IMMS Flashcards
1
Q
What is a Karyotype?
A
number and appearance of chromosomes in a cell
2
Q
Each chromosome contains a DNA duplex of roughly how many base pairs?
A
10^7
3
Q
What is the letter for the short arm of the chromosome?
A
p
4
Q
What is the letter for the long arm of the chromosome?
A
q
5
Q
What are the long and short arms of a chromosome separated by?
A
centromere
6
Q
How many genes are there roughly in humans?
A
22,000
7
Q
What does mitosis produce and what is the purpose of it?
A
produces 2 daughter cells that are genetically identical to parent cells. Growth and replace dead cells
8
Q
What is the term given to cells: not in replication, during replication and after replication?
A
chromatin, chromosomes, chromatids
9
Q
What 4 things occur in G1 stage of interphase?
A
rapid growth
normal metabolic function
new organelles produced
protein synthesis of proteins involved in spindle formation
10
Q
What 3 things happen during synthesis stage of interphase?
A
DNA doubles through DNA replication
Histone proteins double through protein synthesis
Centrosome replication
11
Q
What 3 things happen during G2 stage of interphase?
A
Chromosomes condense
Energy stores accumulate
Mitochondria and centrioles double
12
Q
What 2 things happen during Prophase?
A
chromatin condenses into chromosomes
centrosomes nucleate microtubules and move to opposite poles of nucleus
13
Q
What 4 things happen during Prometaphase?
A
nuclear membrane breaks down
microtubules invade nuclear space
chromatids attach to microtubules
cell no longer has a nucleus
14
Q
What happens in metaphase?
A
chromosomes line up along equatorial plane
15
Q
What happens in anaphase?
A
sister chromatids separate and are pushed to opposite poles of the cells, centromere first, as spindle fibres contract
16
Q
What 3 things happen during Telophase?
A
nuclear membrane reforms
chromosomes unfold into chromatin
cytokinesis begins
17
Q
What 2 things happen during Cytokinesis?
A
cell organelle become evenly distributed around each nucleus
cell divides into two daughter cells with a nucleus in each
18
Q
What are 5 differences of meiosis compared to mitosis?
A
only in gametes
recombination of genetic material results in genetic diversity
2 cell divisions
4 haploid cells produced which are genetically distinct from each other and parent cell
not a cycle
19
Q
What happens in meiosis 1?
A
chromosome number is halved
20
Q
How and when is genetic diversity created in meiosis 1?
A
Crossing over between non-sister chromatids in Prophase 1
Random assortment on the metaphase plate in Metaphase 1
21
Q
What happens in Meiosis 2?
A
Sister chromatids separate
Haploid cells are produced
22
Q
How are spermatogonia formed?
A
lots of mitoses from primordial germ cells
23
Q
How many sperm per ejaculate?
A
100/200 million
24
Q
How are oogonia produced?
A
30 mitoses from primordial germ cell
25
When do oogonia enter prophase 1 of meiosis?
8th month of intrauterine life
26
how does the cytoplasm divide for female gametogenesis?
unequally, forms 1 egg and 3 polar bodies that apoptose
27
When are meiosis 1 and 2 completed?
meiosis 1 is completed at ovulation
| meiosis 2 is only completed if fertilisation occurs
28
What are 2 problems with meiosis?
Non disjunction
| Gonadal mosaicism
29
What is non-disjunction?
failure of chromosome pairs to separate in meiosis 1 or sister chromatids to separate properly in meiosis 2
30
What is Gonadal Mosaicism?
occurs when precursor germline cells to ova or spermatozoa are a mixture of 2 or more genetically different cell lines
31
What are the 3 main causes of disease?
Genetic
Multifactorial
Environmental
32
What is the locus?
the position of a gene/DNA on the genetic map
33
What is polymorphism?
frequent hereditary variations at a locus
34
What is consanguinity?
reproductive union between 2 relatives
35
What is autozygosity?
homozygous by descent, inheritance of the same mutant allele through 2 branches of the same family
36
What is hemizygous?
gene that is carried on an unpaired chromosome
37
What is Penetrance?
proportion of people with a gene/genoptype who show the expected phenotype
38
What is lyonisation?
the process of X chromosome inactivation
39
What is the function of the nucleus?
houses DNA in the form of chromatin within the nucleolus
40
What is the function of mitochondria?
site of oxidative phosphorylation
41
What is the outer and inner membrane of mitochondria the site of?
```
outer = lipid synthesis and fatty acid metabolism
inner = respiratory chain ATP production
```
42
What is the matrix and intramembranous space of the mitochondria the site of?
matrix = tricarboxylic acid (Krebs) cycle
| intramembranous space = nucleotide phosphorylation
43
What is the structure and function of rough endoplasmic reticulum?
highly folded flattened membrane sheets
| site of protein synthesis
44
What is the structure and function of smooth endoplasmic reticulum?
highly folded flattened membrane sheets
| sit of membrane lipid synthesis, processes and stores synthesised proteins
45
What is the structure and function of golgi (cis medial and trans)?
parallel stacks of membrane
Cis receives smooth endoplasmic reticulum vesicles - protein phosphorylation occurs
Medial modifies products by adding sugars, forms complex oligosaccharides by adding sugars to lipids and peptides
Trans proteolysis of peptides into active forms and sprting of molecules into vesicles which bud from the surface
46
Function of lysosomes?
contain digestive enzymes breakdown for most molecules
47
Function of peroxisomes?
contain enzymes that oxidase long chain fatty acids
| produce hydrogen peroxide which can be used to destroy pathogens
48
What is lipofuscin?
membrane bound orange-brown pigment, peroxidations of lipids in older cells, common in heart and liver
49
What are oligosaccharides?
3-12 monosaccharides
50
What are proteoglycans?
long, unbranched polysaccharides radiating from a core protein
51
What are the properties of peptide bonds?
very stable
cleaved by proteolytic enzymes
can have partial double bonds
flexibility around C atoms not involved in bond thus allows multiple conformations
52
What is the primary structure of a protein?
linear sequence of amino acids held together by covalent bonds
53
What is the secondary structure of a protein?
alpha helix - h bonds between each carbonyl group
| beta pleated sheet - h bonds between linear regions of polypeptide chains
54
What is the tertiary structure of a protein?
electrostatic, hydrogen and covalent bonding
| folding into a globular structure
55
What is the quaternary structure of a protein?
2 or more tertiary structures joined together to form a protein
56
What is an isoenzyme?
enzymes that have a different structure and sequence but catalyse the same reaction
57
What is a coenzyme?
cannot themselves catalyse a reaction but bind to an enzyme to activate it
58
What are activation-transfer coenzymes?
form a covalent bond and are regenerated at the end of the reaction
59
What are oxidation-reduction coenzymes?
electrons are transferred from one compound to the other
60
What is myoglobin?
found in the muscle, serves as a reserve supply of oxygen and facilitates the movement of O2 in muscles
61
In which direction is DNA synthesised and why?
5'to3' as DNA polymerase reads template strand from 3'to5'
62
What enzymes are involved in DNA replication?
```
Topoisomerase
DNA helicase
DNA polymerase
Primase enzyme
RNAse H
```
63
What is the role of topoisomerase in DNA replication?
unwinds the double helix by relieving the supercoils
64
What is the role of DNA helicase in DNA replication?
separates the DNA apart by breaking hydrogen bonds between bases, exposing nucleotides
65
What is the role of the primer in DNA replication?
short strand of DNA that us the start point for DNA synthesis
66
What is the role of the single strand binding protein in DNA replication?
keeps 2 strands of DNA apart whilst synthesis of DNA occurs, prevents annealing to form double stranded DNA
67
What is the role of primase enzyme in DNA replication?
RNA polymerase that synthesises the short RNA primers needed to start the strand replication process
68
What is the role of RNAse H?
removes the RNA primers that previously began the DNA strand synthesis
69
Where is the promotor region?
5' of the 1st exon
70
When mRNA leaves the nucleus what type ribosome does it attach to?
80s
71
What is exon shuffling and what does it allow?
exons are not in the same order allows huge variants of antibodies to be produced
72
What does degenerate but unambiguous mean?
many amino acids specified by more than one codon but each codon specifies only one amino acid
73
What 3 factors can turn off gene expression?
activation of repressors
enzymes no longer activated
transcription and processing proteins required for RNA transcription and or processing are no longer produced
74
What is a mis-sense mutation?
single nucleotide change results in a codon that codes for a different amino acid
75
What is a non-sense mutation?
mutation that produces a stop codon resulting in an incomplete usually non-functional protein
76
What is a splice-site mutation?
affects the accurate removal of an intron
77
What is expansion of a tri-nucleotide repeat and what happens in Huntingtons?
normal range of repeats in first part of coding sequence is 15-20. repeats larger than 36 of CAG patient develops Huntingtons. More repeats=earlier onset
78
What is Anticipation?
repeats get bigger when they are passed onto next generation resulting in earlier symptoms of greater severity
79
What is Homeostasis?
property of a system in which variables are regulated so that internal conditions remain stable and relatively constant
80
What happens in Autocrine secretion?
chemical is released from cell into the extracellular fluid and then acts upon the very cell that secreted it
81
What happens in Paracrine secretion?
chemical messengers involved in the communication between cells, released into extracellular fluid, travel short distances, local communication
82
What happens in Endocrine secretion?
production and secretion of hormones into blood, travel longer distances, systemic communication, can affect the whole body
83
What happens in Exocrine secretion?
secretion into ducts then into organ
84
What are the 3 classified types of hormones?
Peptide
Steroid
Amino-acid derivative
85
Explain properties of peptide hormones?
- made from short chain amino acids
- vary in size
- some have carbohydrate side chains
- large, hydrophilic charged molecules that cannot diffuse across a membrane
- bind to receptors on membranes
- fast response
86
Explain properties of steroid hormones?
- synthesised from cholesterol
- water insoluble and lipid soluble
- cross membranes but requires transport proteins in blood
- targets an intracellular receptor
- slow response
87
Explain properties of amino-acid derivative hormones?
- synthesises from tyrosine
| - acts in same way to peptide hormones
88
What is the predominant electrolyte in Intracellular Fluid?
potassium
89
What are the 4 predominant electrolytes in Extracellular Fluid?
sodium, chloride, bicarbonate and Ca2+ (especially in heart and muscle)
90
What is transcellular?
makes up the CSF, digestive juices and mucus
91
What is the total body water/percentage of bodyweight?
42L (approx 60%)
92
What volume/percent of body weight is Intracellular fluid?
28L/40%
93
What volume/percent of body weight is Extracellular fluid?
14L/20%
94
What are the 3 components of Extracellular fluid?
interstitial
plasma
transcellular
95
What volume of 14L extracellular fluid is Interstitial, Plasma, and Transcellular?
```
Interstitial = 10L
Plasma = 3L
Transcellular = 1L
```
96
What is osmosis?
net movement of solvent molecules through a semipermeable membrane to a higher solute concentration
97
What is Osmolality?
measure of the number of dissolved particles per kg of fluid
98
What is Osmolarity?
measure of the number of dissolved particles per L of fluid
99
What is Osmotic pressure?
pressure applied to a solution, by a pure solvent, required to prevent inward osmosis through a semipermeable membrane
100
What is Oncotic pressure?
form of osmotic pressure exerted by protein that tends to pull fluid into its solution - water moves from interstitial fluid into plasma
101
What is Hydrostatic pressure?
pressure difference between capillary blood and interstitial (water and solutes move from plasma into interstitial fluid)
102
What happens when water is lost from ECF?
- change detected by osmoreceptors in the hypothalamus
- ADH/vasopressin release from posterior pituitary
- ADH acts to increase water reabsorption in the collecting ducts of the kidney
103
What happens when there is decreased renal blood flow?
- decrease in water in ECF
- release of renin from the juxtaglomerular kidney cells
- renin converts angiotensinogen to angiotensin I
- angiotensin converting enzyme then converts angiotensin I to angiotensin II
- triggers release of aldosterone from adrenal cortex above kidneys
- angiotensin II and aldosterone increase Na+ reabsorption in kidneys in exchange for potassium or hydrogen excretion
- stimulates ADH release
104
What are the consequences of dehydration?
thirst, dry mouth, inelastic skin, sunken eyes, raised haematocrit, weight loss, confusion and hypotension
105
What are the consequences of water excess?
hyponatraemia, cerebral over-perfusion
106
What is oedema?
excess water in the intercellular tissue space
107
What are the causes of Hypernatraemia?
renal failure, mineralocorticoid excess, osmotic diuresis, diabetes insipidus
108
What are the consequences of Hypernatraemia?
cerebral intracellular dehydration
109
What are the causes of Hyponatraemia?
diuresis, Addisons disease, excess IV fluids and oedema
110
What are the consequences of Hyponatraemia?
intracellular over hydration, hypotension
111
What is Hyperkalaemia?
high potassium
112
What are the causes of hyperkalaemia?
renal failure, diuretics, acidosis
113
What are the consequences of hyperhalaemia?
risk of myocardial infarction
114
What are the causes of hypokalaemia?
diarrhoea, vomiting, alkalosis, hypomagnesaemia
115
What are the consequences of hypokalaemia?
weakness and cardiac dysrhythmia
116
What is Hypercalcaemia?
high calcium
117
What are the causes of Hypercalcaemia?
primary hyperparathyroidism, skeletal metastases, vitamin D toxicity and TB
118
What are the consequences of Hypercalcaemia?
metastatic calcification and kidney stones
119
What are the causes of Hypocalcaemia?
vitamin D deficiency, magnesium deficiency, renal disease, parathyroidectomy and intestinal malabsorption
120
What are the consequences of Hypocalcaemia?
tetany
121
What are glycolipids for in the phospholipid bilayer?
communication, join cells to form tissues and stability
122
What are glycoproteins for in the phospholipid bilayer?
cell to cell recognition, act as receptors
123
What is cholesterol for in the phospholipid bilayer?
maintains fluidity
124
What is the main function of the cell membrane?
act as a selective barrier to the passage of molecules, allowing some molecules to cross whilst excluding others
125
What is the occluding function of the cell membrane?
tight junctions help seal cells together to prevent leakage of molecules
126
What is the anchoring function of the cell membrane?
Actin filaments enable cell to cell adhesion through adherens.
Intermediate filaments enable cell to cell adhesion through desmosomes
127
What is endocytosis?
energetic process to absorb/engluf molecules into a cell
128
What is pinocytosis?
drinking
129
How many kcal/g do carbohydrates, proteins, alcohol and lipids give?
4,4,7,9
130
What is the Basal metabolic rate?
amount of energy needed to keep the body alive in the state
131
What are some factors that increase BMR?
```
high BMI
hyperthyroidism
low ambient temperature
fever/infection
pregnancy
exercise
```
132
What are some factors that decrease BMR?
age
gender (lower for female)
starvation
hypothyroidism
133
What is Daily energy expenditure?
energy to support our BMR and our physical activity + energy required to process food we eat
134
What is a kinase enzyme?
enzyme that adds/removes phosphate group to things from an ATP
135
What is an isomerase enzyme?
enzyme that rearranges structure of substrate without changing the molecular formula
136
What is an aldolase enzyme?
enzyme that creates or breaks carbon-carbon bonds
137
What is a dehydrogenase enzyme?
enzyme that moves hydride ion to an electron acceptor
138
What is an enolase?
enzyme that produces a carbon=carbon double bond by removing a hydroxyl group
139
What happens to the lactate produced in anaerobic respiration?
Released into blood, taken up by brain and heart and converted back to pyruvate.
Taken up by liver where it is sued as a precursor for the formation of glucose
140
Why is glycolysis inhibited in acidosis?
Phosphofructokinase-1 is pH dependant and is inhibited by acidic conditions
141
How does ketogenesis occur?
high rates of fatty acids oxidation primarily in the liver, large amounts of acetyl-CoA generated. Exceed Krebs and synthesise of ketone bodies
142
What are reactive oxygen species (ROS)?
highly reactive oxygen containing compounds that are free radicals (single unpaired electron)
143
What is the formation of ROS?
oxygen reduced by single electron to superoxide. Superoxide reduced to hydrogen peroxide. Hydrogen peroxide reduced to hydroxyl radical which is further reduced to water
144
What is superoxide dismutase?
converts superoxide to hydrogen peroxide and oxygen
145
What is the role of Catalase in ROS formation?
catalyses conversion of hydrogen peroxide to water and oxygen, and protects white blood cells against own respiratory burst
146
What is the role of Glutathione Peroxidase?
catalyses the reduction of hydrogen peroxide to water and a disulphide
147
What are the 3 systems involved in control of hydrogen ion concentration?
Blood and tissue buffering
Excretion of CO2 by the lungs
Renal excretion of H+ and regeneration of HCO3-
148
What are the 3 body buffer systems?
Bicarbonate, Proteins and Haemoglobin
149
Why is bicarbonate an important buffer?
removes CO2 from lungs and bicarbonate is regenerated by kidneys
150
How are proteins buffers?
albumin contains weak acidic and basic group within structure. intracellular proteins limit pH changes within cells. Protein matrix of bone buffers large amounts of H+ ion in patients with chronic acidosis
151
How is haemoglobin a buffer?
binds to CO2 and H+, deoxygenated haemoglobin had the strongest affinity
152
What is respiratory acidosis?
when PaCO2 is above upper limit of normal (greater than 6kPa)
153
What is the most common cause of respiratory acidosis?
decreased alveolar ventilation causing decreased excretion of CO2
154
What is respiratory alkalosis?
excessive excretion of CO2 when PaCO2 is less than 4.5kPa
155
What is the most common cause of respiratory alkalosis?
hyperventilation due to anxiety
156
What is metabolic acidosis?
excess of acid due to increased production of organic acids or reduced buffering capacity due to low concentration of bicarbonate
157
What causes the excess H+ concentration in metabolic acidosis?
tissue hypoxia
158
What are some of the reasons tissue hypoxia occurs?
- reduced arterial oxygen content (anaemia)
- hypoperfusion
- reduced ability to use oxygen as a substrate (cyanide poisoning)
159
How is diabetic ketoacidosis another form of metabolic acidosis?
production of ketone bodies release H+ ions
160
What is metabolic alkalosis?
excessive loss of H+ ions, the excessive reabsorption of bicarbonate or the ingestion of alkalis
161
What can cause excess H+ loss that could then lead to metabolic alkalosis?
loss of gastric secretions such as prolonged vomiting or pyloric stenosis
162
What is the anion gap and the equation for it?
difference in serum concentrations of cations and anions
| Na+K - HCO3+CL
163
What is a normal range for anion gap value?
between 3-11mEq/mol
164
When does an embryo become a foetus?
at the end of week 8
kidneys, liver, brain and lungs beginning to function.
fingers and toes are separate and the external genitalia are formed
165
What is the infundibulum?
part of the fallopian tube with associated fimbriae located near the ovaries
166
What is the ampulla of the fallopian tube?
widest part of the tube, represents the major portion of the lateral tube
167
What is the isthmus part of the fallopian tube
narrower part of the tube that links to the uterus
168
What is the tubal ostium of the fallopian tube?
point where the tubal canal meet the peritoneal cavity
169
What happens to the primary follicles that grow in each ovarian cycle?
number of them begin to grow but usually only one (the dominant follicle) reaches full maturity and only 1 oocyte is discharged at ovulation
170
How is ovulation initiated?
through a surge in LH from the pituitary gland
171
Where does fertilisation take place?
in the fallopian tube, at the junction of the ampulla and the isthmus
172
What happens during the 1st week of the embryonic period?
fertilisation and formation of the blastocyst
173
What happens during the 2nd week of the embryonic period?
implantation and formation of bilaminar embryonic disc
174
What happens during the 3rd week of the embryonic period?
further development of the embryo and formation of trilaminar embryonic disc
175
What happens during the 4th week of the embryonic period?
folding of the embryo
176
What happens from the 5th to the end of the 8th week of the embryonic period?
development of all organs
177
What will happen to the fertilised ovum (zygote) after it undergoes rapid mitotic divisions?
produces a 16 cell morula that enter the uterus on the 3rd or 4th day after fertilisation, a cavity begins to appear and the blastocyst forms
178
What happens to the cells of the blastocyst?
differentiate into 2 cell masses. Inner cell mass = embryoblast. outercell mass = trophoblast
179
What happens to the embryoblast?
differentiates into to layers
- epiblast
- hypoblast
these 2 layers form a flast disc - bilaminar disc
180
What does the epiblast produce?
amnioblasts that line the amniotic cavity superior to the epiblast layer
181
What does the hypoblast produce?
cells that line the blastocyst cavity and the inner surface of the trophoblast which form the exocoelomic membrane (primitive yolk sac)
182
What happens to the trophoblast?
differentiates into cytotrophoblast and syncytiotrophoblast
183
What is the role of lacunae and when/where are they formed?
day 9, develop in the syncytiotrophoblast resulting in maternal sinusoids being eroded so maternal blood can enter the lacunar network and a primitive utero-placental circulation is established
184
How is the extraembryonic mesoderm formed?
new cells appear between inner surface of cytotrophoblast and outer surface of exocoelomic membrane of yolk sac, form a fine, loose connective tissue
185
What happens in the extraembryonic mesoderm?
large cavities develop forming the chorionic cavity. Mesoderm forms 2 layers - splanchnopleuric and somatopleuric. responsible for formation of blood vessels that will connect the embryo to the placenta
186
What are endodermal cells and how are they formed?
in the hypoblast, migrate along inside of the exocoelomic membrane, proliferate gradually and form a new cavity - the secondary yolk sac (definitive yolk sac)
187
What is the connecting stalk and where is it formed?
formed on further development of the trophoblast, contains capillaries which are connected to the chorionic plate (extraembryonic mesoderm) and the embryo
188
How is the formation of placenta initiated?
chorion membrane between foetus and mother, formed by extraembryonic mesoderm and 2 layers of trophoblast. chronic villi emerge from chorion and invade endometrium and allow transfer of nutrients from maternal to fetal blood
189
What is gastrulation?
embryoblast develops into a trilaminar structure known as the gastrula, occurs during the 3rd week
190
What are the 3 germ layers called?
- ectoderm
- mesoderm
- endoderm
191
How does gastrulation begin?
The primitive streak appears on the dorsal mid-sagittal surface of the epiblast
192
What gives rise to the mesoderm and what is the process called?
cells of epiblast migrate towards the primitive streak, detach from epiblast and slip beneath it - invagination
193
What gives rise to the endoderm?
invaginating cells that displace the hypoblast
194
What gives rice to the ectoderm?
the remaining epiblast
195
How is the notochord formed and what does this later become?
Prenotochordal cells invaginating in the node of the primitive streak
The notochord forms a midline axis which serves as the basis of the axial skeleton
196
What structures does the ectoderm give rise to?
- central nervous system
- peripheral nervous system
- sensory epithelium of nose, ears and eyes
- epidermis of skin, hair and nails
- pituitary, mammary and sweat glands
- enamel of teeth
197
What are the 3 parts of the mesoderm?
- paraxial plate
- intermediate plate
- lateral plate
198
What structures does the paraxial plate give rise to?
- somites (supporting tissue of the body)
199
What are the 3 types of somites?
- myotome (muscle tissue)
- sclerotome (cartilage and bone)
- dermatome (dermis of the skin)
200
What structures does the intermediate plate give rise to?
- kidneys
| - gonads and their respective duct systems
201
Where is the lateral plate mesoderm found?
periphery of the embryo
202
What are the 2 layers the lateral plate mesoderm splits into?
- somatic (parietal) layer
| - splanchnic (visceral)
203
What does the somatic layer of the lateral plate mesoderm form?
future body wall
204
What does the splanchnic layer of the lateral plate mesoderm form?
- circulatory system
- connective tissue for the glands
- muscle, connective tissue and peritoneal components of the gut
205
What structures does the endoderm give rise to?
- epithelial lining of the GI tract, respiratory tract and urinary bladder
- parenchyma of the thyroid gland, parathyroid gland, liver and pancreas
- epithelial lining of the tympanic cavity and auditory tube
206
At the beginning of the 4th week, what do somites differentiate into?
myotomes
sclerotomes
dermatomes
207
What is the oropharyngeal membrane?
located at cranial end of the embryonic disc, consists of tightly adherent ectoderm and endoderm cells
208
Where is the cloacal membrane formed?
caudal end of the embryonic disc
209
What does the cloacal membrane consist of?
tightly adherent ectoderm and endoderm cells
210
What happens when the cloacal membrane appears?
the posterior wall of the yolk sac forms a small diverticulum, the Allantois which extends into the connecting stalk
211
What does the cranial area contain?
oropharyngeal membrane, cardiogenic area and septum transversum
212
What is cranial flexion?
brings together the oropharyngeal membrane, cardiogenic area and septum transversum ventrally, forming the ventral surface of future face, neck and chest
213
What is caudal flexion?
brings the cloacal membrane onto the ventral surface of the embryo
214
What is lateral folding?
results in the incorporation of a portion of the yolk sac into the embryo to form the primitive gut
215
What is the primitive gut?
blind-ended tube that divides into the foregut, midgut and hindgut
216
What happens to the midgut?
remains connected temporarily to the yolk sac by the vitelline duct
217
Where is the foregut in the primitive gut?
extends from the oropharyngeal membrane tp the liver bud
218
Where is the midgut in the primitive gut?
from the liver bud to the end of the right 2/3 of the transverse colon
219
Where is the hindgut in the primitive gut?
from the beginning left 1/3 of the transverse colon to the cloacal membrane
