Anatomy and Embryology
Terms
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- Implantation of blastocyst is present in which week?
- 1
- The bilaminar disk is formed within which week?
- 2
- Gastrulation, primitive streak, notochord, neural plate begin to form
- Within week 3
- Neural tube formed, organogenesis, extremely susceptible to teratogens
- Weeks 3-8
- Heart begins to beat, Upper and lower limb buds begin to form
- Week 4
- When do genitalia begin to have male/female characteristics?
- Week 10
- From day 0 to implantation at end of week 1, name stages of embryogenesis
- From day 0 to implantation at end of week 1, name stages of embryogenesis
-
For next 9, name effect on fetus of following teratogens
ACE Inhibitors - Renal damage
- Cocaine
- Abnormal fetal development, fetal addiction
- DES
- vaginal clear cell adenocarcinoma
- Iodide
- congenital goiter or hypothyroidism
- 13-cis-retinoic acid
- extremely high risk for birth defects
- thalidomide
- thalidomide
- warfarin, x-rays
- multiple anomalies
- fetal infections
- congenital malformations
- how many umbilical arteries?
- 2
- what kind of blood do the umbilical arteries carry?
- deoxygenated blood from fetus
- how many umbilical veins?
- 1
- what kind of blood is carried by umbilical vein?
- supplies oxygenated blood from placenta to the fetus
- a single umbilical artery is associated with what anomalies?
- congenital and chromosomal
-
What dervies from the following embyologic layers
Surface Ectoderm - adenohypophysis, lens of eye, epithelial linings, epidermis
- neuroectoderm
- neurohypophysis, CNS neurons, oligodendrocytes, astrocytes, pineal gland
- neural crest
- ANS, dorsal root ganglia, melanocytes, chromaffin cells of adrenal medulla, enterochromaffin cells, pia, celiac ganglion, Schwann cells, odontoblasts, parafollicular - C cells of thyroid, laryngeal cartilage
- mesoderm
- dura connective tissue, muscle, bone, cardiovascular structures, lymphatics, blood urogenital structures, serous linings of body cavities (peritoneal), spleen, adrenal cortex
- endoderm
- gut tube epithelium and derivatives (lungs, liver, pancreas, thymus, thyroud, parathyroid)
- what induces ectoderm to form neuroectoderm (neural plate)?
- notochord
- what is the postnatal derivative of the notochord?
- nucleus pulposus of the intervertebral disk
- Name the precursor for the ectoderm and its purpose
- epiblast, invaginates to form primitive streak
- Cells from the primitive streak give rise to
- intraembryonic mesoderm and endoderm
- How many germ layers in second week and what are they?
- 2, epiblast and hypoblast (remember rule of 2's for second week)
- How many cavities in second week and what are they?
- 2, amniotic cavity and yolk sac (remember rule of 2's for second week)
- How many components to placenta in second week and what are they?
- 2, cytotrophoblast and syncytiotrophoblast (remember rule of 2's for second week)
- How many germ layers in third week and what are they?
- 3, (gastrula): ectoderm, mesoderm, endoderm (Rule of 3's for third week)
- In the 3-8th weeks, fetal erythropoiesis occurs in
- Yolk sac
- In the 6-30th weeks, fetal erythropoiesis occurs in
- Liver
- In the 9-28th weeks, fetal erythropoiesis occurs in
- Spleen
- Erythropoiesis occurs in the Bone marrow from the ---- week onward
- 28th
- Mnemonic for remembering fetal erythropoiesis?
- Young Liver Synthesizes Blood
-
Embryonic structure gives rise to:
Truncus arteriosus - Ascending aorta and pulmonary trunk
- Bulbus cordis
- Smooth parts of left and right ventricle
- Primitive ventricle
- trabeculated parts of left and right ventricle
- Primitive atria
- trabeculated left and right atrium
- Left horn of sinus venosus (SV)
- coronary sinus
- Right horn of sinus venosus (SV)
- smooth part of right atrium
- Right common cardinal vein and right anterior cardinal vein
- SVC
- Saturation level of blood in umbilical vein?
- 80%
- Foramen ovale: its function in fetal circulation?
- Most oxygenated blood reaching the heart via the IVC is diverted through the foramen ovale and pumped out the aorta to the head.
- Ductus Arteriosus: its function in fetal circulation?
- Deoxygenated blood from the SVC is expelled into the pulmonary artery and ductus arteriosus to the lower body of the fetus.
- What happens at birth, when infant takes a breath?
- Decreased resistance in pulmonary vasculature causes increased left atrial pressure vs right atrial pressure; foramen ovale closes; increase in O2 leads to decrease in prostaglandins, causing closure of ductus arteriosus.
- What drug can be given to close a patent ductus arteriosus?
- Indomethacin
- What drug can be given to keep a patent ductus arteriosus open?
- Prostaglandins
-
Fetal-postnatal derivatives
Umbilical vein becomes the: - ligamentum teres hepatis
- umbilical arteries become the:
- medial umbilical ligaments
- ductus Arteriosus becomes the:
- ligamentum arteriosum
- ductus venosus becomes the:
- ligamentum venosum
- foramen ovale becomes the:
- fossa ovalis
- allantois - urachus becomes the:
- median umbilical ligament
- notochord becomes the:
- nucleus pulposus
- urachal cyst or sinus is a remnant of the:
- allantois (urine drainage from the bladder)
-
Aortic Arch Derivatives
1st arch: - part of maxillary artery (1st is MAXimal)
- 2nd arch:
- stapedial artery and hyoid artery (Second = Stapedial)
- 3rd arch:
- common Carotid artery and proximal part of internal carotid artery (C is the 3rd letter of the alphabet)
- 4th arch:
- on left, aortic arch; on right, proximal part of right subclavian artery 4th arch (4 limbs) = systemic
- 6th arch:
- proximal part of pulmonary arteries and (on left only) ductus arteriosus. 6th arch = pulmonary and the pulmonary-to-systemic shunt (ductus arteriosus)
- branchial clefts are dervied from:
- ectoderm
- branchial arched are derived from:
- mesoderm and neural crests
- branchial pouches are derived from:
- endoderm
- mnemonic to remember branchial apparatus derivation:
- CAP covers outside from inside (Clefts = ectoderm, Arches = mesoderm, Pouches = endoderm)
-
Branchial arch 1 derivatives
Meckel's cartilage: - Mandible, Malleus,incus,sphenoMandibular ligament
- Muscles:
- muscles of facial expression, Stapedius,Stylohyoid, posterior belly of digastric.
- Nerve:
- CN IX
-
Branchial Arch 2 derivatives
Reichert's cartilage: - Stapes, Styloid process, lesser horn of hyoid, Stylohyoid ligament
-
Branchial arch 3 derivatives
Cartilage: - greater horn of hyoid
- Muscle:
- stylopharyngeus (Think of pharnx: stylopharyngeus is innervated by glossopharyngeal nerve.
-
Branchial arch 4 to 6 derivatives
Cartilages: - thyroid, cricoid, arytenoids, cornicuate, cuneiform
- Muscles (4th arch):
- mostly pharyngeal constrictors, cricothyroid, levator veli palatini.
- 5th arch:
- makes no major developmental contributions
- Muscles (6th arch):
- all intrinsic muscles of larynx except cricothyroid
- Nerve (6th arch):
- CNX (recurrent laryngeal branch)
-
Branchial arch innervation
Arch 1 derviatives are supplied by: - CN V2 and V3
- Arch 2 derivatives are supplied by:
- CN VII
- Arch 3 derivatives are supplied by:
- CN IX
- Arch 4 and 6 derivatives supplied by:
- CNX
-
Branchial cleft derivatives
1st cleft develops into - external auditory meatus
- 2nd through 4th clefts form:
- temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme.
- Persistent cervial sinus can lead to a:
- branchial cyst in the neck
-
Ear development:
Bone: Incus/Malleus come from: - 1st arch
- Bone: Stapes comes from:
- 2nd arch
- Muscle: Tensor tympani (V3) comes from:
- 1st arch
- Muscle: Stapedius (VII) comes from:
- 2nd arch
- External auditory meatus comes from:
- 1st cleft
- Eardrum, eustacian tube comes from:
- 1st pharyngeal membrane
-
Branchial pouch derviatives:
1st pouch develops into: - middle ear cavity, eustacian tube, mastiod air cells (1st pouch contributes to endoderm-lined structures of ear)
- 2nd pouch develops into:
- epithelial lining of palatine tonsil
- 3rd pouch (dorsal wings) develops into:
- inferior parathyroids (3rd pouch contributes to 3 structures: thymus, left and right inferior parathyroids)
- 3rd pouch (ventral wings) develops into:
- thymus
- 4th pouch develops into:
- superior parathyroids
- Aberrant development of 3rd and 4th pouches -->
- DiGeorge's syndrome --> leads to T-cell deficiency (thymic hypoplasia) and hypocalcemia (parathyroid glands)
-
Thymus
Site of: - T-cell maturation
- Encapsulated or unencapsulated?
- encapsulated
- which branchial pouch?
- from epithelium of 3rd branchial pouches
- Lymphocyte origin?
- lymphocytes are of mesenchymal origin
- cortex is dense with:
- immature T cells
- medulla is pale with:
- mature T cells and epithelial reticular cells and contains Hassall's corpuscles. (think of the Thymus as "finishing school" for T cells. They arrive immature and "dense" in the cortex; they are mature in the medulla.
- What occurs at the corticomedullary junction?
- Positive and negative selection
- Thyroid diverticulum arises from:
- floor of primitive pharnyx, descends into neck.
- Connected to tongue by
- thyroglossal duct, which normally disappears but may persist as a pyramidal lobe of thyroid.
- Formen cecum is:
- a normal remnant of the thyroglossal duct
- The most common ectopic thyroid tissue site is the:
- Tongue!
-
Tongue development
1st branchial arch forms the - anterior 2/3 of the tongue (thus sensation via CN V3, taste via CNVII)
- 3rd and 4th branchial arches form:
- posterior 1/3 of the tongue (thus sensation and taste mainly via CN IX, extreme posterior via CN X).
- Cranial nerves for taste?
- CN VII, IX, X (solitary nucleus)
- Motor innervation is via CN?
- CN XII
- define cleft lip
- failure of fusion of the maxillary and medial nasal processes
- define cleft palate
- failure of fusion of the lateral palatine processes, the nasal septum, and/or the median palatine process.
- diaphragm is derived from:
- Septum transversarium, Pleuroperitoneal folds, Body wall, Dorsal mesentery of esophagus (Several Parts Build Diaphragm. Diaphragm descends during develpoement but maintains innervation from above C3-C5. "C3, 4, 5 keeps the diaphragm alive."
- What is a hiatial hernia
- abdominal contents may herniate into the throax due to incomplete development of the diaphragm.
- What is Intramembranous bone formation
- spontaneous bone formation without preexisting cartilage.
- What is Endochondral bone formation
- ossification of carilaginous molds. Long bones form by this type of ossification at 1o and 2o centers
- What is Meckel's diverticulum
- persistence of the vitelline duct or yolk stalk. May contain ectopic acid-secreting gastric muscosa and/or pancreatic tissue.
- What is the most common congenital anomaly of the GI tract?
- Meckel's diverticulum
- Complications of Meckel's Diverticulum?
- can cause bleeding or obstruction near the terminal ileum.
- Comparison of Meckel's Diverticulum to Omphalomesenteric cyst?
- Cystic dilatation of the vitelline duct.
- It is Associated with
- intussusception and volvulus
- Mnemonic to remember Meckel's diverticulum
- The five 2's: 2 inches long, 2 feet from the ileocecal valve, 2% of population, commonly presents in first 2 years of life, may have 2 epithelia.
- Parcreas is derived from the
- foregut
- ventral pancreatic bud becomes the
- pancretic head, uncinate process (lower half of head), and main pancreatic duct.
- dorsal pancreatic bud becomes:
- everything else (body, tail, isthmus, and accessory pancreatic duct).
- Spleen arises from
- dorsal mesentery but is supplied by artery of foregut.
- Mesonephric (wolffian) duct develops into
- Develops into Seminal vesicles, Epididymis, Ejaculatory duct, and Ductus deferens (SEED)
-
Paramesonephric (mullerian) duct
develops into - Develops into fallopian tube, uterus, and part of vagina.
- Mullerian inhibiting substance is secreted by:
- the testes to suppress development of paramesonephric ducts in males.
-
Bicornuate uterus:
results from and is Associated with -
incomplete fusion of the paramesonephric ducts.
urinary tract abnormalities and infertility - Genital tubercle (male) -->
- glans penis via dihydrotestosterone
- genital tubercle (female) -->
- glans clitoris via estrogen
- urogenital sinus (male) -->
- corpus spongiosum, bulbourethral glands (of Cowper), prostate gland: via dihydrotestosterone
- urogenital sinus (female) -->
- vestiubular bulbs, greater vestibular glands (of Bartholin), Urethral and paraurethral glands (of Skene): via estrogen
- urogenital folds (male) -->
- ventral shaft of penis (penile urethra) via dihydrotestosterone
- urogenital folds (female) -->
- labia minora via estrogen
- labioscrotal swelling (male) -->
- scrotum via dihydrotestosterone
- labioscrotal swelling (female) -->
- labia majora via estrogen
-
Congenital penile abnormalities
Hypospadia - abnormal opening of the penile urethra on inferior (ventral) side of penis due to failure of urethral folds to close.
- Epispadia
- abnormal opening of the penile urethra on superior (dorsal) side of penis due to faulty positioning of the genital tubercle.
- epispadia is associated with
- exstrophy of the bladder
- Which is more common, hypospadia or epispadia?
- Hypospadial; fix hypospadias to prevent UTI's
-
Derivation of sperm parts:
acrosome is derived from - the golgi apparatus and flagellum (tail) from one of the centrioles.
- what does the neck of the sperm have?
- Middle piece (neck) has Mitochondria.
- Sperm food supply is:
- fructose
- Primary oocytes begin and complete meiosis I when?
- begin: during fetal life; complete: just prior to ovulation. Meiosis I is arrested in prOphase for years until Ovulation.
- What phase is Meiosis II arrested in?
- Meiosis II is arrested in METaphase until fertilization. -- "An egg MET a sperm."
- What is polyhydramnios?
- high amount of amniotic fluid (>1.5-2L)
- What is polyhydramnios clinically associated with?
- esophageal/duodenal atresis and anencephaly both of which impair the ability of the fetus to swallow amniotic fluid
- What is the condition leading to low amniotic fluid (<0.5L) called?
- Oligohydramnios
- What 2 conditions is oligohydramnios associated with?
- Bilateral renel agenesis or posterior urethral valves (in males) which results in the failure of the fetus to excrete urine into the amniotic fluid.
- What syndrome can oligohydramnios result in?
- Potter's Syndrome
- What does the term Potter's syndrom describe?
- Bilateral renal agenesis leading to oligohydramnios which results in fetal limb and facial deformaties and pulmonary hypoplasis
- What causes Potter's syndrome?
- Malformation of the ureteric bud
- What results when the poles of both kidneys fuse during development?
- Horseshoe kidney
- What arrests the ascend of the fused kidneys?
- The horseshoe kidneys get trapped under the inferior mesenteric artery.
- Which muscles form the rotator cuff?
- Supraspinatus, Infraspinatus, Teres minor, and Subscapularis (SItS)
- Which muscle helps the deltoid abduct the arm?
- Supraspinatus
- What function does the Infraspinatus muscle have?
- laterally rotates the arm at the shoulder joint
- What is the function of the Teres minor muscle?
- to adduct and laterally rotate the arm (Possible mistake in First Aid)
- Which muscle medically rotates and adducts the arm?
- Subscapularis
- Name the thenar muscles.
- Opponens pollicis, Abductor pollicis brevis, Flexor pollicic brevis
- Name the hypothenar muscles.
- Opponens digiti minimi, Abductor digiti minimi, Flexor digiti minimi
- What functions do the thenar and hypothenar muscles preform?
- oppose, abduct and flex (OAF)
- What structures can be injured when a football player's cleated shoe is planted firmly in the turf and the knee is struck from the lateral side?
- medial collateral ligament (MCL), medial meniscus, and anterior cruciate ligament (ACL) (unhappy triad on the knee joint)
- What does a anterior drawer sign indicate?
- Tearing of the Anterior cruciate ligament (ACL)
- What does abnormal passive abduction indicate?
- A torn Medial collateral ligament (MCL)
- The recurrent laryngeal nerve is a branch of which cranial nerve?
- CN X
- Which muscles does it supply?
- intrinsic muscles of the larynx except the cricothyroid muscle
- What structure does the right recurrent laryngeal nerve wrap around?
- right subclavian artery
- What structure does the left recurrent laryngeal nerve wrap around?
- arch of the aorta and the ligamentum arteriosum
- In what kind of surgery can this nerve be damaged in?
- thyroid surgery
- What happens when this nerve gets damaged?
- hoarseness
- Name the layers of the scalp
- skin, connective tissue, aponeurosis, loose connective tissue, pericranium (SCALP)
- Name the meninges.
- Dura, arachnoid, and pia (DAP)
- What space is found between the dura and arachnoid?
- subdural space
- Between what meninges is the subarachnoid space located?
- between the arachnoid and the pia
- What is found in the subarachnoid space?
- CSF
- In which scalp layer are the emissary veins found?
- loose connective tissue
- List the structures found in the carotid sheath (in the order from lateral, medial, posterior)
- Internal jugular vein, common carotid artery, and vagus nerve (VAN)
- What structure crosses the diaphragm at T8?
- IVC (I 8 10 EGG's AT 12)
- At what T level does the esophagus and vagus nerve cross the diaphragm?
- T10 (I 8 10 EGG's AT 12)
- What structure crosses the diaphragm at T12?
- aorta, thoracic duct, and azygous vein (I 8 10 EGG's AT 12)
- Name the innervation of the diaphragm
- C3, 4, and 5 (phrenic nerve)
- Where can the pain from the diaphragm be reffered to?
- shoulder
- What artery supplies the SA and AV nodes?
- RCA right coronary artery
- The inferior portion of the left ventricle is supplied by what artery 80% of the time?
- RCA via the PD posterior descending artery
- In which artery does coronary artery occlusion most sommonly occur?
- LAD left anterior descending artery
- What artery supplies the anterior interventricular septum?
- LAD left anterior descending artery
- When do coronary arteries fill?
- during diastole
- What is the most posterior part of the heart?
- left atrium
- What can the enlargement of the left atrium cause?
- dysphagia
- What does each bronchopulmonary segment contain?
- 3ยบ (segmental) bronchus and 2 arteries (bronchial and pulmonary) in the center
- What drains along the borders of the bronchopulmonary segments?
- veins and lymphatics
- What runs with the airways?
- arteries
- How many lobes does the right lung has?
- 3 lobes
- Which lung lobe has 2 lobes?
- left
- What is the homologue of the right middle lobe in the left lobe?
- lingula
- Which lung is the more common site for inhaled foregin body?
- right lung?
- Why is 1 lung a more common site for inhaled foregin body?
- Because of the lessvacute angle of the right main stem bronchus
- What is the relation of the pulmonary artery to the bronchus in each lung hilus?
- RALS - right lung anterior and left lung superior
- What does the femoral sheath contain?
- femoral artery, femoral vein, and femoral canal (containing deep inguinal lymph node)
- Does the femoral nerve lie within the femoral sheath?
- no, it lies outside the sheath
- What do you call the entrance of abdominal contents through the femoral canal?
- femoral hernia
- What does the femoral triangle contain?
- femoral vein, aretery and nerve (VAN)
- Where does the femoral hernia protrude to?
- below and lateral to the pubic tubercle
- What are abdominal hernias?
- protrusions of peritoneum through an opening - usually sites of weakness
- What is the name of the hernia in which abdominal structures enter the thorax?
- diaphragmatic hernia
- What is the most common diaphragmatic hernia?
- hiatal hernia
- What happens in this type of hernia?
- the stomach herniates upward through the esophageal hiatus
- What can result from a defective development of pleuroperitoneal membrane in infants?
- diaphragmatic hernias
- From where does a direct hernia protrude?
- from the inguinal (Hesselbach's) triangle - bulges directly through the abdominal wall medial to the inferior epigastric artery
- Which inguinal ring does it go through?
- external inguinal ring only
- Who usually gets a direct hernia?
- older men
- What does the indirect hernia go through?
- the internal (deep) inguinal ring and external (superficial) inguinal ring and into the scrotum
- On which side of the inferior epigastric artery does the indirect hernia enter the internal inguinal ring?
- lateral to the inferior epigastric artery
- Who usually get an indirect hernia and why?
- infants, because of the failure of processus vaginalis to close
- Which structures make up Hesselbach's triangle?
- inferior epigastric artery, lateral border of rectus abdominis, and inguinal ligament
- Where does the inguinal canal start and end?
- begins at the deep inguinal ring and terminates at the superficial ring
- What does the inguinal canal transmit?
- the spermatic cord or the round ligament of the uterus and the genital branch of the genitofemoral nerve
- What structures make up the anterior wall of the inguinal canal?
- aponeuroses of the external oblique and internal oblique muscles
- What structures make up the posterior wall of the inguinal canal?
- aponeurosis of the transverse abdominal muscle and transversalis fascia
- What structures make up the superior wall of the inguinal canal?
- arching fibers of the internal oblique and transverse muscles
- What structures make up the inferior wall (floor) of the inguinal canal?
- inguinal and lacunar ligaments
- From where does the stomach receive its main blood supply?
- from the branches of the celiac trunk
- From where does the celiac trunk arise?
- from the front of the abdominal artery immediately below the aortic hiatus of the diaphragm
- What arteries does the celiac trunk divide into?
- left gastric, splenic, and common hepatic arteries
- What does the left gastric artery run along?
- lesser curvature of the stomach
- What artery does the left gastric artery anastomose with?
- the right gastric artery
- What does the splenic artery run along?
- runs along the superior boarder of the pancrease
- What arteries does the splenic artery give rise to?
- (dorsal pancreatic artery), short gastric arteries and left gastroepiploic artery
- What does the left gastroepiploic artery run along?
- the greater curvature of the stomach
- What does the common hepatic artery divide into?
- hepatic artery proper, right gastric artery, and gastroduodenal artery
- esophageal varices results at the anastamosis of which veins?
- left gastric vein (portal) and azygous (systemic)
- manifestation of portal hypertension at the anastamosis of the superior rectal with the middle/inferior rectal veins
- hemorrhoids
- caput medusae is at anastamosis of which veins
- paraumbilical (portal) and inferior epigastric (systemic)
- the two other sites of portal system anastamosis
- retroperitoneal vein (portal) with renal vein (systemic) and retroperitoneal vein with paravertebral vein (systemic)
- 3 manifestations seen in alcoholic cirrhosis
- esoph. Varices, hemorrhoids, caput medusae "Gut, butt and caput"
- What drains the lymph from right arm and right half of head
- right lymphatic duct
- What does the Thoracic duct drain
- everything that right lymphatic duct does not
- location of pectinate line
- where hindgut meets ectoderm
- innervation, hemorrhoid type, aterial supply and venous drainage above pectinate line
- visceral innervation(not painful), internal hemorrhoids (think of adenocarcinoma association), superior rectal artery(branch of IMA), and superior rectal vein to inferior mesenteric vein to portal system
- innervation, hemorrhoid type, aterial supply and venous drainage below pectinate line
- somatic innervation(painful!), external hemorrhoids (think of squamous cell carcinoma association), inferior rectal artery, inferior rectal vein to internal pudendal vein to internal iliac vein to IVC
- parts of duodenum that are retroperitoneal
- 2nd, 3rd and 4th parts