Respiratory System: A breath of fresh air

Functions of Respiratory System Takes in Oxygen needed to turn nutrients into energy **cellular respiration** Glucose + Oxygen = Carbon Dioxide + Water + Energy (This allows the energy from food to be released by the cells) Provides a transfer site for oxygen into the circulatory system to be circulated through the body. Eliminates Carbon dioxide (formed during cellular respiration). It needs to be removed from the body.

Air composition: 78% Nitrogen 21% Oxygen 0.04% Carbon dioxide Air is a fluid (gas) and it is a mixture of different gases: Air we Inhale: Air we Exhale: 78% Nitrogen 21% Oxygen 0.04% Carbon dioxide ~1% other gases 78% Nitrogen 16% Oxygen 5% Carbon dioxide ~ 1% other gases

Composition of air we inhale is different from composition from air we exhale Exhaled carbon dioxide is higher because of waste collected from cells (5%) Exhaled oxygen is lower because some of it diffuses into the bloodstream to be used for cellular respiration. What happens to gases our bodies don’t use??? EXHALED

Anatomy of the Respiratory System Respiratory System: consists of the respiratory tract and lungs. Respiratory Tract: Channel through which air reaches the lungs. Pathway: Nasal Cavity, Pharynx, Larynx, Trachea, Bronchi Bronchioles, Alveoli Lungs :Alveoli and bronchioles are in lungs

Nasal Cavity Nostrils open into nasal cavities 3 Functions: Filtering: Lined with hair and cilia which protects respiratory tract by filtering particles and trapping dust and dirt. Warming (turbinates)-Shape of nasal cavity allows air to swirl and warm as it comes into contact with the walls. Moisture: Mucus adds moisture to air

Sinus Sinus Turbinates Nostril Uvula Eustachian tube (to ear) Hard Palate Soft Palate

Pharynx *Found at back of mouth *Common passage between respiratory and digestive tract Both air and food pass through it.

Pharynx Larynx Trachea

Larynx (Voice box) Made of cartilage. Connects pharynx to trachea Voice box: because it holds the vocal chords (produces sound by vibrating when air is forced through it) The Epiglottis shuts opening of trachea during swallowing to block airway.

Trachea Function: airway Connects larynx to primary bronchi Made of Cartilage rings that keep it rigid and keep it from collapsing Has cilia, which are hair-like projections, which filter mucus and dirt out of lungs Has some mucus which warms and moistens air

Bronchi Tubes The trachea splits into two bronchi (tubes) Carry air into the lungs. Made up of cartilage rings

Respiratory Defense… … against Foreign Particles: Nostril hair Mucus in the respiratory tract Cilia in the trachea and bronchial tubes

Lungs

Function: to move air to the alveoli for gas exchange Bronchioles Bronchi tubes split up, like tree branches, into small subdivisions called bronchioles. The bronchioles get smaller and smaller until they end in a cluster of alveoli (small air sacs) Function: to move air to the alveoli for gas exchange bronchioles bronchi trachea

Alveolar Network looks like an upside down tree!

Alveoli Alveoli sacs branch off the bronchioles Each Alveolar sac contains many alveoli Alveoli are the functional units of the lungs – **this is where gas exchange takes place** The alveoli fill up with air/oxygen when you breathe in. They are surrounded by many tiny blood vessels called capillaries.

** Semi-Permeable: allows certain substances to pass through** Alveoli Continued: Alveoli have very thin, semi- permeable membranes which allow oxygen and carbon dioxide to pass through them and into or out of your blood stream ** Semi-Permeable: allows certain substances to pass through** There are 300 million in each lung!

Diaphragm: Sheet of muscle extending across the bottom of the rib cage. Controls the lungs increasing and decreasing in volume. When in contracts, it lowers into the abdomen and lowers the pressure in lungs so air can get in. When it relaxes, it rises back up under the ribs and the air is forced out of the lungs, due to the change in pressure.

Respiration Animation

Mechanism for Inspiration and Expiration Inspiration (Inhaling) Expiration(Exhaling) Intercostal muscles contract, ribs move out and up (lift) Intercostal muscles relax, ribs move in and down (lower) Thorax swells Thorax shrinks Diaphragm contracts, moves down into abdomen Diaphragm relaxes, moves up under ribs Volume of rib cage and lungs increases therefore…. Volume of rib cage and lungs decreases therefore… Decrease in air pressure in lungs(lower then outside the body) Air enters lungs, until air pressure inside and outside is equal. Increase in Pressure in lungs (higher then outside body) Causing air to exit lungs (squeezing the particles of air closer together)

How Respiration Works

Gas Exchange For this to happen, we need 2 things: Diffusion: movement from an area of higher concentration of that substance to an area of lower concentration. Semi-Permeable membrane: a membrane that only allows certain substances to pass through. If something cannot pass through a semi-permeable membrane it means the particles are probably to big to pass.

Inhaling (inspiration) Process through which air enters lungs Air pressure in lungs is lower than air pressure outside of body, so air enters lungs

Gas Exchange- Inhaling During inhalation, Alveoli fill up with oxygen. The concentration of oxygen is higher in the alveoli than in the blood vessels. Therefore, oxygen diffuses through the alveolar membrane into the blood, where the concentration of oxygen is lower, and attaches to the red blood cells.

Exhaling Process through which air exits lungs Air pressure in lungs is higher then air pressure outside lungs, so air exits the body

Gas Exchange: Exhaling After cellular respiration of the body cells, the blood has a higher concentration of Carbon dioxide then the lungs. Therefore, the carbon dioxide will diffuse from the blood vessels through the alveoli into the lungs, where the concentration of carbon dioxide is lower. Finally, it will be exhaled out of the body to be eliminated. OXYGEN and CARBON DIOXIDE can diffuse through body and tissue cells, blood vessels (capillaries) and alveoli.

Gas Exchange Lower Concentration of O2 Lower concentration of CO2 Selectively-permeable membrane

Fluids, like air, like to move from areas of high pressure to areas of low pressure.

How our Respiratory System Evolved

Lung Capacity and Respiratory Rhythm Lung capacity is the maximum volume of air we can inhale Inhaling and exhaling are the two movements that form the respiratory cycle Respiratory rhythm is the number of cycles in one minute

OUCH THAT HURTS!!!! When you get hurt in the stomach or back, the sudden impact can temporarily cause the diaphragm muscle to paralyze. During this time, it cannot contract properly and it is hard to breathe. Once the diaphragm is able to contract again, you can breathe normally.

The Respiratory system Inhaling Ribs & sternum Rises when intercostal muscles contract Diaphragm Contracts and lowers Volume of thoracic cavity and lungs Volume increases Air pressure in lungs Pressure decreases Displacement of air Air enters system The Respiratory system Exhaling Ribs & sternum Lowers when intercostal muscles relax Diaphragm Relaxes and rises Volume of thoracic cavity and lungs Volume decreases Air pressure in lungs Pressure increases Displacement of air Air exits system