Question

By and large, the features observed in animals, plants, fungi, and biological organisms, in particular, are representative of their function and shaped by natural selection in the context of their environment. When we, as scientists, observe forms in nature, such as differing limb structures in vertebrates, varying tooth shapes in mammals, a diversity of leaf shapes in trees, or even the different shapes and sizes of cell types, we see both the function of the trait in question as well as the constraints, and possibilities, of living in the physical world. In this lab, you will take some moments to observe a variety of structures representative of the Animal kingdom that have been shaped by natural selection, and whose function may be represented, and therefore inferred, by their form.

During this lab, we will investigate anatomy (form) to understand the physiology (function). Our investigation will begin at the cellular level, comparing cellular shapes and structures of various tissues, allowing us to understand their purpose. We will then bring our focus to an organismal level, using clues of morphology to conclude habits and even behaviors of different species of fish. We will also focus on a specific characteristic, dentition in mammals, to help us to determine their dietary type.

In particular, we will be looking at the relationship between the form and function of:

1) Cells - different cells and a virus

2) Tissues- representatives of animal tissue types,

3) Body Morphology- various fish species

3) Dentition - a variety of vertebrate skulls and the teeth that they possess.

Cells and Viruses

Observe and draw the following cells.  

Plant cell (slide) – Note cell wall, chloroplast

What does this tell you about the functions of this cell?

Pancreatic cell (slide) – Note large amounts of endoplasmic reticulum and ribosomes.

What do these structures reveal about its function?

Virus (Electron micrograph) – Note the lack of organelles. Why do viruses need to infect a host cell to reproduce?

  Table 1

	Drawing of Cell Include total magnification	Organelles observed	Summarize your relationship between the cell’s anatomy and function.
Plant Cell
Pancreatic Cell
Virus

Tissues

Tissues are groups of cells that have similar structure and function together. In this lab, we will investigate the anatomy of various tissue types and investigate the relationship between their structure and function.

Types of tissues we will investigate in this lab include:

• Epithelial – squamous, cuboidal, and columnar
• Connective tissues – connective tissue proper and muscle

Future labs will investigate additional tissue types study different organismal systems.

Epithelial Tissues

Epithelial tissues are comprised of tightly packed cells enabling them to form barriers:

- between the body and the outside world

- to line organs

- to line cavities.

In this exercise, you will be observing three different types of epithelial tissue squamous, cuboidal, and columnar, so named because of their shape.

Squamous

The cells of squamous tissue are flat and thin to allow for the critical diffusion of nutrients and gases in the alveoli of lungs and blood vessels.

(Think of the word squashed to remember the shape.)

Cuboidal

The cells of cuboidal tissue are, as the name implies, shaped like cubes.

Cuboidal cells are found in tubules throughout the body.

Observe the individual cells surrounding the tubules. Notice that when cuboidal cells form the circumference of the tube, they have a slightly trapezoidal shape, allowing the cells to form a tight seal around the tube, and to distribute the force, further supporting its integrity. Think of the keystone of a free-standing arch.

Columnar cells

Columnar epithelial cells are long and often found where large amounts of secretions or active absorption are essential.

Columnar tissue can be found in the intestines secreting enormous amounts of digestive enzymes and absorbing nutrients. They are also located in the trachea of the respiratory tract, where large quantities of mucus are created to help trap particles before they enter the lung.

In the columnar epithelium of the respiratory tract, you can see goblet cells that release mucus and cilia at the apical surface of many of the cells.

How do cilia and mucus in the respiratory tract protect provide protection?

Many columnar epithelial cells produce mucus. These cells are called goblet cells. (To remember their name, think of goblets filled with white mucus.) Look for goblet cells in your intestinal slide.

Table 2 Summary of Epithelial Tissue Analysis

Tissue Type	Draw the tissue which represents the relevant structural features. Be sure to include total magnification!	Describe the structure or form of this tissue	Location in Animal Body (possibly indicated on the slide)?
Simple Squamous
Simple Cuboidal
Simple Columnar

Connective tissue

Connective tissue is so named because it connects tissues and organs throughout the body together.

Connective tissue contains:

• Cells
• Matrix (may be solid or liquid)
• Sometimes fibers are present to enhance strength, resilience, or elasticity.

Examples of connective tissue include:

• Blood
• Bone
• Cartilage
• Adipose (fat)
• Connective tissue proper

Dense regular connective tissue

Ligaments and tendons – are composed of fibers that attach muscle to bone (tendons) or bone to bone (tendons)

You can determine function from the types and placement of the fibers. Look at the two slides.

Slide 1 – Dense regular unilateral fibers

Slide 2 – Dense regular fibers swirl in more than one direction.

Which do you think undergoes forces in many directions?

Which supports forces in predominantly one direction?

Examine the slide below.

     

  

Note the direction of the collagen fibers. Do you feel that the fibers reinforce strength laterally or vertically? Why?

Answer 1

How do cilia and mucus in the respiratory tract protect provide protection?

Cilia beats the mucus secreted by goblet cell in respiratory epithelium... This helps in mucus clearance.. mucus on the other humidifies air and trap the air borne particles like dust , foreign body , etc.. this helps in preventing the dust particle to deposit in alveolus .. because after deposition in alveolus cause its irritation and in long the squamous epithelium present undergo metaplasia and eventually dysplasia and present as squamous cell carcinoma of lungs..

eg as seen in case of silicosis and asbestosis...

dear student u have posted a very long questionand due to constraint of time it is impossible to solve all .. we are actually asked to solve only om e question so i ii have sooved the table and a question...

please post other questions separately...