Which statement best explains why whole-body donors remain an important part of anatomy education, despite the availability of high-quality anatomical models and digital resources?

While examining a whole-body donor, you notice that the location and appearance of some anatomical structures differ slightly from the anatomical model used in class. Which statement best explains this observation?

TRACHEA

The trachea (label 26) is a tube that connects the pharynx and larynx to the left (label 29) and right (label 12) bronchi (and lungs), allowing the passage of air. You will learn more about this in Wk5 & 6.

The trachea has C-shaped rings. 

There are fifteen to twenty incomplete C-shaped tracheal rings of hyaline cartilage that reinforce the front and sides of the trachea to protect and maintain the airway (these are just visible in the specimen below).

The cartilaginous rings are incomplete posteriorly to allow the trachea to collapse slightly so that food can pass down the oesophagus (label 8). Thus there is a membranous wall at the back, without cartilage.

Circular bands of fibrous connective tissue join the tracheal rings together. 

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The trachea is lined with a layer of ciliated pseudostratified columnar epithelium. The epithelium contains goblet cells, that produce mucins, the main component of mucus. Mucus sits on top of the ciliated cells of the trachea to trap inhaled foreign particles that the cilia then move upward where it can be either swallowed into the stomach or expelled as phlegm.

The oesophagus is lined by stratified squamous epithelium without keratin. The epithelium of the oesophagus has a relatively rapid turnover, and serves a protective function against the abrasive effects of food. Protection is conferred by the secretion of mucus from underlying glands.

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Additional resources:

Visit an@tomedia section trachea & main bronchi

Go to An@tomedia (or access via Monash Library), then navigate to:

'Launch An@tomedia' > Thorax > Systems > #16 Trachea & main bronchi (see image below)

Checklist to consider:

1. Visualise the C-shaped rings on anterior and posterior view
2. What prevents the trachea and main bronchi from collapsing on inspiration? Click on the links

The trachea contains in its layers/wall, which of the following:

THE DIAPHRAGM

The diaphragm is the primary muscle used in the process of inspiration, or inhalation. It is a dome-shaped sheet of muscle (and connective tissue) that is inserted into the lower ribs. Lying at the base of the thorax (chest), it separates the abdominal cavity from the thoracic cavity. The diaphragm can clearly be seen separating the two cavities (label 16) in the coronal image below. It is a thin, skeletal muscle that can contract voluntarily. 

During inhalation the diaphragm contracts & flattens, increasing the space for the lungs to fill with air. During exhalation the diaphragm relaxes and its dome shape increases, decreasing the thoracic volume and thereby assisting the lungs to empty.

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These are seen below as:

• aorta (label 4)
• oesophagus (label 3)
• Inferior vena cava (label 10)

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See anterior view of the abdomen below: The oesophagus (label 7) and aorta (label 25) can be seen going through the diaphragm. The vena cava is seen on the right side as a hole in the diaphragm (label 10).

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Additional resources:

1. Watch the The Diaphragm gross-anatomy video in Acland's Anatomy

Navigate to Trunk > MSK structures of the Trunk > 3.2.6 Diaphragm (4:14min)

For access you need to be logged in to the library: go to https://guides.lib.monash.edu/mnhs/anatomy_resources then click on Aclands video atlas then type in "diaphragm" to the search bar (the video is the top result).

Checklist to consider:

1. Note the central tendon of the diaphragm
2. Observe the location of the 3 main holes in the diaphragm - the aortic opening, the eosophageal hiatus and vena caval foramen

You do NOT have to learn about the diaphragmatic attachments, muscles or crura.

The structures traversing the diaphragm include:

Below, is a para-sagittal cross-section through the foot. 

Observe all the articulating bones via the shiny white cartilage present on the apposing surfaces. 

Approximately how many bones can you see in this cross-section?

Identify the spongy (trabecular/cancellous) bone components. Some obvious spongy bone is indicated by label 1. Spongy bone is composed of a network of bony struts, and filled with bone marrow.

Compact (cortical) bone is seen at the periphery of bone, and is solid, dense bone.

Bone is a highly vascular tissue: different bones of the skeleton have different amounts of blood supply.  Some, such as the bones of the toes, have abundant blood supply; some bones have a moderate blood supply, such as the tibia; while others, such as the head of the femur in the hip joint have a limited blood supply.

Bone marrow is the flexible connective tissue in the internal cavities in bones and is a major source of mesenchymal stem cells. It is comprised mainly of blood cells and adipose tissue. 

Which of the following is true of bone marrow? It contains mesenchymal stem cells which are:

Match the structures below with their corresponding letters (in image above):

Identify the labels on the diagram of the adult eye.  

This

is an image of an isolated right temporal bone. Which label indicates the

articular surface of the temporomandibular joint?

Select from the options below to fill in the blanks.

The labelled structure (*) is the __________ fontanelle of an infant. When it closes it will form a complete ________ suture between the ______________ bones.

Match each cranial suture with the bones it unites: