Fetal Circulation

Since the lungs are not used in the fetus (because oxygenated blood comes from the umbilical vessels), blood is shunted around in different ways:
0. Umbilical vessels
Umbilical arteries drains blood from fetal iliac arteries; blood is passed through vessels in the placenta and diffusion between it and the mother's blood can occur, thus delivering nutrients to the fetus and removing wastes. The umbilical vein returns oxygenated blood to the liver (half of which will go through the liver and the other half through the DV)
1. Ductus venosus
This structure bypasses the liver and joins with the IVC to direct oxygenated blood from umbilical vessels to heart and thus the rest of the circulation.
2. Foramen ovale

Since RA receives oxygenated blood (from IVC/DV/Umbilicus), and that the lungs do not supply oxygen at this time, there is a hole between the atria that allows blood to travel from RA to LA so oxygenated blood can be delivered to other systems. The Septum primum on the left side prevents blood going from left to right.

3. Ductus arteriosus
Similar to the foramen ovale, this allows blood to flow between the pulmonary trunk and the aorta.

Embryology of the lungs

Ok, I'm ignoring development of the upper airways, pleura and diaphragm here (mainly because we didn't discuss it and I'll try and deal with it later)

Endoderm forms the epithelia.
Splanchnic mesoderm and neural crest cells form the cartilage, connective tissue and muscles.

So there are roughly 5 stages:
1. Embyonic (from the 4th week)
Development begins in the 4th week where there forms a respiratory (or laryngotracheal) diverticulum (from an opening in the foregut in the embryo).
The diverticulum grows and then folds (tracheo-oesophageal folds) to create the tracheo-oesophageal septum to separate the trachea and lung buds from the oesophagus. There is still a connection with these two - via the larynx which forms from the 4th and 6th pharyngeal arches.
The lung buds are two divisions of the trachea, and these continue to divide so that by 6 months there are more than 17 subdivisions.
2. Psuedoglandular (5-17 weeks)
All of the elements of the lungs have developed except those involved in gas exchange
3. Canalicular (16-25 weeks)
Increase in vascularity of the lungs. Respiratory bronchioles and alveolar ducts form.
4. Saccular (24weeks to birth)
Increase in the number of terminal sacs.
Cuboidal cells become flat squamous epithelia.
By week 20 Type II alveolar cells have been producing surfactant.
Further development of the capillary network
5. Alveolar (late fetal - childhood)
Where alveoli form and continue to develop after birth

Fascination

Humans fascinate me.
Not just how the body works, but the mind too.
Stubbled across a few sites that have intrigued me:
FOUND Magazine
Postsecret
I Found Your Camera
I've been up for an extra hour looking at scanned pictures and postcards with other people's thoughts and scribbles. There's so much about us all that I want to understand better.
Also I wonder if anything that I've ever written has made it online... Now I'm worried.
And also wanting to go to the library more often to find secret love notes stashed between the pages. Or better yet, what I used to do - quietly defile the pages (in pencil I might add) with some secret I couldn't tell anyone.
This is much like finding my old diaries again and reading what I wrote so many years ago. Except I do remember some bits of what I wrote, and recognise the person behind the writing; while these people online are people who I don't know, who have different histories and backgrounds and I'm curious - I want to know more about them.
I'm also insanely jealous about some of the beautiful handwriting shown.
Now I want to go study about handwriting since the way a person writes is fascinating.

One Week

In one week I will be 20. I feel so young and yet I feel like I've wasted time just floating or sailing or drifting along. So many things I want to have done, and haven't. Travel, go on a road trip, write something more than assignments and diary entries, be single, have sex in strange places. Chances of me getting to do these things seem to be getting less and less... maybe when I'm retired I'll have a chance. hmm... kinky.

Party plans are go. I still have to go out and buy fruit and chocolate and juice and ice and serviettes and plastic cups and chips and corn chips and lollies and m&ms and mum's making dip. Ah crap and I have to double check that it's ok I actually hold the party where I've already told everyone it's being held.

Watching strange movie with the chick from xmen. Interesting quote "The longer you are with one person, the more annoying they will become. And you will be annoying too. So, if you want things to be perfect, don't be in a relationship". I know I'm annoying him. But am I making the right choice if I keep pushing him away? Why do I need him to cut the ties? Is it so he's not so hurt?

Yes I'm Aware It's 4:45am

So in the end the HP slash was good, but not necessarily enough romping to justify 12 hours of not studying...
My brain hurts now.
Sleep.
Then study tomorrow.
Oh god I hope Mother doesn't decide to wake me up early...

Procrastinating at its sauciest

I have found my undoing.
I have been home from work since 9:30 this evening and it is currently 1:23am. I have not stopped reading this awesome HP fanfic. Part of me is cursing the steely-fingered one... and the rest of me is laughing too hard at Draco and his awkwardness to care :P
However, this means my total amount of study tonight has been... zero.
Which makes me more like one of Draco's schemes to sabotage others so he can be brilliant.
Ah if only he wasn't so damned devilishly bad-boy cute...
Well I'm only up to their 5th year, so surely this fantastic work of HP fiction cannot go beyond the school years... my study regime hopes...
Meanwhile, boys are annoying.
Also that I keep using big words in msn conversations at 1:30 in the morning is surprising and slightly annoying. So constantly in lethologica - wh/ i think is the state of not knowing the precise word you wish to use at that time. Plus I keep talking like I'm narrating a HP fanfic story... and my brain starts narrating my life.. Can't it give a brief overview of whatever I need to learn about Cardiovascular and Respiratory systems since I know so very very very little right now.
I know I am small, but I feel so tiny when the world is so big and the wealth of knowledge we'll be expected to know (and are expected to know already) is enormous.
*sigh*
Ok, sleep soon, then study in the morning.
Delete links to awesome fanfics and read during holidays.
Also remember to get the third book in Inheritance cycle... will kill anyone who ruins the ending.

List Of Things To Do

Today I finished one assignment and read through the next two that are due, so I can get started on them over the weekend.

Though I have lots of work to do, I'm feeling pretty good :)

Tomorrow I think I need to work on anatomy. Just anatomy, solidly, all day. Friday I should probably look at the legal and ethical issues we've looked at this semester. Then the weekend I really have to go through and work on some of these Learning Objectives. Oh and I have to prepare for the debriefing tute. (So debriefing tute, DHC proposal and D&P reports for the assigns to go). Must also look over history taking and physical examinations! (See Talley and O'Connor).

We've got 5 cases of cardiovascular, 6 of respiratory and 4 of renal. Roughly 10 LOs each case, so that's about 150 LOs and we've got 6 weeks till exams. So roughly 3-5 LOs each day and I'll be right. Putting in perspective like that isn't too bad. Now I just have to knuckle down and do them :P

So here's the final list:
>LOs
>DHC LOs
>DLEPP LOs
>OSCE prep
>Anatomy
>DHC proposal
>D&P report
>Debriefing tutorial

plus my taxes :P