MD2001 Week 8 Flashcards
amount of Cl- extra and intracellularly
110mM extracellularly, 5mM intracellularly of this ion
amount of CHCO3- extra and intracellularly
27mM extracellularly, 10mM intracellularly of this ion
amount of Ca2+ extra and intracellularly
2mM extracellularly, minimal intracellularly of this ion
amount of Mg2+ extra and intracellularly
1mM extracellularly, 10mM intracellularly of this ion
pH extra and intracellularly
7.4 and 7.0 respectively
what is included in the permeability constant equation?
- mobility
- gas constant
- absolute temp
- membrane thickness
- partition coefficient
how does Na+ get pulled through voltage gate?
negatively charged amino acids pull this ion from its water shell so it is small enough to diffuse
how does K+ get pulled through its voltage gate?
carbonyl oxygens strip water from this ion so its small enough to pass this channel
structure of an aquaporin
- 6 trans-membrane alpha helices
- tri-amino acid motif (asparagine-proline-alanine)
- organized into a tetramer
how does vasopressin work?
this drug increases water re-adsorption in kidneys by up-regulation of AQP-2 channels (AQP-3 channels constant)
membrane of an ovum
zona pellucida
what happens when 8 cells are created in an ovum?
compaction occurs here
16+ cell ovum
morula
stage of embryo at 4.5 days
blastocyst: trophoblast and inner cell mass (embryo blast) + blastocoel + trophectoderm
when does blastocyst bind to uterus wall?
this occurs in embryological development at 5.5-6 days
how does the embryonic pole attach to the uterine wall?
anti-adhesion molecule MUC-1 is down regulated so that selectins on embryo bind to glyco-components on uterus
what three membrane proteins are involved in penetration of uterine wall by the embryo?
integrins, laminin, and fibronectin
what happens 1 week into embryological development?
- trophoblast differentiates into syncytiotrophoblast and cytotrophoblast
syncytiotrophoblast invades via MMPs - epiblast and hypoblast form
- amniotic cavity forms within epiblast
what happens 9 days into embryological development?
- spaces develop within syncitiotrophoblast
- hypoblast coats blastocoel to form primary yolk sac
- amnion formed
what happens 1.5 weeks into embryological development?
- chorionic cavity forms behind hypoblast
- blastocyst burrows completely into endometrium
- syncytiotrophoblasts erode capillaries which bleed into spaces
unsuccessful outcomes of human pregnancies and their likelihood
pre-implantation: 30%
post-implantation: 30%
miscarriage: 10%
teratogen
something that causes malformation of an embryo
effects of foetal alcohol spectrum disorder
- growth retardation
- CNS damage
- facial defects: cleft lip, small jaw, wide set eyes, dental/digit issues, small head, short
2 examples of primary active transport (other than Na+/K+) and where they are found
- Ca2+ ATPase transporter - cell membrane and sarcoplasmic reticulum
- H+ ATPase transporter - parietal cells of gastric glands (HCl secretion) and intercalated cells of renal tubules (control blood pH)
types of glucose transporters
GLUT1: placenta and brain GLUT2: transepithelial GLUT3: brain GLUT4: skeletal muscle (insulin dependent) GLUT5: intestinal absorption of fructose
example of a symporter
example of this type of active transport is sodium glucose linked transporter (SGLT)
Na+ to glucose uptake ratio of SLGT2
Na+ to glucose uptake ratio of this isoform is 1:1
which SGLT isoform is found in the intestine?
SGLT1 is found here
where are SGLTs commonly found?
these type of transporters are commonly found in kidney and intestines
what active transporter is found in every cell?
the Na+/K+ pump is found here
mass and power of an alpha subunit of Na+/K+ pump
100kDa, 100,000MW
what structure keeps cell membrane potential in nerve cells?
Na+/K+ pump maintains this in nerve cells
What are the Kms for Na+ and K+ w/ the pump respectively?
their Kms are 20mM and 1mM respectively
what does cardiac glycoside digoxin inhibit?
this drug inhibits K+ binding site n the Na+/K+ pump
equation for therapeutic index
dose producing toxicity in 50% of pop./minimum effective dose for 50% of pop.
Remifentanil
analgesia used during labour; high therapeutic index
therapeutic index of digoxin
its therapeutic index is 2:1
what do diuretics treat?
these drugs treat hypertension and oedema
what drug should not be given along with furosemide?
digoxin should not be given alongside this drug to prevent digoxin toxicity
antidote for digoxin toxicity
Digibind
K+ levels of hypokalaemia
K+ levels
K+ levels of hyperkalaemia
K+ levels >5.5mEq/L
symptoms of hypokalaemia
- abnormal herat rhythms
- muscle damage
- muscle weakness or spasms
- paralysis
furosemide
a common diuretic
symptoms of hyperkalaemia
- nausea
- palpitations
- muscle weakness
device to record membrane potentials
oscilloscope
steps of an action potential
- depolarization reaches threshold
- depolarization increases PNa+ and PK+
- PNa+ shoots up, causing depolarization to +30mV
- PNa+ decreases and potential depolarizes while PK+ increases
- PK+ decreases and membrane potential goes back to rest
what structure on the epiblast defines the anterior?
anterior visceral endoderm
these cells migrate into the primitive streak to form mesoderm and replace hypoblast cells to form endoderm
epiblast cells migrate through this structure to form mesoderm and endoderm
- segments of mesoderm
- paraxial
- intermediate
- lateral
how are somites made?
notch signalling forms these with FGF signal working on a 90min cycle
what forms in front of the primitive node b/w the two layers?
notochord forms here
what growth factor is key in neurulation?
bone morphogenic protein
what does the notochord release to block BMP effects and develop back/neural tissue instead? (3)
- chordin
- noggin
- follistatin
Spemann and Mangold’s experiment
experiment where double node makes double dorsum
why type of epithelium is neurectoderm made of?
this embryological structure is made of columnar epithelium
what happens at week 4 of embryological development?
neural tube fuses at this point of embryological development
2 neural tube defects
- anencephaly (rostral neuropore)
2. spina bifida (caudal neuropore_
what do neural crest cells differentiate into?
- cranial nerve ganglia
- dorsal root ganglia
- autonomic ganglia
- adrenal medulla
- Schwann cells
- craniofacial skeleton
- parafollicular (C) cells
- melanocytes
etc.
2 neural crest disorders
- Waardenburg’s syndrome
2. teacher collins syndrome
how is the gut formed in embryological development?
amniotic cavity cuts off part of yolk sac which becomes this
Meckels diverticulum
remnants of the vitelline duct (yolk sac/gut connection)
outline the scientific method
- observation/experiment
- explanation
- prediction
- experimentation
- confirmation of hypothesis
- peer review
- publication
types of primary studies
- direct experimentation (in vitro/vivo)
- clinical trials
- surveys
types of secondary studies
- review
- systematic review (includes all primary research studies)
- meta-analysis (includes data from all studies)
selective toxicity
method where drugs are toxic to antigen but harmless to host
antibiotics active against bacterial cell membrane and their mechanisms (5)
- beta-lactam and cephalosporin: prevent PGN cross-linking
- glycopeptide: prevent transglycol/peptidation
- cyclic peptide: prevent PGN from exiting membrane
- phosphonic acid: inhibit first stage of PGN synthesis
- lipopeptides: Ca2+-dependent membran depolarisation
dimer of PGN
N-acetylglucoseamine + N-acetylmuramic acid
beta-lactamase resistant penicillins (5)
- methicillin
- oxacillin
- nafcillin
- cloxacillin
- dicloxacillin
2 parenteral cephalospores
- cefuroxime
2. cefotaxime
2 bacterial folate antagonists
- sulphonamide
2. trimethoprim
example of selective toxicity
bacterial folate antagonists are an example of this antibiotic method
how do amino glycosides work?
they inhibit protein synthesis by binding to bacterial ribosome and preventing mRNA reading
how do tetracyclines work?
they prevent tRNA from attaching to ribosome
these three antibiotics prevent association of peptidyl-transferase w/ amino acid
chloramphenicol, erythromycin, and clindamycin do this
how does fluoroquinolone work?
inhibits bacterial DNA topoisomerase II (DNA gyrate), which is used to unwind DNA for transcription
3 broad-spectrum fluoroquinolone
- ciprofloxacin
- ofloxacin
- norfloxacin
2 narrow-spectrum drugs
- cinoxacin
2. nalidixic acid
original Nernst equation
Ex = [RT/zF]lnblablabla