Embryology Flashcards

1
Q

MSK:

• Mesenchyme is the same as_____ ______ _______

A

embryonic connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

MSK:

What is mesenchyme?

A

a loosely organized, mainly mesodermal embryonic tissue which develops into connective and skeletal tissues, including blood and lymph.

From the mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

MSK:

The mesenchymal cells migrate and differentiate into what?

A

into many different types of primitive cell lines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

MSK:

Examples of 3 different types of primitive cell lines?

A
  1. Fibroblasts (adult connective tissue forming cells)
  2. Chondroblasts (cartilage forming cells)
  3. Osteoblasts (bone forming cells)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

MSK:

What does the mesenchyme in the paraxial mesoderm do?

A

it will transform into osteoblasts that will form the bony elements of the vertebral column

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

MSK:

What does the mesenchyme in the somatopleuric mesoderm do?

A

will transform into osteoblasts that will form the pelvic/pectoral girdles and also the bones of the upper and lower limbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

MSK:

What is the process of bone formation known as?

A

Ossification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

MSK:

Whw does bone start to develop?

A

develops during the intra uterine life through 2 types of ossification

  1. Membranous type (intermembranous)
  2. Intra cartilgainous type (endochondral)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

MSK:

What is intermembranous ossifiction?

A

(mesenchymal tissue will directly transform into bone) eg: the flat bones of the skull

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

MSK:

What is endochondral ossifiction?

A

(mesenchymal tissue first gives rise to a hyaline cartilage model of the bone, then the osteoblasts will convert that model into bone) eg: long and irregular bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

MSK:

What is the entire muscular system of the body developed from?

A

mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

• The entire muscular system of the body develops from the mesoderm (except from the muscles of the_____, which develop from the _______ of the optic cups)

A

iris

ectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The cardiac muscles of the heart develop from the _________ ______ surrounding the primitive heart tube

A

splanchnic mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The smooth muscles of the GI tract develop from the _______ _______ surrounding the gut tube

A

splanchnic mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

MSK:

How many pharyngeal arches are there in the human development?

A

5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

MSK:

Each pharyngeal arch has its own:

A

Cartilage skeleton,

muscular component,

sensory nerve supply,

motor nerve supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

MSK:

Muscles of mastication are dervied from which pharyngeal arch?

Which nerve is the muscle innervated by?

A

derived from the 1st pharyngeal arch and are therefore innervated by the Trigeminal nerve (V)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

MSK:

Muscles of facial expression are dervied from which pharyngeal arch?

Which nerve is the muscle innervated by?

A

derived from the 2nd pharyngeal arch and therefore are innervated by the Facial nerve (VII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Uro:

What are the 3 stages in the development of the kidney:

A
  1. Pronephros
  2. Mesonephros
  3. Metanephros
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Uro:

Embryology of the kidney

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Uro:

Embryology of Kidney

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Uro:

Embryology of Kidney

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Uro:

When doe the pronephros develope?

A

It develops during the 4th week of uterine life in the cervical region of the intermediate mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Uro:

What does pronephros contain?

A

The pronephros contains lots of segmental vesicles and has the pronephric duct that grows caudally toward the cloaca

  • The pronephric duct is in the embryo and thus cannot filter materials outside the embryo.
  • Therefore it is said that the pronephros kidney is non-functional in humans thus it degenerates.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Uro:

When is mesonephros developed?

A
  • The Mesonephros kidney follows on from the development pronephros at around the end of the 4th week of uterine life
  • It also comes from intermediate mesoderm and is located in the thoraco-lumbar area where the pronephric duct that was developed in the pronephros stage continue to elongated caudally and become the mesonephric tubules.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Uro:

Does the mesonephros degenerate?

A

Most of this tubules eventually degenerates but leave behind the Mesonephric duct or Wolffian duct which extends towards the cloaca

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Uro:

The mesonephros is the functioning kidney during the __ trimester and it produces urine during weeks____

A

1st

6-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Uro:

When does Metanephros develop?

A

This kidney begins to develop in the 5th week of the embryonic period and

appears in the sacral region of the intermediate mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Uro:

What happens to metanephros during the fifth week?

A

the mesonephric duct from the mesonephros kidney develops an outgrowth called the ureteric duct. This duct is close to the attachment of the cloaca.

The ureteric duct eventually forms the ureter, renal pelvis, major calyces, minor calyces and collecting tubules

  • The ureteric bud interacts with a portion of undifferentiated intermediate mesoderm called the metanephric mesenchyme.
  • This interaction induces differentiation and thus the formation of the renal tubules, glomerulus, loops of Henle, and the distal/proximal convoluted tubules
  • If there is an abnormal interaction between the ureteric bud and the metanephric mesenchyme, several congenital malformation of the kidney may result.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Uro:

Embryology of the Kidney

Part A

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Uro:

Embryology of the Kidney

Part B

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Uro:

Embryology of the Kidney

Part C and D

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Uro:

Embryology of the Kidney

Part E

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Uro:

What is Sexual differentiation?

A

is the process of the development of the differences between males and females from an undifferentiated zygote.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Uro:

What carries the essential gene that determines testicular formation?

A

Y chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Uro:

What induces differentiation of cells derived from the genital ridges into testes?

A

A gene in the sex-determining region of the short arm of the Y, known as SRY leads to the formation of testis determining factor (TDF), which binds to DNA and induces differentiation of cells derived from the genital ridges into testes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Uro:

When are the gonads distinguishable by?

A

weeks 6-8 of gestation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Uro:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Uro:

Outline the embryology of testes

A
  • Between the 3rd month and the end of pregnancy, the testes become transferred from the lumbar area into the future scrotum.
  • This transfer is due to a combination of growth processes and hormonal influences.
  • The gubernaculum testis arises in the course of the 7th week from the lower gubernaculum, after the mesonephros has atrophied. Cranially it has its origin at the testis and inserts in the region of the genital swelling (future scrotum).
  • At the same time, at the inguinal canal along the lower gubernaculum, an evagination of the peritoneum arises, the vaginal process, on which the testes will slide through the inguinal canal.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Uro:

Embryology of the ovaries

A

Mesonephric duct (Wolffian duct) degenerates, small remnants may remain as epoophoron and paroophoron (in the mesentery of the ovary) and Gartner’s cyst’s (near vagina)

  • Paramesonephric duct (Müllerian duct) grows and forms the oviduct (uterine horn) and the end opens into the peritoneal cavity and terminates in fimbria (finger-like extensions extending from the ovary)
  • Away from the ovary, the two paramesonephric ducts fuse in the midline to form the uterus
  • Cortical sex cords form after the primary sex cords degenerate and the mesothelium forms secondary cords
  • The surrounding connective tissue differentiates to form follicle cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Uro:

Embryology of the uterus and vagina

A

The entire vagina is formed from the paramesonephric (Müllerian) duct and does not have a contribution from the urogenital endoderm

  • The initially paired ducts fuse in the midline forming the single body of the uterus
  • The ducts remain separate laterally where they form the uterine tubes (Fallopian tubes, uterine horns)
  • The ducts peripheral attachment site to the urogenital sinus wall is described as the Müllerian tubercle
  • The fused ducts also generate the vagina, under the influence of BMP4
  • Oestrogen will also later alter the vaginal epithelium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What are the three germ layers?

A

Ectoderm, mesoderm and endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Mesoderm splits into……

A

somatic mesoderm (next to endoderm) and splanchnic mesoderm (next to ectoderm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

three main body cavities will form in the space between…..

A

the two mesoderm’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

The three main body cavities are:

A

the pleural cavity,

pericardial cavity

the peritoneum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

________ and _______ mesoderm become the two pleural layers (visceral and parietal respectively)

A

Splanchnic

somatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Resp:

In what week does the laryngotracheal groove form?

A

week 4 of development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Resp:

What happens in week 4 of development?

A
  • the laryngotracheal groove forms
  • This gives rise to the trachea, bronchi and the tracheobronchial tree
  • It then develops into the laryngotracheal diverticulum which by the end of week week 4 forms a globular respiratory bud
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Resp:

• The respiratory bud then divides into 2 outpouchings called ____ ______ __

A

Primary bronchial buds

These buds continue to grow and secondary and tertiary bronchial buds develop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Resp:

What happens to the bronchial buds by the end of week 5?

A

By week 5, the bronchial buds have enlarged and their connections to the trachea form the main bronchi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Resp:

What happens after week 5? (lungs)

A

the lungs begin maturation

This continues up until the age of 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Resp;

Lung maturation

Pseudoglandular stage is between how many weeks?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Resp;

Lung maturation

Canalicular stage is between how many weeks?

A

Canalicular stage 16-26 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Resp;

Lung maturation

Terminal sac stage is between how many weeks?

A

Terminal sac stage 26 weeks to birth

55
Q

Resp:

Lung maturation

Alveolar stage is between how many weeks?

A

Alveolar stage 32 weeks – 8 years old

56
Q

Resp:

What happens in the Pseudoglandular stage?

A
  • By 16 weeks, all the major elements of the lungs have formed…
  • EXCEPT those involved in gas exchange
  • Therefore, respiration isn’t possible and a fetus born at this stage is unable to survive
57
Q

Resp:

What happens in the Canalicular stage?

A
  • Cranial segments of lungs develop faster than caudal
  • Lumen of bronchi and terminal bronchioles are enlarging
  • Lung tissue becomes vascularised
  • Respiration is possible towards the middle/end of this stage
  • It is possible because of the primordial alveolar sacs & vascularisation
58
Q

Resp:

What happens in the Terminal sac stage?

A
  • More terminal sacs develop (they have a very thin epithelium)
  • Capillaries bulge into developing alveoli and adequate gas exchange can occur if the foetus is born after 26 weeks
  • Lung surfactant starts to be produced
  • Capillary networks proliferate rapidly around the alveoli
59
Q

Resp:

What happens in the Alveolar stage?

A
  • Epithelial lining becomes a thin, squamous epithelial layer (these are type 1 pneumocytes)
  • By the late fetal stage, the lungs are capable of respiration because the alveolar capillary membrane is sufficiently thin enough to allow gas exchange
60
Q

Resp:

What are the key difference between the lungs before and after birth:

A
  • Before birth, the lungs are dependent on the placenta for gas exchange
  • After birth, the lungs must become capable to carry out gas exchange themselves (ie: produce surfactant, good circulation)
61
Q

The primitive gut forms during what week?

A

4th week

62
Q

The flat embryonic discs folds to…….

A

forma tubular structure

63
Q

Forma tubular structure is divided into 3 distinct regions. What are they?

A

Foregut

Midgut

Hindgut

64
Q

Gastro:

What does the foregut give rise to?

A

esophagus

stomach

liver

gallbladder

bile ducts

pancreas

proximal duodenum.

65
Q

Gastro:

What does the midgut give rise to?

A

distal duodenum

jejunum

ileum

cecum

appendix

ascending colon

proximal 2/3 of transverse colon.

66
Q

Gastro:

The hingut becomes?

A

distal 1/3 of the transverse colon

descending colon

sigmoid colon

the upper anal canal.

67
Q

Gastro:

GI embryology = mesoderm, ectoderm or endoderm

A

ectoderm

68
Q

Gastro:

Connective tissue, smooth muscle and serosa all arise from the __________ ___________(NOT THE ECTODERM!)

A

splanchnopleuric mesoderm

69
Q

Gastro:

A
70
Q

Gastro:

★ Primitive stomach rotates ________

★ Uneven growth (the p_______ side grows more rapidly causes the J shape of the stomach and the formation of the lesser and greater curvatures)

★ When it rotates, it pulls the _______ ________ over the top of itself – this forms the lesser sac

★ Meanwhile, the _______ is growing in the dorsal mesogastrium so therefore, it is pulled by the stomach rotation into the ____ ________ _____

★ Thus _____ ______ligament between the stomach and the spleen

★ Between the stomach and the liver = l_____ ______ with the free border carrying the hepatic artery, the bile duct and the ____ ______ ___

A

★ Primitive stomach rotates 90 degrees

★ Uneven growth (the posterior side grows more rapidly causes the J shape of the stomach and the formation of the lesser and greater curvatures)

★ When it rotates, it pulls the dorsal mesogastrium over the top of itself – this forms the lesser sac

★ Meanwhile, the spleen is growing in the dorsal mesogastrium so therefore, it is pulled by the stomach rotation into the left hypochondrial region

★ Thus gastro-splenic ligament between the stomach and the spleen

★ Between the stomach and the liver = lesser omentum with the free border carrying the hepatic artery, the bile duct and the hepatic portal vein

71
Q

Gastro:

STOMACH

A
72
Q

Gastro:

STOMACH

A
73
Q

Gastro:

DUODENUM

A
74
Q

Gastro:

  • DUODENUM

★The duodenum is derived from the _____ and _____ (half and half separated by the entry of the bile duct)

★ It is a solid structure at first, and so must undergo _________ (a process to restore the hollow lumen of the duodenum)

★ Failure of recanalization = _________ _______

★ Duodenum rotates to the _____ (stomach rotates to the left)

★ Duodenum has a ______ ____ _____(FG&MG)

A

★The duodenum is derived from the foregut and midgut (half and half separated by the entry of the bile duct)

★ It is a solid structure at first, and so must undergo recanalization (a process to restore the hollow lumen of the duodenum)

★ Failure of recanalization = Duodenal stenosis

★ Duodenum rotates to the right (stomach rotates to the left)

★ Duodenum has a dual blood supply (FG&MG)

75
Q

Gastro:

Pancreas

A
76
Q

Gastro:

PANCREAS

★ The pancreas develops from a ____ and_____ bud

★ The dorsal bud = in the dorsal _______

★ The ventral bud = in the ventral _______

★ The buds _____ and come together in the same plane, they then fuse together

★ The duct of the larger dorsal bud forms the _____ ______ _______

A

★ The pancreas develops from a dorsal and ventral bud

★ The dorsal bud = in the dorsal mesentery

★ The ventral bud = in the ventral mesentery

★ The buds twist and come together in the same plane, they then fuse together

★ The duct of the larger dorsal bud forms the main pancreatic duct

77
Q

Gastro:

LIVER/BILIARY TREE

A
78
Q

Gastro:

LIVER/BILIARY TREE

★The liver forms from the h_______ d_______

★ It enlarges to fill the s_______ t_________ (the space it will occupy)

★ The liver is large in size (see diagram!) – by___weeks, it is forming blood cells

★ The gall bladder duct is solid at first and must undergo r________

★ Failure to recanalize =_______ _______ ______

A

★The liver forms from the hepatic diverticulum

★ It enlarges to fill the septum transversium (the space it will occupy)

★ The liver is large in size (see diagram!) – by 10 weeks, it is forming blood cells

★ The gall bladder duct is solid at first and must undergo recanalization

★ Failure to recanalize = Extrahepatic biliary atresia

79
Q

Gastro:

MIDGUT

A
80
Q

Gastro:

MIDGUT

A
81
Q

Gastro:

MIDGUT

★ At first, the midgut has a wide communication with the y____ ____

★ This narrows to form the_______ _______duct

★ The midgut rapidly elongates and can no longer fit in the abdominal cavity

★ It therefore herniates out of the abdomen and into the ______ _______

★ It undergoes __ ____ _________rotation on departure, and ____ ____ ________rotation on return to the abdomen

A

★ At first, the midgut has a wide communication with the yolk sac.

★ This narrows to form the vitello-intestinal duct

★ The midgut rapidly elongates and can no longer fit in the abdominal cavity

★ It therefore herniates out of the abdomen and into the umbilical cord

★ It undergoes 90 degrees anticlockwise rotation on departure, and 180 degrees clockwise rotation on return to the abdomen

82
Q

Gastro:

HINDGUT

A
83
Q

Gastro:

HINDGUT

★ The endodermal lining also forms the epithelial lining of the______r and u______

★ The _____ ______ opens

★ ________ ______ divides the cloaca anteriorly (urogenital sinus) and posteriorly (rectum)

★ Mucosa of the upper ½ of the anal canal is from hindgut _______

★ Mucosa of the lower ½ of the anal canal is from the ________ (the proctodaeum)

★ Pectinate line demarcates upper from lower half

★ It fills completely and ___________ occurs in wk9

A

★ The endodermal lining also forms the epithelial lining of the bladder and urethra

★ The primitive cloaca opens

Mesenchymal tissue divides the cloaca anteriorly (urogenital sinus) and posteriorly (rectum)

★ Mucosa of the upper ½ of the anal canal is from hindgut endoderm

★ Mucosa of the lower ½ of the anal canal is from the ectoderm (the proctodaeum)

★ Pectinate line demarcates upper from lower half

★ It fills completely and recanalization occurs in wk9

84
Q

what is the first organ to develop within the embryo?

A

the heart

85
Q

Cvs:

When does the heart start to function?

A

It starts to function at the beginning of the fourth week (when the nutritional and oxygen requirements of the growing embryo can no longer be met by diffusion from the placenta)

86
Q

Prenatally, the lungs are not active in gas exchange and therefore the pulmonary vessels are _________

A

vasoconstricted

87
Q

Primordial heart and vascular system starts to develop in weeks…..

A

3 and 4 of pregnancy

88
Q

Cvs:

oxygenated or deoxygenated

Normal veins =

Fetal veins =

Normal arteries =

Fetal arteries =

A

Normal veins = Deoxygenated blood

Fetal veins = Oxygenated blood

Normal arteries = Oxygenated blood

Fetal arteries = Deoxygenated blood

89
Q

CVS:

Step 1 - Fusing

A
90
Q

CVS:

Step 1 - Fusing

what happens?

A

� Start with 2 endocardial tubes (Endothelial strands)

� Lateral folding of these tubes fuses the 2 into 1 endocardial tube

� The pericardial cavity is present around the 1 endocardial tube

91
Q

CVS:

Step 2 - Folding

A
92
Q

CVS:

Step 2 - Folding

� ____ _______ and develops dilations and constrictions

� _____ ______ and the ventricle grow much faster than the rest of the heart and therefore has to fold onto itself creating a U-shape bulboventricular loop

� It then keeps expanding to form a _ - shaped loop

A

Tube elongates and develops dilations and constrictions

Bulbis cordis and the ventricle grow much faster than the rest of the heart and therefore has to fold onto itself creating a U-shape bulboventricular loop

� It then keeps expanding to form a S - shaped loop

93
Q

CVS:

Embryology – Blood flow at this stage

A
94
Q

CVS:
Step 3 - Partitioning

What the happens here

A

3 things now divide 1 common tube into 4 chambers (LA,LV,RA,RV)

3 Steps:

  1. Part the AV canal
  2. Part the atria
  3. Part the ventricles
95
Q

CVS:

Outilines what happens in Step 3

A
  • The endocardial cushions form AV valves
  • Membranous Septum Primum grows from the roof of the atria
  • Little holes allow blood to move from atria to atria via Foramen Primum
  • Little holes become one big hole between atria for continuous blood flow via Foramen Secundum
  • Septum Secundum grows downwards and overlaps Foramen Secundum to form a valve like hole between the atria (Aka Foramen Ovale)
  • Crescenteric muscle forms a median ridge in the floor of the ventricles
  • Myoblasts proliferate and grow upwards to form an interventricular septum
96
Q

CVS:

A
97
Q

CVS:
SHUNTS

A
98
Q

CVS:

What day does cardiac cells start to beat?

A

Day 22/23

99
Q

CVS:

What is the purpose of a yolk sac

A

provides enough nutrients to the embryo

100
Q

CVS:

Where does the fetus get its oxygen from before birth?

A

Placenta

101
Q

CVS:

Identify A- F

A

A = placenta

B = Umbilical vein

C = Ductus venosus

D = Foramen Ovale

E = Ductus arteriosus

F = Umbilical arteries

102
Q

CVS:

What is the purpose of each of these structures in the fetus?

Placenta

Umbilical vein

Ductus venosus

Foramen Ovale

Ductus arteriosus

Umbilical arteries

A

Left umbilical vein brings oxygenated blood to the fetus

Ductus venosus shunts blood away from the liver to the heart via the IVC

Foramen ovale shunts blood from the right to the left to avoid the pulmonary circulation as it is not needed

Ductus arteriosus shunts any blood from the pulmonary trunk to the arch of the aorta

Umbilical arteries carry deoxygenated blood back to the placenta to be oxygenated again

103
Q

CVS:

What are these embryological structures called in the adult? (there are 5 structures in total)

Left umbilical vein =

Ductus venosus =

Foramen ovale =

Ductus arteriosus =

Umbilical arteries =

A

Left umbilical vein = round ligament of Teres (in falciform ligament)

Ductus venosus = ligamentum venosum

Foramen ovale = fossa ovalis

Ductus arteriosus = ligamentum arteriosum

Umbilical arteries = medial umbilical ligaments

104
Q

CVS:

Which one is fetal haemoglobin and which one is maternal haemoglobin?

A

A = fetal haemoglobin

B = maternal haemoglobin

105
Q

CVS:
Why is there a difference in affinity between the adult haemoglobin and fetal haemoglobin (diagram B)?

A

Maternal blood in the placenta is at a lower pO2 and needs to release oxygen as well as take up CO2 from the fetal blood. The fetus has to be able to uptake oxygen more efficiently and so needs to have a higher affinity in order to do so. If a fetus were to have adult haemoglobin, the respiratory gases would bind equally between the two circulations and the fetus would become hypoxic.

106
Q

CVS:
What is patent Forament Ovale?

A

A patent foramen ovale is a type of atrial septal defect that occurs when the atrial walls between the right and left atria fail to fuse and close the connection between them. This can lead to blood bypassing the right ventricle and escaping into the left atrium without having picked up oxygen in the lungs

107
Q

CVS:

which one is before birth and which one is after?

A
108
Q

Neuro:

Where is the nervous system derived from?

A

Ectoderm

109
Q

At the beginning of week 3, a visible line/streak of cells forms on the epiblast layer?

What is this called?

A

Primitive streak

110
Q

This streak deepens to form a groove and a pit forms at the cranial end of the primitive streak. This is called?

A

primitive node

111
Q

CVS:

A
112
Q

CVS:

• The ectoderm cells tunnel from the primitive node _________ and cranially forming a hollow tube known as the ________

A

The ectoderm cells tunnel from the primitive node longitudinally and cranially forming a hollow tube known as the notochord

113
Q

CVS:

The notochord becomes the nucleus pulposus of the_________ _____

A

The notochord becomes the nucleus pulposus of the intervertebral disc

114
Q

CVS:

Growth factors from the axial mesoderm act on the ectoderm, causing ________ cells to differentiate into____________ ______ (this is the neural plate)

A

Growth factors from the axial mesoderm act on the ectoderm, causing ectoderm cells to differentiate into neuro-ectoblast cells (this is the neural plate)

115
Q

CVS:

The cranial end of the neural plate will become the ______ and the caudal end will become the ______ ____

A

The cranial end of the neural plate will become the brain, and the caudal end will become the spinal cord

116
Q

CVS:

A
117
Q

CVS:

  • As the neural plate forms, it sinks in the midline to form the _____ ______
  • There are folds either side of the neural groove that by day __ meet in the middle, this forms the neural tube
  • The neural tube cells will make up all of the matter in the ____ _____
A
  • As the neural plate forms, it sinks in the midline to form the neural groove
  • There are folds either side of the neural groove that by day 25 meet in the middle, this forms the neural tube
  • The neural tube cells will make up all of the matter in the spinal cord
118
Q

CVS:

A
119
Q

CVS:

  • Neural folds merge in the______ of the embryonic disk first and spread cranially and caudally
  • (An error here will cause ____ _____)
  • This whole process is called _________
A
  • Neural folds merge in the middle of the embryonic disk first and spread cranially and caudally
  • (An error here will cause spina bifida)
  • This whole process is called neurulation
120
Q

CVS:

In the neural tube…

  • _______ portion (AKA alar plate) will form the ________ area of the spinal cord
  • ______ portion (AKA basal plate) will form the _____ area of the spinal cord
A
  • Dorsal portion (AKA alar plate) will form the sensory area of the spinal cord
  • Ventral portion (AKA basal plate) will form the motor area of the spinal cord
121
Q

CVS:

A
122
Q

CVS:

  • During neurulation, some cells ‘break off’ from the ____ aspect of the neural tube (these are neural crest cells)
  • _____ ______ _____ will become the sensory neurones of the dorsal root ganglia
  • Neural crest cells extend axons both peripherally and centrally (explaining why we find pseudo-unipolar neurones in the dorsal ganglia)
  • On the other hand, motor axons just extend from neurones in the ____ _____
A
  • During neurulation, some cells ‘break off’ from the dorsal aspect of the neural tube (these are neural crest cells)
  • Neural crest cells will become the sensory neurones of the dorsal root ganglia
  • Neural crest cells extend axons both peripherally and centrally (explaining why we find pseudo-unipolar neurones in the dorsal ganglia)
  • On the other hand, motor axons just extend from neurones in the basal plate
123
Q

CVS:

Embryology of the nervous system- Spinal cord

  • As the mesoderm develops, it becomes _______
  • Axons extend peripherally from the ____ _____ (motor) and neural crest cells (sensory) and grow into the adjacent mesoderm
  • This forms a _____
  • Each pair of somites will turn into a_____ or ______
  • The segmentation of the neural tube explains the segmentation of the spinal cord and why different muscle groups are associated with certain spinal levels
A
  • As the mesoderm develops, it becomes segmented
  • Axons extend peripherally from the alar plate (motor) and neural crest cells (sensory) and grow into the adjacent mesoderm
  • This forms a ‘somite’
  • Each pair of somites will turn into a myotome or dermatome
  • The segmentation of the neural tube explains the segmentation of the spinal cord and why different muscle groups are associated with certain spinal levels
124
Q

CVS:

At the cranial end of the neural tube, it becomes pinched to form 3 distinct primary brain vesicles/regions

What are they?

A
  1. Forebrain (Prosencephalon)
  2. Midbrain (Mesencephalon)
  3. Hindbrain (Rombencephalon)
125
Q

CVS:

  • The wall of the BRAIN vesicles will become the ____ ______
  • The lumen of the vesicles will become the _______ and _____ _____
A
  • The wall of the BRAIN vesicles will become the brain tissue
  • The lumen of the vesicles will become the ventricles and spinal canal
126
Q

CVS:

During what week does the foerbrain and hindbrain subdivide?

A

Week 5

127
Q

CVS:

The forebrain subdivides into:

A
  • Telencephalon (à Cerebral cortices)
  • Diencephalon (à Basal ganglia/hypothalamus)
128
Q

CVS:

The hindbrain subdivides into:

A
  • Metencephalon (à Pons and cerebellum)
  • Myencephalon (à Medulla Oblongata)
129
Q

CVS:

The primary brain vesicles

A
130
Q

CVS:

forebrain and hindbrain both subdivide

A
131
Q

CVS:

A
132
Q

CVS:

  • By 26 weeks, the lateral sulcus is evident
  • By 30 weeks, the cerebellum is distinct
A
  • By 26 weeks, the lateral sulcus is evident
  • By 30 weeks, the cerebellum is distinct
133
Q
A