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Blood Transports
- Oxygen, and nutrients to tissues
- Carbon dioxide, and other waste products from tissues
- Hormones, and immune cells throughout the body
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Blood helps Regulate
- pH
- Fluid volumes
- Body temperature
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Blood Protects
- Against blood loss via clotting
- Against infection via production of some immune cells
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3 TYPES OF PLASMA PROTEINS
- Albumins
- Globulins
- Fibrinogen
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Albumins –
most abundant and important for plasma osmotic pressure
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Globulins –
important in transport of lipids / fat soluable vitamins, and immune system immunoglobulins = antibodies
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Fibrinogen -
blood clotting
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Hemoglobin
Oxygen-carrying protein in RBCs
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Production of RBCs=
Erythropoiesis
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Erythropoietin stimulates
red bone marrow production of more RBCs
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Hgb is degraded into its components:
- Globin (protein)
- Heme
- Iron
- Non-iron part of heme degraded to biliverdin (green pigment)
- bilirubin (
- a yellow pigment), which the liver releases in bile
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WHITE BLOOD CELLS =LEUCOCYTES
- *Formed in red bone marrow
- *Remove wastes, toxins, and damaged /abnormal / invading cells
- *Some are capable of phagocytosis
- *Found in blood as well as in tissues
- *Fight infection / important part of the immune system
- *Some live days and others live months or years
- *Several types
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Granular WBC’s–noticeable granules, lobed nuclei
- Neutrophil
- Eosinophil
- Basophil
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Agranular WBC’s – no granules, non-lobed nuclei
- Lymphocyte
- *B lymphs
- *T lymphs
- Monocyte
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Neutrophils
- Most abundant WBCs, 50-75%
- engulf bacteria by phagocytosis> a major function in curbing infection
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EOSINOPHILS
- Small percentage (2-4%) of WBC’s
- Parasitic infections and allergic reactions
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BASOPHIL
- Least common of all WBC’s (<1%)
- Release histamine during allergic reactions
- Attracts other WBCs
- When it migrates into connective
- tissues >transforms into a mast cell
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MONOCYTE
- Relatively uncommon WBC’s (3-8%)
- Migrates to connective tissues, transforms into phagocytic cells (macrophages, osteoclasts, etc.)
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LYMPHOCYTE
- 25-35% of all WBC’s
- Develop into B and T cells (lymphocytes) cornerstone of our specific immune system
- Most lymphocytes continually move
- among lymphoid tissues, lymph, and blood, spending only a few hours at a time in blood
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B lymphocytes
- Important component of the antibody mediated immune system
- Give rise to plasma cells > antibodies
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T lymphocytes
- Specialized white blood cells
- Kill cells not recognized as coming from the body, and cancerous cells
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PLATELETS= Thrombocytes
- Formed in the red bone marrow from 2000-3000 fragments of a cell called a megakaryocyte
- Function in blood clotting
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STEPS OF HEMOSTASIS (CLOTTING OF BLOOD)
- I. Vascular spasm
- II. Formation of platelet plug
- III. Blood coagulation and fibrous organization
- IV. Clot dissolution - plasmin
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The key events in clot formation are
- Clotting factors are released from injured tissue/ platelets
- These clotting factors convert prothrombin thrombin
- Thrombin causes fibrinogen (plasma protein produced by the liver) to form long strands of fibrin
- Fibrin strands form a web that traps blood cells and forms a clot
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Clotting does not occur without
Vitamin K
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Fibrinolytic System-
- allows us to dissolve clots when they are inappropriate or no longer needed:
- Plasminogen > Plasmin> dissolves fibrin threads
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Agglutination (clumping)
- Occurs when antibodies contact a foreign cell
- This response is used to determine blood type
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Hemolysis
A-A complexes activate the complement system which makes cell develop holes and burst
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Systemic circuit
sends oxygenated blood to the body via the aorta and is powered by the left side of the heart.
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Pulmonary circuit
sends unoxygenated blood to the lungs via pulmonary trunk and is powered by the right side of the heart.
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The arteries that attach to the heart
- Pulmonary trunk
- Arch of the Aorta
- Coronary arteries
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The veins that attach to the heart
- Superior vena cava
- Inferior vena cava
- 4 Pulmonary veins
- The Coronary Sinus
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BLOOD SUPPLY TO MYOCARDIUM
RIGHT CORONARY ARTERY
- Sino-atrial (SA) node artery
- Atrio-ventricular (AV) node artery
- Posterior interventricular artery
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BLOOD SUPPLY TO MYOCARDIUM
LEFT CORONARY ARTERY
- Anterior interventricular artery (Left anterior descending artery – LAD)
- Circumflex coronary artery
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Coronary veins all collect into the
coronary sinus on the back part of the heart then empty into the right atrium
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Purkinje fibers
Special cardiac muscle cells conduct action potential into the myocardium
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CARDIAC OUTPUT (CO)
CO is the volume of blood ejected from the ventricles each minute
- CO = SV x HR
- CO = SV (stroke volume) X HR (heart rate-beats/min)
- Normal CO = 70mL X 75 beats/min. = 5250 mL/min.
- = 5.25 L/min.
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TUNICA INTERNA (INTIMA)
Endothelium (all vessels)* -
simple squamous epithelium
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TUNICA MEDIA
- Smooth muscle*
- Elastic lamina (most prevalent in larger arteries)
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Arterioles
- Smallest arteries
- Prime controllers of blood pressure
- Gatekeepers of capillary networks- open / closed
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Vasoconstriction
Smooth muscle contracts > diameter lumen narrows >decreases blood flow
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Vasodilation
Smooth muscle relaxes > diameter lumen increases > increases blood flow
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Capillaries
- Microscopic-connect arterioles to venules
- Walls one cell thick
- Site of exchange between blood and cells
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Capillary Bed
- Network of capillaries servicing a particular area
- enormous surface area for exchange
- Makes blood flow very slowly, allowing more time for exchange of gases and other materials
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3 mechanisms move blood against gravity to heart
- Contraction of skeletal muscles
- Pressure differences of breathing
- Vein valves
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If blood vessels dilates, even a little, the resistance drops by a power of ___
4
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Autoregulation of blood pressure and blood flow is a complex interplay between:
- •The vascular system
- •The nervous system
- •The endocrine hormones and organs like
- the adrenal gland / kidney
- •The heart
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Sympathetic Stimulation
- Increases heart rate, BP, cardiac contractility
- Dilates pupils
- Dilates lung airways
- Relaxes bowel muscles, but tightens sphincters
- Causes “ goose bumps”
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Parasympathetic Stimulation
- Decreases HR, BP, Contractility
- Constricts pupils
- Constricts lung airways
- Increases gut motility, relaxes sphincters
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Shock (hemodynamic)
failure to deliver adequate O2 and nutrients to tissues, usually due to poor blood flow
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Hypovolemic shock –
due to decreased blood volume
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Cardiogenic shock –
due to weakened heart function
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Vascular shock –
due to inappropriate vasodilation (anaphylactic)
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Obstructive shock –
due to obstruction of blood flow
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Atherosclerosis –
hardening of the arteries
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Hypertension-
- Primary – Chronic- Single specific cause usually can not be identified
- Secondary – due to arterial or kidney disease, or hormonal imbalances
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Aneurysm-
- Ballooning of a vessel
- Atherosclerosis and hypertension > weaken a vessel >causes ballooning > rupture
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Air passing through the respiratory tract traverses the:
- Nasal cavity
- Pharynx
- Larynx
- Trachea
- Primary (1o) bronchi
- Secondary (2o) bronchi
- Tertiary (3o) bronchi
- Bronchioles
- Alveoli (150 million/lung)
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THE LARYNX
Thyroid cartilage (“Adam’s Apple”) + Vocal Cords + Cricoid cartilage 2 mucosal folds = vocal cords; opening between them = the glottis
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THE TRACHEA
- Tube that connects the larynx with the 1° bronchi
- Located just anterior to the esophagus in the mediastinum
- Cartilaginous rings( C-shaped)- insure airway
- stays open
- Lining = epithelium with cilia +mucus secreting goblet cells ---- keep lungs clean
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THE BRONCHIAL TREE
- Two primary bronchi lead from trachea to the lungs
- Bronchi continue to branch smaller until > bronchioles
- All bronchi above bronchioles contain cartilage in walls
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Bronchioles
~1mm diameter and contain smooth muscle
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Constriction or dilation of bronchioles (caused by contraction or relaxation of smooth muscle)
regulates passage of air into the alveoli
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Pulmonary lobule
each alveolus is covered by a capillary bed
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The smooth muscle surrounding bronchioles is under control of _________:
Autonomic Nervous System
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Sympathetic stimulation
airway dilation,
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Parasympathetic stimulation
airway constriction
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ALVEOLI
- •sac-like at end of respiratory passages
- •enveloped by capillaries
- •Lined with simple squamous epithelium - easy exchange of gases
- •lined with surfactant- a phospholipid acts as a film to coat alveoli and keep them open
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STRUCTURE OF ALVEOLUS
- LINING OF AN ALVEOLUS:
- Type-I alveolar cell- Allows exchange of O2 /CO2 between air and blood
- Most numerous type
- Type-II
- alveolar cell- makes surfactant. Deficiency in pre-mature infants > “respiratory distress syndrome of new-born”=RDS
- •Dust cell (Alveolar Macrophage)- gather and digest debris/ bacteria (remember that all macrophages are the garbage men of WBC’s)
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Boyle’s law
- Volume and pressure are inversely related
- V ∝ 1/P
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Air moves in response to pressure gradients
–into lungs when pressure in atmosphere pressure in lungs
–out of lungs when pressure in lungs pressure in atmosphere
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Pressure changes in the lungs are created by
changes in volume of the thoracic cavity
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Volume changes of the thorax are created by the
contraction or relaxation of muscles of the thorax
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The diaphragm is the primary
muscle of ventilation
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Inhalation = Inspiration
- •diaphragm and external intercostal muscles contract
- •diaphragm flattens / rib cage moves up and out
- •volume of thorax increases
- •air pressure around/ in lung decreases
- Atmospheric pressure forces air into lungs
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Dalton’s law
The pressure of each gas in a mixture of gases is directly proportional to the percentage of that gas in the total mixture: PTotal = P1 + P2 + P3 …
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Henry’s law
- Increasing the partial pressure of a gas in contact with a solution will result in more of the gas dissolving into the solution.
- E.g. O2 and blood
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CO2 is transported in the blood in three different forms:
- 1) 7% is dissolved in the plasma, as a gas.
- 2) 70% is converted to carbonic acid (action of enzyme carbonic anhydrase) then dissociates into a bicarbonate ion + H+
- CO2 + H2O⇿ H2CO3 ⇿H+ + HCO3-3) 23% is attached to Hgb (not at same binding sites as oxygen).
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Carbon dioxide-
- Most important chemical influencing breathing rate Chemoreceptors in medulla, aortic bodies, carotid bodies Increased carbon dioxide
- > increased breathing rate
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