3. Blood
• The fluid connective tissue that circulates in the heart, arteries,
capillaries, and veins of a vertebrate animal carrying nourishment and
oxygen to and bringing away waste products from all parts of the body.
• Makes up about 8% of body weight (about 5.6 liters in 70kg man)
• This proportion is less in women and considerably greater in children,
gradually decreasing until the adult level is reached
• Blood in the blood vessels is always in motion because of pumping
action of the heart
4. Blood
• Composed of clear, straw colored, watery fluid
called plasma in which several different types of
blood cell are suspended
• Plasma constitutes 55% of blood volume
• Remaining 45% is accounted for cellular fraction
of blood
• Plasma and blood cells can be separated by
gravity, because cell are heavier than plasma
7. Blood Functions
Transportation: It transports oxygen from the lungs
to the tissues, and carbon dioxide from the tissue to
the lungs for excretion.
• It transports Nutrients from alimentary tract to the
tissue and cell wastes to the excretory organs
principally the kidneys.
• It transports Hormone secreted by endocrine glands
to their targeted glands and tissues.
8. Blood Functions
• It transport heat produced in active tissue to other
less active tissue.
• It transport protective substances e.g antibodies to
the area of infection.
• It transport Clotting factors that coagulate blood,
minimizing bleeding from ruptured blood vessels.
9. Blood Functions
Regulation: circulating blood helps maintains
homeostasis of all body fluids
• Blood also regulate PH through the use of
buffer
• It also adjust body temperature ( flow through
the skin, where excessive heat can be loss from
the blood to the environment.
11. Physical Characteristics of Blood
• Thicker than water
• 7-8 % of total body weight
• Blood volume
» 70 mL/kg of body weight
» 5 - 6 liters in males
» 4 - 5 liters in females
• Temperature - 100.40F
• pH - 7.35 to 7.45
12. Plasma
• Constituents of plasma are water (90-92%), and
dissolving and suspended substances including
– Plasma proteins (7%)
– Inorganic salts
– Nutrients, principally from digested food
– Waste materials
– Hormones
– Gases
13. Plasma proteins
Make up 7% of plasma
– Responsible for osmotic pressure (applied pressure to stop
osmosis) to keep blood within circulation
– Plasma viscosity is due to plasma protein mainly fibrinogen and
albumin
Albumin: (54%) formed in liver, main function is to maintain
osmotic pressure
– Albumin also acts as carrier molecule for lipids and steroid
hormones
14. Plasma proteins
• Globulins: (38%)main functions as
– antibodies (immunoglobulin) produced by lymphocytes
– Transportation of some hormones and mineral salts e.g.
thyroglobin carries the hormone thyroxine and transferrin
carries mineral iron
– Inhibition of some proteolytic enzymes e.g. alpha
macroglobulin inhibit trypsin activity
• Clotting factors: Fibrinogen(7%) is synthesis in liver and
essential for blood coagulation
15. Plasma
• Electrolytes: range of function
– Muscle contraction e.g. Calcium's
– Transmission of nerve impulses (potassium and sodium)
– Maintenance of acid base balance (phosphate)
• Nutrients
– The product of digestion e.g. glucose, amino acids, fatty
acid and glycerol are absorbed from alimentary tract
16. Plasma
• Waste product:
– Urea, creatanine and uric acid are the waste products of
protein metabolism formed in liver and carried in blood to
kidney for excretion
• Hormones:
– chemical messengers synthesized by endocrine glands
• Gases :
– Oxygen, carbon dioxide and nitrogen are transported round
the body dissolved in blood
17.
18. Cellular content of blood
• Erythrocytes (Red Cells) 45% of blood
– Hemoglobin
• Leukocytes (White Cells)
– Granulocytes
• Neutrophils, eosinophils, and basophils
– Agranulocytes
• Monocytes and lymphocytes ( T and B lymphocytes)
• Platelets (Thrombocytes)
20. Red Blood Cells
• RBCs are biconcave
• Anucleated
• 7 micrometer in diameter
• Life span 120 days, then destroyed in spleen (graveyard of RBCs)
• Hemoglobin- quaternary structure, 2 chains and 2 chains.
• A normal RBC count would be: men – 4.7 to 6.1 million cells per
microlitre (cells/mcL) women – 4.2 to 5.4 million cells/mcL
• 1 RBC contains 280 million hemoglobin molecules
21. Red Blood Cells
Function-
Transport respiratory gases, mainly of oxygen but also carry
some carbon dioxide
Their biconcavity increase their surface area for gas
exchange and the thinness of central portion allow fast entry
and exit of gases
The cells are flexible, so they can squeeze through narrow
capillaries and contain no intracellular organelles and leave
more space for hemoglobin
23. Leukocytes (White Blood Cells)
• Largest blood cell and Count only 1 % of blood volume
• Complete cells, with a nucleus and organelles
• Life span of WBC’s is 13 to 20 days.
• Function: important in defense and immunity
• Able to move into and out of blood vessels (diapedesis)
• Can move by ameboid motion
• Can respond to chemicals released by damaged tissues
24. Types of leukocytes
• Mainly two types
– Granulocytes ( Polymorphonuclear leukocytes)
• Neutrophils, Eosinophils and Basophils
– Agranulocytes
• Lack visible cytoplasmic granules
• Monocytes and lymphocytes
25. Granulocytes
• Neutrophils (60-70%)
– Multilobed nucleus with fine granules
– Act as phagocytes at active sites of infection
• Eosinophils (2-4%) biolobed nucleus
– Large brick-red cytoplasmic granules
– Found in response to allergies and parasitic worms
• Basophils (0.5-1.0%) irreguraly shaped nucleus
– Have histamine-containing granules
– Initiate inflammation
26. Agranulocytes
• Lymphocytes (20-25%)
--Single large nucleus
– Large Nuclei, smaller than monocytes
– Play an important role in the immune response
• Monocytes(3-8%)
--Bean shaped nucleus
– Largest of the white blood cells
– Function as macrophages
– Important in fighting chronic infection
27.
28.
29. Function of WBCs
• Scavenging: At the site of injury or infection,
neutrophils in blood and monocytes in the tissue engulf
worn out cells of the body and dead microbes and thus
act as scavengers.
• Diapedesis: Neutrophils show amoeboid movement. They
migrate towards the site of infection, squeeze through
capillary walls to engulf and kill microbes.
•
30. Function of WBCs
• Phagocytosis: On reaching site of infection, neutrophils and
monocytes engulf microbes or foreign matter or the damaged cells.
This is called phagocytosis. By phagocytosis, neutrophils kill
microorganisms and protect the body against infections.
• Inflammation or Inflammatory Reaction: Inflammation is
swelling caused at the site of injury. The blood vessels at this point
release more blood making it red and hot. Due to accumulation of
tissue fluid, the area swells up. The neutrophils and macrophages
migrate through capillary wall by diapedesis and fight against
invading microbes.
31. Function of WBCs
• Formation of Antibodies: Lymphocytes produce
antibodies to kill germs and neutralize their
toxins(poisons produced by bacteria).
• Confer Immunity: Lymphocytes also produce
antibodies to provide life long immunity against
certain diseases.
32. Platelets (thrombocytes)
• Small non nucleated disc 2-4 micrometers in
diameters
• Life span 8-11 days
• Function: promote blood clotting
• fall in platelets count, kidneys release a substance
called thrombopoieten which stimulate platelets
synthesis
33. Blood Vessels
• Blood is carried in a closed system of vessels that begins and
ends at the heart
• The three major types of vessels are arteries, capillaries,
and veins
• Arteries carry blood away from the heart
• Veins carry blood toward the heart
• Capillaries contact tissue cells and directly serve cellular
needs
35. Tunics
Tunica interna (tunica intima)
– Endothelial layer that lines the lumen of all vessels
Tunica media
– Smooth muscle and elastic fiber layer, regulated by
sympathetic nervous system
– Controls vasoconstriction/vasodilation of vessels
Tunica externa (tunica adventitia)
– Collagen fibers that protect and reinforce vessels
– Larger vessels contain vasa vasorum
36. Arteries
• Blood vessel that takes blood away from the heart
to all parts of the body (tissues, lungs, etc). Most
arteries carry oxygenated blood; the two
exceptions are the pulmonary and the umbilical
arteries, which carry deoxygenated blood to the
organs that oxygenate it.
37. Elastic (Conducting) Arteries
Thick-walled arteries - near the heart; the aorta and its major
branches
– Large lumen allow low-resistance conduction of blood
– Contain elastin in all three tunics
– Withstand and smooth out large blood pressure
fluctuations
– Allow blood to flow fairly continuously through the body
38. Muscular (Distributing) Arteries and
Arterioles
Muscular arteries – distal to elastic arteries; deliver blood to
body organs
– Have thick tunica media with more smooth muscle and
less elastic tissue
– Active in vasoconstriction
Arterioles – smallest arteries; lead to capillary beds
– Control flow into capillary beds via vasodilation and
constriction
39. Veins
• Veins are blood vessels that carry blood toward
the heart. Most veins carry deoxygenated blood from
the tissues back to the heart; exceptions are
the pulmonary and umbilical veins, both of which
carry oxygenated blood to the heart.
• The walls of veins are thinner than those of arteries
• The smallest veins are called venules
40. Capillaries
Capillaries - the smallest blood vessels
– The smallest arterioles break up into number of minute
vessels called capillaries
– Walls consist of single layer of endothelial cell sitting on
very thin membrane through which water and other small
molecule can pass
– Allow only a single RBC to pass at a time
42. Heart
• Cone shaped hollow muscular organ
• It is about 10-14 cm long, 9 cm wide and the size of
your fist.
• Its weight is 250 g in women and is heavier in men
(300 g).
• The heart lies in thoracic cavity in the mediastinum.
44. Heart layers
• Pericardium – a double-walled sac around the
heart composed of:
1. A superficial fibrous pericardium
2. A deep two-layer serous pericardium
a. The parietal layer lines the internal surface of the fibrous
pericardium
b. The visceral layer or epicardium lines the surface of the
heart
• They are separated by the fluid-filled pericardial cavity
called pericardial fluid: 25-35 ml.
44
45. Coverings of the Heart: Physiology
• The Function of the Pericardium:
– Protects and anchors the heart
– Prevents overfilling of the heart with blood
– Allows for the heart to work in a relatively
friction-free environment
47. Heart layers
• Myocardium
– Is composed of specialized cardiac muscle found
only in the heart
– Is involuntary
– Thickest layer of heart wall.
– The end branches of cell are close contact with
adjacent cell
48. Heart layers
• Endocardium:
– This lines the chambers and valves of the heart
– It is thin, smooth, glistening membrane that permits
smooth flow of blood inside the heart
– It consist of flattened epithelial cells and it is
continuous with the endothelium lining the blood
vessels
49. Actions of the Heart
Actions of the heart are classified into four types:
1. Chronotropic action----Heart Rate
2. Inotropic action.......Force of contraction
3. Dromotropic action.......Conduction of
impulse
4. Bathmotropic action.......Excitability of
muscles
51. Major Vessels of the Heart
• Vessels returning blood to the heart include:
1. Right and left pulmonary veins
2. Superior and inferior venae cavae
• Vessels conveying blood away from the heart
include:
1. Aorta
2. Right and left pulmonary arteries
51
55. Cardiac Chambers
• Human heart has 4 chambers
– 2 Atria
• Superior = primary receiving chambers, do not actually pump
• Blood flows into atria
– 2 Ventricles
• Pump blood
• Contraction = blood sent out of heart + circulated
• Chambers are separated by septum…
– Due to separate chambers, heart functions as double pump
56.
57.
58.
59. Blood Flow Through Heart
• Blood flows into the Right Atrium from:
– Top half of the body via the Superior Vena Cava
– Bottom half of the body via the Inferior Vena Cava.
– From the heart via the Opening to the Coronary
Sinus.
• Coronary Sinus is the gathering point for deoxygenated
blood gathered by the cardiac veins.
60. CORONARY CIRCULATION
• Heart is supplied by TWO CORONARY
arteries:
1- Right coronary artery---(RCA)
2- Left coronary artery---(LCA)
• These coronary arteries arise at the root of the
aorta.
61. Coronary arteries & their branches
Left coronary artery---- it passes under the left
atrium and divides into two branches:
1. Circumflex Artery
. It continues around the left side of the heart and
supplies blood to the left atrium and posterior
wall of the left ventricle.
2. Left Anterior Descending (LAD)
• It gives off smaller branches to the
interventricular septum and anterior walls of both
ventricles.
62. Right coronary artery ---- It gives off two
branches:
1. Marginal Artery
• It supplies blood to the lateral aspect of the
right atrium and ventricle.
2. Posterior descending artery
• It supplies blood to the posterior walls of both
ventricles.
63. Portal Circulation:
• The portal vein drains almost all of the blood from
the digestive tract and empties directly into the liver.
• This circulation of nutrient-rich blood between the
gut and liver is called the portal circulation.
• It enables the liver to remove any harmful substances
that may have been digested before the blood enters
the main blood circulation around the body—the
systemic circulation.
64.
65. Cardiac Cycle
Cardiac cycle consists of systole and diastole of
atria and ventricles
Atrial Systole (Atrial contraction):
• Lasts about 0.1 sec
• At the same time, the ventricles are relaxed
• Atrial depolarization causes atrial systole.
• Blood is forced via AV valves into the
ventricles.
66. Cardiac Cycle
• Atrial systole contributes 25 ml of blood to the
volume of 105 ml already in each ventricle.
• At the end of ventricular diastole, each
ventricle has 130 ml.
• This blood volume (120—130 ml) is called
end-diastolic volume (EDV).
• The percentage of the EDV ejected (about
60%) is ejection fraction.
67. Ventricular Systole:
• It lasts about 0.3 sec
• At the same time, the atria are relaxed.
• Ventricular depolarization causes ventricular systole.
• The right and left ventricles eject about 70 ml of blood
each into the pulmonary trunk and aorta respectively.
• The blood volume remaining in each ventricle at the
end of systole, about 60 ml, is the end-systolic volume
(ESV).
• Stroke volume (the volume ejected per beat by each
ventricle) equals EDV minus ESV (SV=EDV—ESV ).
68. • Cardiac Output: The amount of blood ejected by
each ventricle in one minute is called cardiac
output (CO).
• Cardiac output = Heart rate × Stroke volume
• Pre-load:
• Degree of tension on muscle when it begins to
contract
• Pre-load = end-diastolic pressure
• After-load: Load against which muscle exerts its
contractile force.
• After-load = pressure in aorta and pulmonary
trunk
69. Cardiac Cycle
• The average time required to complete the cardiac
cycle is usually less than one second (about 0.8
seconds at a heart rate of 75 beats/minute).
– 0.1 seconds – atria contract (atrial “kick”), ventricles are
relaxed
– 0.3 seconds – atria relax, ventricles contract
– 0.4 seconds – relaxation period for all chambers, allowing
passive filling. When heart rate increases, it’s this relaxation
period that decreases the most.
70. Cardiac Cycle
Valves
AV SL Outflow
Ventricular
diastole
Open Closed
Atrial
systole
Ventricular
systole
Closed Open
Early atrial
diastole
Ventricular
diastole
Open Closed
Late atrial
diastole
71. Heart Sounds
• The first sound (lubb) occurs as ventricle
contract & AV valve are closing.
• The second sound (Dupp) occurs as ventricle
relax & aortic & pulmonary valve are closing.
72. Path of Blood
Pulmonary Circuit
Blood flow between the
lungs and heart
Supplied by the Right side
of the heart
Systemic Circuit
Blood flow between the
rest of the body and heart
Supplied by the Left side
of the heart
73. Pulmonary Circulation
• In series with the systemic circulation.
• Receives 100% of cardiac output (3.5L/min/m2).
• RBC travels through lung in 4-5 seconds.
• 280 billion capillaries, supplying 300 million alveoli.
– Surface area for gas exchange = 50 – 100 m2
77. Conduction system of the heart
• The heart possesses the property of
autorythmicity which mean it generates its own
electrical impulses and beats independently of
nervous and hormonal control
• However it is supplied with both sympathetic and
parasympathetic nerve fibers which increase and
decrease respectively the intrinsic heart rate
78. Conduction system of the heart
• The heart responds to a number of circulating
hormones including adrenaline ( epinephrine) and
thyroxine
• Small groups of specialized neuromuscular cells
in the myocardium initiate and conduct the
impulses causing coordinated and synchronized
contraction of the heart muscle
79. Autorhythmic fibers: The Conduction system
• An inherent and rhythmical activity is the
reason for the heart life long beat
• The source of this electrical activity is a
network of specialized cardiac muscle fibers
called autorhythmic fiber because they are self
excitable
