure.
• Blood pressure
– Decreases in
capillaries.
• Blood velocity
– Decreases in
capillaries due
to greater
surface area.
Pulse- a pressure wave created by the ejection
of blood from the left ventricle into the aorta.
Drainage- the flow of
blood back to the heart.
• Accomplished by
– Skeletal muscle contraction.
– Valves in veins.
– Respiratory movements.
Atherosclerosis
• Atherosclerosis- the buildup of lipids in the artery
walls. (athero- yellow; sclerosis- hardening).
• Buildup of fatty deposits (plaques), particularly
LDLs (bad cholesterol), obstructs blood flow.
• Leading cause of heart attacks (death of heart
muscle cells) and strokes (death of brain cells).
Balloon Angioplasty
• A catheter and baloon
are threaded into the
coronary artery to the
point of blockage.
• The balloon is inserted
into the blocked area
and inflated.
• Plaque is pushed to the
artery walls.
Coronary Bypass Surgery
Lymphatic
System
Cardiovascular + Lymphatic
= Circulatory System
Lymphatic Components
• Lymphatic vessels and
ducts.
• Lymph- fluid.
• Lymphatic Organs
–
–
–
–
–
Red bone marrow
Thymus
Spleen
Lymph nodes
Diffuse lymphatic tissue
• Tonsils, adenoids &
Peyer’s patches.
Function #1- Draining excess interstitial fluid
& plasma proteins from tissue spaces.
• About 85% of what
exits the arterial end is
reabsorbed by the
venous end of the
capillaries.
• The 15% that doesn’t
return is excess tissue
fluid, it is absorbed by
the lymphatic system.
Lymph is returned to the bloodstream just
above the heart in the brachiocephalic veins.
Function #2- Transporting dietary lipids and
vitamins from the GI tract to the blood.
Function #3- Facilitating immune responses
by recognizing microbes or abnormal cells
and killing them directly or by antibodies.
Basophil
1%
Eosinophil
3%
Lymphocyte
24%
Neutrophil
66%
Monocyte
6%
White Blood Cells
• Function- fight infection; defend against pathogens that
invade the body.
– Granular leukocytes
• Neutrophils- phagocytosis and destruction of bacteria (pus).
• Eosinophils- destroy worms, lessen the severity of allergies.
• Basophils- release histamine, a chemical that attracts other white
blood cells to the site of infection, causes blood vessels to dilate.
– Agranular leukocytes
• Lymphocytes
– T cells- attack viruses, cancer cells, and transplanted tissue cells.
– B cells- develop into plasma cells that secrete antibodies.
– Natural killer cells- attack microbes and tumor cells.
• Monocytes- develop into phagocytotic macrophages.
Red Bone Marrow
• Spongy bone- site of red and white blood cell production.
– Stem cells in the marrow give rise to all formed elements.
Lymph Node Anatomy
• Bean-shaped organ, up to 1 inch long (125 mm), located along lymphatic vessels.
• Scattered throughout body but concentrated near
mammary glands, axillae, and the groin.
• About 600 per human.
Lymph Node Function
• Lymph nodes filter lymph.
• House macrophages that phagocytize debris,
cancer cells, viruses, and bacteria.
• House lymphocytes that mount attacks on
pathogens.
Spleen
• Anatomy
– 5 inch long organ between stomach and diaphragm.
• Function
– Destroy bacteria and viruses. The white pulp consists of
mostly lymphocytes and macrophages.
– Filter old and damaged red blood cells and pathogens from
blood. The red pulp consists of mostly lymphocytes and
macrophages.
Thymus Gland
• Large in infants (70 g),
atrophied in adult (3 g).
• 2 lobed organ.
• Each lobule has a cortex
and medulla.
• The cortex is tightly packed
with lymphocytes &
macrophages.
• Chief Function
– Aid in the maturation of Tlymphocytes.
Lymphatic Nodules
• Lymphatic nodulesoval-shaped
concentrations of
lymphatic tissue.
– Tonsils- form a ring
around the throat
where they protect
against disease
organisms that are
inhaled or swallowed.
– Peyer’s patcheskeep bacteria from
breaching the wall of
the ileum.
Pharyngeal tonsil (adenoid)
Palatine tonsil
Lingual tonsil