Limbs and Back: Week Three Flashcards
What type of joint is the elbow joint?
Synovial hinge
Name the three joints that make up the elbow
- Radiohumeral joint: head of the radius and the capitulum of the humerus
- Ulnohumeral joint: trochlear notch of ulna and the trochlea of humerus
- Proximal radioulnar: synovial pivot joint between the circumference of the head of the radius and the ring formed by the radial notch of the ulna and the annular ligament.
What are the two collateral ligaments of the elbow?
- Radial collateral ligament: lateral epicondyle to blend with annular ligament
- Ulnar collateral: medial epicondyle to coronoid process
What ligaments encircles the head of the radius?
Radial annular ligaments
When does the axillary artery become the brachial artery?
Lower end of teres major
What branch of the brachial artery runs in the radial grove?
Profunda artery
Is the brachial artery posterior or superior to the median nerve?
Posterior
When does the brachia artery spilt into the ulna and radial arteries?
Cubital fossa
What is the lateral, medial and superior border of the cubital fossa?
- Lateral: brachioradialis
- Medial: pronator teres
- Superior: line between epicondyles
What are the main contents of the cubital fossa?
(Really need beer to be at my nicest)
- Radial nerve
- Biceps tendon
- Brachial artery
- Median nerve
The radial nerve gives of a deep branch and a superficial branch. Which one is sensory and which one is motor?
The deep is motor (gives of PIP) and superficial is sensory.
The flexors of the forearm are mainly innervate by the median nerve. Which two Muslces are the exception?
- Flexor carpi ulnaris (ulnar nerve)
- Lateral part of flexor digitorum profundus (ulnar nerve)
What is the common origin of the forearm flexors?
Medial epicondyle
There is the rule of the three for the forearm extensors. What are the three wrist extensors?
- Extensor carpi radialis brevis
- Extensor carpi radialis longus
- Extensor carpi ulnaris
What are all the forearm extensors innervated by?
Radial nerve
There is the rule of the three for the forearm extensors. What are the three finer extensors?
- Extensor digitorum
- Extensor Indices
- Extensor digiti minimi
There is the rule of the three for the forearm extensors. What are the three thumb extensors?
- Extensor pollicis longus
- Extensor pollicis brevis
- Abductor pollicis longus
What is the function of the brachioradialis?
Flexes forearm.
Where do the triceps attach?
Olecranon of the ulna
What type of joint is the proximal radioulnar joint?
Pivot
In comparison to the bicipital aponeurosis, where about is the medial cubital vein, brachial artery and median nerve?
The median vein is superficial and the brachial artery and median nerve are deep.
What is the process whereby the cells migrate to the primitive streak?
Invagination
Name the layers of the mesoderm, central to lateral.
Primitive streak - notochord - paraxial mesoderm - intermediate mesoderm - lateral plate mesoderm- extraembryonic mesoderm
What two membrane do not have mesoderm?
oropharyngeal and Cloacal membranes
What at does mesoderm differentiation occur at?
Day 17-21
What way do the cells move to form the paraxial mesoderm?
Bilaterally and cranially
What does the intermediate mesoderm form?
Genitourinary system
What are the two layers of the lateral plate mesoderm?
- Somatic (parietal)
- Splanchnic (visceral)
What layer of the lateral plate mesoderm is connected with the amniotic cavity and which with the yolk sac?
- Somatic: amniotic cavity
- Splanchnic: yolk sac
Which Muslces are formed by the ectoderm?
Smooth muslce of pupil, mammary and sweat glands
When do somites appear?
Day 20
What is the rate of somite formation until week 5?
They form 3 pairs a day in a craiocaudal sequence
What is the process of somite formation called?
Somitogenesis
What is the cell transition of cells in the somites?
Mesenchymal to epithelial
What three genes are involved in the clock and wave mechanism?
- Wnt
- FGF8
- Notch
Describe the clock and wave mechanism
The system tell cell to switch from a permissive to non-permissive state.
There is a wave of FGF8 going up and if it meets a cell activated by a notch (clock gene), it makes it become a somite. Wnt is helping.
How many pair are present after around 5 weeks?
42-44
What is a somite?
A block of paraxial mesoderm which gives rise to skeletal muscle
What do cells in the ventral medial layer form?
Sclerotome
What do cells in the dorsal layer form?
Dermoyotome
Name the two layers that the dermoyotome splits into
Dermatome and myotome
What is the function of MYOD and MYF5?
These are transcription factors that activate muscle-specific genes. They allow differentiation of dermomyotome into myoblasts. They allow non-muscle genes to become muscle cells.
Explain the formation of primary myotubes
Myoblasts will secrete ecm and bind via integrin. The cells align and the fuse.
Myogenin mediates this.
What gene can reprogramme fibroblasts and adipocytes to become muslce cells?
MYoD1mRNA
How is MYOD activated?
Wnt (activating) and BMP (inhibiting) combine. They are from lateral plate mesoderm
What tow genes induce Sclerotome formation and where are they from?
Sonic hedgehog and noggin. From the notochord.
What does the Sclerotome form?
Ribs and vertebrae
Where do the primaxial an abaxial muscle originate?
Myotome