36 Questions
Which layer of the skin is derived from surface ectoderm?
Epidermis
At what week of embryonic development do simple cuboidal epithelial cells start to proliferate and form two layers of squamous epithelium?
7 Weeks
What is the process by which the periderm undergoes keratinization and desquamation?
Keratinization
What is the name of the layer that replaces the periderm and forms the future stratum germinativum?
Basal layer
What are the two layers of squamous epithelium formed at 7 weeks of embryonic development?
Periderm and Basal layer
What is the name of the substance formed by the complete exfoliation of peridermal cells?
Vernix caseosa
Which of the following is NOT a layer of the skin?
Mesoderm
At what week of embryonic development does the surface ectoderm of the skin form the primordium of the epidermis?
4 Weeks
What is the significance of the lateral edges in embryonic development?
It connects the intraembryonic and extraembryonic cavities
What is the role of the extraembryonic mesoderm?
It provides direct communication between the intraembryonic and extraembryonic coelom
What is the relationship between the intraembryonic and extraembryonic coelom?
They communicate with each other through the chorion
What is the significance of the head region in embryonic development?
It is crucial for the formation of the intraembryonic coelom
What is formed from the fusion of the intraembryonic and extraembryonic coelom?
The chorion
What is the function of the amniotic folds?
They separate the intraembryonic and extraembryonic coelom
What is the significance of the cranial region in embryonic development?
It is crucial for the formation of the intraembryonic coelom
What is the primary function of the dorsal mesentery?
To provide a pathway for blood vessels, nerves, and lymphatics to reach the gut tube
At 5 weeks, what is the attachment site of the umbilical cord?
The midgut
What is the relationship between the intraembryonic coelom and the yolk sac?
The intraembryonic coelom communicates with the yolk sac
What is the name of the artery that supplies the hindgut?
Inferior mesenteric artery
What is the term for the dorsal mesentery when it is associated with the heart?
Dorsal mesocardium
What is the purpose of the ventral mesentery?
To attach the liver to the ventral wall
Which of the following arteries supplies the foregut?
Celiac arterial trunk
At 5 weeks, what is the attachment site of the liver?
The ventral wall
Which of the following structures is still part of the embryonic body wall?
The liver
What is the result of cranial folding in the embryo?
The pericardial cavity moves to the ventral side of the foregut.
What is the purpose of the pericardioperitoneal canals?
To connect the pericardial and peritoneal cavities.
What is the location of the gut tube in relation to the pericardial and peritoneal cavities?
It is between the pericardial and peritoneal cavities.
What happens to the peritoneum in the embryo?
It has not demarcated the pericardial cavity.
What type of fluid movement occurs between the pericardial and peritoneal cavities?
Convection
What is the relationship between the pericardial and peritoneal cavities?
They are connected by canals.
What is the result of the pleuropericardial folds fusing?
Isolation of the pericardial cavity
At what week of development do the pleural cavities expand into the body wall?
6 weeks
What happens to the pericardial cavity at 5 weeks of development?
It becomes continuous with the pericardio-peritoneal canals
What happens to the somatic mesoderm at 6 weeks of development?
It is split by the expanding lung
What is the result of the lung growing and expanding into the body wall?
The splitting of the somatic mesoderm
What is the location of the pleuropericardial folds at 7 weeks of development?
Medially, ventral to the esophagus
Study Notes
Development of the Integumentary System
- The integumentary system consists of skin and its appendages that protect the body.
- It develops from two germ layers: surface ectoderm and mesoderm.
Development of the Skin
- The skin has two layers: epidermis (superficial epithelial tissue) and dermis (deeper layer of connective tissue).
- Epidermis is derived from surface ectoderm, while dermis is derived from mesoderm.
Development of the Epidermis
- At 4 weeks, the surface ectoderm of the skin (primordium of the epidermis) forms as simple cuboidal epithelium.
- At 7 weeks, the simple cuboidal epithelial cells proliferate and form two layers of squamous epithelium: periderm and basal layer.
- The periderm undergoes keratinization, desquamation, and eventually exfoliation, forming vernix caseosa by week 20.
- The basal layer replaces the periderm and forms the "future stratum germinativum".
Formation of the Pericardial Cavity and Embryonic Cavities
- The pericardial cavity forms and is connected to the intraembryonic and extraembryonic cavities through the pericardioperitoneal canals.
- The cranial folding brings the pericardial cavity to the ventral side of the foregut.
- The dorsal mesentery is the pathway for blood vessels, nerves, and lymphatics to reach the gut tube.
- The pericardioperitoneal canals fuse to form the fibrous pericardium, isolating the pericardial cavity.
- The lung grows and the pleural cavities expand into the body wall, splitting the somatic mesoderm.
- The pleuropericardial folds fuse medially, ventral to the esophagus, and the pleural cavities expand ventrally around the heart.
Learn about the development of the integumentary system, including skin and its appendages that protect the body. Understand the role of surface etoderm and mesoderm.
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