2010 Lab 4

From Embryology
Revision as of 20:40, 18 August 2010 by Z3267024 (talk | contribs) (Cardiovascular and Placenta)

Cardiovascular and Placenta

Objectives

  1. Understand development of early embryo heart and vascular system.
  2. Understand the early placentation events and the development of placental blood vessels.

Introduction

This laboratory will explore the development of the embryonic cardiovascular system, which includes the placental vascular system. We will look through cross-sections of the Carnegie stage 14 embryo and follow the flow of blood through the embryonic vasculature. In this lab, we will also examine placentation.

Stage13 bloodflow.jpg

Introduction

Three components of early circulation

The vascular system of the embryo is formed from blood islands that appear in the extraembryonic mesoderm of the yolk sac and the embryonic mesoderm (primarily splanchnic mesoderm). Both of these clusters fuse together and extend, forming a vast network.

The early circulation has 3 components: Vitelline, Embryonic, Placental Each of these has its own system of arteries and veins.

  • Vitelline - (not shown) the vitelline arteries branch off the dorsal aortas and enter the yolk sac, covering its entire surface. The vitelline veins return red blood cells from the capillary beds to the sinus venosus, posterior to the heart. The vitelline vessels eventually contribute to the portal system of the liver in the adult.
  • Embryonic - blood from the dorsal aorta enters intersegmental arteries, including the arteries of the pharyngeal arches. The blood returns to the heart via the anterior and posterior cardinal veins.
  • Placental - the umbilical arteries receive blood from the aorta. This is carried to the chorionic villi, where exchange occurs with the mother. Waste products are disposed of, nutrients and oxygen are collected, and then the umbilical veins convey the blood to the sinus venosus.

Heart - The heart develops from cardiogenic mesoderm, a region of splanchnic mesoderm lying above the buccopharyngeal membrane. Development begins in week 3 with the formation of a pair of heart tubes. These fuse and form a single tube in week 4, as a result of the embryonic folding processes that occur. As the heart grows, septation events occur, transforming it into a 4-chambered pump. Initially, the ventricles develop above the atria; however simultaneous growth and bending of the tube bring the structures into correct position. In humans, the heart begins to beat on day 22-23.


Stage 14 Embryo

Stage 14 3D CVS reconstruction Small movie page | large movie page | Stage 14 3D small movie | Stage 14 3D large movie

Stage14 planesm.gif
A1 A2 A3 A4 A5 A6 A7
B1 B2 B3 B4 B5 B6 B7
C1 C2 C3 C4 C5 C6 C7
D1 D2 D3 D4 D5 D6 D7
E1 E2 E3 E4 E5 E6 E7
F1 F2 F3 F4 F5 F6 F7
G1 G2 G3 G4 G5 G6 G7

Compare this mid-embryonic cardiovascular system with that existing at the end of embryonic development Stage 22 3D CVS reconstruction


Placentation

Changes in the uterine vasculature with pregnancy
Chorionic villi sampling

Chorionic Villi

  • Compare the features of primary, secondary, tertiary and stemmed villi


Section through the placenta

Group projects

The laboratory will also allow time for work on the group online project. What have your other group members and other groups done so far?


UNSW Embryology Links

Internet links

Embryo Images Unit: Embryo Images Online Early Cell Populations (cardiogenic section) | Cardiovascular Development | Week 3 Development | Week 4 Development | Heart Chambers and Outflow Tract | Atrioventricular Septation | Outflow Tract Septation | Ventricular Septation | Atrial Septation | Atrial Walls Aortic Arch Vessels | Changes at Birth

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Course Content 2009

Embryology Introduction | Cell Division/Fertilization | Cell Division/Fertilization | Week 1&2 Development | Week 3 Development | Lab 2 | Mesoderm Development | Ectoderm, Early Neural, Neural Crest | Lab 3 | Early Vascular Development | Placenta | Lab 4 | Endoderm, Early Gastrointestinal | Respiratory Development | Lab 5 | Head Development | Neural Crest Development | Lab 6 | Musculoskeletal Development | Limb Development | Lab 7 | Kidney | Genital | Lab 8 | Sensory - Ear | Integumentary | Lab 9 | Sensory - Eye | Endocrine | Lab 10 | Late Vascular Development | Fetal | Lab 11 | Birth, Postnatal | Revision | Lab 12 | Lecture Audio | Course Timetable


Cite this page: Hill, M.A. (2019, October 20) Embryology 2010 Lab 4. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_Lab_4

What Links Here?
© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G