Why you might be so miserable...

I am so miserable.  Really, really feel unhappy.

I can tell you what it is and likely you have the exact same reason.

You are not feeding your soul.


You know that feeling when you can smile inside?  For me it is stroking my dog or walking among trees.  Well everything feels different for me at that time. I'm sure there is some science in it.  The videos I watch say how you can change your cells with your thoughts...let me see if I can find one and insert it here.

Also, when I was walking within the countryside I could see myself fill up, just look at this video, you will see no glimmer of being miserable.

I do love Louise Hay, she talks about thoughts and how they can dominate our health.  I do agree with this stuff! 

I'm off to the JACUZZI.  This will fill me up for a couple of hours.  What about yourself? 

Revision: Activation of innate mechanism of immunity

Accuracy is not guaranteed, these are my revision notes.


Question:  Give an account of the activation of innate mechanisms of immunity and evaluate its role in ensuing inflammatory processes

The human body contains many physical barriers to infection and pathogens.  Skin is a major defence barrier.  Mucosal layers in membranes such as the gut, respiratory systems, digestive systems generally,  urinary tract are all protected by the physical barrier.  Eye fluid contains bacterial enzymes.
Peptides in skin prevent bacteria and fungi from entering broken, inflamed areas.  However, at  times, things go wrong.

* Pathogen enters intratissue space
Second lines of defence are needed and the toll like receptors give a reaction. (?)

1. Phagocytes engulf pathogens.
2. Neutrophils (the most abundant type of White Blood Cell) consume pathogens and disintegrate forming pus.
3.  Macrophages - move out of the blood to occupy tissues.  Uses cytoplasmic extensions to engulf and digest.
4. Natural Killer cells (NK cells) - patrol lymph and blood looking for abnormal cells.  Uniquely they can kill your own cells if they are infected with virus or have become cancerous.
- identified by MHC1 (lack of it)
-releases enzyme into the cell to trigger apoptosis.

Internal innate defences include
1. Fever
2. Chemical signals
3. Inflammation

Inflammatory response includes
-Redness
-Swelling
-Heat
-PAin

*Mast cells in connective tissues send out histamine which causes vasodilation.  Allowing more cells to the site to fight the pathogen.
*Heat increases metabolic rate so the cells can heal themselves faster.
*Swelling - forms scabs and triggers lymphatic system which cleans up fluid.
*inflammation also attracts phagocytes and lymphocytes
- neutrophils are beginning to die off at the stage
-skin cells release leukocytosis
-if overrun by virus or serious infection, the hypothalamus raises body temperature into fever.  This also flags the liver and spleen to hold onto iron and zinc which can't contribute to bacterial growth.

When things go wrong:

HIV -

Autoimmunity - attack 'self'

Epidemiology - Bias

"Define and specifically discuss the different types of bias within the context of scientific research and their possible consequences in the nutrition field"

Wiki: In science and engineering, bias is a systematic error.  Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average.

Pre-trial bias = Flawed study design, Selection bias, channelling bias
Bias during trial = Interviewer bias, Recall bias, transfer bias, misclassification of exposure or outcome, performance bias, chronology bias
Bias after trial = Citation bias, confounding


How to avoid bias:
Pre-trail bias

Flawed study designs - clearly define risk and outcome. Standardize and blind data collection.

Selection bias - Select patients using rigorous criteria to avoid confounding results. Chose patients from the same population. Avoid selection bias as outcome is unknown at time of enrolment.

Channeling bias - Assign patients to study cohorts using rigorous criteria

Bias during trial

Interviewer bias - Blind interviewer to exposure status and other factors. Standarize interviewers interaction with patient.
Chronology bias - Avoid using historic controls.

#examgate

Group chat:

Woah that was amazing guys

Yeah thank god. It's over and it was good.

What? Are you guys kidding right?

Anna and I were taking our exams in another room.  The other 4 of our group were in the main exam hall.
All in the hall were told to cross out the last 10 questions and were given another piece of paper which was totally nothing we had revised.

Anna and I were just given the usual paper.  Cutting a very long story short, the head of science was rude, defensive and not at all apologetic for this mistake.  Sadly for Anna and I (but fairly) all questions were erased.

The entire thing has all been a nightmare.  I'm getting sick of all this.

Revision: Fertilisation

Please bear in mind these are my revision notes and I can't quite promise their accuracy.  Do your own research too! Typing these out will help me remember as we are heading into a seen exam this afternoon!


Question: Describe the cellular and molecular events that occur during fertilisation

Approximately 200million spermatozoa are released during ejaculation in intercourse, travelling through the vagina and swimming through the cervix propelled by whip like motions of the flagella.  After which  muscular contractions of the uterus direct them to the fallopian tubes.
This process usually takes between 30 minutes and 2 hours.  Around 200 spermatozoa will reach the oocyte in the fallopian tube.  Only one will fertilise.

Capacitation and the acrosomal reaction must take place before fertilisation can begin.  Secretions from he uterus wall destabilise the plasma membrane surrounding the head of the seprm resulting in the membrane becoming more fluid which helps prepare the sperm for the events of fertilisation.  The sperm become hyperactive as they move through the corona radiata and come into contact with the zonae pellucida.  Here, specific receptor proteins called ZP3 triggers the acrosomal reaction during which the enzymatic contents of the acrosome are released.  These enzymes digest a path through the zonae pellucida into the perivitelline space  and reach the plasma membrane of  the secondary oocyte.  Here the fusion takes place.

To ensure only one sperm fuses a fast and slow block is released preventing any further ZP3 being released and therefore preventing polyspermy.  The slow block is depolarisation and fast block sees
 a wave of intracellular calcium being released causing small cortical granules beneath the oocyte membrane to release their contents.  Thus rendering ZP3 inactive making the zonae pellucid impermeable.

Upon sperm entering, the oocyte undergoes Meiosis 2 and further develops into a female pronucleus. During this time the sperm develops into male pronucleus.  The two pronuclei fuse to form one single diploid nucleus known as a zygote.

Revision - Main characteristic of Viruses.

NB this is my own revision and I cannot promise accuracy - do research.

Question:
a)  Discuss in depth the main characteristics of viruses

Viruses are not classed as living things as they cannot replicate without a host.  They do not have a metabolism.
Viruses spread using cells.
They have a protein coat called a capsid.
Viruses are very small, much smaller than bacteria.
They are difficult to treat.

b) Give a detailed account of the main events involved in a typical virus life cycle

A virus enters the body and locates a host cell.  As it fuses, it uses the protein coat to enter the cell.  Here,  it enters either a lytic cycle or a lysogenic cycle .  Nucleic acid will be used to reform DNA/RNA and change the genetic material of the cell.
The lytic cycle then sees the cell erupt making copies of the other cells.  Leaving holes in the cell membrane gives ease to apoptosis of the cell as it cannot survive without the membrane.
The lysogenic cycle uses DNA to hide in cells until immune comprimisation occurs.

c)  List factors contributing to viral pathogenicity and to the nature and severity of viral diseases.

Pathogenicity refers to the ability of an organism to cause disease (i.e. harm the host).  This ability represents a genetic component of the pathogen and the damage done to the host is a property of the host-pathogen reactions.

Natural killer cells are lymphocytes, they recognise this virus and kill.
The severity of viral diseases is dictated by the immune response. In several immune deficiency diseases including AIDS NK cell function is abnormal.
NK cells binds to cell and releases toxins which produces holes int he target cells membrane creating apoptosis.
NK cells may also contribute to immunoregulation by recreating high levels of influential lymphokines.

Revision: Fertilisation

Q1B - please see previous blog post for Q1A - Remember these are my revision notes and you must do your own research for accuracy.

Question:  Outline the experimental evidence for the role of one molecule in fertilisation

Baibakov et al found human sperm bind to Homo sapiens zonae pellucida but not to those of non-human primates.
Human sperm only bind to zonae pellucid with contained human ZP2.  Recognition of fertilisation within species is dependant on a N-terminal domain of ZP2.  After fertilisation degradation takes place of N-terminal ZP2 to block polyspermy.