BIOCHEMISTRY / PHYSIOLOGY Bld - Dental Decks sample cards.pdf · Which stage in the life cycle of a tooth is ... (ameloblasts , odontoblasts ... Fused or geminated teeth occur during

Bld

The fluid phase of coagulated blood is known as:

• Blood hematocrit

• Blood cells

• Blood serum

• Blood plasma

BIOCHEMISTRY / PHYSIOLOGY

Copyright ©2006 - 2007 ⎯ DENTAL DECKS

• Blood serum → Serum = plasma – fibrinogen

Human blood constitutes about 8% of the body’s weight. It consists of cells and cell

fragments in an aqueous medium, the blood plasma. The proportion of cellular elements,

known as hematocrit, in the total volume is approximately 45%. The blood is the most

important transport medium in the body. It maintains homeostasis and it plays a decisive

role in defending the body against pathogens.

Serum is the clear, thin, and sticky fluid portion of the blood obtained after removal of the

fibrin clot and blood cells. It differs from the plasma in that it lacks fibrin and other

coagulation products.

Plasma is blood minus the formed elements. It is the fluid portion of the blood (it makesup 55% of the blood). It also contains no cells.

Plasma contains:

• Proteins (7%) → consist of albumins, globulins, and fibrinogen.

• Water (91%)

• Other solutes (2%) → consist of metabolic end products, food materials, respiratory

gases, hormones, and ions.

Remember: The other 45% of the blood consists of formed elements → erythrocytes (redblood cells), leukocytes (white blood cells), and thrombocytes (platelets). The function of

platelets in hemostasis is that they agglutinate and plug small ruptured vessels.

Bld

The general term for reactions that prevent or minimize loss of blood from the

vessels if they are injured or ruptured is:

• Homeostasis

• Hemostasis

• Erythropoiesis

• Syneresis



• Hemostasis

Through a three-part process, the circulatory system guards against excessive blood loss. In this

process, vascular injury activates a complex chain of events → vasoconstriction, platelet

aggregation, and coagulation → that leads to clotting. This process stops bleeding without

stopping blood flow through the injured vessel.

Three essential steps for blood clotting:

1.

2.

3.

Homeostasis → tendency toward equilibrium between different but interdependent elementsof an organism.

Erythropoiesis → the production of red blood cells.

Syneresis → liquid separating from a gel due to further solidification or coagulation.

Notes:

1. When blood vessels are ruptured and tissues are damaged, both the extrinsic and intrinsic

pathways are usually activated.

2. In cirrhosis of the liver, prothrombin and fibrinogen levels will be deficient and cause

impaired clot formation.

The production of thrombin from prothrombin during the clotting process requires a

prothrombin activator, which is formed either by way of an extrinsic pathway or by way of

an intrinsic pathway. A tissue factor (tissue thromboplastin) not normally present in the blood

participates in the extrinsic pathway, but only factors present in the blood participate in the

intrinsic pathway.

Prothrombin activator acts enzymatically to catalyze the formation of thrombin from

prothrombin.

Thrombin acts as an enzyme to convert fibrinogen into fibrin threads that enmesh red blood

cells and platelets to form the clot itself.

Bld

Which mineral is important in the formation of hemoglobin?

• Sodium

• Potassium

• Iron

• Magnesium



• Iron

Iron is quantitatively the most important trace element. The human body contains 4 ⎯ 5 g iron,

which is almost exclusively present in protein-bound form. Approximately 75% of the total

amount is found in heme proteins, mainly hemoglobin and myoglobin. Besides hemoglobin

and myoglobin, 15% to 25% of iron is stored in the liver, spleen, and bone marrow mainly in

the form of intracellular iron-protein complexes called ferritin and hemosiderin (a complex offerritin, denatured ferritin and other proteins).

Iron is resorbed almost entirely in the upper part of the small intestine, primarily in the

duodenum. Here it immediately combines in the blood plasma with a beta globulin

apotransferrin, to form transferrin, which is then transported in the plasma. It is bound

loosely with transferrin and can be released to any of the tissue cells at any point in the body.

Approximately 60% of excess iron is stored in the liver. The iron stored in ferritin is called

storage iron. Important: Iron can only be resorbed by the bowel in bivalent form (i.e., asFe2+). For this reason, reducing agents in food such as ascorbate (Vitamin C) promote iron

uptake.

Notes:

1. The dominant factor controlling absorption of iron from the GI tract is the saturation of

mucosal cells with iron.

2. Hemochromatosis is an iron-storage disease that results in the deposition of iron

containing pigments in the peripheral tissues with characteristic bronzing of the skin,

diabetes and weakness.

3. Bilirubin is a product of heme degradation.

Bld

O blood type is referred to as:

• Universal recipient

• Universal donor

• Neither of the above



• Universal donor

Type O people do not produce ABO antigens. Therefore, their blood normally will not be rejected

when it is given to others with different ABO types. As a result, type O people are universal donors

for transfusions. AB type people do not make any ABO antibodies. Their blood does not discriminate

against any other ABO type. Therefore, they are universal receivers for transfusions.

All humans and many other primates can be typed for by the ABO blood group. There are four types:

A, B, AB, and O. There are two antigens and two antibodies that are mostly responsible for the ABO

types. The specific combination of these four components determines an individual's type. The table

below shows the possible permutations of antigens and antibodies with the corresponding ABO types

("yes" indicates the presence of a component and "no" indicates its absence in the blood of an

individual).

For instance, type A people will have the A antigen on the surface of their red cells (as shown in the

table below). As a result, anti-A antibodies will not be produced because they would cause the

destruction of their own blood. However, if B type blood is injected into their systems, anti-B antibodies

in their plasma will recognize it as alien and burst or agglutinate the introduced red cells in order to

cleanse the blood of alien protein.

ABOBlood Type

Antigen

A

Antigen

B

Antibody

Anti-A

Antibody

Anti-B

��A yes no no yes

B no yes yes no

O no no yes yes

AB yes yes no no

Bld

The amount of oxygen bound to hemoglobin:

• Is directly proportional to the partial pressure of O2

• Increases if the temperature increases

• Decreases if the Pco2 increases

• Increases if DPG concentration increases

• Is constant between Po2’s of 40 and 100 mmHg



• Decreases if the Pco2 increases →→ the Bohr effect

Hemoglobin is the oxygen-bearing protein of red blood cells and constitutes about

33% of the cell weight. Oxygen is picked up in the blood (from the lungs) and forms

oxyhemoglobin (HbO2); blood leaving the lungs is saturated with oxygen and carries

oxygen to the tissues with decreased oxygen pressure; oxygen splits away from the

hemoglobin and creates reduced hemoglobin (HHb).

The combination of hemoglobin (Hb) with oxygen (O2) is reversible, and whether Hb

binds with or releases O2 depends in large part on the oxygen partial pressure

(Po2). When the Po2 is relatively high, (as in the pulmonary capillaries), Hb has a

higher affinity for O2 and is 98% saturated. At a lower Po2, (as in the tissuecapillaries), Hb has a lower affinity for O2 and is only partially saturated.

The following situations also promote the release of oxygen from oxyhemoglobin

(***Oxygen dissociation curve shifts to the right)

• Increase in diphosphoglycerate (DPG)• Increase in tissue temperature → exercise, physical activity

• Decreased pH → increased arterial H+ ion concentration.

Tth Hist

Identify the following areas of a developing tooth bud on the schematic drawing

below.

• Oral epithelium

• Dental lamina

• Enamel organ

• Dental sac

• Dental papilla

ANATOMIC SCIENCES


Oral epithelium

Enamel organ

Dental papillaDental sac

Dental lamina

Tth Hist

The four distinct layers of the enamel organ include all of the following except:

• Outer enamel epithelium

• Inner enamel epithelium

• Stratum granulosum

• Stratum intermedium

• Stellate reticulum

6

ANATOMIC SCIENCES


• Stratum granulosum

Four layers of the enamel organ:

1.

2.

3.

4.

Remember: After enamel formation is completed, all of the above structures of the enamel

organ become one and form the reduced enamel epithelium. This is important in the

formation of the dentogingival junction, which is an area where the enamel and epithelium

come together as the tooth erupts into the mouth. This forms the initial junctional epithelium

(or epithelial attachment), which later migrates down the tooth to assume its normal position.

Outer enamel epithelium (OEE) → the outer cellular layer of the enamel organ (verythin). It outlines the shape of the future developing enamel organ.

Inner enamel epithelium (IEE) → the innermost cellular layer of the enamel organ (verythin). The cells in this layer will become ameloblasts and produce enamel. This layer is

essential for the initiation of dentin formation once enamel is formed.

Stratum intermedium → this area lies immediately lateral to the inner enamel epithelium

(thicker than both the OEE and IEE). This layer of cells seems to be essential to enamel

formation (prepares nutrients for the ameloblasts of the IEE).

Stellate reticulum → this area is the central core and fills the bulk of the enamel organ. It

contains a lot of intercellular fluid (mucus type fluid rich in albumin) which is lost just

prior to enamel deposition.

Tth Hist

Which stage in the life cycle of a tooth is attained by ten weeks, when the dental

papilla invaginates deeply into the core of the bud of the developing tooth?

• Initiation (Bud stage)

• Proliferation (Cap stage)

• Differentiation (Bell stage)

• Apposition

• Calcification

• Eruption

• Attrition

7

ANATOMIC SCIENCES


• Differentiation (Bell stage)

1. Initiation (bud stage) → initial interaction between oral epithelium and mesenchyme

(ectomesenchyme), formation of dental lamina. Congenital absence of teeth results

from an interruption in this phase.

2. Proliferation (cap stage) → shape of tooth becomes evident, enamel organ is formed.

3. Differentiation (bell stage) → final shaping of tooth, cells differentiate into specific tis-

sue forming cells (ameloblasts, odontoblasts, cementoblasts, and fibroblasts) in enam-

el organ. Histodifferentiation and morphodifferentiation occur during this stage.

4. Apposition → cells that were differentiated into specific tissue-forming cells begin to

deposit the specific dental tissues (enamel, dentin, cementum, and pulp).

5. Calcification → mineralization

6. Eruption

7. Attrition

Notes:1. Fused or geminated teeth occur during initiation and proliferation stages of tooth

development.

2. Dentinogenesis imperfecta and amelogenesis imperfecta occur during histodif-

ferentiation.

Tth Hist

Remnants of the epithelial root sheath that remain following its disintegration during

root formation are called:

• Accessory root canals

• The epithelial rests of Malassez

• The dentinoenamel junction (DEJ)

• The cementoenamel junction (CEJ)

8

ANATOMIC SCIENCES


• The epithelial rests of Malassez

The epithelial rests of Malassez are remnants of Hertwig's epithelial root sheath and can

be found as groups of epithelial cells in the periodontal ligament. Some rests degenerate,

others become calcified (form cementicles).

Remember: The purpose of Hertwig's epithelial root sheath is to mold the shape of the

root and stimulate the differentiation of odontoblasts, which will produce root dentin.

After this root dentin is deposited, the cervical portion of the root sheath breaks down

and this new dentin comes in contact with the dental sac. This contact stimulates cells

from the dental sac to differentiate into cells, that will produce cementum, the PDL, and

the alveolar bone proper.

Important: The continuity of Hertwig's epithelial root sheath must be broken in order for

cementum to be deposited during tooth development (cementogenesis).

Hertwig’s epithelial root sheath is characterized by:

• The formation of cell rests (rests of Malassez) in the PDL when the sheaths functions

have been accomplished.

• The absence of a stellate reticulum and a stratum intermedium.

Pdl / G

The periodontium is a collective term for the supporting structures of the teeth. All of the

following are considered to a part of the periodontium except:

• The gingiva

• The periodontal ligament

• The cementum

• The alveolar bone

• The pulp

DENTAL ANATOMY & OCCLUSION

Copyright ©2006-2007 ⎯ DENTAL DECKS

CementumLamina

propria of

gingiva

Periodontal

ligament

Alveolar

bone

Pulp

• The pulps

The periodontium refers to the functional unit of tissues that surrounds and supports the teeth.

It consists of the two sections: (1) Gingival unit, composed of the free and attached gingiva

and the alveolar mucosa. (2) Attachment apparatus, which includes the cementum,

periodontal ligament, and the alveolar bone proper.

Important information to remember:

1.

2.

3.

4.

The interdental gingiva is that part of the free gingiva that occupies the interdental spaces

coronal to the alveolar crest. It is the triangular gingival mass which is situated between

the teeth in the area beneath the tooth contact points. It consists of two papillae (onebuccal and one lingual) that are connected by the concave-shaped interdental col. This

col conforms to the shape of the contact area and is not present at all when teeth are not

in contact.

The attached gingiva is that portion which is firm, dense, stippled, and bound to the

underlying periosteum, tooth, and bone. It extends from the mucogingival junction to the

free gingival groove.

The free gingiva (also called the marginal gingiva) is that portion which is unattached to

underlying tissues and helps to form the sides of the gingival crevice (sulcus). It extends

from the free gingival groove to the gingival margin.

In the absence of periodontal disease, the configurations of the crest of the interdental

alveolar septa are determined by the relative positions of the adjacent CEJs. The width is

determined by the tooth form present.

Pdl / G

The portion of gingiva that extends from the gingival crest to the crest of the bone is

called the:

• Attached gingiva

• Free gingiva

• Mucogingival junction

• Free gingival groove



• Free gingiva

Components of the Gingiva:

1.

•

•

•

2.

Notes:

1. The mucogingival junction separates the attached gingiva from the alveolar mucosa.

2. The free gingival groove separates the free gingiva from the attached gingiva.

Free gingiva (unattached or marginal gingiva) → the collar of tissue that is not

attached to the tooth or alveolar bone. It is approximately 1 to 3 mm wide and forms

the soft tissue wall of the gingival sulcus next to the tooth. Other structures of the free

gingiva include:

Gingival margin → the 1 mm narrow band of gingiva that forms the immediate

collar around the base of the tooth. This area is first to show symptoms of

gingivitis.

Gingival sulcus → area between the unattached gingiva and the tooth. Pop-

corn hulls get trapped in this area.

Epithelial attachment (junctional epithelium) → joins the gingiva to the tooth

surface.

Attached gingiva → is that part of the gingiva which is attached to the underlying

periosteum of the alveolar bone, to the cementum by connective tissue fibers and

the epithelial attachment. It is present between the free gingiva and the more movable

alveolar mucosa.

Pdl / G

Gingival fibers are found within the:

• Attached gingiva

• Free gingiva

• Mucogingival junction

• Attached and free gingiva



• Free gingiva

The collagen fibers (connective tissue fibers) that support the gingiva and attach it to the

tooth and alveolar bone are called gingival fibers. These fibers are continuous with the

periodontal ligament. The PDL is also considered to be connective tissue. It surrounds

the root and connects it with the alveolar bone by its principal fibers (also collagenousfibers).

The collagen fibers of the gingiva are further classified into four groups as follows:

circumferential (circular), dentogingival, dentoperiosteal, and alveolo-gingival fibers.

Note: Transseptal fibers are sometimes classified as a separate group of gingival fibers.

Notes:

1. The gingival apparatus is a term used to describe these gingival fibers and the

epithelial attachment.

2. The gingival ligament includes the dentogingival, alveologingival, and circum-

ferential fibers.

Perm-T

Which tooth has the longest crown length?

• Maxillary canine

• Maxillary lateral incisor

• Maxillary central incisor



• Maxillary central incisor → the average length of the crown is 10.5 mm. The length of the root is

approximately 13 mm.

Crown → it is the longest and widest anterior tooth. The distal outline is more convex than the mesial

outline. It is the most prominent tooth in the mouth. The crown outline is wider mesiodistally than faci-

olingually.

Root → one root with a single root canal. It is conical with a blunt apex. This root is the only maxillary

tooth that is as thick at the cervix mesiodistally as faciolingually (the others are thicker faciolingually thanmesiodistally). It is not unusual to find definite pulp horns in the incisal region of the tooth.

Surfaces → the mesial curvature of the cervical line is larger than any other tooth. The distoincisal cor-

ner is more rounded (convex) than the mesioincisal corner. The mesial and distal contact areas are cen-

tered faciolingually (as are all permanent incisors). The cingulum is well-developed and is located off-

center toward the distal.

Occlusion → occludes in centric with the mandibular central and lateral incisors (same in protrusiveand there is no contact in retrusive).Distinguishing features → the maxillary central incisors have the narrowest incisal embrasures.

Compared to other incisors, they have the greatest axial inclination relative to the occlusal plane. They

usually have three mamelons and four developmental grooves.

Facial Lingual Incisal Mesial Distal

Maxillary Right

Central Incisor

Vir

All of the following viruses are paramyxoviruses except:

• Mumps virus

• Measles virus

• Influenza A, B, and C viruses

• Respiratory syncytial virus (RSV)

• Parainfluenza virus

MICROBIOLOGY / PATHOLOGY


• Influenza A, B, and C viruses

The influenza viruses are classified as orthomyxoviruses. Both paramyxoviruses and orthomyx-

oviruses are enveloped, single-stranded, negative-stranded RNA viruses. The paramyxoviruses

differ from orthomyxoviruses in that their genomes are not segmented, they have a larger

diameter, and their surface spikes are different. Note: The cytopathic effect for paramyxoviruses

is syncytia formation (they induce cells to form multinucleated giant cells).

Virus Disease Treatment RNA viruses: Influenza A virus Parainfluenza virus Respiratory syncytial virus Rubella virus Measles virus Mumps virus Rhinovirus Coronavirus Coxsackievirus DNA viruses:

Herpes simplex virus type 1 Epstein-Barr virus Varicella-Zoster virus Adenovirus

Influenza Croup Bronchiolitis and pneumonia in infants Rubella MeaslesParotitis, meningitis Common cold Common cold Herpangina, hand-foot-and-mouth

Gingivostomatitis Infectious mononucleosis Chickenpox, shingles Pharyngitis, pneumonia

Amantadine None Ribavirin None None None None None None

Acyclovir in immunodeficient patients None Acyuclovir in immunodeficient patients None

Vaccine Available

+ ��+ + + ��

Vir

Which two of the following herpes viruses do not cause a vesicular rash, both in

primary infections and in reactivations?

• Epstein-Barr virus (EBV)

• Varicella-zoster virus (VZV)

• Herpes simplex virus type 1 (HSV-1)

• Herpes simplex virus type 2 (HSV-2)

• Cytomegalovirus (CMV)



• Epstein-Barr virus (EBV)• Cytomegalovirus (CMV)

Virus Primary Infection Recurrent Infection

HSV-1 Gingivostomatitis Herpes labialis, encephalitis, keratitis

HSV-2 Herpes genitalis Herpes genitalis

VZV Varicella (chickenpox) Zoster

EBV Infectious mononucleosis None

CMV Congenital infection (inutero), mononucleosis

None

Disord

Neurofibromatosis is a (an):

• Sex-linked dominant disorder

• Autosomal recessive disorder

• Sex-linked recessive disorder

• Autosomal dominant disorder



• Autosomal dominant disorder

Neurofibromatosis (sometimes known as Elephant Man’s disease) is an autosomal dominant

disorder that affects the bone, the nervous system, soft tissue, and the skin. It causes the

formation of multiple, pedunculated, soft tumors (neurofibromas), and café-au-lait spots.

Two major subtypes exist: Neurofibromatosis Type 1 (NF-1), von Recklinghausenneurofibromatosis), which is the most common subtype and is referred to as peripheral NF,

and Neurofibromatosis Type 2 (NF-2), which is referred to as central NF.

NF-1 is long lasting (chronic). It mostly affects nerves of the outer parts of the body

(peripheral nervous system). Symptoms begin at birth or early in life. People with NF-1

usually develop:

• Multiple birthmarks → six or more light brown-colored birthmarks (café-au-lait spots) may

be located anywhere on the body including the mouth and tongue.

• Multiple neurofibromas → a person with NF-1 may have any number of neurofibromas -

from none to hundreds. The tumors are usually small, painless and slow growing.

• Lisch nodules in the eyes → small brown tumors (Lisch nodules) often appear on the

colored part of the eye (iris) in people with NF-1.

NF-2 (also known as bilateral acoustic neurofibromatosis), is less common and mostly

affects the central nervous system, causing tumors of the brain and spinal cord. Hearing

loss that begins in the teens or early 20s is often the first symptom. People with NF-2

usually develop:

• Auditory nerve tumors

• Other complications → affected people may also have ringing in the ear(s), headaches, facial

pain / numbness and trouble balancing.

Bact

All of the following statements concerning Staphylococcus aureus are true

except:

• It is a gram-negative coccus that typically grows in a linear fashion and is a very

uncommon bacterial pathogen

• It is the most common cause of suppurative infections involving the skin, joints,

and bones and is the leading cause of infective endocarditis

• It is coagulase positive whereas other Staphylococci are coagulase negative

• It possesses a surface protein (protein A), that binds the Fc receptor of IgG,

thereby blocking complement activation by the classical pathway



• It is a gram-negative coccus that typically grows in a linear fashion and is a very

uncommon bacterial pathogen

***This is false; it is a gram-positive coccus that typically grows in grape-like clusters and is

one of the most common bacterial pathogens.

Staphylococcus aureus cannot invade through intact skin or mucous membranes, and infection

usually begins with traumatic inoculation of the organism. Once inside the body, it secretes a

number of enzymes and toxins that harm most tissues. Note: The cell wall of S. aureus contains

ribitol phosphate teichoic acid.

S. aureus infection usually produces suppuration and abscess formation. It most commonly

causes skin infections. Some examples include boils, carbuncles, and styes; scalded skin

syndrome and toxic shock syndrome; osteomyelitis; infections of burns or surgical wounds;

respiratory tract infections; septicemia; bacterial endocarditis; and staphylococcal food

poisoning.

Coagulase-negative staphylococci (less virulent than S. aureus):• S. epidermis → the most frequent cause of infections associated with medical devices.

• S. saprophyticus → the frequent culprit of acute urinary tract infections in young women.

Remember: Staphylococci are facultative anaerobes that grow by aerobic respiration or by

fermentation that yields principally lactic acid. The bacteria are catalase-positive and

oxidase-negative. S. aureus can grow at a temperature range of 15 to 45 degrees and at NaCI

concentrations as high as 15 percent. Nearly all strains of S. aureus produce the enzyme

coagulase.

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BIOCHEMISTRY / PHYSIOLOGY Bld - Dental Decks sample cards.pdf · Which stage in the life cycle of a tooth is ... (ameloblasts , odontoblasts ... Fused or geminated teeth occur during