Introduction&

Early Embryology

Human Structure & Development ANHB 2212

Semester 1 – 2008

Dr. Avinash Bharadwajavinash@anhb.uwa.edu.au

Welcome! The Promise :

An exciting unit! All possible help during the course of the unit Improvements… already in place

Last year’s SPOT – both 2212 and 1102!

Unit Coordinators Avinash Bharadwaj Julie Hill

Lecturers Assoc Prof Geoff Meyer Yours truly + +

Demonstrators/Tutors

Prerequisites other than A&HB Units…?

“Prescribed reading”… Integrated with learning resources Available well before the actual classes In case of difficulty (unlikely )…

… Contact me!

More About the Unit Learning load (?) and help

Directed self-study Pre-lab prep is essential

Resources, especially website www.lab.anhb.uwa.edu.au/anhb2212 Some resources and features on WebCT. WebCT URL : http://webct.uwa.edu.au Lab manual – available in co-op shop soon Textbooks (“Recommended”) Course Reader : Online, includes “prescribed” reading

What’s in It for You? Wide variety of student background and goals Integrated Structure, Function and Development

Componets are not separable! Separation in labs inevitable…

Carefully selected content Relevance to all streams considered

Assessment designed to facilitate all streams Core topics… “Other areas”

Must be activated immediately Class List emails for important announcements Check your email regularly. Auto redirect to other accounts is not encouraged.

Mails coming from other accounts are likely to be auto deleted.

UWA Student email account

ANHB computing account

For accessing web material on G.03 computers Now can be done through the Histology Lab. You can do it on Thursday, Week 1 Lab!

You do not need this for computers other than in the A&HB building.

The Unit website is “open” – needs no username or password as of now.

Lab Allocation – OLCR Lab time allocations only through OLCR. If problems persist, see

Wendy Colangelo, Ground floor, A&HB Building. Adjustments done only for genuine reasons, mostly

timetable clashes. Mutual exchange between two students : Both must

see Wendy together! Allocation will settle down in a week’s time!

Communication Offices : Avinash : 1.77, First floor, A&HB

Julie : 1.75, First floor, A&HB

Email : avinash@anhb.uwa.edu.au

jhill@anhb.uwa.edu.au

In general, Policy-related mails and those with subject

related questions to Avinash

Admin-related mails to Julie.

Subject header must include : “ANHB2212”, your name,

and a word or two about the subject. E.g.

ANHB 2212 – Jane Smith – Embryology question

Teaching Strategies – Lectures Theme based

Slide-show and printable versions available in advance.

No handouts! Not incorporated in the lab manual.

Recorded on Lectopia

Teaching Strategies – Labs Anatomy labs : “free movement”.

Visit all tables Check for exhibits in the centre or on the boards.

Histology labs are “sit-down”!

For Both Labs Directed self study Pre-lab study is essential Attendance/worksheets : Stick to the allotted tutor. Roving resource persons.

Teaching Strategies – Tutorials Interactive, Q-A sessions. Usually a week after the topic.

Time to study/understand, identify ‘gaps’. Questions not supplied in advance! Essay writing practice during tutorials.

Attendance at Labs and Tutorials is compulsory and recorded.

Penalties apply for absence without valid reason.

Email Julie regarding absence.

Unit Outcomes Detailed specific outcomes listed on the website Do not read all at once! Assessment carefully matched with outcomes.

In general… Critical thinking and analysis is encouraged. HUGE lot of guidance on the Unit website. Correct use of language is essential

Assessment

Continuous assessment : 20% of total unit mark 2x30 min tests – Weeks 5 and 9 (Tutorial hour) MCQs, Short answer Qs, True / False Qs

End-of-semester Examination : Written (3 hours) : 50% of total unit mark

MCQs, SAQs, One short essay Lab (1.5 to 2 hours):

25 – 30 Spot questions : 30% of total unit mark.

Actual marks are scaled to these weightages.

Other Assessment Events

Formative, do not count towards final mark. Short notes / Essays written during tutorials

Marked and returned for feedback Pre-test in Week 1 Tutorial

Feedback to coordinators Mock lab test (Week 8) administered as

practice. (If possible, also in Week 13).

For This Week… Recap (also if you have not done ANHB

1101/1102) : Course Reader Chapters 1, 2 and 3. Chapter 2 : Details of mitosis and meiosis not

examinable. Lab preparation : PowerPoint files on the Unit

website (Link given on the website).

Early Embryology

Recap of ANHB 1101/1102 (or equivalent) Many facets… Tailoring to HSD 2212 Some important concepts

Why and How

Embryology

Gross Form, Correlation

Errors in development Structural Molecular(Clinical aspects)

Real life aspects (“non medical”)

Evolutionary mirror

Cellular and Molecularphenomena

Fertilisation Ovum and Oöcyte Second meiotic division Site of fertilisation Sperm : Acrosomal reaction Zona pellucida Single sperm…

Fertilisation

Completion of meiosis II Polar bodies (Also dealt with in Week 11)

Restoration of diploidy Initiation of cleavage Chromosomal sex determination Genetic and evolutionary implications

Paternal and maternal chromosomes Further mixing during next gametogenesis (crossing

over)

Cleavage Nuclear-cytoplasmic ratio Division by reduction of cell volume Planes of cleavage Polarity…? Inner cell mass and trophoblast

formed later Transport through the uterine tube Zona pellucida… retained until implantation

Blastocyst

Inner cell mass Trophoblast

Invasive nature Zona pellucida disappears Implantation

Trilaminar Embryo Epiblast and Hypoblast Hypoblast ≠ entoderm! Primitive streak Cell migration Mesoderm and entoderm

E

H

Y H

Notochord & Neural Tube Notochord

Axis Induction…

Neural plate Neural groove Neural tube and crest

Divisions of Mesoderm Paraxial

Lateral plate

Intermediate

Segmentation Paraxial mesoderm

“Somites”

Each somite Sclerotome Dermomyotome

Fate of Germ Layers Ectoderm

Epidermis (not skin!) ++ Mesoderm

Muscle, Connective (including skeletal) tissues Some epithelial structures

Parts of urogenital systems Endothelium of heart and blood vessels “Serous membranes”

Endoderm Lining epithelium of digestive system

Head, Tail and Lateral Folds

Flat three-layered embryo … three dimensional tube

Endoderm encloses a cavity …digestive system

Changes in the relative positions of certain regions Further correlation with the development of the heart

and digestive system

The Developing Human – Three Phases

Early development Embryonic phase – organogenesis The foetal period Differentiation, Histogenesis and Functional

development

Last Slide