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Phase 1 Med > IMMS > Flashcards

IMMS Flashcards

1
Q

How many chromosomes are found in humans?

A

46 chromosomes, 22 pairs of autosomes and 1 pair of sex chromosomes

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2
Q

Define Karyotype

A

number and appearance of chromosomes in a cell. Spreads are arranged
in size order, biggest is pair 1 and smallest is pair 22, sex pair is pair 23

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3
Q

Which phase in the cell cycle is the longest?

A

Interphase

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4
Q

Which events occur in Interphase

A

G1 - rapid growth, New organelles produced, protein synthesis
S - DNA replication, Histones replicate, Centrosomes replicate
G2 - Energy stores accumulate and mitochondria duplicate

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5
Q

What occurs in Prophase?

A

Chromatin condenses into chromosomes

Centrosomes nucleate microtubules and move to opposite poles

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6
Q

What occurs in Prometaphase?

A

Nuclear membrane breaks down
Microtubules invade nuclear space
Chromatids attach to microtubules

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7
Q

What occurs in Metaphase

A

Chromosomes line up on the equator of the cell

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8
Q

What happens in Anaphase

A

Sister chromatids separate and are pushed to opposite poles of the cells, centromere
first, as spindle fibres contract

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9
Q

What happens in telophase?

A
  • Nuclear membrane reforms

- Chromosomes unfold into chromatin

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10
Q

What happens in cytokinesis?

A

Cytokinesis is where the cell divides into two genetically identical daughter cells

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11
Q

Which genetic disease arises from trisomy 21?

A

Down Syndrome

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12
Q

What is meiosis used for and what does it produce?

A

Used to produce gametes

4 haploid cells are produced (genetically different)

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13
Q

Name two ways in which genetic diversity arises in meiosis and when do they occur?

A

Independent assortment - a random assortment of the chromosomes, new combinations - METAPHASE 1
Crossing over - Between non-sister chromatids, alleles are exchanged - PROPHASE 1

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14
Q

What occurs in meiosis 2?

A

Sister chromatids separate and haploid cells are produced

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15
Q

Briefly describe gametogenesis in males

A
  • Primordial germ cell
  • lots of mitoses
  • Spermatogonia produced
  • Begins at puberty
  • Cytoplasm divides equally
  • process takes 60-65 days
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16
Q

Briefly describe gametogenesis in females?

A
  • Primordial germ cell
  • 30 mitotic divisions
  • oogonia produced
  • oogonia enter prophase 1 (8th month if intrauterine life)
  • process suspended
  • enter ovulation, the cytoplasm divides unequally
  • 1 egg , 3 polar bodies
  • Meiosis 1 completed at ovulation
  • Meiosis 2 completed at fertilisation
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17
Q

Describe Non-Disjunction

A

Failure of chromosome pairs to separate in Meiosis 1 or sister
chromatids to separate properly in meiosis 2.
- can result in monosomy, trisomy

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18
Q

Describe Gonadal Mosaicism

A

• Occurs when precursor germline cells to ova or spermatozoa are a mixture of two or
more genetically different cell lines (due to errors in mitosis)
• One cell line is normal, the other is mutated
• Incidence increases with advancing paternal age
- Most common in males

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19
Q

Define Genotype

A

the genetic constitution of an individual

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20
Q

Define Phenotype

A

The appearance of individual results from the interaction of the
environment and the genotype

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21
Q

Define Allele

A

One of several alternative forms of a gene at a specific locus;

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22
Q

What is polymorphism

A

frequent hereditary variations at a locus. Doesn’t cause problems
(thats mutations). Polymorphisms can be you more/less efficient or make you more/
less susceptible to disease.

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23
Q

define consanguinity

A

the reproductive union between two relatives

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24
Q

Define Homozygous and heterozygous

A
  • Homozygous: both alleles are the same at a locus

* Heterozygous: alleles at a locus are different

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25
Q

Define penetrance

A

Proportion of people with a gene/genotype who show the expected
phenotype

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26
Q

Define variable expression

A

Variation in clinical features (type and severity) of a genetic
disorder between individuals with the same gene alteration

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27
Q

Define sex limitation

A

Expression of a particular characteristic limited to one of the sexes

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28
Q

What is a multifactorial condition?

A

Diseases due to a combination of genetic and

environmental factors.

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29
Q

Summarise autosomal dominant inheritance.

A
  • Manifests in the heterozygous state.
  • Male to Male transmission is seen.
  • Both males and females are affected equally.
  • The disease is present in several generations.
  • There is a 50% chance of offspring having the disease.
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30
Q

Summarise autosomal recessive inheritance.

A
  • Manifests in the homozygous state.
  • The disease is often not seen in every generation.
  • 25% chance of offspring having the disease.
  • 50% chance of offspring being carriers.
  • Healthy siblings have a 2/3 chance of being carriers.
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31
Q

Give an example of an autosomal dominant condition.

A

Huntington’s disease

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32
Q

Give an example of an autosomal recessive condition

A

Cystic fibrosis

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33
Q

Give two examples of X-linked conditions

A
  • Haemophilia

- Duchenne muscular dystrophy

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34
Q

Summarise X-linked inheritance

A
  • No Male-Male transmission
  • all daughters from an affected male are carriers
  • sons unaffected
  • Males can never be carriers
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35
Q

Define lyonisation.

A

One of the female X chromosomes becomes inactivated early in embryogenesis.

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36
Q

What is imprinting?

A

some genes have only one of the two alleles active, either maternal or paternal

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37
Q

Which symbol on a pedigree chart shows a termination of pregnancy

A

triangle with a line through it

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38
Q

Which symbol on a pedigree chart shows a miscarriage?

A

triangle

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39
Q

which symbol on a pedigree chart shows a stillborn - sex unknown

A

Diamond

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40
Q

What process occurs on the outer membrane of mitochondrion?

A

Lipid synthesis

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41
Q

Where in a cell does the Krebs cycle take place?

A

Matrix

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42
Q

Name 2 places DNA can be found.

A
  1. Nucleus of a cell.

2. Mitochondria (purely maternal DNA).

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43
Q

What process occurs on the inner membrane of mitochondrion?

A

Electron transport chain - oxidative phosphorylation

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44
Q

What is the role of the RER

A

Protein synthesis

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45
Q

Describe the role of the SER?

A

Lipid synthesis

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46
Q

What is the function of the golgi apparatus?

A

Processes and modifies ER products.

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47
Q

What is the cis face of the golgi apparatus?

A

The cis face is nearest the nucleus and receives ER vesicles.

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48
Q

What does the medial Golgi do?

A

It modifies products by adding sugars forming oligosaccharides

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49
Q

What does the trans face of the golgi do?

A

It sorts molecules into vesicles.

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50
Q

What are the functions of vesicles?

A

Transports and stores materials. These are membrane-bound organelles.

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51
Q

What are lysosomes?

A
  • Derived from golgi
  • H+/ATPase on surface
  • enables acid hydrolases to work
  • breakdown debris and bacteria and cell organelles
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52
Q

What is the role of peroxisomes?

A

Oxidise long-chain fatty acids - involved in fatty acid beta oxidation

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53
Q

How do HbS sub-units cause sickling?

A

They bind to the cytoskeleton which causes sickling.

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54
Q

What the smallest type of filamentous protein found in cells?

A

Microfilaments - actin forms a bracing mesh

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55
Q

What the largest type of filamentous protein found in cells?

A

Microtubules - tubulin - arise from centrosomes - in all cells apart from erythrocytes

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56
Q

Give an example of an intermediate filament

A

Desmin

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57
Q

What is the role of intermediate filaments?

A

Spread the tensile forces through the tissues - reduces cell damage

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58
Q

What is lipofuscin?

A

Orange-brown pigment - peroxidation of lipids - found in older people - wear and tear pigment

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59
Q

Describe the primary structure of proteins?

A

The sequence of the amino acids - held together by covalent bonds

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60
Q

Describe the secondary structure of proteins

A

Formation of beta-pleated sheets and alpha helixes due to H-bonds

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61
Q

Describe the tertiary structure of proteins

A
  • Overall 3D shape of a protein

- ionic bonds, disulphide bridges, van der Waals and hydrophobic forces

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62
Q

Describe the quaternary structure of a protein

A

Two or more polypeptide chains joined together - e.g haemoglobin

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63
Q

What is an isoenzyme?

A

enzymes that have a different structure and sequence but catalyse the
same reaction

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64
Q

What is a Coenzyme?

A

they cannot in themself catalyse a reaction but can help enzymes to
do so. They can bind with the enzyme protein molecule to form the active enzyme

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65
Q

Which part of an immunoglobulin does the antigen bind to?

A

variable domain

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66
Q

What is the function of topoisomerase?

A

it unwinds the DNA double helix by relieving the supercoils.

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67
Q

In what direction does DNA polymerase read?

A

3’ to 5’ (but replication occurs in the 5’ to 3’ direction).

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68
Q

What is a promoter sequence?

A

The promoter region controls when and where the RNA polymerase will attach to DNA so transcription can commence.

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69
Q

what is the role of single-stranded binding protein (SSB) in DNA replication?

A

keeps two strands of

DNA apart whilst synthesis of new DNA occurs

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70
Q

What is the role of DNA ligase

A

joins the short DNA pieces (Okazaki fragments) together into one
continuous strand.

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71
Q

What is the role of a primer?

A

Short strand of DNA that is the start point for DNA synthesis

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72
Q

Briefly describe translation.

A

A tRNA with a complementary anticodon to the codon on mRNA binds. Peptide bonds from between amino acids = polypeptide chain.

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73
Q

What is splicing?

A

Removal of introns

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74
Q

Which part of the gene contains coding sequences

A

Exons

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75
Q

List 3 features of the genetic code.

A
  1. Non-overlapping
  2. Universal
  3. Degenerate
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76
Q

What is a mis-sense mutation?

A

A single nucleotide change results in a codon coding for a different amino acid. This can result in a non-functional protein or can have no effect (degenerative nature of the genetic code).

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77
Q

What is a non-sense mutation?

A

A single nucleotide change that produces a premature stop codon. This results in an incomplete/non-functional protein.

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78
Q

What is an in-frame deletion?

A
  • Complete codon removed
  • less catastrophic
  • reading frame not altered
79
Q

What is an out of frame deletion?

A
  • reading frame is altered

- can be catastrophic

80
Q

What is it called when a child shows a phenotype for a disease younger than their father/mother does? e.g. in huntington’s disease.

A

Anticipation.

81
Q

What is anticipation?

A

repeats get bigger when they are

transmitted to the next generation resulting in earlier symptoms of greater severity

82
Q

Describe autocrine communication

A

Chemical is released from cell into the
extracellular fluid and then acts upon the very cell that
secreted it

83
Q

Describe paracrine secretions

A

Chemical messengers involved in the
communication between cells, released into extracellular
fluid - travel short distances, local communication. E.g
Acetylcholine at neuromuscular junction

84
Q

Describe endocrine secretions?

A
  • Secrete into blood
  • travel long distances
  • can affect the whole body
  • organs involved
85
Q

Describe exocrine secretions?

A

Secretions into ducts and then into organs

86
Q

compare paracrine and endocrine secretions

A
  • Paracrine travel in extracellular fluid
  • endocrine travels in the blood
  • endocrine affects organs and more things
  • paracrine short distance and endocrine long distance
87
Q

Define hormone

A

A molecule that acts as a chemical messenger

88
Q

Name the three types of hormones

A

1) Peptide
2) Steroid
3) amino-acid derivative

89
Q

Give a brief description of peptide hormones

A
  • made from short chains of amino acids
  • large hydrophilic charged molecules
  • cannot diffuse across the membrane - receptors on the membrane
  • Pre-made and stored in vesicles
  • dissolves in blood
  • quick response
    e. g - insulin, TSH, ADH
90
Q

Give a brief description of steroid hormones

A
  • Synthesised from cholesterol
  • Water-insoluble, lipid-soluble
  • Requires transport in blood
  • intracellular receptor
  • no storage
  • slow response
  • directly affects the DNA
91
Q

Give a brief description of amino acid hormones

A

Synthesised from tyrosine, acts in same way to peptide. Examples;
adrenaline, thyroid hormones (thyroxine (T4) and triiodothyronine (T3))

92
Q

What is the predominant electrolyte in ICF?

A

K+

93
Q

What is the predominant electrolytes in ECF?

A

sodium, chloride, bicarbonate and calcium

94
Q

what is interstitial fluid?

A

The fluid which surrounds the cells, does not circulate

95
Q

Water distribution: how much water is there in:

a) the ECF?
b) the ICF?

A

a) 14L

b) 28L

96
Q

Water distribution: how much water is there in the (ECF):

a) interstitial fluid
b) plasma

A

a) interstitial - 11L

b) plasma - 3L

97
Q

Water distribution: How much water is there in the ICF?

A

28L

98
Q

Define insensible loss

A

Water loss that we are unaware of. It is comprised only of solvent and can not be measured.

99
Q

Name 3 hormones involved in water homeostasis.

A
  1. Aldosterone.
  2. ADH - antidiuretic hormone.
  3. ANP - atrial natriuretic peptide.
100
Q

If a patient has diabetes insipidus and is not producing any ADH what is her blood and urine osmolality after 3 hours of water deprivation going to look like?

A

Blood osmolality would be high.

Urine osmolality would be low - very dilute urine.

101
Q

How much water does a typical person have

A

42L (roughly 60% of bodyweight)

102
Q

What are the osmotically active solutes in the ICF

A

K+

103
Q

What are the osmotically active solutes in the ECF?

A

Sodium, chloride, glucose and urea

104
Q

Define osmosis

A

net movement of solvent molecules through a semipermeable membrane
to a higher solute concentration (i.e. lower water conc.)

105
Q

Define osmolality

A

the measure of the number of dissolved particles per kg of fluid

106
Q

Define osmolarity

A

measure of the number of dissolved particles per L of fluid

107
Q

Define osmotic pressure

A

pressure applied to a solution, by a pure solvent, required to
prevent inward osmosis, through a semipermeable membrane

108
Q

Define oncotic pressure

A

form of osmotic pressure exerted by protein that tends to pull fluid
into its solution - water moves from interstitial fluid into plasma

109
Q

What is hydrostatic pressure?

A

Pressure difference between capillary blood(plasma) and

interstitial fluid - water and solutes move from plasma into interstitial fluid

110
Q

What happens when water is lost from ECF?

A

increase in osmolality in ECF

111
Q

Name the 4 types of oedema.

A
  1. Lymphatic.
  2. Venous.
  3. Hypoalbuminaemic.
  4. Inflammatory.
112
Q

Electrolyte homeostasis: what is the cause(s) of hypernatremia? And what are the risks?

A

Cause - water deficit (poor intake, diabetes insipidus etc).
Risks - Dehydration.
(High sodium = low H2O which dehydrates the brain).

113
Q

Electrolyte homeostasis: What is the cause(s) of hyponatremia and what are its risks?

A

Causes: Excess water due to IV fluids, diuretics.
Risks: Overhydration - headache, confusion

114
Q

Electrolyte homeostasis: What is the cause(s) of hyperkalemia and what are its risks?

A

Causes: renal failure, acidosis, diuretic inhibitors.
Risks: Cardiac arrest.

115
Q

Electrolyte homeostasis: What is the cause(s) of hypokalemia and what are its risks?

A

Causes: D+V, alkalosis, diuretics.
Risks: weakness and dysrhythmia.

116
Q

Electrolyte homeostasis: What is the cause(s) of hypercalcemia and what are its risks?

A

Causes: hyperparathyroidism, Vit D toxicity, malignancy.
Risks: renal stones and metastatic calcification.

117
Q

Electrolyte homeostasis: What is the cause(s) of hypocalcemia and what are its risks?

A

Causes: renal disease, Vit D deficiency, intestinal malabsorption.
Risks: tetany (spasms).

118
Q

List 4 functions of a plasma membrane.

A
  1. Physical boundary for the cell.
  2. Regulates the movement of substances.
  3. Has receptors for cell to cell signalling.
  4. Attaches the cell to the external environment.
119
Q

Name 4 molecules you’d find in a plasma membrane.

A
  1. Cholesterol
  2. Glycoproteins
  3. Glycolipids
  4. Integral proteins
120
Q

What are tight junctions?

A

Binds cells together to prevent leakage of molecules in between them.

121
Q

What are adherens junctions

A

Join actin bundle in one cell to a similar bundle in the other cell
- keeps cells to together

122
Q

What are desmosomes

A

Attach cells via the intermediate filaments.

- resists shearing forces

123
Q

What are hemidesmosomes?

A

anchor intermediate filaments in a cell to the basal

lamina

124
Q

What is the function of gap junctions?

A

allows the passage of small water-soluble ions and
molecules
- electrical conduction

125
Q

Name 3 mechanisms by which a molecule can move across a plasma membrane.

A
  1. Diffusion - movement down a concentration gradient.
  2. Facilitated diffusion.
  3. Active transport - uses ATP, against a concentration gradient.
126
Q

Describe the process of exocytosis?

A

Vesicle from the golgi apparatus, fuse with the plasma cell membrane, resulting in the
expulsion of waste or the secretion of enzyme/hormones

127
Q

Which dietary energy source provides the most energy?

A

lipid (9kcal/g - gives the most energy per gram)

128
Q

Define basal metabolic rate?

A
  • amount of energy needed to keep the body alive in the
    rest state.
  • typically (24kcal/kg/day)
  • requirement 0.8g/kg ideal body weight protein per day
129
Q

What factors increase BMR?

A

Being overweight, pregnancy, low temperature, exercise, hyperthyroidism

130
Q

What factors decrease BMR?

A

Increasing age, being female, starvation, hypothyroidism

131
Q

How much energy is stored as triglycerides?

A

15kg

132
Q

How much energy is stored as glycogen? And where is it stored?

A

350g

  • 200g in the liver
  • 150g in muscle
133
Q

How much energy is stored as protein?

A

6kg

134
Q

What are the products of glycolysis?

A

2 ATP, 2 NADH, 2 Pyruvate

135
Q

What is the rate-limiting enzyme in glycolysis?

A

Phosphofructokinase-1

136
Q

Where in a cell does glycolysis take place?

A

Cytoplasm

137
Q

Describe the full process of glycolysis

A

-

138
Q

Briefly describe what happens in anaerobic respiration.

A

NAD is regenerated from NADH. Pyruvate, from glycolysis, forms lactate. Lactate dehydrogenase catalyses this reaction. NAD goes back to glycolysis so ATP can be produced.

139
Q

Name 3 allosteric inhibitors of PFK-1.

A
  1. Acidosis.
  2. ATP.
  3. Citrate.
140
Q

Name an allosteric activator of PFK-1

A

AMP

141
Q

Where in a cell does the Krebs cycle take place?

A

The matrix of the mitochondria

142
Q

Draw the Krebs cycle

A

-

143
Q

Name 3 regulators of citrate synthase - Krebs cycle

A
  • ATP Allosteric inhibitor
  • NADH Allosteric inhibitor
  • Succinyl CoA competitive inhibitor
  • Increased citrate, increased inhibition
144
Q

How does isocitrate dehydrogenase affect the rate of reaction

A
  • Key rate-limiting step
  • ICDH reduces concentration of citrate
  • speeds up citrate synthase
145
Q

Name 5 regulators of alpha-ketoglutarate dehydrogenase

A
  • inhibited by its products
  • NADH
  • Succinyl CoA
  • GTP
  • ATP
  • ROS
146
Q

What is thought to activate alpha-ketoglutarate dehydrogenase?

A

Ca2+

147
Q

What is the product of fatty acid beta-oxidation?

A

Acetyl CoA.

148
Q

Where does oxidation of fatty acids occur

A

Inside the mitochondria

149
Q

What is the importance of acylcarnitine?

A

It is required to transport fatty acids longer than 12 carbons into the mitochondria for beta-oxidation.

150
Q

What occurs during the fatty acid beta-oxidation process?

A

sequential removal of 2-carbon units by oxidation at the

beta-carbon position of the fatty Acyl-CoA molecule.

151
Q

What is produced after each round of beta-oxidation?

A

1 mol of NADH, 1 mol of FADH2 & 1 mol of
Acetyl CoA.
- Acetyl CoA used in Krebs
- NADH/FADH2 used in oxidative phosphorylation

152
Q

What is the difference in the fatty acid yield from 1 mol of glucose and 1 mol of fatty acid?

A

Fatty acid oxidation yields significantly more energy per carbon than the oxidation of glucose.

1 mol of glucose - 38 moles of ATP
1 mol of fatty acid - 146 moles of ATP

153
Q

Why don’t fatty acids act as a fuel source for the central nervous system

A

Fatty acids cannot get through the blood-brain barrier

154
Q

Where does oxidative phosphorylation occur

A

At the inner membrane of the mitochondria

155
Q

What is the role of the cytochrome-C oxidase complex in oxidative phosphorylation?

A

It transports H+ out of the mitochondrial matrix.

156
Q

What transports H+ out of the mitochondrial matrix?

A

Cytochrome-C oxidase complex.

157
Q

Name 4 ways in which ATP can be produced?

A
  • Krebs cycle.
  • Glycolysis.
  • Oxidative phosphorylation.
  • Substrate level phosphorylation.
158
Q

Oxidative phosphorylation: What enzyme transports protons into the mitochondrial matrix?

A

ATP synthase.

159
Q

Where does ketogenesis usually occur?

A

In the liver

160
Q

Why does ketogenesis occur?

A
  • high rates of fatty acid beta oxidation
  • exceed the capacity of krebs cycle
  • results in ketogenesis
161
Q

When would ketogenesis occur?

A

During high rates of fatty acid oxidation, too much acetyl CoA is produced; this overwhelms the Krebs cycle and so you get ketone body formation

162
Q

Briefly describe how diabetic ketoacidosis occurs?

A
  • reduced supply of glucose
  • leads to decline in insulin circulation
  • increase fatty acid oxidation
  • increased Acetyl-CoA leads to ketone body formation
  • exceeds ability for tissues to oxidise them
  • ketones are strong acids - lowers pH
163
Q

List 3 causes of metabolic acidosis?

A

Renal failure, loss of HCO3-, excess H+ production.

164
Q

List 2 causes of metabolic alkalosis.

A

Vomiting (loss of H+), increased reabsorption of HCO3-.

165
Q

What enzyme of glycolysis is inhibited in acidosis?

A

Phosphofructosekinase-1 (PFK-1 is pH dependent).

166
Q

Name 3 allosteric inhibitors of PFK-1.

A
  1. Acidosis.
  2. ATP.
  3. Citrate.
167
Q

Lipids have hydrophobic and hydrophilic parts. What is this called?

A

Amphipathic.

168
Q

State the ideal pH with ranges of blood

A

ideal pH 7.4 ( 7.35-7.45)

169
Q

What occurs in the first week of embryonic life?

A

Fertilisation and formation of the blastocyst [F for first =

fertilisation]

170
Q

What occurs in the second week of embryonic life?

A

Implantation and formation of bilaminar embryonic disc [2nd

week = 2 = bilaminar]

171
Q

What occurs in the third week of embryonic life?

A

Further development of the embryo and formation of trilaminar
embryonic disc [3rd week = 3 = trilaminar]

172
Q

What occurs in the fourth week of embryonic life?

A

Folding of the embryo [F for 4th = F for folding]

- from flat disk to cylinder

173
Q

What occurs in weeks 5-8 of embryonic life?

A

Development of all the organs

174
Q

What occurs at the end of the 8th week?

A

all organs have developed and the embryo looks like an

adult and is called a foetus

175
Q

What is the Morula?

A

Morula is a 16 cell structure arising from the fertilised ovum through mitosis
- floats freely in uterus, no nutrition as not implanted

176
Q

When does the Morula enter the uterus?

A

3-4th day after fertilisation

177
Q

When does implantation of the blastocyst occur?

A

end of the first week after fertilisation

178
Q

What is the blastocyst composed of?

A

Inner cell mass - becomes the embryo

Trophoblast - becomes the placenta

179
Q

What are the two spaces called that are present inside the blastocyst?

A

Amniotic cavity and yolk sac

180
Q

as the embryo grows there is a slight folding on the caudal ectoderm what is this called?

A

primitive streak

181
Q

What happens at the primitive streak?

A

The ectoderm cells break away and spill into the primitive streak under the ectoderm

182
Q

Where are the two areas where the ectoderm and the endoderm are not separated by the mesoderm.

A
    • the oropharyngeal membrane - forms the opening of mouth

- - The cloacal membrane - anus opening

183
Q

What does the ectoderm form?

A
  • PNS
  • CNS
  • Sweat glands
  • Posterior pituitary
  • Skin
  • Hair
  • Nails
  • enamel of teeth
  • lens of eyes
  • sensory epithelium of nose, ear and eye
184
Q

What does the endoderm form?

A
  • Epithelial lining of the GI tract, respiratory tract and urinary bladder
  • parenchyma of the thyroid gland parathyroid and liver and pancreas
  • epithelial lining of the tympanic cavity and auditory tube
185
Q

Name the three different components of the mesoderm?

A
  • Paraxial plate mesoderm
  • intermediate plate mesoderm
  • lateral plate mesoderm
186
Q

What does the paraxial plate mesoderm form?

A
  • Somites which give rise to:
    A. Myotome (muscle tissue)
    B. Sclerotome (cartilage and bone)
    C. Dermatome (dermis of the skin)
187
Q

What does the intermediate plate mesoderm form?

A

Urogenital system

  • gonads and respective duct systems
  • kidneys
188
Q

What does the lateral plate mesoderm form?

A

Two layers
1. Somatic (parietal) layer: forms the future body wall
2. Splanchnic (visceral) layer forms:
- Circulatory system
- Connective tissue for the glands
- Muscle, connective tissue and peritoneal components of the
way of the gut

189
Q

Describe Cranial flexion

A

Brings the oropharyngeal membrane, the cardiogenic area and septum transversum ventrally and brings heart into thoracic position and septum transversum to the diaphragm

190
Q

Describe caudal flexion

A

brings the
cloacal membrane onto the ventral
surface of the embryo

191
Q

What occurs during lateral folding

A 
- incorporation
of a portion of the yolk sac
(which is lined with
ENDODERM) into the embryo
to form the primitive gut
- It also leads to the formation of
body cavities
192
Q

Describe the boundaries of the primitive foregut, midgut and hindgut

A
  • Foregut: Extends from oropharyngeal membrane to the liver bud
  • Midgut: from liver bud to the end of the right 2/3 of transverse colon
  • Hindgut: from beginning left 1/3 of transverse colon to the cloacal
    membrane
193
Q

What is the name of the temporary connection between the yolk sac and the midgut?

A

Vitelline duct

Phase 1 Med (7 decks)

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