Vertebrate Body Plan Week 3

Question 1

The __________ mesoderm forms the urogenital system.

Answer 1

Intermediate mesoderm

Question 2

The _________mesoderm forms the future body wall.

Answer 2

Lateral plate mesoderm

Question 3

Where does the notochord derive from?

Answer 3

Mesoderm

Question 4

What does the notochord form into?

Answer 4

It is the precursor to the axial skeleton by forming nucleus pulposus

Question 5

What else forms around the notochord? (2 names)

Answer 5

Vertebral bodies also called the primitive chordata

Question 6

What are somites? What are they made of?

Answer 6

Somites are epithelial balls of cells formed in segmental pairs along the neural tubes from the paraxial mesoderm.

Question 7

What is neurulation?

Answer 7

Neurulation is the formation of the neural tube that eventually becomes the CNS.

Question 8

Describe the three steps of neurulation

Answer 8

1. The notochord forms from mesoderm cells after gastrulation is complete.
2. Signals from notochord cause inward folding of the ECTODERM at the neural plate.
3. Ends of the neural plate disconnect to form the autonomous neural tube.

Question 9

During neurulation, what germ layer folds inwards?

Answer 9

Ectoderm

Question 10

What is the fetal period?

Answer 10

Weeks 9-38; all organs are developed, size enlargement is occuring.

Question 11

Clinicians use ________ age to determine due date.

Answer 11

Gestational age

Question 12

Describe the difference between fertilization and gestation.

Answer 12

Fertilization begins at conception.

Question 13

How long is the birth period “gestationally” vs based on the fetal age.

Answer 13

40 weeks and 38 weeks respectively

Question 14

During which time period will death of the embryo occur due to congenital anomalies?

Answer 14

0-3 weeks

Question 15

During which time period will malformation of the embryo occur? What is an example?

Answer 15

3-8 weeks (heart defect)

Question 16

During which time period will their be functional disturbance of a fetus?

Answer 16

8-38 weeks (mental deficiency)

Question 17

What is a birth defect?

Answer 17

Term for congenital malformation such as a physical anomaly.

Question 18

What is a congenital disorder?

Answer 18

A condition existing at birth and often before birth that develops during the first month of life regardless of causation

Question 19

Teratology

Answer 19

Study of causes and biological processes leading to abnormal development

Question 20

Teratogen

Answer 20

Any agent that causes a birth defect

Question 21

What are the 3 key characteristics of vertebrate body plan?

Answer 21

Bilateral, Body Cavity (tube within tube) and Vertebrate

Question 22

What is organeogensis?

Answer 22

The development of organs from Weeks 3-8

Question 23

Describe the teratology of thalidomide

Answer 23

Thalidomide was used as medication to reduce morning sickness among pregnant woman but it also ended up causing birth defects. Scientists did not know drugs could cross the placental barrier.

Question 24

When is limb development at a critical period ?

Answer 24

Weeks 4 and 5

Question 25

When is heart development at a critical period?

Answer 25

Weeks 3-6

Question 26

Describe the birth defect thalidomide caused.

Answer 26

Phocomelia; blood supply to formation of long bones is inhibited by thalidomide causing limb development to results in majority shoulders.

Question 27

Who is susceptible to congenital anomalies?

Answer 27

Higher maternal age, genetic predispositions, environmental factors

Question 28

What is the migration pattern of epiblasts?

Answer 28

Caudal to Cranial , Mesial and Lateral

Question 29

What do somites differentiate into?

Answer 29

Vertebrae, muscles of the back and body, dermis of the skin