Embryonic Development Week 8

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Questions and Answers

What is the role of the mesonephros during kidney development?

It is the definitive kidney in the fetus.

It forms the first rudimentary kidney.

It is responsible for amniotic fluid production.

It begins to produce urine as the pronephros regresses. (correct)

During which week of development do the facial structures start becoming recognizable?

Week 8 (correct)

Week 6

Week 12

Week 10

What is the functional significance of kidney development prior to birth?

It initiates the formation of facial features.

It allows the fetus to breathe independently.

It helps in the development of neural structures.

It is crucial for filtering blood and removing waste. (correct)

Which part of the brain is not a distinct region by Week 8?

Thalamus Signup and view all the answers

What essential functions do the developing facial structures serve after birth?

Feeding, breathing, and facial expression Signup and view all the answers

Why is the early development of the kidneys important for fetal fluid balance?

They contribute to amniotic fluid production. Signup and view all the answers

What begins to form into the nostrils during facial feature development?

Nasal pits Signup and view all the answers

Which organ system is refining its functionality during Week 8 alongside others?

Nervous system Signup and view all the answers

What part of the eye begins to develop in Week 8, although not fully functional yet?

Iris Signup and view all the answers

Which structures of the inner ear are noted to be beginning development during Week 8?

Cochlea, Vestibule, and Semicircular canals Signup and view all the answers

Which functional significance is associated with the development of limbs in Week 8?

Setting the stage for coordinated movements Signup and view all the answers

What is the significance of the ossicles formed from mesodermal tissue in Week 8?

They transmit sound waves. Signup and view all the answers

Which layer of the retina is noted to be forming include photoreceptor cells?

Ganglion cell layer Signup and view all the answers

At Week 8, how is the external ear described in relation to other facial structures?

Underdeveloped compared to other structures Signup and view all the answers

How does the development of the auditory nerve during Week 8 contribute to the inner ear structures?

It connects the inner ear to the brain. Signup and view all the answers

What is crucial about eye formation in Week 8 for future visual system development?

It lays the foundation for vision. Signup and view all the answers

What is the role of the foramen ovale during fetal heart development?

To allow blood to bypass the fetal lungs Signup and view all the answers

During which week does septation of the heart chambers begin?

By Week 8 Signup and view all the answers

What is one functional role that liver cells begin to take on by Week 8?

Production of bile Signup and view all the answers

Why does fetal circulation include shunts like the ductus arteriosus?

To bypass the non-functional lungs Signup and view all the answers

What is the significance of proper heart septation before birth?

To prepare the heart for efficient functioning post-birth Signup and view all the answers

How does the growth rate of the embryo affect the intestinal loop formation?

It results in the loop herniating into the umbilical cord Signup and view all the answers

What anatomical division is formed by the ventricular septum?

Divides the left and right ventricles Signup and view all the answers

What marks the transition from the embryonic period to the fetal period at Week 8?

Major organ systems have formed in rudimentary forms Signup and view all the answers

What significant change occurs in the internal organ function by Week 8?

Metanephros begins to function Signup and view all the answers

Which of the following events primarily involves apoptosis during Week 8?

Reduction of webbing between fingers and toes Signup and view all the answers

At Week 8, which feature indicates the further differentiation of the upper limbs?

Visible digital rays Signup and view all the answers

What anatomical features are becoming distinct for the lower limbs by Week 8?

Evident knees and ankles Signup and view all the answers

During Week 8, which structure begins to retract back into the abdominal cavity?

Midgut Signup and view all the answers

Which statement accurately describes limb development during Week 8?

Digital differentiation progresses and webbing diminishes Signup and view all the answers

Which statement best describes the general progress of organ systems by Week 8 of embryonic development?

Major organ systems are formed but not fully functional Signup and view all the answers

Study Notes

Week 8 Embryonic Development

Week 8 marks the transition from the embryonic to the fetal period.
The embryo reaches about 25-30 mm in crown-rump length.
All major organ systems are formed, though rudimentary.
Facial features, including the eyes, nose, and mouth, are developing.

Limb Development

Limbs are more developed, with clear shapes of arms and legs.
Elbows, wrists, and fingers are evident, though digits are still partially webbed.

Internal Organ Function

Kidneys (metanephros) begin functioning, producing urine.
Midgut retracts back into the abdominal cavity placing intestines in their finalized positions.

Eye Development

Eyes are more prominent and their basic structure is well-formed.
Iris (colored part of the eye) begins to develop, but not fully functional yet.
Retina forms various layers, including ganglion and photoreceptor cells (rods and cones).

Ear Development

External ear (pinna) develops from auricular hillocks.
External ear takes shape.

Heart Development

The heart begins development and its chambers (atria and ventricles) are separating.
Atrial septum forms; a foramen ovale allows blood to bypass the lungs.
Ventricular septum is also forming, completing the four-chamber structure.

Blood Circulation

Fetal circulation is established; blood bypasses the lungs through shunts.
The heart pumps blood efficiently, supplying oxygen and nutrients.

Gastrointestinal Development

Midgut forms a loop and herniates into the umbilical cord.
The loop eventually returns to the abdominal cavity.
Liver cells (hepatocytes) are beginning to produce bile.
Arrangement of digestive organs is important for proper function.

Kidney Development

Pronephros regresses, and mesonephros takes over urine production.
Mesonephros eventually forms functional kidneys (metanephros).
Kidneys are crucial for filtering blood and removing waste.

Craniofacial Development

Facial structures (eyes, nose, mouth) are becoming more recognizable and differentiated.
Maxillary and mandibular prominences fuse to form jaws.
These structures are crucial in feeding, breathing, and facial expression.

Nervous System Development

Forebrain, midbrain, and hindbrain are distinguishable.
Neural tube segments are more defined.
Basic structures like the brainstem, cerebellum, and cerebrum begin forming.
Allows for future sensory processing, motor control, and autonomic functions.

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Description

Explore the crucial changes that occur during Week 8 of embryonic development. This quiz covers the transition to the fetal period, the development of major organ systems, and the formation of facial features. Test your knowledge on the advancements in limb and organ development during this stage.