Quick fact. Ready?
Children are far more sensitive when it comes to absorption of heavy metals into the body upon exposure, especially when on an empty stomach. This is why lead poisoning is such a major concern for those with children in the family.

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hello my finals are next week and this is what i have been up to in the past couple of weeks… actually studying… lol…
(studying and getting my heart pulled back into haikyuu hEAVEN HELP ME I LOVE OIKAWA TOORU)
on another note, i got my results back for my second anthropology midterm and ya girl got an A+!! now if only i could get those kinds of grades in physiology and microbio 🤔

Saturday, March 11 (2017)

I’m trying to get better at studying regularly and have a more structured approach. So instead of telling myself that I have x amount of time to study physiology, I’ll write down specific topics and try to master them. Since I like to go into details and really understand the concepts, I have to set some time limits. Otherwise, I’ll just run out of time and get panicky. Also, I have to remind myself more often that I don’t study for grades but to master the topics, and a comparison is the thief of joy.

Neurotransmitters

Central nervous system

  • Glutamate 
  • GABA 
  • Glycine 
  • Dopamine 
  • Serotonin 
  • Noradrenaline 
  • Histamine 
  • Orexin 
  • Endorphins 

Peripheral nervous system 

  • Noradrenaline 
  • Acetylcholine 

Neurotransmitter synthesis/packaging 

  • Some neurotransmitters are readily available amino acids eg Glutamate, glycine 
  • Some are synthesised by the cells that secrete them eg GABA, noradrenaline, dopamine 

Noradrenaline synthesis:

Packaging

  • In the presynapse, neurotransmitter is contained in vesicles 
  • The neurotransmitter must be packaged into the vesicle ready for release 
  • Uses transporters and proton gradients to package 

[packaging and release - above]

  • Neurotransmitter release is quantal – Each vesicle contains the same amount of neurotransmitter 
  • Therefore it is the number of vesicles fusing which determines the post synaptic potentials 
  • membranes must fuse for release - membrane fusion is energetically unfavourable so must be catalysed by something

SNARE Hypothesis 

  • Proteins on the presynaptic membrane ‘grab’ proteins on the vesicle membrane 
  • These SNARE proteins pull the two membranes close together 
  • SNARE proteins provide most of the energy for membrane fusion
  • v-SNARE (VAMP2) – on vesicle membrane 
  • t-SNAREs (syntaxin1A, SNAP-25) on target membrane 
  • Bind together to make SNARE complex 
  •  SNARE ‘zippering’ forces the membranes close together 
  • Spontaneous, highly energetically favourable 
  • Once assembled, they require ATP hydrolysis to separate them 
  •  Ca2+ binding to synaptotagmin provides extra energy to fuse the membranes

Neurotransmitter release

  • synaptic vesicle release sites are highly organised and regulated
  • exocytose into synaptic cleft

presynaptic active zone:


Neurotransmitter detection

  • Ionotropic (ion channel coupled) – Glutamate, GABA, Glycine 
  • Metabotropic (G-protein coupled) – monoamines, histamine etc. 
  • Some have both kinds, e.g. glutamate, GABA 
  • Ionotropic responses are faster 
  • Metabotropic responses can have more diverse effects 

Glutamate receptors

  • Glutamate is the main excitatory neurotransmitter in the brain 
  • Three classes of ionotropic receptor – AMPA – NMDA – Kainate 
  •  Named after pharmacological agonists 
  • All let in positive ions when they bind glutamate 
  • Glutamate also has a family of metabotropic receptors – mGluRs – These modulate neurotransmission 

AMPA Receptors 

  •  Main fast excitatory receptor 
  • Strength of a synapse is largely determined by its complement of AMPARs
  •  More AMPAR in the post-synaptic membrane = stronger synaptic transmission 

NMDA Receptors 

  • Minor role in postsynaptic firing 
  • Major role is in synaptic plasticity 
  • NMDA receptors are calcium permeable 
  • require strong neurotransmitter release to open 
Pregnancy - physiology

Hormones

  • hCG - human chorionic gonadotropin - present in blood and urine, produced by blastocyst and placenta
  • Low levels of hCG could mean miscarriage, ectopic pregnancy, miscalculation of dates
  • High levels = molar pregnancy (cells that normally form a baby dysfunction and form cysts instead), multiple pregnancy (twins etc), miscalculation of dates
  • Progesterone increases fat deposition in early weeks and stimulates appetite
  • Increased oestrogen from corpus luteum promotes mammary gland development (breasts enlarge)
  • And inhibits ovulation via negative feedback [OES decreases GnRH release by hypothalamus –> linhibition of FHS and LH –> no ovulation]
  • Relaxin (secreted by corpus luteum) softens connective tissue in preparation for labour - not specific, all joints can be affected
  • Peaks in early and late pregnancy

Physical changes

Blood pressure

  • As early as 4 weeks into pregnancy 
  • plasma volume increase
  • caused by the affects of oestrogen and progesterone on the kidneys

OES and Prg cause vasodilation 

  • less resistance = less pressure
  • Heart rate increases by 25% to compensate
  • stroke volume increases 
  • increased overall cardiac output by 50% in third trimester

Direct action of enlarged uterus:

  • compresses the descending aorta and inferior vena cava 
  • decreased venous return - less blood in means less blood out, less blood in ventricle –> reduced pressure on walls –> reduced force to exit –> reduced placental perfusion
  • increased aortic pressure
  • increased heart rate
  • [shouldn’t sleep on back for this reason]

Outcomes:

  • Fall in blood pressure (can cause collapse if serious)
  • Can cause foetal hypoxia even without mother symptoms

Haematological changes

  • red cell mass increase by 20% (renal - increased erythropoietin production in response to detection of blood oxygenation and sodium/water balance)
  • Plasma volume increases more than RBC count does, causing the impression of decreased haemoglobin (anaemia)
  • Increased tendency to clot (hypercoagulable)
  • due to increase in clotting factors and plasma fibrinogen
  • platelet production increase (however count drops due to increase in activity and consumption) - function remains normal]
  • WBC count may increase due to an increase in granulocytes

Respiratory changes

  • Increased chest diameter, diaphragmatic expression and elevation
  • dyspnoea common (difficulty breathing)
  • breathing becomes more costal (mouth) than abdominal 
  • mainly mediated by progesterone levels (cause bronchial and smooth muscle relaxation and hypersensitivity to CO2)

Changes to the urinary system

  • cardiac output increase –> increase in renal plasma flow and glomerular filtration
  • increase in urea, creatinine, urate and biocarbonate clearance 
  • with progesterone, renin and aldosterone up water retention increases
  • can lead to urinary stasis and increased risk of UTI
  • Any drugs given that are excreted renally must be given in much higher quantities consequently

Gastrointestinal changes

  • Appetite increase + cravings 
  • Gastric reflux sphincter relaxation (increased indigestion, also due to increased intra-gastric pressure (expanding uterus)) 
  • gallbladder dilated 
  • GI motility decreased and transit time slower 
  • albumin and protein decrease 
  • cholesterol twice normal value

Muskuloskeletal 

  • Calcium reuptake into bloodstream results in mild decalcification of bones 
  • relaxin softens joints (pubic symphysis + alters gait (waddling))
  • abdominal muscles stretch to elastic limit 
  • stretch marks (stria gravidarum) caused by rupture of elastic fibres and small blood vessels 

Reproductive changes

  • Massive increase in mass
  • Placenta growth (nutrition, excretion, immunity, endocrine) 

Parental blood supply 

In all aspects of life, the body and mind are constantly adapting. Our muscles become stronger with continuous contractions. Our minds become more resilient against reoccurring stressors. Our immune system learns to react faster to incoming bacteria. Humans are astounding, really. We are so completely flexible towards improvement, not only physically, but mentally as well.

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25.02.16 | Spending whole day with physiology 📚✨

Like I mentioned before, I have a huge physiology exam next week, so I really need to study hard this weekend. Truth be told, it’s not going great, but at this point I don’t have time for panicking and all I can do is revise as much as I’ll manage- hope it’ll be enough.

Hope you all have a much more productive day! 👌🏻✨ 

olga

instagram

#Repost @doctordconline (@get_repost)
・・・
🔴I used a mnemonic:👉EDF ICE RED
__

Engagement
Descent
Flexion

Internal rotation
Crowning
Extension

Restitution
External rotation
Delivery of head and shoulders. .. Now, it is upto you to understand these steps

If you like this video, then tag @@ your friends.. From @twas_medical
#labor #laboranddelivery #pregnancy #video #instavideo #gynecology #obstetrics #pediatrics #physiology #pathology #usmle #usmlestep1 #usmlestep2 #doctor #doctordconline #nhs #nurse #nursing #hospital #patient #mbbs #md #amc #plab @doctordconline

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