Week 1 Flashcards
General arrangement of the trunk and the bony rib cage and sternum
Label the main stages of the development of the embryo
What stage is this? What week does it occur in? label it
Blastocyst stage
Week 1 day 6
- Blastocyst cavity
- Inner cell mass
- Outer cell mass
- Zona Pellucida
Label the parts of the blastocyst. What week does this happen?
- Blastocyst Cavity
- Inner cell mass
- Outer cell mass
- Zona Pellucida
What is the two layered embryo known as? What week does this happen? Label the main parts
Bilaminar Disc: Week 2
- Developing Amniotic Cavity
- Epiblast
- Hypoblast
What is the three-layered embryo known as? What week does this happen? Label the layers, including what they were formally known as.
Trilamina Disc: Week 3
- Ectorderm (formally eipiblast)
- Mesoderm (newly created)
- Endoderm (formally hypoblast)
How does the long axis develop? What week does This happen? Label the embryo
Process of gastrulation: Cells from epiblast multiply and migrate through the opening known as the primitive streak.
Week 3
- Primitive Streak
- Endoderm
- Mesoderm
- Ectoderm
What will the following layers become:
Ectoderm
Mesoderm
Endoderm
Ectoderm: (outer layer) Skin (epidermis only), Hair, Nails, Sebaceous glands and Nervous system.
Mesoderm: (middle layer), Connective tissue, muscle, kidneys and gonads
Endoderm: (Inner Layer), Lining of gut tube (except mouth and anus), Lining of lungs (e.g. Trachea, Bronchi and Alveoli), Glands that branch of gut tube (E.g. Liver, Pancreas), Urinary bladder and Trachea
What is the part highlighted in blue? What layer is it growing in? What is its purpose? What does it become the template for?
The Notochord:
- A rod-like structure which grows deep in the mesodermal layer
- As the notochord develops it elongates the trilaminar disc to produce a distinct long axis of between the cranial and caudal ends
- This becomes a template for bilateral symmetry
Label the following developing cross section through the embryonic disc.
Breifly explain the different components of the middle layer (what will they become)?
A. Ectoderm, B. Mesoderm, C. Endoderm
1. Limb Buds: Future limbs
2. Paraxial Mesoderm: (runs parallell to axis) Cartilage, Skeletal Muscle and Dermis
3. Lateral Plate Mesoderm: Body wall, wall of gut, Heart and circulatory system
4. Intermediate Mesoderm: Kidneys and Gonads
Label it. What have they been derived from? What is the point of them? What will they differentiate into?
The Somites:
- Derived from the paraxial mesoderm (each side of the notochord)
- Responsible for the segmentation of the embryo
The Somites will differentiate to form:
- The Axial skeleton (Ribs, sternum, vertebrae, hyoid, skull bones)
- The Associated musculature (Muscles of the back and body wall)
- The associated connective tissue (Ligaments, Tendons, and dermis)
List the bony components of the thorax?
- Sternum
- 12 pairs of ribs
- 12 thoracic vertebrae
What type of cartilage is at the end of each rib connecting them to the sternum? What features does this type of cartilage display? What is the cartilage reffered to when in relation to the ribs?
Hyaline cartilage:
Contributes to elasticity and flexibility
- Known as costal cartilage when in relation to the ribs
Which ribs attach directly to the sternum? Which ribs attach indirectly? What is the “network” of cartilage that indirectly attaches these ribs to the sternum?
1-7 are direct
8 - 10 indirect and the cartilage network that indirectly joins them is known as the costal margin?
Label the 3 sections of the sternum
- Manubrium
- Body of sternum
- Xiphoid Process
How does the sternum ossify? what classification of bone is it?
Flat bone
The sternum ossifies through a process known as segmental endochondral ossification.
There are 6 ossification centres which fuse by the age of about 25
Manubrium: 1
Body: 4
Xiphoid Process: 1
Label the image. What is the difference in attachment type between parts labelled 3 and 4? What type of a facet is “4” known as?
- Jugular or suprasternal notch
- Clavicular notches (SAY LEFT OR RIGHT)
- 1st Costal notch (SAY LEFT OR RIGHT)
- 2nd Costal notch (SAY LEFT OR RIGHT)
The difference between the 1st and 2nd costal notch is the 1st costal notch is rough and part of a cartilagenous attachment for rib 1, Whereas the 2nd costal notch is smooth and part of a synovial attachment for rib 2.
The 2nd Costal notch is known as a demifacet (2 half facets)
What is the name of this JOINT? is the surface rough or smooth and why? and what import surface land mark does the anterior angle make up?
The manubriosternal joint
Rough surfaces “joined” by a fibrocartilaginous pad
This makes up the sternal angle (angle of louis)
Label the borders of the sternum body.
- Superior border
- Lateral Borders
- Inferior border
Label the parts of a typical rib.
- Head of rib
- neck of rib
- shaft of rib
label the components. If this was rib number 6 what vertebrae would components labelled 1 and 3 articulate with?
- Superior articulating demifacet of rib __ on the right side
- Crest of head of rib number ___ on the right side
- Inferior articulating demifacet of rib ___ on the right side
The superior articulating demifacet of rib 6 would would articulate with T5, and the inferior articulating demifacet of rib 6 would articulate with T6
Label the following components. What type of surface does “1” have and why? What is the purpose of “2a” and “2b”?
- Crest of neck
- Tubercle of the rib
2a. Articular facet of tubercle of the rib
2b. Non articular part of the tubercle of the rib
The crest of the neck has a rough surface as it partakes in ligament attachment.
The articular facet is smooth and part of a synovial joint with the transverse process of the vertebrae, whilst the non-articular part is rough and serves a point for ligament attachment.
Label the following. What is the purpose if “3”?
- superior border of the rib
- Inferior border of the rib
- Costal groove
The costal groove is there to house the neurovascular bundle
Label 3, 4, and 5. which rib is this? What makes you so sure? is this a superior or inferior view (and why)? What structures run through features 1 and 2 ? what attaches to feature 3? what is feature 5 the boundary for?
- Scalene tubercle, 4. Lateral border, 5 medial border
This is the left 1st rib; It is much shorter, flatter, wider, and more horizontal than the others. It contains 1 articular facet on the head, 1 articular facet on the tubercle and it lacks a discrete angle (instead it is fused with the tubercle). This is a superior view as the surface is much rougher (the inferior surface is relatively smooth). The subclavian artery runs through the groove posterior to the scalene tubercle and the subclavian vein runs anterior to the scalene tubercle. The anterior scalene muscle attaches to the scalene tubercle. The medial border is the boundary for the thoracic inlet.
What rib is this? what makes you so sure? What muscle attaches to feature “A”?
Right 2nd rib; It still consists of a superior and inferior surface similar to rib 1, The costal groove is present (not visible in this image). The angle is seperate (discrete) from the tubercle. Head has two demifacets that articulate with body of T1 and T2 vertebrae. Has a rough tuberosity midshaft on the superolateral aspect.
Seratus anterior attaches to the costal tuberosity.
Which rib is this? what makes you so sure? What is the significance underlying this ribs head and tubercle?
The right 11th rib; There is no anterior attachment, only will have a small tip of costal cartilage, Has a head but no distiguishable neck, has a poorly marked tubercle (if any), only has a slight discrete angle with a shallow costal groove. With this rib only having one facet on the head and no facet on the tubercle, this means that the head only articulates in one place on the vertebral body, and that the tubercle does not articulate with the vertebrae at all.
Which rib is this? What makes you so sure? What is the significance underlying the head of this rib?
This is the right 12th rib. The reason we can determine this is that it has no anterior attachement, Small tip of costal cartilage, much smaller, poor markings, no neck, tubercle, angle or costal groove. The singular facet on the head of this rib indicates that the head only articulates in one place on the vertebral body.
What two points does a typical rib articulate with posteriorly? what are these two joints called?
The body and the transverse process of the vertebrae:
Body of vertebrae + head of rib = costovertebral joint
Transverse process + tubercle of rib = costotransverse joint
What is this? What direction does it face? What is it bounded by? What is it the passage for?
Superior thoracic aperture. IT points down anteriorly (oblique).
It is bounded:
Posteriorly: Vertebral body of T1
Laterally: Medial border of first rib
Ant/Lat: costal cartilage of first rib
Ant: Superior border of manubrium
Passage for: Trachea, oesophagus, nerves (E.g. Vagus and Phrenic), Blood vessels (E.g. Common carotid Artery)
What is this? What direction does it face? What is it bounded by? what spans across it?
Inferior Thoracic aperture:
- Points down posteriorly (larger and oblique)
Bounded:
Post: T12 vertebral body
Post/Lat: Inferior border of rib 12 and tip of rib 11
Ant/Lat: Costal margin (costal cartilages of ribs 7-10)
Ant: Xiphoid process of sternum
Spanned by respiratory diaphragm
What is this abdominal boundary known as? What is is bounded by (1 - 4)? What muscle spans across it?
The inferior pelvic aperture (aka pelvic outlet)
Bounded:
Ant: 1.a. = Pubic symphysis and 1.b. = Pubic arch
Lat: 2. Ischial tuberosities
Post/lat: 3. Sacrotuberous ligaments (only visible on the left side)
Post: Coccyx
Spanned by pelvic diaphragm
What 3 main structures/structural features can we find at the level of the sternal angle?
- Biforcation of the trachea
- Arching of the aorta
- Azygous vein draining into Superior Vena Cava
How would you describe the location of the apex of the heart?
At the junction between the 5th left intercostal pace and the midclavicular line.
How would you describe the location of the gall bladder?
At junction of 9th rib and right costal margin
