2010 Lab 4

From Embryology

Cardiovascular and Placenta

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.


Objectives

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


Early circulation

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.

Three components of early circulation

Stage13 bloodflow.jpg


Cardiovascular Movies

Heart1 looping icon.jpg
Heart Looping

Stage 13 Embryo

Stage 13 3D CVS Reconstruction

Stage13-CVS-icon.jpg

Cardiovascular


About Stage 13 Embryo Sections - This image is from a serial section of a 6mm CRL pig embryo with some features of the Stage 14 embryo. This embryo is approximately equal to the day 42 human embryo. Use these serial images to identify internal features and relationships that exist within the embryo at this stage. Then compare these images with the later features of the Carnegie stage 22 human embryo.

Links: Carnegie stage 13 - serial sections | Carnegie stage 13 | Embryo Serial Sections
Stage 13 image 099-icon.jpg
Stage 13 Serial unlabeled images

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

Embryo Stage 13 Serial labeled images

A1L  A2L  A3L  A4L  A5L  A6L  A7L

B1L  B2L  B3L  B4L  B5L  B6L  B7L

C1L  C2L  C3L  C4L  C5L  C6L  C7L

D1L  D2L  D3L  D4L  D5L  D6L  D7L

E1L  E2L  E3L  E4L  E5L  E6L  E7L

F1L  F2L  F3L  F4L  F5L  F6L  F7L

G1L  G2L  G3L  G4L  G5L  G6L  G7L

Compare this mid-embryonic cardiovascular system with that existing at the end of embryonic development.

Stage 22 3D CVS Reconstruction

Stage22-CVS-icon.jpg

Cardiovascular

Placentation

Compare the features of a normal and gravid uterus.

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

Mesenchymal stem cells in chorionic villi

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?
  • Tutorial on image uploading for your project.


Original UNSW Embryology Links

External 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 2010

Embryology Introduction | Cell Division/Fertilization | Lab 1 | 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 | Stem Cells | Stem Cells | Endocrine | Lab 10 | Late Vascular Development | Integumentary | Lab 11 | Birth, Postnatal | Revision | Lab 12 | Lecture Audio | Course Timetable


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

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