Transcript Blood and the Circulatory System

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
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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