The Respiratory System Ch Respiratory Tract Anatomy pp. 284 to 287

What is breathing? When you breathe in it is called inspiration or inhalation. When you breathe out it is called expiration or exhalation. Air travels to the lungs via a series of tubes, and then leaves via the same path.

This is called tidal breathing. In and out like a tide. On its way in, air is filtered by coarse hairs, mucus, and cilia in your nostrils, and by cilia in the airways and the rest of the nasal cavity. What is a booger?

Nose hairs!

Air is warmed by the blood vessels giving off heat near the airways and nasal passage. Air is moistened by the the wet surface of the nasal passage and airways. As air moves out in the opposite direction, it cools and looses its moisture. Cold air holds less water vapour than warm air. Moisture deposited on trachea or the nose.

Respiration Anatomy and Function The nostrils open up to nasal cavities on each side. Narrow chambers separated by a septum made of bone and cartilage. Upper recesses of nasal cavity has olfactory cells that act as odor receptors. Nerves send signals from receptors to brain.

Olfactory Receptors!

Lacrimal, (tear), glands drain into the nasal cavity via ducts. So runny nose when you cry! Nasal cavities also connected with the mucus- lined, air-filled, cranial sinuses. If connection gets blocked and mucus accumulates, you get a sinus headache. The Biology 12 Witch Project

The nasal cavity opens up in the back to the nasopharynx. Pharynx, (throat), divided into three parts: 1.Nasopharynx where nasal cavity opens up. 2.Oropharynx where oral cavity opens up. 3.Laryngopharynx where larynx opens up. Air travels through the pharynx into the larynx.

Larynx!!! Nasopharynx Oropharynx Laryngopharynx

The larynx is a cartilaginous triangular box located at the front of the neck. Its opening is called the glottis. During swallowing, the glottis moves up against the epiglottis to prevent food from entering it. Also known as the voice box because it contains the vocal cords!

The vocal cords are mucosal folds supported by elastic ligaments. They are stretched over the glottis. Vibrate and produce sound as air passes through them. When males go through puberty, growth of the vocal cords and larynx is much more rapid and accentuated than in females. Leads to deeper voice and Adam's apple.

When speaking or singing, you modify your pitch by stretching your vocal cords over the glottis. Low pitch Higher pitch

The glottis opens up into the trachea, or windpipe. Trachea connects the larynx to the bronchi. It lies ventral to the esophagus, which means in front of it. The trachea is reinforced by c-shaped cartilaginous rings to keep it open. You can feel their ridges on your neck. The esophagus can close, but not your trachea!!!

The trachea is lined with ciliated and mucus covered cells so that debris can be captured and pushed out. Ruined by smoking!!! It destroys the cilia. Trachea Bronchi Bronchioles Cilia

The trachea goes down into the chest and divides into the right and left bronchus. Bronchi for pleural. Bronchi branch into tinier secondary bronchi, which then branch into tiny bronchioles. As they branch, their walls get thinner, and the small rings of cartilage disappear. Every single bronchiole terminates in a cluster of small air-filled sacs called alveoli.

Alveoli make up the lungs. Left lungRight Lung Alveoli

The lungs occupy the thoracic cavity. The right lung is made of three lobes, the left lung is made up of two lobes. The left lung is smaller to make room for the heart which is slightly to the left.

The base of the lungs is broad and concave to fit with the domed shape of the diaphragm. They also partially curve around the heart.

The alveolar sac is made of epithelial cells like those lining your digestive tract and body cavities. Surrounded by a network of capillaries. They are thin enough for gas exchange. O 2 diffuses across alveoli to the blood in the capillary. CO 2 does the opposite. A layer of surfactant lines the insides of the alveoli to reduce water tension which would cause the alveoli to collapse.

There are roughly 300 million alveoli in your lungs. Lungs are filled with so many air spaces, that a piece of lung tissue would float on a glass of water!!!