8- How does the Brain Develop as an Organ? Flashcards
When does life start?
At conception- when the sperm meets the egg
When is gestation?
From conception until birth
How long is human gestation?
9 months long (normally)
Why is the first couple of weeks of gestation a critical period?
Because stem cells begin to differentiate into different types of organs or tissues
What DNA does a zygote contain?
50% DNA of the father, 50% DNA of the mother, creating a new set of genes unique to the baby
What does one single cell on day 1 become?
Many cells due to division
What do cells become when they keep dividing on day 1?
A mass of undifferentiated cells
What 2 things happen on days 4-6?
Differentiation begins to happen, and cells cluster together to form the placenta
What is the role of the placenta?
A temporary organ that supplies nutrients and blood from the mother to the baby
What happens on day 7 of gestation?
The fertilised egg implants into the uterine wall
What are different cells like in the early stages of an embryo?
Not functionally different
What are cells called in the early stages of an embryo?
Pluripotent or omnipotent
What do cells have the potential to do in the early stages of an embryo?
To activate certain genes and grow into specific organs
When is the inner cell mass present?
In the early stages of an embryo
Why are stem cells called stem?
They are the stem of the whole organism
What can stem cells later do?
Develop into many types of cells
What potential do stem cells have?
Therapeutic potential for many neurodegenerative disorders
When do cells begin to differentiate?
2nd week of prenatal development
When do layers emerge?
Days 10-16
What are the 3 layers?
Ectoderm (external), mesoderm (middle), endoderm (internal)
What develops from the ectoderm? (5)
- Nervous system
- Eyes
- Skin
- Hair
- Nails
What develops from the mesoderm? (6)
- Muscle
- Bones
- Heart
- Blood vessels
- Kidneys
- Genitals
What develops from the endoderm? (3)
- Digestion system
- Respiration system
- Excretion system
What do parts of the ectoderm turn into?
A ‘neural plate’
What does the ‘neural plate’ become when it starts to curve?
A ‘neural tube’
What does the inner part of the neural tube develop into?
The central nervous system
What does the outer part of the neural tube develop into?
The peripheral nervous system
What can happen if both sides don’t close properly?
It could lead to very serious developmental disorders
What results from the lower part of the neural tube failing to close?
Spina bifida
What happens to the spinal cord with spina bifida?
Spinal cord comes out of bone structure so nerves are exposed
What is a key symptom of spina bifida?
A weak bladder/bowel and weakness in legs
What is spina bifida thought to be caused by?
Genetic and non-genetic factors combined
What does the upper part of the neural tube failing to close result in?
Anencephaly
What causes problems in anencephaly?
The brain is unable to develop
What is thought to be the cause of anencephaly?
An interaction of genetic and environmental factors
Why is a healthy diet important in gestation?
It is crucial to the baby’s health
Why are certain vitamins important in gestation?
For triggering genes that facilitate brain development
What is folic acid?
A dietary supplement important for formation of the neural tube
How much could folic acid reduce the incidence of defects by?
90%
What does the rostral end of the neural tube develop into?
The brain
What does the prosencephalon develop into?
The cortex, diencephalon, telencephalon
What does the mesencephalon develop into?
The tectum and tegmentum
What does the rhombencephalon develop into?
The cerebellum, brainstem, and pons
What does the caudal end of the neural tube develop into?
The spinal cord
What part of the brain grows rapidly in size from birth to age 2?
The frontal region
When does the pace of brain growing slow down?
Age 4
When is the brain roughly a similar size to an adult brain?
Age 10 onwards
What is the main difference between an adult brain and a child’s brain?
Adult brain has greater neural connectivity
