ANATOMY AND PHYSIOLOGY
 BLOOD
 Function of blood
 One of the body's connective tissues
 Transports oxygen from the lungs to the cells and carbon dioxide waste from the cells
to the cells.
 Protect the body from disease
 Carries nutrients from the digestive system to the cells
 Transports waste from the cells to the kidneys
 Composition
 Blood contains red blood cells, white blood
o cells, and fragments of cells called platelets suspended in a water-based, pale,
somewhat yellow fluid known as plasma.
 The average human has 5 liters of blood
 Accounts for 8 percent of the total body weight
 Blood is alkaline with a pH between 7.35 and 7.45
o Acidosis
o Alkalosis
 PLASMA
 Definition: liquid portion of whole blood with the cells removed.
 fluid portion of the blood
 blood has not clotted
 Components of plasma:
 92 percent water
 7 percent protein
 1 percent ions
o Sodium (Na+)
o Potassium (K)
o Calcium (Ca)
o Magnesium (Mg)
o Chloride (Cl-)
o Bicarbonate (HCO3-)
 SERUM
 Definition: plasma minus it‘s clotting factors such as fibrinogen
 Liquid portion of clotted blood
o Blood is allowed to clot and the clear serum is removed (no fibrinogen or other
clotting factors)
 Most commonly used body fluid for chemical analysis
 RED BLOOD CELLS
 Characteristics
 also known as erythrocytes
 Have little internal organization and no nucleus or organelles
o organelles are small structures within cells which perform dedicated functions
o basically a small organ within a cell
 Each blood cell is a flexible, biconcave disk (thinner at the center than at the edge)
 Primary purpose of RBC's in the body is to transport oxygen
 Number of RBC's in the body
 average adult male has approximately 5.4 million RBC's per cubic millimeter
(microliter)
 average adult female has approximately 4.8 million per cubic millimeter of blood
 RBC Production
 RBC's are produced in the red bone marrow of bones.
 The process of RBC formation is called erythropoiesis
 HEMOGLOBIN
 Contained in the ectoplasm of red blood cells
 Hemoglobin is a protein chemical which has a red pigment that gives it's color to
erythrocytes
 Hemoglobin contains the element iron, making it an excellent vehicle for transporting
oxygen and carbon dioxide
 As blood passes through the lungs, oxygen molecules attach to the hemoglobin
 as the blood passes through the body‘s tissue’s, the hemoglobin releases the oxygen
to the cells
 the empty hemoglobin molecules then bond with the tissue's carbon dioxide or other
waste gases
 DESTRUCTION OF RED BLOOD CELLS
 Red Blood Cells circulate in the bloodstream for approximately 120 days.
 Older cells and damaged cells are then engulfed by phagocytes in the spleen, liver, and bone
marrow, and the red blood cells are broken down
 The hemoglobin is broken down to release it's amino acids, which can be reused for
synthesizing new protein
 The iron portion of the hemoglobin is brought to the bone marrow for new hemoglobin
formation, and any excess iron is stored in the liver
 WHITE BLOOD CELLS (Leukocytes)
 Primary Function: to defend the body‘s tissue against infection and substance foreign to the
body
 A normal adult has approximately 7000 white blood cells per cubic millimeter of Blood
 Types of WBC's (5 different types in two major groups)
 Granulocytes which have granules in their cytoplasm and include the following:
 Neutrophils
o comprise about 60 percent of the white blood cell count in the body
o the neutrophil's primary function is phagocytosis (devours foreign substances)
 Basophils
o least numerous blood cells
o help initiate inflammation process at the site of an injury
 Eosinophils: function during an allergic reaction
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Agranulocytes have no granules in their cytoplasm and include the following:
 Lymphocytes
o account for about 30 percent of all white blood
o serve as an important part of the body’s immune system
 Monocyes largest of all white blood cells function primarily as phagocytic (engulfing)
cells
Purpose for examination of WBCs
 White blood cell population of the body can provide valuable insight into disease
 An elevated white blood cell count may indicate a microbial infection
 Also, noting whether particular WBC’s are high in number can be valuable.
 This data is obtained by a differential white blood cell count
 a general reduction of white blood cells is called leucopenia
 an above average population of white blood cells is called leukocytosis
leukocytosis may also indicate cancer of white blood cells called leukemia
 PLATELETS
 Characteristics
 also called thrombocytes, platelets are blood elements produced in the bone marrow
 technically, platelets are not cells because they consist of fragments of cytoplasm
enclosed by membranes
 Platelet production
 platelets form from large cells called megakaryocytes in the red bone marrow
 bits of megakaryocyte cytoplasm pinch off within membranes and are released into
circulation
 approximately 300,000 platelets exist per cubic millimeter of blood
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Platelet function
 work along with fibrinogen, calcium, and vitamin K to form clots
 a clot begins to form when blood is exposed to air
 a dried external clot is a scab
 an internal clot is a bruise
 FLUID, ELECTROLYTE, AND ACID/BASE BALANCE
 Homeostasis of the body environment depends on a balance of fluids, electrolytes, acids and
bases
 In the normal body, the levels of fluids and electrolytes remain constant
 the input of water and electrolytes is balanced by selective elimination through the
excretory system
 if serious depletion occurs immediate replacement is critical
 Electrolytes
o the products of substances that dissociate into electrically charged
components when they dissolve in water
o for example, the compound sodium chloride dissociates into sodium ions and
chloride ions, which are electrolytes carrying electrical charges
 Acid
o a chemical compound that liberates hydrogen ions into a solution
o examples of acids in the body are hydrochloric acid and lactic acid
 Base
o a chemical compound that takes up hydrogen ions from a solution, leaving the
solution with an excess of hydroxyl (-OH) ions
o a base in the body is ammonia
 Body fluids
 the fluid content of the body refers to the amount of water in the body
 the amount of water can vary, depending upon the weight, sex, age, and fat content
of the individual
o for instance, woman have a relatively lower water content than men because
a woman's body contains a higher percentage of , and fat tissue contains very
little cellular water
o water makes up about 60% of the body weight for an adult male and about
50% of a female's body weight
 Fluid compartments: The body's total water content can be divided into two fluid
compartments
 Intracellular fluid compartment
o refers to the water in all body cells
o almost two-thirds of the body's water exists in this compartment
 Fluid compartments: The body's total water content can be divided into two fluid
compartments
 Intracellular fluid compartment
o refers to the water in all body cells
o almost two-thirds of the body's water exists in this compartment
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Fluid compartments
 consists of the body area outside the cells
 extracellular fluid provides a relatively constant environment for the cells
Extracellular fluid compartment continued
 approximately one-third of the body water exists in this compartment
 extracellular fluid contains large amounts of sodium, chloride, and bicarbonate ions
and small amounts of potassium, magnesium, calcium, phosphate, sulfate, and
organic ions
 water enters the body through the digestive tract and as a result of chemical reactions
that produce water as end products
 water leaves the body by several exits
o the kidneys excrete urine
o the lungs give of water in expired air
o the skin gives off sweat
o the intestines eliminate water in feces
 in general terms, the amount of water exiting the body equals the amount entering
the body
Electrolyte balance
 the quantities of various electrolytes taken into the body must equal the quantities
lost by the body
 in the extracellular fluid, two types of ions can be found
o Cations: which are positively charged (sodium Na+)
o Anions: which are negatively charged (chloride Cl-)
Sodium Ions
 Sodium ions account for about 90% of the cations in extracellular fluid
 when the input of sodium ions exceeds the output, water is also retained in the body,
and the volume of plasma and extracellular fluid Increases
o may cause edema: an abnormal accumulation of fluid in extracellular body
tissues
o may also cause weight gain
o when the output exceeds the input a decrease occurs in the volume of plasma
and extracellular fluid, and the blood pressure lowers
o when the input of sodium ions exceeds the output, water is also retained in
the body, and the volume of plasma and extracellular fluid Increases
 may cause edema: an abnormal accumulation of fluid in extracellular
body tissues
 may also cause weight gain
 when the output exceeds the input a decrease occurs in the volume of
plasma and extracellular fluid, and the blood pressure lowers
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Regulation of sodium levels
o reflects how well the kidney is working and is affected by blood pressure
o when the blood pressure drops, the blood flow to the kidney is reduced, and
the filtration rate diminishes, resulting in less sodium filtered
o as the concentration of salt and water increases, the blood pressure elevates
and the sodium excretion increases
Potassium
 Potassium is the primary intracellular cation
 It functions in electrical activity of the muscle and nerve tissue
 In the extracellular fluid, potassium influences the balance of acid and base
 Excessive potassium can cause fibrillations of the heart
 Deficits of potassium can cause arrhythmia of the heart
Other ions
 Other ions balanced in the body are calcium, magnesium, sulfate, chloride phosphate,
and bicarbonate
 Calcium ions have roles in blood clot formation, muscle contraction, hormonal
activity, nerve conduction, and as structural components of teeth and bones
 The most common extracellular anion is chloride, which is almost always linked to
sodium
 there are many sources of hydrogen ions in the metabolism of the body
o during the respiration of glucose, carbon dioxide reacts with water to form
carbonic acid which dissociates to release bicarbonate ions and hydrogen ions
o the breakdown of fatty acids and amino acids also results in acid compounds
 The regulation of the concentration of hydrogen ions in the body occurs primarily by
acid base buffer systems
Acid/Base buffer system
 A buffer is a solution that prevents substantial changes in the pH when either an acid
or a base enters the system
 Usually a buffer system contains a carbonic acid and a salt of that acid.
 an example is the carbonic acid and sodium bicarbonate system
o A solution containing both carbonic acid and sodium bicarbonate
o Should a strong acid such as hydrochloric acid enter the system, it will react
with the bicarbonate ions of the sodium bicarbonate producing carbonic acid
and sodium chloride
o Carbonic acid is a weaker acid than hydrochloric acid, and therefore the
increase in hydrogen ions in the solution will be minimal
o If a strong base such as sodium hydroxide enters the solution it will react with
the carbonic acid to produce sodium bicarbonate a weaker base than sodium
hydroxide, and there will be a minimum base shift
 URINARY SYSTEM
 Primary function: regulates the composition and concentration of the extracellular fluids
surrounding the body cells
 extracellular fluids
 known as interstitial fluids
 include plasma and fluids surrounding tissue
 The urinary system accomplishes its functions by forming urine from blood plasma in the
kidneys and associated ducts and organ
 KIDNEYS
 Location
 The kidneys are attached to the posterior abdominal wall of the body outside the
peritoneum
 They lie lateral to the vertebral column and are held in place by adipose and
connective tissue
o Adipose tissue is fatty tissue that surrounds internal organs
o Adipose tissue serves as a cushion and as a nutrient reserve
 In an adult each kidney weighs about 4 oz and is about the size of a fist
 They lie lateral to the vertebral column and are held in place by adipose and
connective tissue
o Adipose tissue is fatty tissue that surrounds internal organs
o Adipose tissue serves as a cushion and as a nutrient reserve
 In an adult each kidney weighs about 4 oz and is about the size of a fist
 Microscopic structure
 More than a million microscopic units called nephrons make up the interior of each
kidney
 The purpose of these nephrons is the production of urine
 A nephron looks like a tiny funnel with a very long stem
 Kidney function
 Regulates the volume of blood plasma and thereby contributes to blood pressure
 Controls the concentration of waste products in the blood
 Regulates the concentration of the plasma‘s electrolytes
 Contributes to the acid/base level of the plasma
 The kidneys 2 million or more nephrons form urine by a series of 3 processes
 Filtration of water and other dissolved substances out of the blood
 Reabsorptions of water and other dissolved substances needed by the body back into
the blood
 Secretion of waste molecules and excess ions into the urine
 URINARY SYSTEM
 Once urine has formed it drains out of each kidney and down the ureter into the urinary
bladder
 To leave the body, urine passes from the bladder down the urethra and out its external
opening