Human Anatomy & Physiology of the Respiratory System

We often complete the daily tasks of living without thinking about the respiratory system. We breathe in and out and take for granted one of our most vital organ systems. The respiratory system provides the oxygen necessary to sustain life. It consists of both upper and lower respiratory tracts. It is divided into two functions: conducting and respiration.

Function

1. The function of the respiratory system is to give us a surface area for
exchanging gases between the air and our circulating blood. It moves that
air to and from the surfaces of the lungs while it protects the lungs from
dehydration, temperature changes and unwelcome pathogens. It also plays a
part in making sounds such as talking, singing, other nonverbal sounds and
works with the central nervous system for the ability to smell.

Upper Respiratory Anatomy

2. The upper respiratory system consists of the nostrils (external nares),
nasal cavity, nasal vestibule, nasal septum, both hard and soft palate,
nasopharynx, pharynx, larynx and trachea. Within the nostrils, course hairs
protect us from dust, insects and sand. The hard palate serves to separate
the oral and nasal cavities. There is a protective mucous membrane that lines
the naval cavities and other parts of the respiratory tract. It is secreted
over the exposed surfaces and then the cilia sweeps that mucus and any
microorganisms or debris to the pharynx, so it is swallowed and then
destroyed in stomach acids.

Lower Respiratory Anatomy

3. The trachea branches off into what is known as the bronchi (more commonly
called bronchial tubes). These two main bronchi have branches forming the
bronchial tree. Where it enters the lung, there is then secondary bronchi.
In each lung, the secondary bronchi divides into tertiary bronchi and in turn
these divide repeatedly into smaller bronchioles. The bronchioles control the
ratio of resistance to airflow and distribution of air in our lungs. The
bronchioles open into the alveolar ducts. Alveolar sacs are at the end of the
ducts. These sacs are chambers that are connected to several individual
alveoli, which makes up the exchange surface of the lungs.

The Lungs

4. The human respiratory system has two lungs, which contain lobes separated
by deep fissures. Surprisingly, the right lung has three lobes while the
left one has only two lobes. The lungs are made up of elastic fibers that
gives it the ability to handle large changes in air volume. The pleural cavity
is where the lungs are located. The diaphragm is the muscle that makes up the
floor of the thoracic cavity and plays a major role in the pressure and volume
of air moving in and out of the lungs.

Significance

5. Our lungs filter and deliver oxygen that is necessary for healthy red blood
cells. It is important that we keep the respiratory tract healthy through
proper rest, hydration, diet and exercise.

How to Tell a Monocot From a Dicot

Plants that produce seeds are put into two categories: monocots and dicots. This distinction is more than just a bit of scientific trivia. The difference between monocots and dicots has been exploited by manufacturers of weed killers. Their chemicals are made to target dicots, not monocots. Since grass is a monocot and most weeds are dicots, this works out very well for our lawns. Knowing how to tell a monocot from a dicot will let you predict which plants will be affected by your lawn sprays. Read on to learn how to tell a monocot from a dicot.


Instructions

Step 1

Observe the sprouts and look at the cotyledons. The “cot” in monocot and
dicot is short for “cotyledon.” The cotyledon is the “seed leaf” that the
seed puts out when it sprouts. A monocot has a single seed leaf (“mono” means
“one”) and a dicot has two seed leaves (“di” means “two”). This observation
can only be made when the seed is just sprouting.

Step 2

Observe the roots. Monocots have short fibrous roots that stay close to the
surface. Dicots have a long, central tap root that goes deep into the ground.
Dicots may also have other roots, too, surrounding the tap root.

Step 3

Observe the veins in the leaves. The veins in monocots run parallel to each
other, as seen in grass leaves. Monocot leaves tend to be long and narrow.
The veins in dicot leaves branch out like the veins in your hands.

Step 4

Observe the petals of the flowers. Monocot petals come in multiples of three
such as three, six or nine. Dicots petals and sepals come in multiples of
four or five--four, eight and 12 or five, 10 and 15.

Step 5

Observe a cross section of the stem under a microscope. Monocots have their
vascular bundles scattered randomly throughout. Dicots have their vascular
bundles arranged neatly in a circle, as if they were placed on imaginary
spokes coming out of the center.

Step 6

Monocots mainly belong to the grass family of plants. Examples of monocots
are grass, wheat, oats, barley, corn, rice, bamboo, onion, asparagus, lilies,
bananas and palm trees.

Step 7

Dicots are mainly broad leaf trees, ornamental flowers, and fruits and
vegetables. Examples of dicots include maple and oak trees, fruit trees,
grapes, strawberries, daisies, marigolds, roses and garden vegetables such
as tomatoes, squash, beans, peas and potatoes.