Exam 2 - Lecture 32 (Digestive & Respiratory System) Flashcards
What 2 things support intestinal development?
- Elongated dorsal mesentery
2. Cranial mesenteric artery
From what does the cecum form?
As an evagination of the caudal limb of the intestinal loop
What happens during physiological herniation of the intestine during development?
Developing intestine moves out of the embryo into the yolk sac
How many degrees does the cranial limb of the developing intestinal tract move and what does it form?
270 degrees; root of mesentery
What closes the cloaca?
cloacal membrane
What divides the cloaca?
Urorectal septum
Where does the urorectal septum form?
Junction of hindgut and allantois (urogenital sinus)
Which way does the cloaca divide?
Caudally
What does the urorectal septum divide the cloaca into?
anal membrane and urogenital membrane
What are the 3 steps to cloacal separation?
- Urorectal septum moves towards cloaca to divide it
- Septum fuses with the cloacal membrane
- Formation of anal membrane and urogenital membrane
What are the 4 malformations of the intestinal tract?
- Intestinal stenosis
- Intestinal atresia
- Atresia ani
- Urorectal fistula
What is intestinal stenosis?
Narrowing of intestines
What is intestinal atresia?
Section of intestine disappears
What is atresia ani?
Anal membrane doesn’t break down
What is a urorectal fistula?
Abnormal connection between rectum and urogenital system where the septum failed to divide.
What do the pharyngeal arches give rise to as a whole?
pharynx and part of the face
What 4 things can you find in the pharyngeal arches?
- Aortic arch
- Cartilage rod
- Nerve (cranial)
- Muscle
The 1st pharyngeal arch gives rise to CN # __?
V (trigeminal n.)
What bones does the 1st pharyngeal arch give rise to?
Mandible, maxilla, incus, malleus
What muscles does the 1st pharyngeal arch give rise to?
Muscles of mastication and rostral digastricus
The 2nd pharyngeal arch gives rise to CN # __?
VII (facial n.)
What bones does the 2nd pharyngeal arch give rise to?
Hyoid bones and stapes
What muscles does the 2nd pharyngeal arch give rise to?
Muscles of facial expression and caudal digastricus
The 4th and 6th pharyngeal arches give rise to CN # __?
X (Vagus n.)
What cartilage do the 4th and 6th pharyngeal arches give rise to?
laryngeal
What muscles do the 4th and 6th pharyngeal arches give rise to?
4th = cricothyroideus 6th = intrinsic laryngeal muscles
The caudal laryngeal nerve is a terminal branch of the _____.
Recurrent laryngeal nerve
What does the left recurrent laryngeal nerve wrap around in the thoracic cavity?
Ligamentum arteriosum
What does the right recurrent laryngeal nerve wrap around in the thoracic cavity?
R subclavian a.
What causes cleft lip?
Medial nasal and maxillary processes don’t meet
What causes cleft palate?
Secondary palates fail to meet each other, and can also fail to meet with the primary palate
What part of the palates become the hard palate?
Rostral 1/3
What part of the palates become the soft palate?
Caudal 2/3
What is another name for cleft lip?
Cheiloschisis
What is another name for cleft palate?
Palatoschisis
At what timepoint does the secondary palate close?
Outside of the critical period
In which direction does the trachea separate from the esophagus?
Caudal –> cranial
What does early lung development deal with?
Large airway conduction (NOT gas exchange!!)
When are the majority of alveoli produced?
Postnatally
What part of the lungs increases in mass in order for them to grow?
mesodermal part
Why is it important for the SA of the lungs to increase when they expand in the fetus?
Important for drawing fluid away by lymphatic vessels
What are the 3 lung malformations?
- Pulmonary hypoplasia
- Tracheal hypoplasia
- Tracheoesophageal fistulas
What is pulmonary hypoplasia?
Underdevelopment of lung
What is tracheal hypoplasia?
Underdevelopment of trachea
What is a tracheoesophageal fistula?
Abnormal connection between the esophagus and trachea
