Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Embryo > Lecture 5 > Flashcards

Lecture 5 Flashcards

1
Q

What week will our upper and lower limbs begin to form?

A

Week 4

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

What grows first: upper or lower limbs?

A

Upper limbs. Our body likes to shunt blood to our heads, thus, our upper limbs will grow and develop quicker.

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

When does primary ossification occur?

A

Week 12

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

For our limbs to be made, what do we need?

A

For our limbs to be made, we are going to need MUSCLE, CARTLAGE and CONNECTIVE TISSUE.

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

How do we form our limbs?

A

To form our limbs, we will begin with a layer of [limb forming mesoderm]. This layer of limb forming mesoderm will contain different kinds of mesoderm, because we need to form muscle, cartilage and connective tissue (mesenchyme). Thus, the mesoderm will have 1. Paraxial mesoderm (myotome), to form out muscles 2. Somatic layer of the lateral plate mesoderm to form our [cartilage, bone and connective tissue.] This limb forming mesoderm will release FGF10, causing the overlying ectoderm to thicken and become our AER (apical ectodermal ridge). The AER will then release FGF 8 and 4, which will stimulate the mesoderm to grow and proliferate PROXIMAL–> DISTAL.

we are trying to codense our cartllage

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

How does proximal –> distal growth occur?

A

The reciprocal signaling of limb forming mesoderm releasing FGF10 and apical ectoderm ridge releasing FGF8 and 4.

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

What is special about the mesoderm that becomes bones?

A

It is already fated to become certain bones via concentration gradients of FGF10 and FGF8 and 4.

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

What is the most proximal thing formed (which is formed first)?

A

Stylopod

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Stylopod makes what?

A

Humerus and femur

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

What forms after the stylopod?

A

Zeugopod. In our upper: radius and ulna Lower: tibia and fibula

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

What is the most distal thing formed?

A

Autopod In our upper: carpals, metacarpals and digits Lower: tarsals, metatarsalsnd and digits

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

Order of things formed proximal–>distal

A
  1. Stylopod 2. Zeugopod 3. Autopod

SZA

(humerus, radius/ulna/metacarpals)

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

In limb development, what happens in week 5?

A
  1. Hand and foot plates form.

Hands before foot

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

In limb develpoment, what happens in week 6?

A
  1. Digital rays (bones) of the hand are formed because of the condensing of the somatic layer of the lateral plate mesoderm

Here, the entire limb is cartilaginous.

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

In limb develpoment, what happens in week 7?

A
  1. Digital rays (bones) of the FEET are formed
  2. Osteogenesis of long bones begin
  3. Limbs begin to rotate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In limb develpoment, what happens in week 8?

A

Seperate digits are formed VIA apoptosis due to BMP (not having webbed feet is due to BMP)

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

Limb musculature is derived from what part of the somite?

A

Dorsolateral Remember, are you DL? DM me.

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

After proximal–>distal growth, what happens?

A

Limb musculature will begin during the 5th week. Our muscles will be derived from our dorsolateral plate of the somites.

  1. Motor neurons (from NEURAL TUBE-neuroectoderm) will enter the bud in week 5. As our muscles grow, they will pull the cell with.
  2. Sensory neurons (from neural crest) will THEN FOLLOW
  3. Neural crest WILL ALSO give rise to schwann cells to myelinate.
19
Q

When do sensory neurons enter?

A

Sensory neurons will enter following the entrance of motor axons. Neural crest cells travels in the same direction as the neural extoderm. Neural crest cells also give rise to schwaan to myelinate.

20
Q

Limb rotation occurs when?

A

Week 7.

21
Q

How do limbs move in week 5?

A

Upper and lower limbs grow out laterally and cephallicaly

22
Q

How do limbs move in week 6?

A

Pals and soles of the feel will point medially

23
Q

How do limbs move in week 7?

A

Limb rotation occurs. Upper limbs will rotate 90 degrees laterally. Lower limbs will rotate 90 degrees medially.

24
Q

Blood supply of the limbs

A

Intersegmental arteries from the aorta will come off and go to the limb bud. There, they give rise to primary axial artery.

In the upper limbs, primary axial artery–> Brachial artery and the common interrosseous.

In the lower limbs, primary axial artery–> deep artery of the thigh and the posterior tibial artery

ia angiogenesis, we get the adult patter in the arm

25
Q

Lower limb blood supply

A

Intersegmental artery–> Primary axial artery–> deep artery of the thigh and posterior tibial artery Via angiogensism we get remodling

26
Q

Club foot (1/1000)

A

Most common MSK defect

Sole of the foot is turned medially, plantar flexed and inverted

But all anatomical structures are present.

27
Q

What causes club foot?

A
  1. Abnormal limb rotation
  2. Too little amniotic fluid

2x more males than F

28
Q

Developmental hip dysplasia

A

Females

Can be due to

  1. Generalized joint laxity
  2. Underdevelopment of the acetabulum of the hip bone
29
Q

Patterning, so that we get different shapes and patterns of the bone is due to

A

HOX gene.

30
Q

What regulates the positioning of limbs along the craniocaudal axis?

A

HOX genes

31
Q

What is responsible for Dorso-ventral patterning

A

Dorsal surface (extensors)–> WNT7

Ventral surface (flexors)- BMPS

The Apical ectodermal ridge is responsible for signals of dorsal-ventral patterning to begin.

32
Q

What is responsible for the patterning of our flexor muscle?

A

BMPS

33
Q

What is responsible for the patterning of our extensors?

A

Extensors=dorsal patterning

WNT7

34
Q

What sets up dorso-ventral patterning?

A

Apical ectodermal ridge

35
Q

Anterior-posterior (AP) patterning is established by what?

A

ZPA-Zone of polarizing agent

ON THE POSTERIOR SIDE OF THE THE LIMB (little finger and ulna side)

36
Q

ZPA releases

A

SHH and retonoic acid to create posterior elements (ditits 5,4,3 and then ulna)

37
Q

Lost of ZPA (SHH and retanoic acid) results in

A

Lost of posterior elements (ulna, pinky)

38
Q

Upregulation of ZPA (SHH and retanoic acid) results in

A

additional posterior elements (ulna, pinky polydactly

39
Q

Duplication of ZPA results in

A

dupplication of posterior elements little fingers on both sides othe thumb

40
Q

What are formed first? Posterior elements or anterior?

A

Posterior (little finger ulna).

41
Q

Disruption of the A-P patternning causes what?

A

Loss of anterior elements (thumb/ radius)

42
Q

Limbs form from epimere or hypomere?

A

Hypomere because we are forming our HYPAXIAL MUSCLES

43
Q

What forms first?

  1. Proximal or distal?
  2. Anterior or posterior?
A
  1. proximal
  2. Posterior (pinky, ulna)

Embryo (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions