Transcript Chapter 11

Chapter 11
Blood
Lecture Outline
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Blood function & composition
Red blood cells
Blood types
Blood clotting
Blood is a mixture of cells and plasma
Human Blood after centrifugation
• ~55% Plasma
• ~45% Red blood cells
• <1% White blood cells and
platelets (“buffy coat”)
Blood plasma
• Water
• Nutrients
• Solutes- Na+, Cl-,
wastes, CO2, etc.
• Contains humoral
immune elements
• Some innate immunity
All blood cells are part of the
hematopoetic stem cell lineage
Hematopoetic stem cells differentiate
into all blood cells
• Pluripotent- able to
become any one of
many cell types
• Includes T cells, B
cells, macrophages,
etc.
Red blood cells carry oxygen and CO2
• Lose nucleus in
development
• Short-lived, no repair
• Packed solid with
hemoglobin
• Membranes designed to
maximize surface area
• Facilitate gas transfer
Hemoglobin
• The oxygen-carrying
protein
• Heterotetrameric protein
• 2 alpha subunits, 2 beta
• Each subunit holds a
Heme group
• Each heme holds an Fe++
ion
• Each Fe++ can bind an
O2
Hemoglobin binding curve
• In areas of High O2
(e.g., lungs)- binds O2
very well (picks up O2)
• In areas of Low O2 (e.g.,
muscles) binds O2
poorly (drops off O2)
• Myoglobin binds O2 in
muscle & organ tissues
Cystic Fibrosis and Sickle Cell Anemia
exhibit Mendelian Inheritance
• Both are recessive
disorders
• Both exhibit
multiple
phenotypic traits
for a single gene
defect (pleiotropy)
Sickle cell anemia
• Genetic inheritance
• A point mutation in
DNA
• Causes malformation of
hemoglobin
• Oxygen transport
inhibited
• Pleiotropic
Platelets assist with blood clotting
• Recruit plasma protein
fibrinogen to a cut
• They release clotting
factors
• Clotting factors convert
fibrinogen to fibrin
• Fibrin net prevents
blood loss
The liquid part of blood is called
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4.
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A) water.
B) plasma.
C) serum.
D) extrastitial fluid.
E) anionic fluid.
The Immune system is the body’s
defense system
• Against:
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Bacteria
Viruses
Protists
Other living invaders
Toxins
Foreign debris
Cancerous cells
• The immune system is
complex
• Defends against threats
known and unknown
White blood cells come in a great
variety of types
Phagocytic white blood cells devour
bacteria
Blood
• Blood functions in transportation, protection,
and regulation
• Blood consists of plasma and formed elements
• Blood types are determined by antigens on
the surface of red blood cells
• Blood clotting occurs in a regulated sequence
of events
Composition of Blood
Figure 11.1
Composition of Blood
Table 11.1 (1 of 3)
Composition of Blood
Table 11.1 (2 of 3)
Composition of Blood
Table 11.1 (3 of 3)
Plasma and Formed Elements
• Plasma
– Makes up about 55% of blood
– About 93% water
– Remaining 7% consists of dissolved substances
including nutrients
• Ions, dissolved gases, hormones, plasma proteins, and
waste products
Plasma and Formed Elements
• Plasma proteins include
– Albumins
• Needed for the water-balancing properties of plasma
– Globulins
• Transport lipids and fat-soluble vitamins
• Some are antibodies
– Clotting proteins
• I.e., fibrinogen
Plasma and Formed Elements
• Stem cells give rise to the formed elements
– Platelets
– White blood cells
– Red blood cells
• All transported by the plasma
Formed Elements
Figure 11.2
Plasma and Formed Elements
• Platelets
– Sometimes called thrombocytes
– Fragments of larger precursor cells called
megakaryocytes
– Essential to blood clotting
Plasma and Formed Elements
Table 11.1 (1 of 3)
White Blood Cells
• White blood cells (WBCs)
– Also called or leukocytes
– Help defend the body against disease
– Remove wastes, toxins, and damaged and
abnormal cells
White Blood Cells
Table 11.1 (2 of 3)
White Blood Cells
• Nucleated cells that are produced in the red
bone marrow
• One type, the lymphocyte, can be produced in
the lymph nodes and in other lymphoid tissue
White Blood Cells
• WBCs have the unique ability to move to the
site of infection, inflammation, or tissue
damage
• Some WBCs are capable of phagocytosis
White Blood Cells
Figure 11.3
Red blood cell
• Often little contrast
under LM
• >99% of visible cells
under the microscope
Platelets
• For blood clotting
White Blood cells come in a wide
variety of types
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Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Macrophages
WBC’s can be categorized
according to a few criteria
• Function:
– Innate immunity vs.
– Adaptive immunity
• Frequency:
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Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
• Cell structures:
– Granulocytes
– Agranulocytes
Granulocytes
• Contain Granules
• For innate immunity
• Granules contain
cellular weaponry and
signals
• 3 major types:
– Eosinophils
– Basophils
– Neutrophils
Neutrophils
• “Neutral-loving”
• Most common
granulocyte
• Lobed nucleus
Eosinophils
• “Acid loving”- bind to
acidic stain (red)
Basophils
• “Base-loving”- bind to
basic stain (blue)
• Involved in allergic
reactions
Agranulocytes
• Lymphocytes
• Monocytes
Monocytes
• Can respond quickly to
infection
• Can differentiate into:
– Macrophages
– Dendritic cells
Lymphocytes
• No granules
• Smaller cell, larger
nucelus
• Three major types of
lymphocyte:
• T cells- 65%
• B cells-25%
– Adaptive immunity
• Natural killer (NK) cells
10%
– Innate immunity
White Blood Cells
• Five types of white blood cells
• Two groups based on the presence or absence
of granules in their cytoplasm
– Granulocytes
– Agranulocytes
White Blood Cells: Granulocytes
• Granulocytes are classified on their staining
ability
– Neutrophils do not stain
– Basophils stain purple with a basic stain
– Eosinophils stain pink with the stain eosin
White Blood Cells: Granulocytes
Table 11.1 (2 of 3)
White Blood Cells: Granulocytes
• Neutrophils
– The most abundant of the WBCs
– Engulf microbes by phagocytosis, thus curbing the
spread of infection
• Pus
– Dead neutrophils, along with bacteria and cellular
debris
– Associated with infection
White Blood Cells: Granulocytes
• Eosinophils
– Defend against parasitic worms
– Lessen the severity of allergies
White Blood Cells: Granulocytes
• Basophils
– Release histamine
• A chemical that attracts other white blood cells
• Causes the blood vessels to dilate
– Also play a role in some allergic reactions
White Blood Cells: Agranulocytes
• Agranulocytes
– Lack granules
– Monocytes
– Lymphocytes
White Blood Cells: Agranulocytes
Table 11.1 (3 of 3)
White Blood Cells: Agranulocytes
• Monocytes
– The largest of the formed elements
– Develop into macrophages
• Phagocytic cells that engulf invading microbes, dead
cells, and cellular debris
White Blood Cells: Agranulocytes
• B lymphocytes
– Give rise to plasma cells, which produce
antibodies
• Proteins that recognize specific molecules called
antigens on the surface of invading microbes or other
foreign cells
White Blood Cells: Agranulocytes
• T lymphocytes
– Specialized white blood cells
– Kill cells not recognized as coming from the body,
or cells that are cancerous
Red Blood Cells
• Red blood cells (RBCs)
– Also called erythrocytes
– Transport oxygen to the cells
– Carry about 23% of the total carbon dioxide
– Shaped like biconcave disks and are very flexible
– No nucleus
Red Blood Cells
Figure 11.4
Red Blood Cells
• Hemoglobin
– Molecules in the RBCs
– Bind to oxygen, making oxyhemoglobin
• Needed for aerobic respiration
• Hemoglobin has a much greater affinity for
carbon monoxide
– Odorless and tasteless
– An insidious poison
Structure of Hemoglobin
Each hemoglobin
molecule consists
of four polypeptide
chains (globins).
Each polypeptide chain
contains a heme group
with an iron atom that
binds to oxygen.
Oxygen molecules
bind to hemoglobin
Oxygen molecules
released
Each hemoglobin
molecule can carry
up to four molecules
of oxygen.
Figure 11.5
Red Blood Cells
• Produced in the red bone marrow
• Live about 120 days
• When cells in the kidney detect a decrease in
oxygen they release erythropoeitin
– A hormone that can speed RBC production
• Undergo phagocytosis in the liver and spleen
– The heme in hemoglobin is salvaged and sent to
the bone marrow for recycling
– Remainder is degraded to bilirublin
Red Blood Cells
Figure 11.6
Red Blood Cells
PLAY
Animation—Blood
Red Blood Cell Disorders
• Anemia
– Several types
– The blood’s ability to carry oxygen is reduced
– Can result from too little hemoglobin, too few red
blood cells, or both
• Symptoms
– Fatigue, headaches, dizziness, paleness,
breathlessness, and heart palpitations
Red Blood Cell Disorders
• Iron deficiency anemia
– Most common
– Leads to inadequate hemoglobin production
• Causes
– A diet that contains too little iron
– An inability to absorb iron from the digestive
system
– Blood loss
Red Blood Cell Disorders
• Hemolytic anemias
– Occur when red blood cell destruction exceeds
production
• Causes
– Infections
– Defects in the membranes of RBCs
– Transfusion of mismatched blood
– Hemoglobin abnormalities
Red Blood Cells
• Sickle-cell anemia
– An example of a hemolytic anemia
– Caused by genetically abnormal hemoglobin
• RBCs form a sickle shape when the blood’s oxygen
content is low
– Results in RBCs that are fragile and rupture easily,
clogging small blood vessels and promoting clot
formation
Red Blood Cell Disorders
• Pernicious anemia
– Occurs when there is insufficient production of
red blood cells
• Lack of vitamin B12 due to the lack of intrinsic factor
secretion from the stomach lining
White Blood Cell Disorders
• Infectious mononucleosis
– Viral disease of the lymphocytes caused by the
Epstein–Barr virus
White Blood Cell Disorders
• Leukemia
– A cancer of the WBCs that causes the number of
WBCs to increase
– These cells do not function as normal WBCs
Blood Types
• Genetically determined by the glycoproteins
found on the surface of RBCs
• Named by the antigen found on the surface of
the cell
–A
–B
– AB
–O
Blood Types
Table 11.2
Blood Types
Figure 11.7a
Blood Types
Figure 11.7b–c
Blood Types
• Agglutination, or clumping
– Occurs when someone’s antibodies contact a
foreign cell
Blood Types
• Rh factor
– Another important antigen
– Becomes critical during pregnancies of Rhnegative women
• Individuals who have Rh antigens on their
RBCs are Rh-negative
Blood Types
• Rh-negative person will not form anti-Rh
antibodies unless he or she has been exposed
to the Rh antigen
– Transfusion
– Having given birth to a Rh-positive baby
Rh Factor
Figure 11.8 (1 of 4)
Rh Factor
Figure 11.8 (2 of 4)
Rh Factor
Figure 11.8 (3 of 4)
Rh Factor
Figure 11.8 (4 of 4)
Blood Types
• Hemolytic disease of the newborn
– Anti-Rh antibodies can develop in the mother
– They can cross the placenta, destroying the Rhpositive fetus’s RBCs
– The baby may die or be very anemic
• Rhogam
– A serum containing antibodies against the Rh antigens
– Given to Rh- mothers to prevent the production of
anti-Rh antibodies
Blood Types
PLAY
Animation—Blood Types
Blood Clotting Occurs in a Regulated
Sequence of Events
• The clotting process begins when, upon injury,
a blood vessel spasms to reduce blood flow
Blood Clotting Occurs in a Regulated
Sequence of Events
Figure 11.9
Blood Clotting
• Collagen fibers then form in the wound that
snag platelets
• When platelets contact collagen fibers, they
swell, form extensions, and stick together to
form a platelet plug
Blood Clotting
• Next, prothrombin activator converts
prothrombin to thrombin
– Causes fibrinogen to form long strands of fibrin
– Fibrin strands form a web that traps blood cells
and forms a clot
Blood Clotting
• When the wound is healed
– Plasmin, formed from plasminogen, digests the
fibrin strands of the clot
• If even one of the clotting factors is lacking,
the process can be slowed or completely
blocked
• Vitamin K is needed to synthesize
prothrombin in the liver
– Clotting does not occur without it
Hemophilia
• Hemophilia
– Inherited condition
– Prevents one or more of the clotting factors from
being made
– The affected individual bleeds excessively and
needs to have the clotting factors restored
Blood Clotting
• Formation of unnecessary blood clots can
have immediate health consequences
– Clots can disrupt blood flow
– A clot that continues to circulate is called an
embolus
– When it lodges in a vessel it is called a thrombus
• Can cause a heart attack or stroke