Day 1.1.1 Flashcards
Cingulum aka
Linguocervical ridge
What is the cingulum
Lingual lobe of an anterior tooth
Where is cingulum located
It makes up the bulk of the cervical third of the lingual surface
Teeth with centrally located cingulum
- Maxillary Lateral incisor
- Maxillary Canine
- Mandibular central incisor
Tooth numbers of teeth with centrally located cingulum
6, 7, 10, 11, 24, 25.
Teeth with cingulum located off-centre to the distal
- Maxillary Central Incisor
- Mandibular Lateral Incisor
- Mandibular Canine
Total number of cingula in each dentition
12
Characteristics common to all mandibular anteriors
- Indistinct Cingula
- Smooth lingual anatomy
- No lingual grooves or pits
- Incisal edges lingual to root axis line
- Facial convexity - continuous incisoapically
Which anterior teeth have a continuous convexity from incisal edge to apex?
Mandibular anteriors
How many teeth do mandibular central incisors occlude with?
One - Maxillary central incisor
In how many planes is the occlusion of mandibular central incisors measured?
Three -
- Centric
- Protrusive
- Lateral protrusive
On which aspect of the central incisors is the alveolar process thinnest?
Facial
Is local infiltration effective for anaesthetising central incisors? Why (not)?
Yes, because of the thinness of the alveolar process facial to the central incisors
Which teeth in the mouth exhibit labial ridges?
Canines (lower and upper)
6, 11, 22, 27.
Which proximal aspect of the anterior teeth shows greater CEJ curvature?
Mesial.
What is the most reliable way to distinguish between mandibular central and lateral incisor?
In facial view, the mandibular lateral incisor (23, 26) crown tips slightly to the distal relative to the root.
Between 24 and 23, whose crown is larger mesiodistally?
23
Between 25 and 23, which one is more bilaterally symmetrical?
25
On which one out of 26 and 24 is the cingulum placed slightly distal to the centre?
26
In 24, which marginal ridge is longer?
Neither. They are the same length.
In 23, is the mesial marginal ridge shorter than the distal marginal ridge?
No. Vice versa.
Are all proximal contacts at the same level for mandibular incisors?
No. 23 and 26 have distal proximal contacts more apical than mesial contacts.
24 and 25 have contacts at the same level
Among all the mandibular incisors, which proximal contact is the most apical?
Laterals (23, 26)
Which incisal angles are the most rounded in mandibular incisors?
Distoincisal angles of laterals
Between the lingual and facial cervical lines of mandibular incisors, which one is positioned more apically?
Lingual
What is the shape of the proximal aspects of anterior teeth?
Triangle
Name all triangular aspects in the oral cavity
All anterior teeth - proximal aspects
Name all rhomboids in the oral cavity
Mandibular posteriors - proximal aspects
Name all Trapezoids with their longest side on the occlusal, in the oral cavity
All anteriors - facial aspect
All posteriors - facial aspect
Name all trapezoids with their shortest side occlusal, in the oral cavity
All maxillary posteriors - proximal aspects
What is the basic shape of the cross section of the pulp canal in mandibular incisors?
Elliptical
Which one has a larger root, 24 or 23?
23 (in all dimensions)
Which incisal edge is straighter, 25 or 23?
25
Which part of the incisal edge is curved on 23 and 26?
Distal
What is different about the incisal edge of the mandibular lateral when compared to the mandibular central?
It is slightly curved and rotated on the distal
which is the only anterior tooth in which distoincisal angle is as sharp as mesioincisal angle?
mandibular central incisor
What speech sounds do anterior teeth play a role in
v
f
th
What is the axial inclination of the anterior teeth when viewed from the sagittal plane
facially inclined
which aspects of incisors have proximal contacts in incisal third?
mesial of 8, 9
all contacts of lower incisors
What aspects of incisors have contacts at junction?
Distal of 8, 9
mesial of 7, 10
What is the only aspect of incisors that has contacts in middle third?
Distal of 7, 10
Where is the pulp cavity widest in maxillary central?
cervical level
Outline of pulp chamber of 8, 9 in young individuals?
triangle with base labially placed
Shape of pulp chamber of 8, 9 in old individuals
more round or crescent shaped due to secondary dentin deposition
Which one is bigger, young or old pulp chamber in 8, 9?
Young
Anterior tooth that has contacts in both anterior and posterior segments of opposite arch, at MIP.
Maxillary canine
MIP?
Maximum intercuspation
Does maxillary canine have contact on cusp tip?
no
Where does the maxillary canine fall in MIP?
The facial embrasure between the mandibular canine and first premolar
Contact points of 6, 11
Mesial - junction
Distal - middle third
IS the 6 wider faciolingually or cervicoincisally?
faciolinguallly
Are mesial and distal halves of 6 symmetric?
Yes
Where is cusp tip of 11 placed relative to root axis line?
labial or at
What is the CEJ curvature of 6?
2.5mm mesial
Contour height of 11
facial / lingual - 0.5mm both in cervical third
How to differentiate between right and left upper canine
distal surface is fuller and more convex than the mesial surface
is the curvature of cervical line uniform in 6?
no - mesial is greater than distal
Is curvature of mesial surface same as distal in 11?
No mesial is straighter
Are cusp ridges uniform in 6?
No distal is longer
Are contact points in 10 at the same level?
No.
What is the difference between labiolingual and mesiodistal aspects of 6
It’s thicker Labiolingually
Position of cusp tip relative to central long axis of 6
Labial and mesial to central long axis
Which contact of 11 is placed more cervical?
Distal
In what direction, if at all, will the apical third of the root curve in 11?
Distal
What lies mesial and distal to labial ridge?
Developmental depressions - shallow
Which labial ridges are more pronounced? 6, 11 or 22, 27?
6, 11
Which are the only cusped teeth that feature a functional lingual surface rather than occlusal surface?
Canines
Which surface of the canines is functional?
Lingual
Describe the shape of the distal portion of facial surface of 6
Middle third - convex
Cervical third - concave
Is cervical line visible from incisal view in 11?
No because of convexity of crown
When do maxillary canines erupt?
Between 11, 12 years of age
After which teeth do 6 and 11 erupt?
Premolars
When do Mandibular canines erupt?
Between 9 and 10 years of age
Which canines erupt first?
Mandibular
Do premolars erupt before or after canines?
Before Maxillary canines, after mandibular canines
Teeth that erupt between 6 - 7 years of age
Mandibular centrals - 24, 25
Maxillary and mandibular first molars
Teeth that erupt between 7-8 years of age
Maxillary centrals, Mandibular laterals
Teeth that erupt between 8-9 years of age
Maxillary laterals
Teeth that erupt between 9-10 years of age
Mandibular canines
Teeth that erupt between 10-11 years of age
Maxillary first premolars
Teeth that erupt between 10-12 years of age
Maxillary second premolars
Mandibular first premolars
Teeth that erupt between 11-12 years of age
Maxillary canines
Mandibular second premolars
Teeth that erupt between 11-13 years of age
Mandibular second molar
Teeth that erupt between 12-13 years of age
Maxillary second molar
Teeth that erupt around 17-21 years of age
All third molars
Which one has more pronounced cingulum, 6 or 27?
6
Which one is wider mesiodistally, 6 or 22?
6
Which one has a more straight mesial border (viewed facially), 11 or 22?
22
Which one has more incisally placed contacts, 11 or 27?
27
Cusp tip position of mandibular canine
Displaced lingually
Which cingulum is more pronounced - 6 or 27?
6
Which one has a distally displaced cingulum, 11 or 27
27
Longest cusp ridge on permanent canines
Distal
Most prominent labial ridge on permanent canines
Middle
Which third is the distal contact of 27 in?
Middle third
Which third is the mesial contact of 22 in?
Incisal third
From mesial aspect, which one is longer, 6 or 27?
- Also narrower
In 27 is lingual surface bulbous?
No. flat.
How are marginal ridges on 22 and 27?
Parallel or slightly converging
Describe lingual pits and grooves in 27
None
Which one is more symmetrical 6 or 27? (Incisal aspect)
27
What is a peculiar characteristic of cusp ridges of mandibular canines?
Distal cusp ridge is rotated
CEJ curvature of 27
1 mm distal
Contour height of 22
< 0.5mm
Where is contour height of 27 located facially or lingually?
Both - cervical third
Which is the longest tooth in the mouth?
Maxillary canine
Which dimension of canines is greater - faciolingual or mesiodistal?
Faciolingual
Which permanent tooth has the longest crown?
Mandibular canine
Which surface of 27 is parallel with the long axis of the tooth?
Mesial (nearly)
Enumerate all nonsuccedaneous teeth
Permanent first, second and third molars
What are nonsuccedaneous teeth
Teeth that do not move into a position formerly occupied by a primary tooth
What primary teeth are visible at age 1 year?
Maxillary and mandibular incisors
Which teeth erupt at 6-10 months age?
Mandibular centrals
Which teeth erupt at 8-12 months of age?
Maxillary centrals
Which teeth erupt at 9-13 months of age?
Maxillary laterals
Which teeth erupt at 10-16 months of age?
Mandibular laterals
Which teeth erupt at 13-19 months of age?
Maxillary first molar
Which teeth erupt at 14-18 months of age?
Mandibular first molar
Which teeth erupt at 16-22 months of age?
Maxillary canines
Which teeth erupt at 17-23 months of age?
Mandibular canines
Which teeth erupt at 23-31 months of age?
Mandibular second molars
Which teeth erupt at 25-33 months of age?
Maxillary second molars
Which teeth shed at 6-7 years of age?
Maxillary and mandibular centrals
Which teeth shed at 7-8 years of age?
Maxillary and mandibular laterals
Which teeth shed at 9-11 years of age?
Maxillary and mandibular first molars
Which teeth shed at 9-12 years of age?
Mandibular canines
Which teeth shed at 10-12 years of age?
Maxillary canines
Maxillary and mandibular second molars
By when is the calcification of roots normally completed?
Age of 3-4
At what stage of root formation does active eruption of teeth occur?
After two thirds of the root is formed.
List reducing sugars
Lactose Maltose Glucose Galactose Fructose
What kind of carbon do reducing sugars contain?
Free anomeric carbon
What is an anomeric carbon in reducing sugars?
Oxygen on C1 Atom is available for redox reaction
What is the anomeric carbon in reducing sugars called?
Carbonyl group
When is the carbonyl group on reducing sugars active?
When it is not attached to any other structure.
The carbonyl on which kind of sugars has reducing properties?
Monosaccharides.
When are the reducing properties of the carbonyl group lost?
When it forms a glycosidic bond
Reducing sugar test
Classically used to screen for diabetes due to excess free glucose in blood
What kinds of reactions are used to test for diabetes today?
Glucose oxidase linked reactions
Which sugar contains no free anomeric carbon?
Sucrose
Why does sucrose not contain free anomeric carbon?
Because the reducing groups of both glucose and fructose are involved in the glycosidic bond
How do monosaccharides combine into larger molecules?
They form glycosidic bonds
How do glycosidic bonds form?
Hydroxyl group of anomeric carbon of monosaccharide reacts with -OH or -NH group of another compound
What are te typical compounds that monosaccharides combine with to form glycosidic bonds?
- Alcohol
- Purine
- Pyrimidine
- Another sugar
Glucosuria
Presence of glucose in urine
Causes of glucosuria
Low insulin
High blood sugar
Impaired tubular reabsorption
High GFR
Threshold for glucosuria
160-180 mg/d
Glycosidic bond aka
Glycosidic linkage
What is a glycosidic bond
Two bond link between the rings in an oligosacharide or polysaccharide
Name a glycosaminoglycan functioning in synovial fluid
Hyaluronate
Glycoproteins
- Conjugated proteins
- Contain one or more saccharides lacking a serial repeating unit
- Covalently bound to a protein
What is the difference between proteoglycans and glycosaminoglycans?
Carbohydrate chains of proteoglycans are called glycosaminoglycans
How are GAG chains incorporated in proteoglycans?
GAG chains are linked covalently to a protein core
How many distinct classes of proteoglycans?
6
Name the 6 classes of proteoglycans
- Chondroitin sulphate
- Dermatan sulphate
- Keratan sulfate
- Heparan sulfate
- Heparin
- Hyaluronate
What % of carbohydrates do Proteoglycans contain?
95%
What kind of glycoproteins resemble carbohydrates more than they do proteins?
Proteoglycans
Which type of proteoglycan is different from the others and how?
Hyaluronate -
- Not sulfated
- Not covalently attached to protein
Features common to all GAGs
- long unbranched heteropolysaccharides
- Largely made up of disaccharide repeating units
- Contain hexosamine and a uronic acid
Common components of GAGs
Sulfate groups
How are sulfate groups linked to monosaccharides
Ester bonds
How are sulfate groups linked to Glucosamine
Amide bonds to the amino group of glucosamine
Why are GAGs highly charged
- Carboxyls of uronic acids
- Sulfate groups
Function of GAGs in connective tissue
- Lubricants
- Support elements
What components of GAGs are important in their roles in connective tissue
- Electrical charge
- Macromolecular structure
What part of cellular structure do GAGs inhabit
Extracellular matrices and cell surfaces
On a cellular level what is the function of GAGs
They participate in
- Cell adhesion
- Signaling
Where will you find Hyaluronate
- Synovial fluid
- Vitreous humor
- ECM of loose connective tissue
What are the distinguishing characteristics of Hyaluronate?
- Large polymers
- Shock absorbing
What kind of GAG do you find in cartilage?
Chondroitin sulfate
What are all the locations where you find Chondroitin sulfate?
Cartilage
Bone
Heart Valves
What is the most abundant GAG?
Chondroitin sulfate
What kind of GAG do you find in bone?
Chondroitin sulfate, keratan sulfate
What kind of GAG do you find in Skin?
Dermatan sulfate
What kind of GAG do you find in heart valves?
Chondroitin sulfate, dermatan sulfate
What kind of GAG do you find in vitreous humor?
Hyaluronate
What kind of GAG do you find in Basement membranes?
Heparan sulfate
What kind of GAG do you find in cornea?
Keratan sulfate
What kind of GAG do you find in cartilage aggregated with chondroitin sulfates?
Keratan sulfate
What is the most heterogenous GAG?
Keratan sulfate
What GAG serves as an anticoagulant?
Heparin
Which one is more sulfated – heparin or heparan sulfate?
Heparin
Where do you find heparin?
It is a component of intracellular granules of mast cells lining the arteries of the lungs, liver and skin
What GAG is shock absorbing?
Hyaluronate
What kind of GAG do you find in ECM of loose connective tissue?
Hyaluronate
Which GAG is a component of cell surfaces?
Heparan sulfate
What does heparan sulfate contain more of than heparin?
Acetylated glucosamine
Where do you find heparin?
It is ta component of intracellular granules of mast cells lining the arteries of the lungs, liver and skin
What kind of GAG do you find in blood vessels?
Dermatan sulfate
What kind of bond is between glucose and fructose?
O-glycosidic bond
Where is the bond between glucose and fructose broken?
Intestine
What intestinal enzyme breaks down the bond between glucose and fructose?
Sucrase
What is the sugar formed due to the conjugation of glucose and fructose?
Sucrose
What kind of bond is present between two monosaccharides in a disaccharide?
Covalent
How many sugar units does a disaccharide contain?
Two
What is beer sugar?
Maltose
What kind of reaction joins the two components of maltose?
Condensation reaction
What happens in a condensation reaction?
A molecule of water is removed
What kind of bond is created between two molecules of glucose after a condensation reaction?
Glycosidic bond
What are the two components of maltose?
2 molecules of glucose
What is milk sugar?
Lactose
What is table sugar?
Sucrose
Components of Lactose
Glucose and galactose
Components of Sucrose
Glucose and fructose
What is the function of the intestinal enzyme invertase?
Conversion of sucrose into glucose and fructose
Where in the intestine are the enzymes that convert disaccharides into absorbable monosaccharides?
Small intestine
How are monosaccharides absorbed?
By enterocytes
What larger structures can monosaccharides link up to form?
- Disaccharides
- Oligosaccharides
- Polysaccharides
What kind of bond do disaccharides have?
O-glycosidic bond
What is an O-glycosidic bond?
When oxygen is involved in a glycosidic bond - -OH of anomeric carbon reacts with -OH of another compount
What is an N-glycosidic bond?
When nitrogen is involved - -OH of anomeric carbon bonds with -HN of another compound
What compounds contain O-glycosidic bonds?
Polysaccharides
What compounds contain N-glycosidic bonds?
- Glycoproteins
- Nucleotides
What is the most important of the aldohexoses?
D-glucose
What kind of carbohydrates are glucose, fructose and galactose?
Monosaccharides
Types of monosaccharides
- Trioses
- Tetroses
- Pentoses
- Hexoses
What kind of monosaccharide is erythrose?
Tetrose
What kind of monosaccharide is glyceraldehyde?
Triose
What kind of compound is dihydroxyacetone?
Monosaccharide - triose
What kind of compound is ribose?
Monosaccharide - pentose
Types of monosaccharides based on most-oxidised functional groups
Aldoses and ketoses
What monosaccharides occur as cyclic rings in nature?
5, 6, 7, 8 carbon atoms
Examples of naturally occuring cyclic ringed carbohydrates
Ribose
Glucose
Fructose
Galactose
What is the naming of configurations of simple sugars based on?
The absolute configuration of glyceraldehyde
What is a chiral carbon
Asymmetric carbon
The names of which compounds are determined by absolute configuration of glyceraldehyde?
- Monosaccharides
- Amino acids
What is the difference between the D form and the L form?
In a Fisher projection, D form has hydroxyl group on right, L form has hydroxyl group on left.
Which form of sugars are the most common in nature?
D form - related to D-glyceraldehyde
What is xylose?
A monosaccharide
What is mannose?
A monosaccharide
What does glucan transferase hydrolyse?
Glycogen
What is the solubility of polysaccharides?
They are insoluble because they have large molecules
Main functions of polysaccharides in living organisms
- Storage molecules
- Structural materials
What are the structural polysaccharides?
Cellulose
What polysaccharides act as storage molecules?
- Starch
- Glycogen
Polysaccharides that contain a single monosaccharide species
Homopolysaccharides
List of homopolysaccharides
- Starch
- Glycogen
- Dextrans
- Glucans
What kind of molecules are contained in starch?
alpha glucose molecules
What kind of reactions bind molecules in starch?
Condensation reactions
Main components of starch
Amylose
Amylopectin
What kinds of chains do amylopectin molecules form in starch?
Highly branched chains with alpha-1,6 linkages
What enzyme acts on starch?
Alpha amylase
What kind of chemical reaction does alpha amylase have with starch?
It rapidly hydrolyses starch
Where is alpha amylase secreted from?
- Parotid
- Pancreas
What component of starch is unbranched?
Amylose
What compound creates straight chains in starch?
Amylose
How many glucose residues does glycogen contain?
10,000 to 40,000.
How are glucose residues held together in glycogen?
a-1,4 glycosidic bonds
How does branching occur in Glycogen?
1 in 12 glucose residues serves as a branch point
What kinds of bonds do branch points have within glycogen?
a-1,6 glycosidic bond
What part of the body is glycogen especially abundant in?
Liver
How are glucose units removed from glycogen?
Glycogen phosphorylase
How is glycogen cleaved beyond a branching point?
2 enzymes:
Glucantransferase
amylo-alpha-1,6-glucosidase
What is the most common organic compound on earth?
Cellulose
What is “dietary fiber”?
Cellulose
What is “roughage”?
Cellulose
Which carbohydrate acts as a hydrophilic bulking agent for feces?
Cellulose
What linkages are part of cellulose?
B1-4 linkages
What are the monosaccharides that makes up cellulose?
Glucose
What does the term glycan refer to?
- Polysaccharide or
- Oligosaccharide
What is the ground surface of extracellular matrix made up of?
Proteoglycans
How are GAGs attached to the protein in proteoglycans?
In a brush-like fashion
Functions of Proteoglycans
- lubricants
- extracellular matrix
- Being a molecular sieve
What kind of proteins are glycoproteins?
Conjugated proteins
How is the carb portion of most glycoproteins different from proteoglycans?
it is shorter and branched.
What is special about the glyco- part of glycoproteins
They lack a serial repeating unit
What kinds of molecules do glycoproteins serve as?
- Hormones
- Enzymes
- Antibodies
- Structural proteins
What are glycolipids aka?
Sphingolipids
Where are glycolipids found?
In cell membrane
What part of the glycolipid extends into the extracellular space?
Carbohydrate portion
What are glycolipids derived from?
Ceramide - a lipid
Types of glycolipids
- Cerebrosides
- Globosides
- Gangliosides
Which ones are long and straight - Proteoglycans or Glycoproteins?
Proteoglycans
Role of glycolipids
Cell membrane receptors
How does chondroitin sulfate provide structure?
It holds water and nutrients, allows other molecules to move through cartilage
Roles of chondroitin sulfate
- Building block for proteoglycan molecules
- Anti-inflammatory
Why is the function of chondroitin sulfate of holding water and nutrients important?
Cartilage doesn’t have a blood supply
How does chondroitin sulfate help in joints?
It contributes to
- Strength
- Flexibility
- Shock absorption
Ground substance aka
Extracellular matrix
Functions of ground substance
- Holds the cells of a tissue together
- Provides a porous pathway for diffusion of nutrients and oxygen to individual cells
How does ground substance help get nutrients and oxygen to individual cells?
By providing a porous pathway
What is ground substance composed of?
- heteropolysaccharides (GAGs)
- (linked to) protein
- (to form) proteoglycans
- fibrous proteins
Name an enzyme that liquefies the ground substance
Hyaluronidase
Actions of hyaluronidase
- Splits hyaluronic acid
- lowers the viscosity of ground substance
- Increases the permeability of connective tissue
- Increases the absorption of fluids
Which is the only GAG that is not attached to a protein?
Hyaluronate
How are dextrans produced?
Extracellularly by bacteria and yeast
What is the constituent monosaccharide in dextrans?
Glucose
What is the enzyme used to produce dextrans?
Glucosyl transferase
What is glucosyl transferase aka
Dextran sucrase
What is the substrate from which Dextrans are created?
Sucrose
Are there any side products from dextran production?
Yes - fructose
How is fructose formed from the dextrification of sucrose?
Fructose is formed into levans (fructans)
How is fructose created as a byproduct of dextran production stored?
It is stored intracellularly as reserve nutrients.
What is the most notable bacteria that produces dextran from sucrose?
Strep mutans
Name a sticky polymer of glucose
Dextran
What kinds of linkages do glucose molecules have within dextran?
a-(1,6) linkages with some a-(1,3) branches
How are dextrans created from sucrose?
Glucosyl transferase splits sucrose into glucose and fructose and links the glucose molecules into a dextran polymer
How is the dextran stored after creation?
IT is deposited as a thick glycocalyx around the cell
How are dextrans related to dentistry?
They seem to be essential for the cariogenecity of Strep mutans.
How does adhesion of bacteria to tooth surface increase on creation of dextrans?
Fructans (levans) - the byproducts of dextran production - increase adhesion of bacteria to tooth surfaces and promote formation of dental plaque
How are fructans formed?
From the fructose moiety of sucrose by the enzyme fructosyl transferase
Fructosyl transferase aka
levan sucrase
Essentially, what are fructans?
Reserve nutrients for bacteria
Which one is more abundant - cones or rods?
Rods
What pigment do rods contain?
Rhodopsin
What kind of pigment is rhodopsin?
Photopigment
Are rods responsible for color vision or cones?
Cones
What are rods used for?
Dark adaptation
Where are rods and cones located?
Retina
What is the innermost layer of the eye?
Retina
What are the visual receptors of the retina?
Rods and cones
How many types of photopigments are there?
4
What are the different types of photopigments?
Rhodopsin (rods)
Photopsin I, II, III
Melanopsin
What are the major components of a photopigment?
Opsin - a protein
Retinal - a chromophore molecule
Function of opsins
They confer specific light-sensitive properties on each photopigment
Are opsins uniform throughout?
They differ from pigment to pigment
What is Retinal produced from?
Vitamin A
How is rhodopsin synthesised?
Retinal is added to an opsin to synthesize rhodopsin
What characterises the entire rod system?
A relative lack of colour discrimination
How are rods distributed in the retina?
They are numerous in the periphery of the retina
What are the different types of cones?
3 - Red green and blue
How are cones distributed in the retina;?
They are concentrated in the centre of the retina, esp in the fovea.
How do rods work?
During dark adaptation, rhodopsin is synthesised in the rods
What causes night blindness?
Severe Vitamin A deficiency over many months
When are cones principal photoreceptors?
- Daylight
- Brightly lit areas
Are rods more abundant or cones?
Rods
Which ones are more sensitive, cones or rods?
Rods
Which have greater acuity, rods or cones?
Cones
What is the cornea?
The crystal clear dome that covers the front of the eye
What part of the eye is responsible for the majority of the bending of light rays?
Cornea, NOT lens
Which part of the eye does the majority of the focusing, cornea or lens?
Cornea
Does the shape of the cornea change?
No. (Age related changes aside)
What is the role of the lens in focusing the light?
It finishes the focusing of the light
Of the cornea and lens which one can change shape
Lens
How does the eye focus on near objects?
Lens fine tunes vision by changing shape to focus on near objects
What part of the eye is affected in cataract?
lens
What part of the retina receives the focus of the object of regard?
Fovea
What kinds of cells are packed in the area of the fovea?
Cones
Which one is watery - aqueous humour or vitreous humour?
Aqueous
Where is vitreous humour found?
Posterior segment of the eye
What is vitreous humour?
Thick, gelatinous material
What do you call the point where the cornea ends and the iris begins?
Iridocorneal angle
Where is the Canal of Schlemm located?
Next to the iridocorneal angle
What separates the chambers of the anterior segment of eye?
Iris
Zonule aka
Suspensory ligaments
What does the zonule connect
Ciliary body and lens
What part of the ear does a sound wave strike first?
Tympanic membrane
How many types of labyrinths does the cochlea have?
2 - bony and membranous
Where is endolymph found?
Membranous labyrinth of cochlea
What do you find in the bony labyrinth of the cochlea?
Perilymph
What is the last part of the ear to be stimulated before transmission of nerve impulses along the cranial nerve?
Hair cells on the organ of Corti
What membrane stimulates the cochlear parts to move?
Membrane of the oval window
Major divisions of the ear
External
Middle
Inner
What part of the ear is the vestibule located in?
Inner ear
what are the parts of the vestibule?
Saccule and utricle
Parts of the external ear
- Auricle
- External auditory canal
Auricle aka
Pinna
What part of the ear directs sound waves?
Pinna
Cerumen aka
Brown earwax
What part of the ear serves as a resonator?
External auditory meatus
What does the external auditory meatus contain?
Hair
Cerumen
Contents of the middle ear
- Auditory Tube
- Ossicles
Middle ear aka
Tympanic cavity
Which bone is the middle ear located in?
Temporal
What fills the middle ear?
Air
Name the ossicles
Malleus
Incus
Stapes
How much do the ossicles amplify sound?
22-fold
How does sound travel from the tympanic membrane to the oval window?
Ossicles
Contents of the inner ear
- Vestibule
- Semicircular canals
- Cochlea
What is the inner ear formed of?
A membranous labyrinth within a bony labyrinth
What is the major function of the vestibule?
It is associated with a sense of balance
What part of the ears is concerned with equilibrium?
Semicircular canals
What are the membranes contained within the cochlea?
- Vestibular
- Basilar
What part of the inner ear is responsible for hearing?
Cochlea
What is the shape of the organ of Corti?
Spiral
What are the receptors for hearing and where are they present?
Hair cells, located within the organ of Corti
What is the basic functional unit of hearing?
Cochlea
What is the function of cochlea?
Transforms fluid vibrations from sound waves into a nerve impulse
What part of the ear is the tympanic membrane in?
Middle ear
What part of the ear is the eustachian tube in contact with?
Tympanic cavity in the middle ear
What is used to induce mydriasis?
Tropicamide
What does tropicamide do?
Induces mydriasis
The pupil is abnormally dilated in miosis or mydriasis?
Mydriasis
Causes of miosis
- Normal reaction to an increase in light
- Some drugs
- Pathological conditions
Causes of mydriasis
- Drug induced
- Disease
Nearsightedness aka
Myopia
Where are faraway objects focused wrt the retina in myopic patients?
In front of the retina
Causes of Myopia
- Steeper than normal cornea
- Longer than normal eye
What kind of lenses are used to treat myopia?
Concave
Where does light focus in hyperopia?
Behind the retina
Farsightedness aka
Hyperopia
Causes of hyperopia
- Flatter cornea
- Shorter eye
What kinds of lenses are used to treat hyperopia?
Convex
Causes of astigmatism
Non-uniform curvature of the lens
Treatment of astigmatism
Cylindric lenses
Causes of presbyopia
Loss of elasticity of lens with age
Treatment of presbyopia
Bifocals
Normal range for Hb in women
12-16 g/dL
Normal range for Hb in men
13-18 g/dL
Structure of Hb
Quaternary protein consisting of four tertiary polypeptide chains
What kind of polypeptide chains does Hb have?
2 alpha
2 beta
What are the iron-containing heme groups associated with in Hb?
Polypeptide chains (4)
How many Hb molecules does a single erythrocyte contain?
Up to 300 million
How many iron atoms does one Hb molecule contain?
4
How many Oxygen molecules can one Hb molecule bind to?
One
What is the maximum oxygen carrying capacity of one Hb molecule?
8 atoms of oxygen
How many mL is one dL?
100 mL = 1 dL
Normal blood values of Hb in a newborn
14 - 20 g/dL
What does Hb value depend on?
- Number of RBCs
- Amount of Hb in each RBC
Conditions with low Hb value
- Anemia
- Hyperthyroidism
- Cirrhosis of liver
Conditions with high Hb value
- Polycythemia
- COPD
- Congestive Heart Failure
Bohr effect
Very strong in the fetus - acid in the tissues assists in oxygen unloading from Hb, to promote oxygen delivery to the tissues
Hb in which blood is more saturated? Leaving the lungs or returning?
Leaving - 98%
Returning - 75%
What is the difference in mechanisms of transport of oxygen and carbon dioxide in blood?
97% of O2 is transported with Hb
Only 30% of CO2 is transported as carbaminohaemoglobin
What are the mechanisms of transportation of CO2 in blood?
Bicarbonate
Carbon Dioxide
Carbaminohaemoglobin
What % of total plasma protein is Albumin?
60%
What % of the colloid osmotic pressure of the plasma does albumin contribute to?
80%
What is colloid osmotic pressure vital for?
Preventing edema
How many amino acids are contained within Albumin?
585
How many carbohydrates are present within Albumin?
none
What is the effect of albumin on plasma viscosity?
It does not increase it to the same extent as more elongated proteins of the same molecular weight
What is the molecular weight of albumin?
66,000 D
What is the isoelectric point of albumin?
Acidic
How does the kidney treat albumin?
Because of its isoelectric point and its molecular weight, it is not excreted by the kidneys
Is albumin present in interstitial fluid and lymph?
Yes, in lower concentrations than in plasma
What is the difference in amounts of plasma between interstitial fluid and plasma?
Total amount in interstitial spaces slightly exceeds that in vascular compartment
How is albumin returned to the blood from the interstitial spaces?
Lymph
Which one is more, interstitial fluid volume or plasma volume?
Interstitial fluid (12% of body volume)
Plasma is 4.5% of body volume.
Why does albumin contribute so much to colloid osmotic pressure of the plasma?
Because it is one of the most hydrophilic plasma proteins
What does colloid osmotic pressure depend on?
The amount of water and electrolytes that a protein attracts to its surface
What is the importance of colloid osmotic pressure?
It is necessary to prevent edema
What is the force that is opposite to the colloid osmotic pressure?
Hydrostatic pressure
Which of the two forces - hydrostatic pressure and colloid osmotic pressure - pushes fluid from the blood into the interstitial space?
Hydrostatic pressure
How is the fluid balance across the endothelium maintained?
As long as hydrostatic pressure and colloid osmotic pressure cancel each other out
At what albumin concentration does edema occur?
When it drops below 2 g/dL
Other causes for edema
- Increase in capillary permeability
- Venous obstruction
- Impaired lymph flow
- Congestive heart failure with an increased venous pressure
Which organ in the body is chiefly responsible for regulation of osmotic pressure in the body?
Kidney. It regulates the reabsorption of water in response to ADH
WHat does albumin have binding sites for?
- Fatty acids
- Thyroxine
- Cortisol
- Heme
- Bilirubin
- Many other metabolites
What are the majority of plasma proteins?
Glycoproteins (not albumin)
What is the principal hormone for serum calcium regulation?
Parathormone
How much Calcium ions does the human body contain?
1-1.5 k
Where is most of the calcium of the body contained?
98% of the calcium of the body is contained in the mineral substance of the bone
What are other substances that control calcium levels?
- Vitamin D
- Calcitonin
What substances increase serum calcium levels?
PTH
Vitamin D
What does calcitonin do to blood calcium levels?
It tones down blood calcium
Are people with Parathyroidism more or less susceptible to fractures?
More, because PTH primarily increases concentration of serum calcium
What happens to renal calcium excretion in hyperparathyroidism?
Decreased (in order to increase blood calcium levels)
What effect does PTH have in elderly people?
Bone resorption with low dietary calcium is intensified
When do you observe increased calcium blood levels?
- Hypervitaminosis D
- Hyperparathyroidism
- Bone cancer
- Other bone diseases
When do you observe decreased calcium blood levels?
- Severe diarrhea
- Hypoparathyroidism
- Avitaminosis D
What are the disorders precipitated due to Avitaminosis D?
- Rickets
- Osteomalacia
What hormones work together to keep a balance within serum calcium levels?
PTH and Calcitonin
What hormone is complementary to Calcitonin?
PTH
How does calcitonin counteract actions of PTH?
When PTH increases serum calcium, calcitonin tones down this level by
- depositing more in bone
- increasing the excretion
What is normal plasma phosphorous concentration?
4 mg%
What regulates plasma phosphorous concentration?
Parathyroid hormone
How does PTH regulate plasma phosphorous concentration?
Increased hormone causes the kidneys to increase the rate of phosphate excretion, which decreases the plasma phosphate concentration
What hormones increase bone resorption?
PTH
Vitamin D
What does Calcitonin do to bone?
It decreases bone resorption
Which Ca regulatory hormone has no role to play in kidneys or intestines?
Calcitonin
Which hormone is secreted when serum Calcium is low?
PTH
Does serum levels of phosphate have an effect on PTH levels?
No
What % of body weight is blood?
8%
What is hematocrit
Proportion of cellular elements of blood
What is the most important transport medium in the body?
Blood
Serum = blood minus ?
Fibrin clot and blood cells
Physical nature of serum
Clear, thin and sticky fluid
How does serum differ from plasma?
Serum lacks fibrin and other coagulation products
Plasma = blood minus ?
Formed elements
What % of blood is plasma?
55%
What are the contents of plasma?
Proteins
Water
Other solutes
What % of plasma is proteins?
7%
What proteins are contained within plasma?
Albumins
Globulins
Fibrinogen
What % of plasma is water?
91%
What is the major content of plasma?
Water
What are the trace elements of plasma (other solutes)?
Metabolic end products Food materials Respiratory gases Hormones Ions
What % of blood is hematocrit?
45%
What are the formed elements?
Erythrocytes
Leukocytes
Thrombocytes
Function of platelets
Hemostasis - agglutinate and plug small ruptured vessels
How many steps are in the process of hemostasis?
Three
- Vasoconstriction
- Platelet aggregation
- Coagulation
What is the need for an extrinsic or intrinsic pathway?
These pathways form prothrombin activator, which helps in production of thrombin from prothrombin
